Modeling of column experiments - Goldschmidt Conference Archive

Goldschmidt Conference Abstracts

Mineralogical Magazine www.minersoc.org

2238

Modeling of column experiments – Influence of glass micro balls

VRATISLAV !ABKA, IVAN BRUSK" AND JAN #EMBERA Institute of Novel Technologies and Aapplied Informatics

Technical University of Liberec, Studentska 2, 46117 Liberec, Czech Republic ([email protected])

Our paper is focused on modeling of a laboratory

experiment using the software package The Geochemist’s Workbench. We simulate a column experiment in which water solution flows trough a porous soil. The subjects of our interest are the interactions between water solution and porous soil. In some in-situ decontamination technologies, sinking-in reagents are used to be used. Column experiments are important for preparation and verification of such decontamination activities.

To verify the experiment configuration we decided to begin with the simplest case of the column experiment: the flowing water solution is pure distilled water and the porous medium is inert glass micro balls. Even in such a simple experiment we could observe unexpected change of pH of water solution after passage through the column. We try to understand this observation and simulated in mentioned software.

The results of the study will be presented.

Platinum group minerals (PGM) in chromite lode deposits from the

Sulawesi ophiolite belt F. ZACCARINI1*, A. IDRUS 2, G. GARUTI1,

O.A.R. THALHAMMER1 AND F.M. MEYER3 1University of Leoben, Dept. Appl. Geol. Sci. Geophysics,

Leoben, Austria(*correspondence: [email protected])

2Gadjah Mada University, Dept. Geol, Eng., Yogyakarta, Indonesia

3RWTH Aachen University, Inst. Min. Econ. Geol., Aachen, Germany

Some localities in Indonesia including Borneo and

Sulawesi host PGM-bearing podiform (ophiolite)-type chromitites. Borneo is the locality type of two platinum group minerals (PGM), the rare vincentite and laurite, the most common Ru minerals. These PGM have been found in placers, however, data on the occurrence of PGM in lode deposits of Indonesian Archipelago are very poor. We present a mineralogical investigation on lode chromite deposits and associated PGM from the Sulawesi ophiolite belt. The investigated chromitites were sampled in the South and Southeast Arms of Sulawesi. According to the #Cr (0.51-0.88), in both the localities chromite composition varies from Cr-rich to Al-rich. TiO2 is low in the Southeast Arm chromitites (0.07-0.28 wt%), whereas in the South Arm chromitites its values are comprised between 0.08 up to 0.55 wt%. Small PGM, 1 to 10 µm in size, have been found in both the localities and in Cr- and Al-rich chromitites. The most abundant PGM is laurite that occur included in fresh chromite or in contact with chlorite along cracks of the chromite. Laurite forms polygonal crystals and it occurs as single phase or in association with amphibole, chlorite, Co-pentlandite, apatite and other PGM. Small grains of irarsite (less than 3 µm) have been found associated with small blebs of awaruite and Co-pentlandite in the chromite gangue composed of chlorite. One grain (2 µm in size) containing Ru and Fe was found in the rim of a laurite occurring with Co-pentlandite in the chromite crack, filled with chlorite. The results suggest that the studied chromitites could have crystallized from different melts varying in composition from MORB formed in back-arc setting (Al-rich) to boninites related with subduction zone (Cr-rich). The bimodal composition and the anomalous enrichment in TiO2 observed in some chromitites, may also indicate vertical zoning due to the fractionation of a single magma batch during its ascent, implying accumulation of Cr-rich chromitites at deep mantle levels and formation of the Al-rich ones close to the Moho-Transition Zone. All the laurite are considered to be magmatic in origin, i.e. entrapped as solid phases during the crystallization of chromite. Irarsite possibly represents a low temperature exolution product.



2239

Challenges in the identification of redox reactive Fe(II) mineral phases

in suboxic aquifer sediments J.M. ZACHARA, T. PERETYAZHKO, J.P. MCKINLEY,

CHONGXUAN LIU AND A.R. FELMY Pacific Northwest National Laboratory, Richland, WA, USA

The kinetics of 99Tc(VII) reduction, as the pertechnetate anion [99TcO4

2- = 10-6 mol/L], were investigated in a series of suboxic aquifer sediments from the U.S. DOE, Hanford site exhibiting an average pH = 8. Reaction rates varied markedly displaying half-lives ranging from 2 to 110 d. Rate constants did not normalize to extractable Fe(II) concentration. The heterogeneous reaction products, as identified by EXAFS analysis, were adsorbed 99Tc(IV) clusters (n = 2-4) that did not vary in size with reduction rate. Iron was not observed in the second coordination sphere. The Fe mineralogy of the sediments was investigated using a combination of chemical extraction, x-ray diffraction, variable temperature Mossbauer spectroscopy, and analytical electron microscopies; revealing the presence of a complex Fe(II) mineral suite containing variable concentrations of pyroxenes, siderite, Fe(II)-phyllosilicates (smectites, illites, and mica), and magnetite. Direct correlations between 99Tc reaction rates and Fe(II) mineralogy were not evident. The most reactive sediment was titrated with higher levels of 99Tc (10-4 mol/L), with the distribution of Fe(II) mineral phases monitored by Mossbauer spectroscopy after 99Tc(VII) reaction. Spectral peak positions for siderite at 4.5 K decreased during titration from 29% to 6% of the total area, transforming to those of Fe(III) oxide, providing presumptive evidence that siderite was one of several reactive phases. Additionally, 99Tc(VII)-oxidized sediment was screened by digital autoradiography to identify 99Tc(IV)-containing mineral phases. These phases were manipulated for analysis by electron microprobe and micro-x-ray diffraction. A significant fraction of the 99Tc(IV)-containing phases were Fe-micas as observed in a previous investigation with sediments from another location. Residual siderite did not appear to contain 99Tc(IV). We conclude with a discussion of: i.) the challenges involved in the identification of redox active phases using macroscopic and microscopic techniques and ii.) kinetic versus thermodynamic controls on redox reactivity in mineralogically heterogeneous subsurface sediments.

Evaluation of rock properties and rock structures in the micron-range with sub-micron X-ray Computed

Tomography G. ZACHER1*, M. HALISCH2, O. BRUNKE1 AND

T. MAYER1 1GE Sensing & Inspection Technologies GmbH, Niels-Bohr-

Str. 7, 31515 Wunstorf, Germany 2Leibniz Institute for Applied Geophysics, Stilleweg 2, 30655

Hannover, Germany

In recent years high resolution X-ray Computed Tomography (CT) for geological purposes contribute increasing value to the quantitative analysis of rock properties. Especially spatial distribution of minerals, pores and fractures are extremely important in the evaluation of reservoir properties. The possibility to visualize a whole plug volume in a non-destructive way and to use the same plug for further analysis is undoubtedly currently the most valuable feature of this new type of rock analysis and will be a new area for routine application of high resolution X-ray CT in the near future.

The paper outlines new developments in hard- and software requirements for high resolution CT. It showcases several geological applications.

The results were performed with the phoenix nanotom and recently phoenix nanotom m, the first 180 kV nanofocus CT system tailored specifically for extremely high resolution scans of samples up to 240 mm in diameter and weighing up to 3 kg with voxel-resolutions down to <300 nm. These characteristics with respect to spatial resolution principally allow CT measurements which valuably complement many absorption contrast setups at synchrotron radiation facilities (Withers 2007 [1]; Brunke et al. 2008 [2]; Kastner et al. 2010 [3]).

[1] Brunke et. al. (2008) „Comparison between x-ray tube-based and synchrotron radiation-based $CT” in Developments in X-Ray Tomography VI, edited by Stuart R. Stock, Proceedings of SPIE, Vol. 7078. [2] Withers (2007) “X-ray nanotomography”, Materials Today, 10(12), 26-34. [3] Kastner et. al. (2010) “A comparative study of high resolution cone beam X-ray tomography and synchrotron tomography applied to Fe- and Al-alloys”, in NDT & E Int. vol 43, pages 599-605.



2240

Robust trace element analysis of rutile by LA-ICP-MS

T. ZACK* AND M. BARTH Institut für Geowissenschaften, Universität Mainz, Germany

(*correspondence: [email protected])

Several recent studies reporting trace element results for rutile by LA-ICP-MS using spot sizes as large as 40 µm. However, even Q-ICP-MS are sensitive enough to have a suitable signal-to-background ratio for a number of important trace elements in most natural rutiles (e.g., V, Cr, Fe, Zr, Nb, Sn, Hf, Ta, W and U) at spot sizes of only 10 µm. Here, counting statistics give errors better than 5% for Zr concentrations on the 100 ppm level (translating to analytical errors in metamorphic temperatures of only a few °C). Still, the level of accuracy is so far unknown at such small spot sizes mostly due to a lack of suitable rutile standards.

Recently, we have proposed to use three natural (R10, R19, Diss) and one synthetic (Sy) rutiles as secondary mineral standards [1]. These minerals are sufficiently homogeneous and analyzed by several techniques (EMP, SIMS, ID-MC-ICP-MS) for a range of trace elements to test LA-ICP-MS performances. Therefore, we have run several LA-ICP-MS profiles with variable spot sizes (10-40 µm) along the same EMP and SIMS profiles as reported in [1].

Most importantly, it is found that spot size differences can have a severe effect on calculated rutile concentrations for such small spots. For example, calculated Zr concentrations for rutile systematically deviate by 40% between 10 and 40 µm. This makes it an absolute neccessity to always use identical spot sizes at such small scales. Furthermore, it can be demonstrated that an accuracy of <10% is reached for most trace elements for the rutile standards R19 and Diss when R10 is used as a matrix matched standard under the exact same analytical conditions.

The demonstration of an accuracy of <10% for 10 µm spot analysis for rutile by LA-ICP-MS significantly opens up the field of rutile geochemistry. In Mainz, with the help of a fast-washout large format cell and automization, we routinely use such small spot sizes for rutile trace element analysis with a sample throughput of >60 samples/hour. Applications are found e.g., in pre-scanning for high-U detrital rutiles suitable for U/Pb dating [2] and fine-scale Nb diffusion profiles [3].

[1] Luvizotti et al (2009) Chem Geol 261, 346-369, [2] Zack et al (in press) Contr Min Petrol, [3] Cruz-Uribe et al, MinMag, this volume

Effect of plant-microbial associations on weathering of basalt, granite,

schist, and rhyolite DRAGOS ZAHARESCU1*, KATERINA DONTSOVA12,

JON CHOROVER12, TRAVIS HUXMAN13, RAINA MAIER2 AND JULIA PERDRIAL2

1B2 Earthscience, The Univ. of Arizona, Tucson, AZ, USA, ([email protected], [email protected], [email protected])

2Dep. of Soil, Water & Environmental Science, The Univ. of Arizona, Tucson, AZ, USA ([email protected], [email protected])

3Dep. of Ecology and Evolutionary Biology, Univ. of Arizona, Tucson, AZ, USA, ([email protected]) The goal of this study was to measure how plant–microbe

interactions affect the initial weathering of four distinct rock types (basalt, granite, schist, and rhyolite) and the extent to which this weathering results in chemical denudation versus biomass accumulation or re-precipitation of dissolution products. This initial phase of experiment focused on denudation. We hypothesised that the presence of plants will increase weathering but decrease denudation (i.e., we will see more mineral transformation but less element loss from system in the presence versus absence of plants). To achieve research objectives, we conducted a series of environmentally–controlled, greenhouse experiments that involved measuring plant uptake, mineral transformation and chemical denudation in basalt (35.9% An64 plagioclase, 6.5% diopside, 11.9% forsterite, and 45.7% basaltic glass), granite (28.8% quartz, 31.1% K-feldspar, 32.8% albite, and 7.2% muscovite), rhyolite (32.6% quartz, 15.9% albite, and 51.5% K-feldspar in crystalline form, plus yet unquantified glass fraction), and schist (23.8% quartz, 22.8% K-feldspar, 14.2% albite, 7.6% amphibole, and 31.7% biotite), as affected by presence and growth of microbiota and vascular plants. The experiments also included plant-free (but microbially-colonized) and abiotic (sterile) controls. Buffalo Grass (Buchloe dactyloides) and Ponderosa Pine (Pinus ponderosa) were employed as model plant species. Plants were grown in 4 cm (diameter) by 30 cm (length) Plexiglas columns filled with granular study materials. Columns were equipped with micro-suction cup solution samplers to collect soil solution. Solution was analysed to deptermine pH, cations and metals, anions, and aqueous phase organic matter chemistry. Concentrations of low molecular weight organic acids in soil solution and drainage water were also determined.



2241

Did the glacial Atlantic overturning circulation run backwards?

R. ZAHN1*, I.R. HALL2, G.M. HENDERSON3, P. MASQUÉ1 AND A.L. THOMAS3

1Universitat Autònoma de Barcelona, Institut de Ciència i Tecnologia Ambientals, Departament de Física, 08193 Bellaterra, Spain (*correspondance: [email protected])

2School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, U.K.

3Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK

Recently Pa/Th profiles from the South Atlantic were

published [1] that display structures very different from Pa/Th profiles in the North Atlantic. It was argued that these profiles indicate i) deep waters leaving the glacial Southern Ocean had a Pa/Th fingerprint not much different from that of NADW today, due to extensive Pa scavenging; ii) a basin-scale meridional Pa/Th gradient developed in the glacial Atlantic that run opposite to that of today, reflecting a more substantive northward flow of “southern sourced water” (SSW). This concept, in our view, reconciles an apparent conflict between !Nd measured on Fe-Mn oxide coatings on planktonic foraminifera at the Bermuda Rise and Pa/Th data at the same location: the first indicating northward flowing SSW at the LGM while the second supposedly reflecting southward flowing “northern source water” (NSW) [2].

We borrow the provocative title from the conveners because it reflects the debate over how far we can take the proxy records. The interplay between NSW and SSW is reflected by a suite of proxy data e.g., stable carbon isotopes ("13C), Pa/Th and nutrient-based trace element ratios (Cd/Ca). Pa/Th profiles are scarce and meridional gradients must be mapped using Pa/Th from a range of different water depths while gas-exchange normalized "13Cas suggests a prominent role of SSW in the glacial AMOC. Taking all evidence at face value suggests the glacial AMOC received a stronger water mass contribution from the southern hemisphere oceans. At the same time several questions arise: does scavenging of Pa in the Southern Ocean outcompete lateral advection and so depleting the water column of Pa? Do radiogenic isotope and nutrient-based proxies uniquely identify water mass end members? How robustly do the proxies reflect the AMOC in the past, including physical near-bottom flow speeds? These questions are not easy to answer but they help refine the direction of future work.

[1] Negre et al. (2010) Nature 468, 84-88. [2] Roberts et al. (2009) Science 327, 75-78.

Xenon the magnificent KEVIN ZAHNLE

NASA Ames Research Center, Moffett Field CA 94035 ([email protected])

Xenon is the heaviest noble gas and the heaviest gas likely

to be found in a primoridal atmosphere. It would seem to be the least likely gas to escape. Yet there is probably more evidence for massive Xe escape from Earth than for any other element save helium. Nonradiogenic atmospheric Xe is strongly mass fractionated (by about 4% per amu) compared to any of its plausible solar system sources. By contrast, Kr is only mildly fractionated, if at all. Xenon is also relatively underabundant with respect to Kr.

Radiogenic Xe also suggests escape. Radiogenic 129Xe (from 129I decay, half-life 15.7 Myr) is present in the atmospheres of Earth and Mars but at less than 1% the qunatity expected given the primoridal abundance of 129I, Radiogenic Xe from spontaneous fission of 244Pu (half-life 82 Myr) is also notably underabundant. The upper limit on fissogenic 136Xe in air is about 1 part in 6 of Earth's cosmic complement from 244Pu. This is an upper limit because it depends on U-Xe (rather than solar Xe) being the primordial Xe of Earth. U-Xe makes modeling Earth’s Xe much easier, but it has not otherwise been seen in the solar system.

For Xe escape to explain the dearth of fission Xe in air, escape must have taken place late enough in Earth’s story that 244Pu was extinct. The mechanism would have affected Xe but not Kr or Ar. One possibility is that Xe escaped as an ion, probably in polar winds of hydrogen and hydrogen ions channelled by planetary magnetic fields. This can occur because Xe, alone among the noble gases, is more easily ionized than hydrogen. Thus Xe will tend to be present oin the H-H+ wind as Xe+, whilst the other noble gases would be neutral. Because of the Coulomb force, at 2000 K and 1% H ionization, diffusivity of Xe+ is 3 orders of magnitude lower than that of neutral Xe or Kr. The Xe+ ions are therefore dragged to space by the protons. Under these circumstances fractionating hydrodynamic escape can apply uniquely to xenon among the noble gases over a wide range of hydrogen escape fluxes.



2242

The solubility of Au and Cu in andesite melts

ZOLTAN ZAJACZ1,2, PHILIP A. CANDELA1, PHILIP M. PICCOLI1, MARKUS WÄLLE2 AND

CARMEN SANCHEZ-VALLE2 1Laboratory for mineral deposits research, University of

Maryland, College Park, MD, USA, ([email protected])

2Institute of Geochemistry and Petrology, ETH Zürich, 8092 Switzerland

We conducted experiments in MHC cold seal vessels at

1000 oC and 200 MPa to study the solubility of Cu and Au in andesite melts as a function of the Cl and S content of the silicate melt and oxygen fugacity of the system. A gold activity of 0.99 and a Cu activity of 0.01 were imposed by using AuCu alloy capsules.

At an fO2 of NNO-0.2, the solubility of Au shows a positive linear correlation with the S concentration in the melt, and increases from 41±8 ng/g (1%) in a S-free melt to 1547±52 ng/g in a melt with 344±20 µg/g S, a condition near pyrrhotite saturation. Chlorine has a relatively minor positive effect on Au solubilty; a S-free andesite melt with 1.00±0.01 wt% Cl contained only 112±20 ng/g Au.

The effect of fO2 on the solubility of Au is significant, leading to 0.18±0.04 log unit increase in Au solubility for 1 log unit increase in fO2 in a S-free, Cl-bearing melt, which is approximately consistent with +1 valence of Au in the silicate melt. In S-bearing melts, the effect of fO2 on gold solubilty is further complicated by the following (or a similar) reaction: Au+FeS(melt)+H2O(melt)=AuSH(melt)+FeO(melt)+0.5H2(g) Accordingly, a maximum in Au solubility is observed just at the low fO2 end of the S2-/S6+ transition, however, it is much smaller than that shown by Botcharnikov et al. (2011) [1].

The apparent solubility of Cu at an fO2 of NNO-0.2 and aCu of 0.01, ranges between 45±1 and 78±1 µg/g and shows a weak positive correlation with the S and Cl concentration in the melt. Moderate excess solubitly over that predicted assuming a dominant CuO0.5(melt) species is observed in S-bearing experiments in the fO2 range of the S2- to S6+ transition and above. Variation in the K2O/Na2O and FeO/Na2O ratios in the melt did not siginificantly affect Au and Cu solubilites.

Model volatile/melt parition coefficients of Cu and Au suggest that volatiles exsolving from andesite magmas are efficient at extracting Au, but inefficient at extracting Cu. [1] Botcharnikov, Linnen, Wilke, Holtz, Jugo & Berndt (2011), Nature Geoscience 4, 112-115.

Cryogenic cave carbonates – A new tool for estimation of former

permafrost depths K. !ÁK1*, M. FILIPPI1, R. !IVOR1 AND D.K. RICHTER2

1Institute of Geology AS CR, v.v.i., Rozvojová 269, 165 00 Praha 6, Czech Republic (*correspondence [email protected], [email protected], [email protected])

2Ruhr-University Bochum, Institute of Geology, Mineralogy and Geophysics, Universitätsstr. 150, 44801 Bochum, Germany ([email protected])

Geochemical processes in the Earth's critical zone largely

depend on the presence or absence of a permafrost (perennially frozen ground, i.e. soil and rock remaining at or below 0 °C for at least two consecutive years, [1]). While the areal extent and depth of present-day permafrost zone are relatively well known [1], the extent, duration, and depth of permafrost during Pleistocene glacials are much less understood. Here we present a new tool for the estimation of former permafrost minimum depth based on the occurrence of a specific type of secondary carbonate in caves.

Cryogenic cave carbonate (CCC) is a unique type of secondary carbonate formed in caves during freezing of common calcium bicarbonate water by the expulsion of dissolved load by the growing ice. CCCs can be identified based on their typical morphology and occurrence, by U-series dating fitting into glacials, and especially by specific C- and O-isotope geochemistry, which proves their formation during water freezing [2, 3, 4]. CCCs were formed at the transitions from glacials to interglacials or from stadials to interstadials and occur as accumulations of loose crystals and crystal aggregates on the cavity bottom, where they were deposited after melting of the ice filling of the cavity. CCCs show a unique isotope composition with "18O values down to -25 ‰ (PDB), and "13C values up to +6 ‰.

We collected data for all known CCC occurrences in a belt parallel to the southern edge of the Weichselian continental glaciation (southern Poland, Slovakia, Czech Republic, central Germany), dated them by U-series method, and evaluated their depths under the surface. When using data from isolated cavities only, which cannot be cooled by air circulation, a minimum Weichselian permafrost depths in this belt can be estimated at 30–70 m under the surface (the study was supported by the project GA CR P210/10/1760). [1] French (2007) The periglacial environment, 3rd ed., 458 p. [2] !ák et al. (2004) Chem. Geol. 206, 119-136. [3] Richter & Riechelmann (2008) Internat. J. Speleology 37, 119-129. [4] !ák et al. (2008) Quat. Internat. 187, 84-96.



2243

A combined Earth-Moon Si isotopes model to track rocks petrogenesis

T. ZAMBARDI AND F. POITRASSON Géosciences Environnement Toulouse, CNRS– UPS – IRD,

France. ([email protected])

Silicon is after oxygen the second most abundant element in the Earth’s crust. As such, its stable isotope variations in geological materials may represent important mass transfer between terrestrial reservoirs. Despite early analytical limitations and although Si isotopes were not expected to fractionate significantly during high temperature magmatism, studies conducted more than 15 years ago [1, 2] hinted that Si isotope compositions of granitoids may be heavier than that of mafic igneous rocks.

In this study, we determined the silicon isotope signatures of a set of igneous terrestrial rocks that includes andesites, monzogranites, granites of different types, as well as 8 lunar samples including basalts and highlands anorthosites. Analytical methods involved alkaline fusion of the powdered samples, cationic exchange chromatography and high resolution MC-ICP-MS in the wet plasma mode. Long-term (3 years) external reproducibility for "30Si and "29Si was given by repeated measurements of BHVO-2. It yielded 2 standard deviations (2SD) of 0.076‰ and 0.047‰, respectively, for individual measurements.

A comparison between lunar and terrestrial bulk igneous rocks reveals that Si isotope composition become slightly, thought significantly enriched in heavy isotopes as a function of felsic mineral abundances. We interpret this in terms of global planetary differentiation processes. However, the terrestrial trend is more scattered, which reveal the occurrence of sources and processes that do not exist on the Moon, probably because they involve water. Terrestrial andesites may be isotopically heavier than other lunar and terrestrial igneous rocks with similar silicon contents whereas S-type granites are isotopically much lighter than other granite types. These results are interpreted as the influence of seawater or hydrothermal fluids on andesitic sources and the occurrence of sediments containing the products of aqueous weathering in S-type granite protoliths. The fact that Si is a major element in igneous rocks, but not a major constituent of water like O, makes its isotopic composition likely more robust against alteration and weathering of the studied rocks, yet delivering significant information in terms of source of the magmatic bodies studied. [1] Douthitt (1982) Geochim. Cosmochim. Acta 46, 1449-1458. [2] Ding et al. (1996) Geol. Publish. House, Beijing, China, 125 pp.

Melting condition and evolution of fissural volcanism in the island of

Faial (Azores archipelago) VITTORIO ZANON1, ANGELO PECCERILLO2 AND

JOSÉ MANUEL PACHECO1 1Centro de Vulcanologia e Avaliação de Riscos Geológicos,

Universidade dos Açores, Rua Mãe de Deus 9500-501, Ponta Delgada, Portugal ([email protected])

2Dipartimento di Scienze della Terra, Univeristà di Perugia, Piazza Università, 1 06100 Perugia, Italy ([email protected])

Two WNW-ESE-trending fissure zones, which are

separated by NNW-SSE transtensional faults, are the expression of the regional extensional tectonics in the island of Faial. Several monogenetic centres and a large stratovolcano were generated along these faults.

Erupted magmas are nepheline- to hypersthene normative basalts to hawaiites, generated at about 2110-1600 MPa (~63 km deep, in the spinel facies) and 1367-1407°C.

Mafic rocks of the westernmost fissure zone have lower MgO and HREE, and higher Na2O, P2O5, TiO2, Zr, Nb, Th, LILE and LREE than those from the easternmost fissure zone. All these differences are related to slightly different melting degrees (between 3 and 5%), which also reflect the different silica saturation degrees. However, near-primary melts of these two fissure zones show LILE contents, particularly Ba, which are among the highest in the whole Atlantic area. This feature, together with the common presence of fluid inclusions in many ultramafic xenoliths sampled, evidence the occurrence of a metasomatic event prior to mantle source melting.

Hawaiites evolved from basalts by 18-25% fractional crystallization of Mg-olivine, diopside and Ca-plagioclase, at 560-700 MPa (~17-21 km deep). There is no evidence for magma ponding at intracrustal depths.

Fractionation of mafic phases generated cumulate layers at the crust-mantle boundary. Ascending basaltic melts sampled these olivine-and-clinopyroxene bearing layers to generate ankaramites which show MgO content lower than primary melts. These peculiar lithologies crop out along the western margin of the stratovolcano, possibly along faults that directly tapped the cumulate layers.



2244

Release of silica from micas by alkaliphilic anaerobes

D. G. ZAVARZINA1*, A. V. SAVENKO2, N. I. CHISTYAKOVA3, A. A. SHAPKIN3 , T. N. ZHILINA1

AND G.A. ZAVARZIN1

1Winogradsky Institute of Microbiology RAS, Moscow 117312, Prospect 60-letiya Oktyabrya 7/2, Russia (*correspondence: [email protected])

2,3 Lomonosov Moscow State University, 2 Geographic and 3Physics Depart., Leninskie Gory, Moscow

119992, Russia

Soda deposits are formed at the final stages of continental CO2-weathering. It could occur under alkaline conditions either chemically, which seems favorable, or biotically. There are two main groups of alkaliphilic microbial agents that act in anaerobic conditions on the water-rock contact: a) fermentative hydrolytic decomposers of particulate organic matter, e.g. cellulose, capable to produce organic acids as the products of metabolism; b) respiratory anaerobes, utilizing dissolved compounds with external electron acceptors.

We studied the interaction of pure cultures of microbes with biotite and glauconite during 165 days under alkaline conditions at pH 9.5 and total mineralization was 15 g/l. Mössbauer spectroscopy, IR-specrtoscopy and solubility of micas in water were used for the investigation of the solid phase. Fermentation products were recorded during the bacterial growth.

Following combinations were studied: (i) chemical alkalinolysis of micas under sterile conditions; (ii) biotic alkalinolysis of micas by alkaliphilic Clostridium alkalicellulosi [1], which produces organic acids and ethanol from cellulose; (iii) biotic alkalinolysis by alkaliphilic dissimilatory iron-reducer Geoalkalibacter ferrihydriticus [2] with acetate as an electron donor; (iiii) combined binary culture of Cl. alkalicellulosi and G. ferrihydriticus with cellulose as organic substrate.

Release of silica under experimental conditions for the both minerals was as following: (i) no release; (ii) no release; (iii) release of silica, formation of new soluble phase; (iiii) release of silica, formation of new soluble phase.

It is proposed that the anaerobes with respiratory metabolism are more effective than fermentative in bioweathering of rock-forming minerals as micas with release of silica. Chemical weathering even under most favorable conditions is far less pronounced than microbe-mineral interactions. [1] Zhilina et al. (2005) Microbiology, 74, 642-653. [2] Zavarzina et al. (2006) Microbiology, 75, 775-785.

Evidence for evolution of growth media in superdeep diamonds from

Sao-Luis (Brasil) D.A. ZEDGENIZOV1*, A.L. RAGOZIN1, V.S. SHATSKY1, H. KAGI2, S. ODAKE2, W.L. GRIFFIN3 D. ARAUJO3 AND

O.P. YURYEVA1 1V.S. Sobolev Institute of Geology and Mineralogy, 3

Koptyuga ave., 630090, Novosibirsk, Russia (*correspondence: [email protected])

2 Geochemical Research Center, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan

3GEMOC ARC National Key Centre, Macquarie University, NSW 2109, Australia

Diamonds from Sao-Luis (Brazil) are known to be

originated from the depths of transition zone and lower mantle [1]. In this study we consider some aspects of the composition and evolution of growth media for diamonds from this locality.

CL imaging has revealed the complex growth history for most diamonds, reflecting their formation in several stages. Nitrogen content in an individual diamonds varies from several to 500 ppm. An apparent tendency for the 3107 cm-1 peak intensity to increase with increasing the nitrogen content gives support to the idea that the conditions favouring the incorporation of nitrogen in these diamonds might also favour the incorporation of hydrogen. Specific feature of diamonds from Sao-Luis is extremely high nitrogen aggregation state (90-100 %B1). The set of luminescence centers N3, H3, H4, 490.7 is typical for all diamonds. Radiation-induced centers with peaks at 536 and 576 nm are often observed.

The total range of carbon isotope composition in diamonds studied by SIMS makes up from -3.3 to -20.3 ‰ of "13C. Some diamonds show local variations of "13C between different growth zones (up to 7 ‰).

The dominant inclusions in studied diamonds are CaSi-perovskite and AlSi-phases. MgSi- and CaTi-perovskites, ferropericlase, native iron, coesite and zircon have also been found. Raman shift of coesite peak show high residual pressure (>3 GPa at ambient temperature).

FTIR study of some microinclusion-bearing diamonds showed that water and carbonates are not major components of diamond-forming fluids. LA-ICPMS bulk composition has significant enrichment in Ca, Fe and Al and strong depletion in Mg. Trace elements show general enrichment in Ti and V and depletion in Sr, LREE and Ni. Most probable source for such environments might be fluids from deeply subducted rocks of metasomatized oceanic lithosphere.

[1] Kaminsky et al. (2001) Contrib. Miner. Petrol. 140, 734-753.



2245

Mobility of trace elements in ombrotrophic peat bogs

LEONA ZEMANOVA1*, MARTIN NOVAK1, PETRA PACHEROVA1, ARNOST KOMAREK2

1Czech Geological Survey, Geologicka 6, 152 00 Prague 5, Czech Republic (*correspondence: [email protected])

2 Faculty of Mathematics and Physics, Charles University, Sokolovska 83, 186 75 Prague 8, Czech Republic

The geochemical cycles of many trace elements have been

altered by human activity. Peat bogs are often used as an archives of past pollution. Concentration patterns of individual elements downcore can be recalculated into rates of historical atmospheric deposition. However, vertical mobility of trace elements in the petlands could “smear out” the historical record. We performed a peat transplant experiment to test the mobility/immobility of six trace elements (Mn, Fe, Pb, Zn, Cu and Ti), buried in organic soil. Three replicated cores from a peat bog situated in a heavily polluted area in northern Czech Republic were transplanted into a peat bog situated in unpolluted southern Czech Republic, and vice-versa. After 18-months, peat cores were excavated, taken to the laboratory and analyzed. Two different patterns were observed. The first group of elements (Fe, Mn) was characterized by convergence of concentration patterns to their host site, regardless of whether the host site was originally richer or more deficient in these elements. The second group of elements (Pb, Zn, Cu, Ti) was resistant to change during the transplant experiment, with concentration patterns unchanged. Our transplant experiment showed that not just lead but also copper and zinc could be used in retrospective peat pollution studies because there was no evidence of post-depositional mobility.

Concurrence of Mid-Miocene high Sr/Y granite and leucogranite in the

Yardoi gneiss dome, Tethyan Himalaya, Southern Tibet

LINGSEN ZENG1*, LI-E GAO1, KEJIA XIE2 AND GUYUE HU1

1Institute of Geology, Chinese Acadmy of Geological Sciences, Beijing 100037 (*correspondence: [email protected])

2Institute of Tibetan Research, Chinese Academy of Sciences, Beijing 100085

We report a new suite of porphyric granite and

leucogranite in the Yardoi gneiss dome (YGD) in the easternmost of the Northern Himalayan Gneiss Domes (NHGD), south of the Yarlung-Tsangpo suture. SHRIMP and LA-ICP-MS zircon U/Pb dating show that the porphyric granite dikes (PGD) and garnet-bearing leucogranites (LG) formed at ~17.7 Ma to ~20.0 Ma and at ~17.1 Ma, respectively. Both suites of granite have high Na/K (>1.30) ratios. The PGDs are characterized by (1) high Sr (>450 ppm), low Rb (<95 ppm) and Y (<6 ppm), and high Sr/Y (>86) ratios; (2) no Eu anomalies; and (3) low initial 87Sr/86Sr ratios (<0.7098) and higher !Nd (>-8.5) values. In contrast, the LGs have (1) lower Sr (<130 ppm) and higher Rb (92-130 ppm); (2) pronounced negative Eu anomalies with Eu/Eu*<0.55; and (3) relatively higher Sr (87Sr/86Sr(t)=0.7136-0.7148) and unradiogenic Nd (!Nd(t)=-7.7~-11.1). These data demonstrate that these Mid-Miocene granites have major and trace element and radiogenic isotope compositions similar to those of >35 Ma granites[1,2], but significantly different from those granites of similar ages in the High Himalya as well as in the NHGD[3]. High Sr/Y and relatively unadiogenic Sr isotope compositions in the PGDs could be derived from partial melting of mafic materials formed during previous compressional thickening event which was triggered by the input of juvenile heat and material associated with the Miocene E-W extension. An AFC process (plagioclase fractional crystallization and comtamination by crustal materials) could be a primary factor leading to the formation of these LGs. Concurrence of high Sr/Y granites and leucogranites in NHGD indicates that the Miocene rifting could have played an important but previously unrecognized role in producing the Himalayan leucogranite.

Supported by SinoProbe-2 and NSFC (41073024). [1] Zeng et al. (2009) Chin Sci Bull 54, 104-112. [2] Zeng et al. (2011) EPSL 303, 251-266. [3] Zhang et al. (2004) EPSL 228, 195–212



2246

Organic geochemistry characteristics for mudstones in the Permian Zhesi Formation, Eastern Inner Mongolia, China: A new instance showing good hydrocarbon potential in the marine

strata X.P. ZENG*, X.L. PENG, N. LIU AND C. CHEN

College of Earth Sciences, Jilin University, Changchun, 130061, China (*correspondence: [email protected])

More and more instances show that the marine strata has

an effiective hydrocarbon potential as the terrestrial one did. And the study on the characteristics of organic geochemistry of the Permian Zhesi Formation in eastern Inner Mongolia provides an opportunity to achieve a breakthrough in marine petroleum exploration in northeastern China. The thickness of the mudstones in the Zhesi Formation is about 1000 m and 30 dark mudstone outcrop samples were collected. The values of TOC are distributed in 0.3%~1.67% (average 0.81%). 90% of the values are greater than 0.5% which is taken as the lower limit of the abundance of organic matter, while 20% of the values exceed 1.0%. It suggests that the source rocks are up to the medium-good hydrocarbon potential. The kerogen type is mainly &2 and the highest pyrolysis temperatures are in the range of 469~549'. Ro values are between 2.5% and 4.28%. The source rocks are in high to over mature stages. It is worth noting that the geochemical index of the outcrop samples in the study area are similar to the core ones in the Zhesi Formation, Songliao Basin which have been proved to have a good hydrocarbon potential. Therefore the outcrop mudstones in the eastern Inner Mongolia should be considered to be of a good hydrocarbon generated prospect.

This research was financially supported by the Natural Science Foundation of China (40972075) and the Strategic Research Center of Oil & Gas Resources (14B09XQ1201).

Phase equilibrium for the aqueous system containing ammonium,

magnesium and chloride at 323.15 K Y. ZENG1, 2*, X. D. YU1, J. Y. YANG3 AND J. HONG1

1Department of Geochemistry, Chengdu University of Technology, Chengdu, 610059, China (*correspondence: [email protected])

2 Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions, Chengdu, 610059, China;

3 Development & Comprehensive Utilization of Marine Sedimentary Brine Sichuan Provincial Key Laboratory, Chengdu, 611530, China Phase equilibrium and phase diagram can give basic data

for crystallization process. In the technology of exploit potassium from Pingluoba underground brine (Sichuan, China), magnesium ion accumulates in the mother liquid to form an aqueous system containing magnesium, ammonium and chloride. In this paper, the solubility of the system was measured using an isothermal solution method at 323.15 K.

Figure 1 is the phase diagram of the system at 323.15 K. The diagram consists of two invariant points, three univariant curves and three crystallization fields corresponding to single salts MgCl2·6H2O, NH4Cl and the double salt NH4Cl·MgCl2·6H2O. The incommensurate invariant point E1 is saturated with salts NH4Cl and NH4Cl·MgCl2·6H2O, and the mass fraction of its equilibrium solution is w (NH4Cl) 7.27 % and w (MgCl2) 25.87 %. The other invariant point E2 is saturated with salts MgCl2·6H2O and NH4Cl·MgCl2·6H2O, and the mass fraction of its equilibrium solution is w (NH4Cl) 0.30 % and w (MgCl2) 35.98 %. Results show that the salt MgCl2 has salting out effect to the salt NH4Cl.

Figure 1 Phase diagram of the system containing ammonium magnesium and chloride at 323.15 K

The authors acknowledge the support of the Project of the

China Geological Survey(1212010011809), the Research Fund from the Development & Comprehensive Utilization of Marine Sedimentary Brine Sichuan Provincial Key Laboratory (2009-230).



2247

S isotope investigation of a redox-stratified system dominated by chemotrophic sulfide oxidation

AUBREY L. ZERKLE1,2, JENNIFER L. MACALADY3, DANIEL S. JONES3 AND JAMES FARQUHAR1

1Dept. of Geology and ESSIC, University of Maryland, College Park, MD, USA

2Currently at School of Civil Engineering and Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, UK, ([email protected])

3Dept. of Geosciences, Pennsylvania State University, University Park, PA, USA

Anoxic and sulfidic conditions seem to have been

common in parts of stratified Precambrian oceans. The fate of sulfide in these systems would presumably have depended on the availability of oxidants and the depth of the redox interface. Before widespread oxygenation of the surface oceans, sulfide in shallow waters reaching the photic zone would have been oxidized by anoxygenic phototrophs. Increasing oxygenation of surface waters would have driven the redox interface deeper into the ocean (and eventually into the sediments), where chemotrophic oxidation utilizing newly available oxidants (e.g., O2 and NO3

-) would have taken over. We are using multiple S isotopes to examine S cycling processes and resulting isotope signatures in biofilms dominated by chemotrophic S-oxidizing organisms in the sulfidic Frasassi cave system (central Italy). Fractionations between sulfide and S0 in these biofilms are larger than those previously measured in the laboratory, and vary with stream chemistry, with larger fractionations occurring at higher O2/H2S. Mass balance models of sulfate, sulfide, and S0 isotope values point to a complex sulfur cycle within the biofilms. Fractionations between sulfate and sulfide plot outside the range of (34S vs )33S published for natural systems dominated by sulfate reduction, and could provide a fingerprint for oxidative S cycling in modern (and potentially ancient) environments.

Density and apparent molar volume of binary electrolyte aqueous

solutions at elevated temperatures D. ZEZIN*, T. DRIESNER AND C. SANCHEZ-VALLE

Institute of Geochemistry and Petrology, ETH Zurich, Clausiusstrasse 25, 8092 Zurich, Switzerland (*correspondence: [email protected]; [email protected], [email protected])

Essentially all aqueous fluids encountered in geothermal

and hydrothermal environments represent multicomponent electrolyte mixtures. Quantitative modeling of geothermal reservoir processes therefore requires thermodynamic properties of such solutions. While experimental data are available for most pure electrolyte solutions, the properties of multi-electrolyte solutions are largely unstudied at elevated temperatures and pressures above the vapour pressure saturation curve. This lack of experimental data precludes the derivation of accurate pressure dependencies in thermodynamic models of excess thermodynamic properties of aqueous species in geothermal fluids.

We present the results of an experimental study on the volumetric properties of binary electrolyte solutions at temperatures up to 300 °C and pressures up to 400 bar over a wide range of compositions and ionic strengths. We used a vibrating-tube densimeter to measure the relative density of aqueous solutions containing mixtures of alkali and alkali earth chlorides. Pressure, temperature and composition dependence of density and other derived properties of binary mixtures were constrained. Mean apparent molar volumes of the electrolyte solutions were calculated from the experimental data and compared to various mixing models from the lterature. The data will be used in the ongoing development and/or parameterization of models for the calculation of excess thermodynamic properties (Hingerl et al., this conference). The results of this study will permit a quantitative modeling of the properties of complex aqueous solutions and simulation of fluid-rock interaction processes occurring in geothermal systems.



2248

The solubility of gold in water-hydrogen sulphide vapours

D. ZEZIN1*, A. MIGDISOV2 AND A.E. WILLIAMS-JONES2 1Institute of Geochemistry and Petrology, ETH Zurich,

Clausiusstrasse 25, 8092 Zurich, Switzerland (*correspondence: [email protected])

2Department of Earth & Planetary Sciences, McGill University, Montreal, H3A 2A7 Canada

Although the formation of high-suphidation epithermal

deposits of Au has generally been attributed to hydrothermal mobilization of ore components by saline aqueous liquid, pressure-temperature conditions favour the domination of vapour over liquid in these magmatic hydrothermal ore-forming systems. In view of this and the longevity of many magmatic-hydrothermal systems, it is reasonable to consider the possibility, that vapour rather than liquid may be the principal ore fluid for high-sulphidation epithermal deposits. To test this hypothesis, we have experimentally investigated the solubility of gold in H2O-H2S gas mixtures. The speciation and stability of gold species were evaluated in gas-only system at temperatures from 300 to 400 °C and pressures up to 265 bar, with hydrogen fugacity constrained by the reaction H2+S=H2S. Results of the experiments demonstrate that Au can be dissolved in significant concentrations in aqueous vapours. As the fugacity of gold increases with the fugacity of H2S (in both pure H2S gas and H2O-H2S mixtures), it follows that formation of stable volatile sulphide species and their solvation by H2S (AuS(H2S)n) control the solubility of gold in the gas phase. Moreover, as the solubility of Au in the vapour phase increases with the fugacity of H2O, it also follows that gold solubility is enhanced by formation of species hydrated by H2O molecules, AuS(H2O)m. These results provide strong evidence that H2S plays an important role in the vapour transport of gold.

The relative importance of solvation/hydration of sulphide and chloride complexes was assesed for vapours of composition similar to those of natural low-density magmatic-hydrothermal fluids. As these vapours are mostly water rich, gold will be transported in the vapour dominantly as hydrated gold complexes. The data on the stoichiometry and stability of gold species presented in this study represent an important contribution to our knowledge of the chemical properties of volatile metal species. Equally important, they permit accurate modeling of vapour-related processes involved in the mobilization, transport and deposition of gold in magmatic hydrothermal systems, notably those of epithermal environments.

Water resources issues in the basin of transboundary Selenga river D.TS.-D. ZHAMYANOV, I.D. ULZETUEVA, V.S. BATOMUNKUEV AND E.D. SANZHEEV

Baikal Institute of Nature Management SB RAS, 8, Sakhyanova Str., Ulan-Ude, 670047, Russia, (*correspondence: [email protected])

According to the United Nations, in the world is more than

260 rivers belonging by several states. Within their basins it is formed about 80 % of a world river flow and lives about 40 % of a world's population [1].

The Selenga river basin is located in the centre of the Euroasian continent, in a zone of a world watershed of Arctic and Pacific oceans basins and closed basin of the Central Asia. In the landscape relation the Selenga river basin is situated in contact area of taiga and steppe natural zones that predetermines development in this territory the natural environment, which is characterised by a high level of a biological variety and hypersensibility to external influences.

The intergovernmental border divides the Selenga river basin into 2 inadequate parts: its prevailing top part is situated in the territory of Mongolia, bottom – in the Russian Federation. The river Selenga – the main inflow of lake Baikal, the importance and uniqueness of which natural characteristics are recognised by the world community as object of the World natural heritage of UNESCO and are legislatively fixed only at the Russian level. Now the Russian-Mongolian relations in the field of protection of water resources are regulated on the basis of the intergovernmental Agreement for protection and use of transboundary waters (1995).

In a boundary control point in 1992-2008 years Fe, Cu, Zn, phenols and nitrogen were constantly marked above permitted standard content. The greatest values of concentration of polluting substances are marked in 1997, 2001, 2002, 2004 years. Thus in separate years presence of pesticides and mercury was fixed, which are according to the Russian requirements is inadmissible for lake Baikal basin. In 2010 for the lake Baikal the government of the Russian Federation enters even more rigid acceptable exposure standards.

The basic sources of pollution are treatment facilities of big cities of Mongolia and Republic of Buryatia (Russian federation) (Ulaanbaator, Darkhan, Erdenet, Ulan-Ude, Gusinoozersk, Zakamensk), and also the mining enterprises (especially gold mining) in Selenga river basin.

[1] Danilov-Danilyan, 2006.



2249

Whether has platinum group elements (PGE) enriched in sulfide-rich black shale series in Southern

Anhui Province? YONG ZHAN1,2, HAIJIAO YOU1,2, YOUFEI GUAN1,2,

GUODONG SHI2 AND MAOYAN MA2 1China Gezhouba Group Corporation, P.R.China

([email protected]) 2Anhui University of Architecture, P.R. China

The PGE enriched in black shale series can be found in many places in China, such as Yunnan, Guizhou, Hunan, Gansu, as well as in Shanxi Province. In southern Anhui Province, the Early Cambrian black shale series are developed widely. But whether has PGE enriched in sulfide-rich black shale series is unclear.

The black shale series in southern Anhui Province, belonging to Lower Yangtze depression area, located in the Jiangnan deep-fault zone and suffered multi-stage tectonic movements, where magmatic activities show a polycyclic feature. The black shale series of Hetang Formation in southern Anhui is very stable in the whole Yangtze region and it's sequence corresponds with Niutitang Formation in western Hunan and Guizhou. The black shale series in southern Anhui mainly develop carbonaceous chert, carbonaceous shale, Si-bearing carbonaceous mudstone with the horizontal laminar, rhythmic bedding, wavy bedding, striped bedding and water ripple structure and contain star-shaped pyrite and pyrite aggregates in term of laminar distribution locally. The black shale series belongs to marine hydrothermal deposit that represents an abnormal marine sedimentation, and the sediment environment changes from the anoxic reducing environment in early stage to the half-reduction-oxidation environment in late stage [1]. PGE distribute in black shale series in Hunan-Guizhou region, especially in Ni-Mo sulfide ore bed, and spots of PGE can be found in part. The content of Re (Pd) is 1030~5550*10-9, up to 10280*10-9; Os content is 60~150*10-9, up to 190*10-9; Pt content is 50~580*10-9, up to 690*10-9[2].

The black shale series in southern Anhui is the same as Hunan-Guizhou in sequence, geological features, geochemical characteristics and genesis, so there is a great probability for enrichment and metalogeny of PGE in black shale series in southern Anhui. And the black shale series in southern Anhui should be given a systematic study.

This research was financially supported by the Natural

Science Foundation of Anhui Provincial Education Department of China (NO.KJ2010A070).

[1] Xu et al. (2009) Acta Petrologica Et Mineralogica 28(2), 118-128. [2] Liu. (2002) Jilin Geology 21(4),1-8.

Hydration crystallization process in mafic-felsic mixing magmatic system: A case study from the Dabie orogen

(East-central China) C. ZHANG1,2*, F. HOLTZ1 AND C. MA2

1Institute of Mineralogy, Leibniz University of Hannover, Callinstr 3, D-30167 Hannover, Germany (*correspondence: [email protected])

2State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, 430074 Wuhan, China

Hydration crystallization processes, which refer to

hydrous minerals-forming reactions in the late stages of magma evolution, have essential influence on the evolution and composition of solid phases and liquids of hydrous magmas as well as on the evolution of water content in residual melts. For quantitatively modeling igneous systems involving hydrous crystllization processes, the knowledge of physico-chemical conditions, i.e. X, T, P, aH2O, fO2, prevailing in magmas is a prerequisite.

The Liujiawa intrusion is an igneous complex located at the eastern boundary of the Dabie orogen, consisting of mafic and felsic components of distincitive origins. We identified five lithologically different parts: amphibole-rich cumulate, biotite-pyroxene gabbronorite, diorite, dioritic porphyry and granite. Geochemical data indicate that the gabbronorites ressemble the most primitive basaltic magmas, while the granites represent continental crust-derived magmas. Fractional crystallization and magma mixing processes have generated other lithologies. The low An content (<An60) of plagioclase and the crystallization sequence (opx prior to cpx) indicate a water content lower than 2.8 wt% H2O in the parental melts. Biotite (16 wt%) is the only hydrous mineral in the gabbronorite, except for trace amounts of amphibole, while biotite is absent in the amphibole-rich cumulate (amphibole 48 wt%). In the diorite, a clear evidence of magma mixing is given by helminthoid clinopyroxene relics in the core of euhedral amphiboles. Textural and chemical data indicate that biotite and amphibole formed from incongruent hydration reactions of orthopyroxene and clinopyroxene, respectively. Continuous formation of amphibole at various T-P-aH2O conditions are revealed by systematically varying chlorine and Al concentrations. To summarize, hydrous crystallizations, as part of the vertical evolution of intracontinental magmatism, are responses to various physico-chemical conditions, and the fractionation including hydrous minerals have significant contributions to the petrological and geochemical characteristics of final rocks.



2250

Mineralization features and metallogeny of polymetallic deposit in black shale series in Southwest China

CHENGJIANG ZHANG , ZHENGQI XU AND SHIJUN NI Chengdu University of Technology, Chengdu, 610059, China

(*correspondence: [email protected])

Black shale series is widely distributed in the Late Sinian-Early Cambrian in Southwest China. Its lithologic characters are: carbonaceous shale or slate, carbonaceous dolomite, siliceous dolomite, silicalite and phosphorite. It is accompanied with mineralization and enrichment of Mo, V, U, Hg and P. Its mineralization features and metallogeny are studied through systematic sampling and analysis.

The mineralization features are: (1) Black shale series is the source bed, in which the contents of U and other metal elements are higher. (2) Uranium mineralization is accompanied with the features of multi-elements. At present, the mainly found types include: U-P, U-Hg, U-Mo, U-V and U-Au. (3) Uranium mineralization occurs near the center of submarine hydrothermal venting-flowing of black shale series. At some special geological positions, such as the center of submarine hydrothermal venting-flowing, Mo, Ni and U, as well as platinum group elements, concentrate and mineralize. (4) Uranium mineralization in black shale series is obviously related with the transformation effect in the later period and is the necessity for the forming of large and rich uranium deposit in black shale series in Southwest China. There are apparent proofs for the later transformation effect on uranium mineralization in black shale series. For example, in Baimadong Uranium Deposit and Jinsha Uranium Deposit in Guizhou Province, the stratohorizons with uranium of higher content are all accompanied with fault structure, tectonic breccia and hydrothermal alteration of silicification.

Metallogeny of U-Polymetallic deposit in Black Shale Series in Southwest China mainly undergoes the following stages: 1) Early enrichment: Primary enrichment of Uranium of higher content (uranium anomaly) in the depositing and diagenetic period of black shale series is the prelude of metallization of Uranium deposit in Southwest China. 2) Later transformation effect: Transformation of the shallow fluid causes the re-enrichment of Uranium (uranium ore occurrence, small or middle-scale uranium deposit); 3) Superimposed mineralization: Superimposition and transformation of the deep fluid causes the formation of rich and large ore (large-scale Uranium deposit).

Geochronology and Sr-Nd-Pb-Hf isotopic compositions of gabbroic intrusions adjacent to Southern Shang-Dan Suture Zone in the Qinling orogen, central China

CHENG-LI ZHANG*, LIANG LIU AND LEI LI State Key Laboratory of Continental Dynamics, Northwest

University, Xi’an, 710069, China (*correspondence: [email protected]) Shang-Dan Suture Zone (SDSZ) is a main tectonic

boundary between North and South Qinling belts in Qinling Oregon, central China, and marked by a discontinuous tectonic lens of island-arc volcanic-sedimentary rocks, which were intruded by gabbroic intrusions to south side of SDSZ in east Qinling. The U-Pb zircon age, Hf and whole-rock Sr-Nd-Pb isotopes for the gabbros are reported in order to assess their source signatures and tectonic settings.

The U-Pb ages of 478±11Ma and 434.7±4.4Ma have been obtained from Fushui and Ziyu gabbroic intrusion, respectively. Both of them have quite similar Pb isotopic compositions, of which the initial 206Pb/204Pb ratios of Fushui gabbros rang from 18.1154 to 18.3353 and the Ziyu gabrros from 18.0195 to 18.0851. However, the Fushui gabbros has much high initial 87Sr/86Sr (0.70785~0.71191) and negative !Nd(t) (-5.43~-2.79), showing a relatively enriched mantle reservoir with DMM and EM2 signatures. In contrast, Ziyu gabbros possess low initial 87Sr/86Sr (0.70353~0.70426) and positive !Nd(t) (+3.98~+4.19), displaying a slightly depleted mantle source. In addition, Ziyu gabbros posses a wide ranges of !Hf(t)=-39~+10, evidently indicating contamination resulted by the continental materials during transfer through crust. Furthermore, both gabbros are characterized by the island-arc magmas with a relatively enriched LILE, poor HFSE and evident depletion of Nb, Ta and Ti. Thus, we infer that both gabbroic intrusions have resulted from subduction-related processes during early Paleozoic, and the mantle source changes from the Fushui to Ziyu intrusions present subduction of the ancient Qinling oceanic crust during 478Ma and break off of the Qinling oceanic plate around 435Ma due to arc-continent collision.

This research project was supported by the National Key Basic Science Research Project of China (2009CB825003).



2251

Geogical significations of Qiatekaer Cu-Ni-Sulfide mineralized occurrence in West Kangguer ductile shear belt, Jueluotage area, Eastern Tianshan,

Northwest China D.Y. ZHANG, T.F. ZHOU*, F. YUAN AND Y. FAN

School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China (*correspondence: [email protected])

Geology and geophysics of the Qiatekaer occurrence

The Qiatekaer Cu-Ni occurrence is located in the east section of Kangguer deductile shear belt, eastern section of Jueluotag tectonic belt, Eastern Tianshan, Xinjiang, China. which have the same geological setting as the Cu- Ni deposits in the east part. The mafic dyke out crops in Qiatekaer area was found sulfides such as pyrite and pentlandite, and Ni concentration of some mineralized gabbros reach more than 400ppm, and Cu-Ni mineralized abnormalities are obviously indentified by geophysical methods such as gravity, magnetism and CSAMT [1].

Discussion

Geological characters indicate that Qiatekaer area has large potential to form Cu-Ni deposits, and there are obvious Cu-Ni sulfide mineralization judged by geochemical and geophysical characters[2, 3]. The identification of Qiatekaer Cu-Ni sulfide mineralized occurrences gives good direction to further explorer Cu-Ni deposits along the Kangguer deductile shear belt, which extends more than 500 kilometers.

The research is sponsored by the National Key Basic Science Research project of China (2007CB411304), the National Natural Science Foundation of China (41040025, 40772057), the Program for New Century Excellent Talents in University (NCET-10-0324) and the Anhui Provincial Natural Science Foundation for Distinguished Young Scholars (Grant No. 08040106907, 04045063).

[1] Hao (2010) 305 Conferrence Report, Tianjin (in Chinese). [2] Su BX(2010) PhD thesis 1-237 (in Chinese). [3] Li et al. (2006) Acta Geoscientica Sinica 27 (5), 424-446 (in Chinese).

Microanalysis of trace element in Fe oxide and sulphides using LA ICP-

MS and EMPA DEXIAN ZHANG1,2,3*, BRIAN RUSK3, NICK OLIVER3 AND

TAGEN DAI1,2 1School of Geosciences and Info-physics, Central South

University, Changsha, Hunan Province, China,410083 (*correspondence: [email protected])

2 Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,China,410083

3Economic Geology Research Unit, School of Earth and Environmental Sciences, James Cook University, Townsville, QLD, Australia

Our aims are to investingate the trace element

concentrations and distributions in natural Fe oxides and sulfides using LA ICP-MS combined with EMPA,which are predominantly important in the study of ore genesis, economic geology of ore deposit.

In our study we analysed 267 individual magnetite and 139 pyrite in 48 samples using a GeoLas 193 nm excimer laser ablation system coupled to a Varian 820-MS series ICP-MS, and conducted elemental maps on 12 magnetite grains and sulphides grains on a Jeol JXA8200 super-probe at the Advanced Analytical Center (AAC) at James Cook University. The laser system parameters are :repetition rate:10 Hz, laser beam energy: 8J/cm2, analysis time: 65 (30s measurement of background (laser off) and 35s analysis signal), external standard: NIST SRM 610, 612 and Mass -1, the internal standard: Fe.

EMPA trace element maps indicate that magnetite is not zoned with respect to trace element distribution, so we can use analysis limited spot on magnetite to represent the whole concentration of individual grain. The typical detection limits for a 45 micron spot are Li (1.62 ppm), Na (518ppm), Mg (0.58 ppm), Al (0.93 ppm), Si (80 ppm), K (1.41 ppm), Ca (18.39 ppm), Ti (0.17 ppm), V (0.03 ppm), Cr (1.13 ppm), Mn (0.29 ppm), Fe (5.73 ppm), Co (0.03 ppm), Ni (0.89 ppm), Cu (0.28 ppm), Zn(0.96 ppm), Ga (0.55 ppm)), Ge (0.82 ppm), As (0.17ppm), Mo (0.03 ppm), Ag (0.01 ppm), In (0.08 ppm), Sn (0.11 ppm), Sb (0.03 ppm), Ba (0.29 ppm), W (0.005 ppm), Au (0.004 ppm), Pb (0.01 ppm), Bi (0.003 ppm), Th (0.001 ppm)

The results suggests that LA ICP-MS combined with EMPA is a effective and powerful tools to investigate the trace element concentration and distribution in Fe oxides and sulphides.



2252

Simulating foam transport in the vadose zone at the continuum scale

Z. FRED ZHANG1*, MARK D. WHITE1 AND MARTIN W. FOOTE2

1Energy and Environment Directate, Pacific Northwest National Laboratory, Richland WA 99352 USA (*correpondence: [email protected])

2MSE Technology Applications, Inc., Butte, MT 59701 USA

The nuclear wastes residing in the deep vadose zone at the Hanford Site near Richland, WA, USA, threaten the underlying groundwater [1]. To immobilize the contaminants, aqueous and/or gaseous amendments may be carried by foam and injected into the contamination region. Foam is an emulsion-like, two-phase system in which gases are dispersed in a liquid and separated by thin liquid films. Foam has a very low density and a very high apparent viscosity. The transport of foam in the vadose zone is complex in that the number of lamellae present governs foam flow characteristics such as viscosity, relative permeability, and interactions between injected and residential fluids. We have developed a simulation capability into the STOMP numerical simulator [2] to model the transport of foam and the amendments contained in foam. Bench-scale lab experiments were conducted by injecting pre-generated foam into an initially unsaturated system containing one or more types of sediments. Soil water content and foam pressure were measured with time at multiple locations. The Figure below shows the simulated moisture-content distribution during the injection of foam into a two-dimensional flow cell. Further work is warranted for better understanding the foam transport mechanism in the vadose zone and parameterizing the model.

Figure 1: Simulated moisture content distribution during the injection of foam. [1] United States Department of Energy (2010), DOE/RL-2010-89, Revision 0. [2] White and Oostrom (2006), PNNL-15782, Pacific Northwest National Laboratory.

The significance of Cenozoic magmatism from the Eastern margin

of the Eastern Himalayan syntaxis HONGFEI ZHANG, FABIN PAN, WANGCHUN XU,

LAISHI ZHAO AND YONGHAO YE State Key Laboratory of Geological Processes and Mineral

Resources, China University of Geosciences, Wuhan 430074, China ([email protected])

Previous studies show that the adakitic rocks have

magma crystallization ages between 10~18 Ma in central Gangdese belt (west of 92°E) and 22~26 Ma in eastern Gangdese (east of ~ 94°E) [1,2,3,4]. It seems that the magma crystallization ages for the Gangdese adakitic magmatism tend to an increased variation from west to east. However, whether this variational trend extend to far eastern Gangdese is uncertain because previous work on the far eastern Gangdese adakitic magmatism lacks high-precision geochronological data. If the age variational trend for the adakitic magmatism is true, an interesting issue is what continental dynamic process taken place along the Gangdese belt.

We carried out an integrated study of U-Pb zircon dating, geochemistry and Sr-Nd-Hf isotopes for two granitoid intrusions in Motou area, the eastern margin of the eastern Himalayan syntaxis. U-Pb zircon dating shows their magma crystallization ages of ~28 Ma. These granitoids have adakitic geochemical signatures. Our result further confirms the age variation of the adakitic magmatism along the Gangdese belt. We suggest that the adakitic magmatism resulted from break-off of the subducted Indian continental slab and a westward propagation model for the slab break-off can account for the age variation and magma generation. [1] Chung et al., 2009. Tectonophysics, v. 477, p. 36-48. [2] Ji et al., 2009. Chemical Geology, v. 262, p. 229-245. [3] Xu et al., 2010. Lithos, v. 114, p. 293-306. [4] Zhang et al., 2010, Contributions to Mineralogy and Petrology, v. 160, p. 83-98.



2253

Modeling of hyporheic zone of surface water - groundwater with 3S

technology JING ZHANG1*, HUILI GONG2 AND XIAOJUAN LI3

1The Key Laboratory of Resource Environment and GIS of Beijing, Capital Normal University, Beijing 100048, P. R. China (*correspondence: [email protected])

2College of Resource Environment and Tourism, Capital Normal University, Beijing 100048, P.R. China

3College of Resource Environment and Tourism, Capital Normal University, Beijing 100048, P.R. China

Hyporheic zone of surface water - groundwater is a

mixture of surface water and ground water zone where the biogeochemical activities in the region are very strong. Moreover, this zone is mainly affected by natural factors and human factors. The physical, chemical and biological processes are often occurs within the hyporheic zone, and affect the water movement, solute transport processes and the process of biological activities. Massive algae blooms are one of the biggest problems that rivers/lakes/coasts face today in China. For example, before the Beijing 2008 Olympic Games opening, Qingdao Olympic Sailing Venue, the green algae covers a third of the sea off the city of Qingdao. Algae are often caused from high nitrogen containing components of untreated waste, and nitrogen is a detergent and the main ingredient in plant fertilizer. The hope Green Olympic Games and current situation make so many Chinese people unease. Rapid development of computer technology and geo-information technology provides an objective basis for truly integrated cross-disciplinary. Global Earth Observation System of aerospace, aviation and ground coordination with multi-temporal and spatial resolution has been more and more widely applied in geochemical, hydrological, ecological and environmental studies. With the advanced development of 3S technology (Remote Sensing, Geographic Information System, Global Positioning System), monitoring, measuring and modeling biogeochemical processes and its ecological function in hyporheic zone of groundwater and surface water is more visualized and reliable. This talk will focus on an overview of application of 3S on biogeochemical processes in hyporheic zone of groundwater and surface water in China with some preliminary modeling studies [1]. [1] Under the auspices of National Natural Science Foundation of China (No.40901026) and Supported by Beijing Municipal Science & Technology New Star Project Funds (No.2010B046).

Recycling subcontinental plagioclase-rich lower crust in the

North China craton JUN-BO ZHANG1,2, WEN-LI LING1,2*,

YONG-SHENG LIU1,2, SHAN GAO 1,2, TIMOTHY KUSKY1, ZI-WAN CHEN1,2, XIAO-FEI QIU1 AND MENG CHE1

1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China (*correspondence: [email protected])

2Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China

Foundering of eclogitic lower crust into the convecting

mantle has been proposed to explain the unusually evolved chemical composition of Earth’s continental crust. However, whether the granulitic lower crust is also removable remains unclear due to its relatively lower density. Here, we report a geochemical study of distinct phenocrystal clinopyroxene and silicic melt inclusions hosted by early Cretaceous high-Mg andesite (HMAs) from Shandong province, eastern North China craton, which suggests recycling of plagioclase-rich lithologies. Three types of clinopyroxenes are recognized. Type I and II clinopyroxenes show normal- and reverse zonation, respectively, and both are featured by clear negative Eu anomalies in their cores. Type III clinopyroxene occurs in a remnant poikilitic texture with a high-Mg# core, but with no Eu anomaly, and encloses low-Mg# olivine grains. Both olivine and clinopyroxene crystals of the andesite contain high-Si and low-Mg melt inclusions, which are enriched in alkali metals and have low Eu/Eu*, showing a nature akin to their host clinopyroxenes and HMAs. It is thus suggested that the HMAs were derived from lower-degree melting of recycling plagioclase-rich lithologies. These rocks are interpreted as granulitic lower crust returned into the convecting mantle, which then interacted with mantle peridotite via partial melting. If so, our scenario also provides a critical guide for making high-Mg andesite and continental crust and that the granulitic component input could play a key role in the subcontinental mantle heterogeneity.



2254

A LA-ICP-MS study of garnet from the Nihe iron deposit,

Anhui Province, China LEJUN ZHANG*, TAOFA ZHOU, YU FAN, FENG YUAN,

LING MA AND BING QIAN School of Resources and Environment Engineering, Hefei

University of Technology, P.R. China (*correspondence: [email protected])

The Luzong volcanic basin is located at the central part of

the Middle and Lower Yangtze River area and contains numerous important Cu-Au-Fe deposits. The Nihe iron deposit is a newly discovered large scale iron deposit in the western part of the Luzong volcanic basin. In the contact zone of the diorite porphyry intrusion and the trachyandesite of Zhuanqiao Formation occur anumbers of garnet in the Nihe iron deposit. This study presents LA-ICP-MS data for garnets from the Nihe iron deposit, discusses the factors controlling incorporation of trace elements into garnets, and strengthens the potential of garnet trace elements geochemistry as a tool to help understand the evolution of hydrothermal fluids.

Garnets from the Nihe iron deposit range from Adr48Grs52 to almost pure andradite (Adr>99). LA-ICP-MS data show that the garnet have detectible Zr, V, U, Sc, Nb, Th, Zn, Ga, Cr, Ge, Hf, Sr, Ta, Pb and REE (!442~1301ppm, avg. 812ppm). All the garnets are show typical LREE-enriched and HREE-depleted patterns, with a strong positive Eu anomaly. Incorporation of trace element into garnet is in part controlled by its crystal chemistry, with a coupled substitution mechanism(eg. [X2+] VIII -1[REE3+] VIII +1 [Si4+] IV -1 [Z3+] IV +1). Variations in textural, optical features and geochemistry of the garnet are largely controlled by fluid composition. Garnet composition and zonation record the history of the hydrothermal fluid and can be used to identify fluid changes in physicochemical properties.

This research was supported by funds from the National Natural Science Foundation of China (Grant No. 40830426, 40803015), Research Fund for the Doctoral Program of Higher Education (Grant No. 20100111110010), Deep Exploration Technology and Experimentation (SinoProbe-03)and the Science Research Project of CODES, Centre of the Excellence in Ore deposits, University of Tasmania (Grant No. CODES2009 P2. N3).

Formation mechanism of foliated (garnet-bearing) granites of the Tongbai-Dabie orogenic belt:

Evidence from the Mamiao cross section

L. ZHANG1*, Z. ZHONG1, H. ZHANG1 AND W. SUN2 1State Key Laboratory of Geological Processes and Mineral

Resources, Faculty of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, P. R. China (*correspondence: [email protected])

2Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, the Chinese Academy of Sciences, Guangzhou, 510640, China

High pressure (HP) metamorphic rocks are important for

understanding the genesis of the foliated (garnet-bearing) (FGB) granites in the Tongbai-Dabie orogenic belt. Based on a study on geochemistry of HP metamorphic rocks and FGB granites from the Mamiao cross section in the Tongbai-Dabie orogenic belt, the relationship between these rocks are discussed. The regular pattern of variation trends of elemental compositions of the HP metamorphic rocks, as well as the similarity in the isotopic compositions suggests the continuous evolutional relationship of retrograde metamorphism between the HP rocks. The changes in elemental compositions between HP gneisses and FGB granites are significantly different from variations of elemental compositions occurred during the retrograde metamorphism of HP eclogites. These differences in geochemistry presented in this study and previous studies suggest that there is no continuous evolutional relationship of retrograde metamorphism between the FGB granites and the HP metamorphic rocks. The magma source of the FGB granites was most likely from retrograded metamorphism and depressional partial melting of the UHP gneisses.

This research was supported by NSFC of China (No. 40873044) and the Chinese National Key Project for Basic Research (No.2006CB403502).



2255

Kinetic experiments of some silicate mineral dissolutions in water from a

subcritical to a supercritical state RONGHUA ZHANG, SHUMIN HU AND XUETONG ZHANG

Institute of Mineral Resources, Chinese Academy of Geological Sciences, Lab.Geochemical Kinetics. Baiwanzhuang road 26, Beijing 100037

([email protected]) Measurements of steady-state dissolution rate of pyroxene,

quartz, garnet, albite and actinolite in water were performed using flow through reactor (well mixed) from a subcritical to a supercritical state at temperatures from 25 to 435°C at 23-33 MPa. Minerals used in experiments are collected through microscope, cleaned and analyzed chemically. Usually, all reactive solutions were undersaturated with respect to the mineral. A few secondary product phases were found on the reacted surface. The kinetic experiments indicate that the measured dissolution rates of the minerals at T +300°C coincide with previous experiments of quartz, diopside and albite published in literatures. The dissolutions are stoichiometric, when the release ratio of molar concentrations of metal Mi versus molar concentration of Si in outlet solutions ,Mi/,Si is identical to the stoichiometric number Ni in solid. The stoichiometric dissolution of pyroxene in water is present at near 200°C, and it for albite in water is at 300°C. Dissolution rates (rSi) for quartz, diopside, hedenbergite, albite, garnet in water were found to increase with increasing T from 25 to 300°C. Experiments indicate that the rates of pyroxene and albite decrease with increasing T from 300 to 400°C. The maximum release rates of Si for those minerals are reached at 300°C. The maximum rates for quartz are at about 374°C. The different metals of the minerals often behave the different release rates. Usually, the release rates of Na, Ca, Mg, Fe, Al of minerals are often higher than Si at T<300°C, and the metal Mi-H+ exchange reactions are faster at low temperature. The hydrolysis of Si-O-Si bond and metal ion-H+ exchange reactions at T< 300°C are different from reactions at T 300°C. Because, the effects of water solvent properties (lowering density and dielectric constant within the region from a sub-critical to supercritical state, hydrogen networks of water molecules break) affect dissolution rates, e.g., dissolution rates of Si vary with 1/dielectric constant.

Note: This project is supported by the projects of 2010G28, 2008ZX05001-003-006, K1006, SinoProbe-07-02-03, SinoProbe-03-01-2A.

Melting of juvenile lithospheric mantle: Geochemical evidence from

Neoproterozoic mafic-ultramafic rocks in South China

SHAO-BING ZHANG*, RONG-XIN WU AND YONG-FEI ZHENG

School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China (*correspondence: [email protected])

While many studies deal with the fate of ancient SCLM,

less attention has been paid to the fate of juvenile lithospheric mantle. We present a geochemical study of a Neoproterozoic mafic-ultramafic complex in the eastern Jiangnan orogen, South China. Harzburgite is significantly depleted in Ca and Al, suggesting significant melt extraction; gabbro and spilite have low contents of TiO2 and P2O5. While all the mafic rocks show the arc-like patterns of REE and trace element distribution, the harzburgite is complementary to the mafic rocks in the spidergrams. Zircon U-Pb dating on the gabbro gave three groups of ages at 891±13 Ma, 824±3 Ma and 764±19 Ma, respectively. The 891±13 Ma zircons are less common and unzoned or weakly zoned in CL images, which are interpreted as residues from magma source. The 824±3 Ma zircons are dominant and show clear magmatic zoning, representing crystallization age of the gabbro. The 764±19 Ma ages result from reworking of the collision orogen in response to supercontinent breakup. The harzburgite, troctolite and gabbro have positive -Nd(t) values of 3.29 to 5.69 and lower initial 87Sr/86Sr ratios of 0.7033 to 0.7059, whereas the spilites show neutral -Nd(t) values of -1.24 to 0.40 and higher initial 87Sr/86Sr ratios of 0.7039 to 0.7068. In particular, the gabbro rich in zircons has the highest -Nd(t) values of 5.69 and the youngest Nd model age of 1.03 Ga. Lu-Hf isotope analyses on the zircons from the gabbro gave positive -Hf(t) values of 10.2 to 12.1 at t = 824 Ma and Hf model ages of 0.90 to 0.98 Ga Ma. The positive -Hf(t) and -Nd(t) values as well as the small differences between the magma crystallization age and the Hf-Nd model age for the gabbro indicate its derivation from partial melting of an isotopically depleted mantle source. Along with available data in the Jiangnan orogen which suggests the postcollisional tectonic setting, it is concluded that the mafic-ultramafic rocks were derived from partial melting of the juvenile lithospheric mantle that probably formed by arc-continent collision at about 900 Ma, and underwent partial melting at about 820 Ma. Therefore, the gabbro and spilite represent the melts, whereas the harzburgite would be the restites after melt extraction. This provides geochemical evidence for anatexis of juvenile lithospheric mantle in the postcollisional regime.



2256

Phase equilibrium of the Cd-bearing systems at 298 K: Cd2+//Cl-, SO4

2-, NO3

--H2O quaternary system ZHANG SHIPENG1, HUANG YI2, 3* AND NI SHIJUN3

1College of Materials and Chemistry & Chemical Engineering, Sichuan, PRC

2Department of Geochemistry, Chengdu University of Technology, Sichuan, PRC (*correspondence: [email protected])

3Applied Nuclear technigues in Groscience Key Laboratory of Sichuan Proviance, PRC

Solid- Liquid Equilibrium of quaternary system Cd2+//Cl-,

SO42-, NO3

--H2O at 298 K were studied by an isothermal solution saturation method. Experimental results indicate that there are three univariant curves BE, AE and CE, one invariant point E and three crystallization fields in the quaternary system. The quaternary system belongs to a simple type, and there’re no double salts or solid solution existing. The crystallization zones of equilibrium solid phases are CdCl2·H2O, CdSO4·H2O, and Cd(NO3)2·8H2O, respectively. The composition of the invariant point is CdCl2·H2O, CdSO4·H2O, and Cd(NO3)2·8H2O, respectively. The physico-chemical properties of solution in the quaternary system show regular changes along with the increased cadmium concentration. The results indicated that Cd(NO3)2·8H2O possessed the highest solubility among those three salts, which means a strong transfer of Cd ion and a high pollution risk of soil environment. And the solubility of CdSO4·H2O would be restrained as the salts existing together.

A simulation study of hydrocarbon gas generation from Fischer–Tropsch synthesis with varying carbon source and hydrogen in a gold tube system

ZHANG SHUICHANG, MI JINGKUI AND HE KUN Key Laboratory for Petroleum Geochemistry, China National

Petroleum Corporation The Fischer–Tropsch synthesis (FTS) is a widely accepted

mechanism for the formation of abiogenic gases, but the experimental results from different laboratories vary considerably and can rarely match the natural occurrence [1-3]. Our FTS experiments were conducted in a sealed gold tube on Fe and Ni catalysts using graphite and CO2 with distinctive isotopic composition as the starting material by reduction in pure hydrogen at 400 °C and 50 MPa for 2-60 h. Results show that synthesis between gaseous phase carbon (CO2) and H2 is easier than solid phase carbon (graphite) counterpart and 13C depleted CO2 is more reactive than 13C enriched CO2. After short reaction time carbon isotopic compositions of hydrocarbons from all three FTS experiments decrease in (13C values of C2 to C4 alkanes with respect to CH4, showing so-called inverse trend. With increasing reaction time, synthesis was gradually shifted to thermal cracking. 13C depleted gas from thermal cracking mixed with 13C enriched residual gas leads to partial reversal and normal isotopic distribution among C1-C4 alkanes. Hydrocarbon gases from the FTS will finally decompose to carbon and hydrogen if reaction time is longer enough.

FTS experiments running under laboratory condition from low to high temperature differs from abiogenic synthesis of hydrocarbons in natural systems, which is a cooling process from high to low temperature either under aqueous hydrothermal or volcanic intrusion condition. Hydrocarbons generated from the FTS experiments may be decomposed via thermal cracking and isotopic composition among gaseous components can show all possible distribution patterns. FTS-type natural reactions occur under certain PT condition and hydrocarbon gases generated have no further decomposition and may hold a fixed “inverse” isotopic distribution. This may explain the controversial isotopic distribution patterns observed from varying FTS experiments.

[1] Charlou et al. (1998) GCA 62(13), 2323-2333. [2] McCollom etal. (2006) EPSL 43(1-2),74-84. [3] Taran et al. (2010) GCA 74, 6112-6125.



2257

Reactive transport modeling of carbon sequestration in volcanogenic

sandstone formations SHUO ZHANG1*, DONALD J. DEPAOLO2 AND TIANFU XU3

1307 McCone Hall, University of California, Berkeley, CA 94720-4767, USA (*correspondence: [email protected])

2475 McCone Hall, University of California, Berkeley, CA 94720-4767, USA ([email protected])

3Earth Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA ([email protected])

Geological storage of carbon dioxide in deep saline

formations can decrease the accumulation of CO2 in the atmosphere, and thus slow down global warming. Most injected CO2 remains for a long time as either a separate supercritical phase or in solution in brine; both forms constitute increased risk of leakage back to the surface or other environmental impacts Mineralogical trapping of injected CO2 is more secure but usually very slow. For standard sandstones (quartzite and arkose) investigated so far, it takes up to 10000 years to achieve 5 percent CO2 mineralization [1]. Volcanogenic sandstones have relatively high reaction rates and larger amounts of reactive minerals, which means that if they were used for storage, there could be a larger fraction of CO2 mineralized in a shorter time. However, porosity and permeability tend to decrease with increase of volcanic rock fragments (VRF) in sandstones, which limits the rate of CO2 injection. We have attempted to quantitatively evaluate these tradeoffs to assess the feasibility of using volcanogenic sandstone to achieve highly secure CO2 storage. We determined relationships between VRF percent, porosity, permeability and CO2 injection rate from available geological data, and used TOUGHREACT to evaluate the trade-off between higher reactivity and lower porosity and permeability. Preliminary results show that roughly 5% VRF is optimal, and can result in almost complete CO2 mineralization, but this depends on the magnitude of reactive surface area (RSA) specified. Varying RSA between 2 cm2/g and 50 cm2/g changes the fraction mineralized from 13% to almost 100% at 1000 years. Baseline simulations were done with a 1-D model. A corresponding 2-D radial model shows a slight increase of mineralized CO2 due to a larger interface between the CO2 plume and saline water.

[1] Audigane, P., et al. (2007) American Journal of Science 307(7): p. 974-1008.

Biomethylation potential of mercury depends on the kinetics of HgS

precipitation T. ZHANG, H. HSU-KIM* AND M.A. DESHUSSES

1Duke University, Civil & Environmental Engineering, Durham, NC 27708, USA (*correspondance: [email protected])

Monomethylmercury (MeHg) is an extreme neurotoxin

that accumulates in food webs and poses a significant risk to human health. In natural aquatic systems, the predominant mechanism of MeHg production is microbial methylation of inorganic mercury (Hg) by sulfate-reducing bacteria (SRB). MeHg production rates are largely controlled by the availability of Hg species for uptake into SRB and the productivity of those microbes. In sediments, sulfide controls Hg speciation due to its high abundance and strong affinity to bind Hg2+. Previous studies have demonstrated that natural organic matter (NOM) interferes with the precipitation of HgS(s) by preventing aggregation of HgS nanoparticles that are formed during the initial stages of precipitation. We hypothesize that bioavailable Hg concentration is related to the kinetics of HgS precipitation, and not necessarily to equilibrium speciation of Hg in sulfidic porewater.

We conducted methylation bioassays using pure cultures of two methylating SRB, Desulfobulbus propionicus (1pr3) and Desulfovibrio desulfuricans (ND132). The bacterial cultures were exposed to three different forms of Hg-sulfides, including dissolved Hg(NO3)2 and Na2S, humic-coated HgS nanoparticles (<30 nm), and metacinnabar particles (>1000 nm), which were formulated to represent three different ‘aging’ states of mercury in sulfidic sediments. Our results showed that methylation rates were greatest with the dissolved Hg-sulfide treatment. In the treatments with HgS nanoparticles, MeHg production was observed at a rate that was significantly faster than the metacinnabar treatment. These results may be due to: 1) the relatively poor crystallnity of HgS nanoparticles compared to bulk minerals that are inherently less soluble; 2) the larger extent of nanoparticle-bacteria surface contact that allows nanoparticulate Hg to be spatially more accessible for the methylating bacteria than micro-scale metacinnabar. Moreover, methylation potential appeared to decrease as HgS nanoparticles ‘aged’ (16 hrs~1 week), which may be attributed to the enhanced crystallinity of nanoparticles during aging. Overall, our study points to a new paradigm for modeling aqueous mercury speciation in anaerobic environments and the bioavailability of inorganic mercury to methylating bacteria.



2258

The bioleaching effect of agitation speed on low-grade chalcopyrite ore

under the combined catalysis W. M. ZHANG1,2 *

1State Key LaboratoryBreeding Base of Nuclear Resources and Environment, East China Institute of Technology, Nanchang 330013, China (*correspondence: [email protected] )

2 School of Civil and Environmental Engineering, East China Institute of Technology, Fuzhou 344000, China

Chalcopyrite is the most important copper mineral. It is,

however, relatively recalcitrant to chemical and bacterial oxidation because of its special crystal structure and electrochemistry in contrast to many other copper minerals. It is essential to find some desirable methods to enhance chalcopyrite bioleaching. The purpose of this work is to study the bioleaching of agitation speed on low-grade chalcopyrite ore under the combined catalysis

The low-grade chalcopyrite ore used in this study was obtained from Yongping Copper Mine, SE-China. The particle size was less than 5 mm. The chemical composition is as follows: 0.40% Cu, 14.12% Fe, 13% S. The chemical phase analysis showed that chalcopyrite is 0.38% and the other copper minerals 0.02%. The mixed Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans used in this study were isolated from acid mine drainage at Yongping Copper Mine. Leaching experiments were carried out in 10 L plastic drum with 800 ml 9K + S medium without Fe2+, 200 ml inoculation, 25%(W/V) pulp density, 3.0 g/L activated carbon, 2.0 mg/L Ag+, 8.0 g/L Fe2+ and 1.20 pH (the pH values were controlled within 1.50 with sulphuric acid during the bioleaching processes). The agitation speeds were 120, 150, 180, 240 and 300 rpm ,respectively.

The results show that the agitation speed has a great effect on the bioleaching of low-grade chalcopyrite ore under combined catalysis of activated carbon, Ag+ and Fe2+. The agitating speed of 300 rpm is most beneficial to the dissolution of copper, in this case, the leaching rate of copper reaches 84% after 456 h leaching, which is 37% higher than that at 120 rpm. It is found that it is more favorable to the bioleaching of low-grade chalcopyrite ore if the redox potential is controlled at 580-620 mV.

Variation of hydro-chemistry in lower reaches of the Chinese

Golmud-river and its effects on the groundwater

ZHANG WENJIE AND TAN HONGBING School of Earth Sciences and Engineering, Hohai University,

Nanjing, 210098

Major chemical compositions of Golmud-River in Qinghai, China have been measured in order to understand the spatial changeable characteristics and uncover their formation mechanism. In the lower reaches, the river is divided into two dominate tributaries of west river and east river. The principal chemical compositions of Golmud-River change significantly after it flows into alluvial-pluvial fan through Golmud city. With respect to the upper reaches, the chemical composition of west river changes slightly while the TDS of the east river increases greatly with an average of 1566.028 mg/L and reaches to a peak value of 2956.160mg/L in the same geological features. In order to figure out this abnormal variation, hydrological characteristics of the two rivers are researched. TDS of West River varies from 360.061 mg/L in the upper reaches to 552.166 mg/L in the lower reaches. Such characteristic indicates that chemical compositions of West River are principally dominated by dissolution of weathered chemical components along the river course. In contrast, the sharp rise of TDS of east river could arise owing to fluctuations of groundwater table which is about 1~3m and higher than groundwater critical evaporation depth. Moreover, groundwater table has been rising with the ascending of water leakage since the completion of hydropower station in upper reaches. Consequently, a large amount of salts are carried upward to the surface and greatly accumulated under strong evaporation. Hence, a conclusion can be drawn that significant high salinity of East River originates from soil salinization which is due to groundwater table ascending and strong evaporation.



2259

Influence of humic acids on pyrene sorption by carbon nanotubes

XIAORAN ZHANG, MELANIE KAH AND THILO HOFMANN*

Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria (*correspondence: [email protected])

Understanding the interactions between organic

contaminants and carbon nanotubes (CNTs) is essential for evaluating the materials’ potential environmental impact and their application as sorbent. Although a great deal of work has been published in the past years, data are still limited in terms of compounds, concentrations, and conditions investigated. This can be mainly explained by limitations associated with the generally-applied batch sorption test set ups. The present study focuses on the effects of humic acids (HA) on the sorption of organic contaminants onto CNTs. The presence of HA may have two opposite effects on sorption. On one hand, competition between HA and organic contaminants can result in a decrease in sorption to CNTs. On the other hand, HA are known to disperse CNTs and we showed in a previous study that sorption capacity is directly related to surface area. The presence of HA may thus increase sorption of organic contaminants through an increase in the available surface area. The balance between these phenomena remains unclear as classical separation techniques (e.g. centrifugation or filtration) are not adequate to efficiently separate the CNTs and liquid phase under conditions where CNTs are partially dispersed. We previously validated a passive-sampling method to study sorption of PAHs. The method is applicable to dispersed CNTs and we here use it to investigate the influence of HA on the sorption of pyrene. Sorption isotherms were determined over a wide concentration range. Changes in isotherm shapes were interpreted in terms of sorption mechanisms for a range of HA concentrations (0-200 mg/L).

Changes in the sorbent properties as a function of HA concentration are essential to understand and distinguish the various processes involved. CNTs settling behaviour, size distribution in suspension and particle diameter in the supernatant were determined by UV-vis spectrometer, particle size analyzer (CIS-100) and dynamic light scattering, respectively. Preliminary results confirmed the strong dispersing effect of HA on CNTs. The size range of CNTs decreased from 0-60 µm down to 0-8 µm in suspensions containing 0 and 200 mg/L HA, respectively. The speed of settling also decreased dramatically with increasing HA concentration, but after 2 d, particles remaining in the supernatant had similar diameters for all HA concentrations (200 nm), as compared to the control without HA (650 nm). Together with the isotherm analysis, these results will allow a better understanding of the interactions between organic contaminants and CNTs in complex environmental matrices.

Chemical sensors based on Zr/ZrO2 electrode for measurement of pH in a subcritical to supercritical aqueous

water XUETONG ZHANG, RONGHUA ZHANG AND SHUMIN HU

Institute of Mineral Resources, Chinese Academy of Geological Sciences, Lab.Geochemical Kinetics. Baiwanzhuang road 26, Beijing 100037 ([email protected])

A Zr/ZrO2 oxidation electrode was fabricated for in situ

measurement of pH values in aqueous solutions at elevated temperatures. Combined with an Ag/AgCl reference electrode, the Zr/ZrO2 sensor responded rapidly and precisely to the pH of the solutions over a wide range of temperatures. The Zr/ZrO2 electrode was made by oxidizing Zr metal wire with a Na2CO3 melt to produce a thin film of ZrO2 on the Zr wire surface. The nanostructure of the ZrO2 thin film was characterized using high-resolution transmission electron microscopy (HRTEM) observations. The nature of the nanostructured ZrO2 thin film on the Zr of the Zr/ZrO2 electrode plays a vital role in the construction of Zr/ZrO2 chemical sensors, particularly when the electrode is utilized for in-situ measurement of the electrochemical parameters of aqueous solutions at high temperatures and pressures.

Electric probe analyses of the ZrO2 thin films revealed that the Zr/ZrO2 interface is divided into 5 zones from the outermost zone to the center: 1) prismatic and oxygen-rich ZrO2 zone; 2) ZrO2; 3) oxygen-rich Zr; 4) oxygen-bearing Zr; 5) Zr metal. Especially, the outermost oxygen-rich ZrO2 zone of the films is composed of nanometer-sized monoclinic crystals.

The experimental measurements of the Zr/ZrO2 sensor potential against an Ag/AgCl reference electrode indicate that the sensor potential responds linearly with the pH of NaCl-HCl-H2O (and NaCl-NaOH-H2O) over the temperature range from 20 to 200°C. The slope of the potential versus pH plot at 200°C is close to the theoretical value of the Nernstian slope for the test solution at electrochemical equilibrium. The Zr/ZrO2 sensor is expected to find use for in situ measurement of pH in aqueous fluids in natural processes over a wide temperature range, especially for hydrothermal vent fluids at mid-ocean ridges.

This project is supported by the project of 2010G28, 2008ZX05001-003-006, K1006, SinoProbe-07-02-03, SinoProbe-03-01-2A.



2260

On the quantification of OC and EC and their isolation for radiocarbon

measurement by a modified thermal/optical method

Y.L. ZHANG1,2,3*, N. PERRON2,4, A.S.H. PRÉVÔT2, L. WACKER5 AND S. SZIDAT1,3

1Department of Chemistry and Biochemistry, University of Bern, Berne, Switzerland ([email protected])

2Paul Scherrer Institut (PSI), Villigen, Switzerland 3Oeschger Centre for Climate Change Research, University of

Bern, Berne, Switzerland 4 Now at: Devision of Nuclear Physics, Lund University,

Lund, Sweden 5Lab. of Ion Beam Physics, ETH Hönggerberg, Zurich,

Switzerland

Carbonaceous aerosols, which comprise the large fractions of elemental carbon (EC) and organic carbon (OC), badly affect climate and human health. However, there is a large uncertainty about detailed apportionment and quantification of its sources due to the large number of origins and chemical compounds associated with the aerosols. Radiocarbon (14C) measurements of EC and OC allow an improvement in carbonaceous aerosol source apportionment, leading to a full and unambiguous distinction and quantification of the contributions from non-fossil and fossil sources (Szidat, 2009). The principle technique of thermal-optical analysis (TOA), which employs laser light absorption to distinguish EC from the pyrolyzed OC, is widely accepted for determination of OC and EC concentrations. However, the challenge of TOA methods lies in physically differentiating the OC and EC. Early removal of EC in the inert phase (He) and the formation of char due to pyrolysis of OC can lead to large errors in 14C measurements of OC and EC, if using the conventional protocols such as IMPROVE, EUSAAR-2 and NIOSH. Here, we present a new protocol including four-stage thermal treatments optimized for isolating OC, mixture of refractory OC and non-refractory EC and refractory EC for 14C measurement. In our protocol, the charring was found to be significantly reduced to less than 5% when analyzing the water-extracted filters under pure O2 mode (65ml/min) for summer and winter filters from Gothenburg (Sweden), Moleno and Zurich (Switzerland). And both charring carbon and refractory OC could be evolved completely before native EC throughout the analysis. OC and EC together with other carbonaceous fractions could be isolated for 14C measurement by the present TOA method. Furthermore, a new TOA protocol for OC/EC determination including pure O2 pre-treatment was developed to reduce the uncertainty in EC determination from charring and light-absorbing organic compounds (also called “brown carbon”) compared to other protocols. [1] Szidat, Science 323, 470-471 (2009). [2] Ruff et al., Radiocarbon 49, 307-314 (2007).

Degassing history of Earth YOUXUE ZHANG

Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005, USA ([email protected])

“Once upon a time, there were few data but many models.

Now, there are many data but no models.” Noble gas isotopes have provided much of our

understanding of Earth’s early history [1-3]. Various degassing models have been developed, including degassing of the whole mantle, degassing of all gases at similar relative rate [1], solubility-controlled degassing [2], and steady-state degassing models [4]. This report will evaluate various degassing models with recent data. For example, helium outgassing flux has been lowered by more than a factor of two based on sophisticated ocean general circulation models [5], which also impacts on the estimated degassing flux of carbon. Years of measurements and progress have allowed isotopic ratios of various mantle reservoirs being pieced together [6]. For example, 129Xe/130Xe in OIB mantle is found to be lower than that in MORB mantle [7]. Missing Xe has been found to be a non-issue [8]. Nucleogenic 21Ne production rate relative radiogenic 4He has been revised [9-10], which leads to an interesting neon paradox that nucleogenic 21Ne production in the whole silicate Earth is barely enough to supply nucleogenic 21Ne in air. Although non-nucleogenic mantle neon is solar, nonradiogenic mantle argon is atmospheric [11]. Nonradiogenic mantle helium is commonly thought to be similar to Jupiter. For Kr and Xe, the jury is still out. I will address what the new data mean in terms of Earth’s degassing, whether the new data can be modeled consistently, or whether we are now suffering from too many data.

[1] Allegre et al. (1986/87) EPSL 81, 127-150. [2] Zhang & Zindler (1989) J. Geophys. Res. 94, 13719-13737. [3] Zhang (1998) Geochim. Cosmochim. Acta 62, 3185-3189. [4] Pocelli & Wasserburg (1995) Geochim. Cosmochim. Acta 59, 4921-4937. [5] Bianchi et al. (2010) EPSL 297, 379-386. [6] Jackson et al. (2009) EPSL 287, 519-528. [7] Graham (2002) Rev. Mineral. Geochem. 47, 247-317. [8] Zhang (2002) Earth-Sci. Rev. 59, 235-263. [9] Yatsevich and Honda (1997) J. Geophys. Res. 102, 10291-10298. [10] Leya and Wieler (1999) J. Geophys. Res. 104, 15439-15450. [11] Raquin et al. (2009) EPSL 287, 551-558.



2261

Anaerobic cultivation and degradation capability evaluation of

microorganisms in petroleum-contaminated

groundwater at low temperature YULING ZHANG, XIAOSI SU*, SHENGYU ZHANG AND

HUANCHI JIN

Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University (*correspondence: [email protected]), (State major projects for water pollution control and treatment Technology 2008ZX02707-007)

In this study, water and soil samples were collected from

the shallow groundwater in vertical direction of a petroleum contaminated site in the northeast of China. Cultivation research of anaerobic microorganisms and microbial degradation test of TPH were carried out using 0# diesel oil as the sole carbon source. Microorganisms were enriched in the four traditional culture media by anaerobic pyrogallic acid method [1,2].

Figure 1: Hydrogeologic profile of petroleum-contaminated site

Figure 2: Morphology of three kinds strains which had the most degradation effect on TPH under the microscope Discussion of results

Species and relative density of microorganisms were heterogeneous in different layers of groundwater after 10 days’ cultivation at 10'. All of these strains had a certain extent of degradation effect on TPH in oxygen limited environments under low temperature, with three kinds of which had a degradation efficiency of more than 60%.

[1] Zhang Yu-Ling et al. (2008) Journal of Harbin Institute of Technology 40, 1481-1484. [2] Zhang Lan-Ying et al.(2007) Chemical Research in Chinese Universities 23, 1-4.

Characteristic and the formation conditions of chlorite in granite-type

uranium ore-field, South China ZHANSHI ZHANG1,2*, GUOLIN GUO1 AND ZHENPING

JIANG 1Key Laboratory of Radioactive Geology and Exploration

Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, Jiangxi, 344000, China (*correspondence: [email protected])

2Key Laboratory of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang, 330013, China

Granite-type uranium deposits were the most important

uranium mining deposit type in China currently. Chloritization was one of the most developed hydrothermal alterations during the uranium mineralization, and also developed before and after the mineralization. Quarry operation had proven that chloritization-type-ore not only the important supplement of the traditional silicification-type-ore but also a new high-grade type ore. Three representative granite-type uranium ore fields in South China had selected in this study. Based on the field investigation, representative chloritization-uranium-ore had been sampled. Separating of clay minerals, XRD analysis and electron probe microanalyser(EPMA) had been employed to study the characteristic and the formation condition of the chlorite.

It is revealed the assemblage type of clay minerals were chlorite-illite or illite-chlorite types. Chlorite distributed in the rocks either in pseudomorph of biotite or vermiform and flaky conglomeration in veins. Brunsvigite and Ripidolite had been distinguished based on the chemical composition based on EPMA analyze, magnesium and iron chemical composition of chlorite varied greatly, chlorite was mostly derivated from the argillaceous rock based on nAl/n(Al+Mg+Fe) value, escept some from the magnesium-rich fluid which might announce that there were some chlorite and even the chloritezation-type-ore had be contaminated by Mafic-rich fluid. The formation temperature varied in 163�287' had been calculated. The temperature of chlorite which related to the formation of uranium deposit is higher than the chlorite which formatted before and after the uranium mineralization. And the temperature is closed to the temperature of uranium deposit. The chlorite formed under reduction condition. Dissolve-precipitation and dissolve-transfer-precipitation were the formation mechanism.

This work was supported by the National Natural Science Foundation of China (Grant No: 40972068 and No: 40772068).



2262

Hydrogen isotope fractionation in marine algae: Salinity effect ZHAOHUI ZHANG1,*, WEIMING GONG1 AND

KUNSHAN GAO2 1Department of Earth Sciences, Nanjing University, 22

Hankou Road, Nanjing, 210093, China. (*correspondence: [email protected])

2State Key Laboratory for Marine Environmental Sciences, Xiamen University, Xiamen, 361005, China With the advance of GC-IRMS technology, compound-

specific hydrogen isotopes of algal biomarkers have been widely used in hydrology reconstruction in paleoceanography. However, the salinity effect on hydrogen isotope fractionation in marine algae remains largely unclear. We have cultured five different species of myarine algae, Prymnesiophyceae Emiliana huxleyi (CCMP 1516), Prymnesiophyceae Geophyrocapsa oceanica (CCMP 2051), Dinophyceae Prorocentrum minimum (CCMP 1329), Navicula climacosphenae bootyh, Coscinodiscophyceae Thalassiosina pseudomanh (CCMP 1335) in artificial sea water with different salinities while keeping other parameters the same. Cell density was measured on a Z2 Coulter® Particle Count and Size Analyzer. Algal biomarkers are analyzed for structure identification on GC-MS and measured for hydrogen isotope ratio on GC-IRMS. Salinity effect in hydrogen isotope fractionation will be discussed.

ID-TIMS zircon U-Pb age of Yulonggou intrusive rocks and its

geological significance in South Qilian Mountains, NW China

ZHAO-WEI ZHANG1,2, WEN-YUAN LI1, YONG-BAO GAO1,2 AND ZHOU-PING GUO1

1Xi’an Center of Geological Survey(Xi’an Institute of Geology and Mineral Resource), CGS, Xi’an, Shaanxi 710054, China

2Chang’an University,Xi’an,Shaanxi 710054,China ([email protected])

Yulonggou intrusive rocks, belongs to Riyueshan-Hualong

basic-ultrabasic rocks belt, the belt has developed a number of intrusive rocks related closely with copper-nickel mineralization, it is great significance for the emplacement time and mineralization characteristics of basic-ultrabasic rocks to guide prospecting in Hualong area. The paper reports partial achievements of magmatic type copper-nickel ore resources potential evaluation in Hualong county, Qinghai Province, mainly by fieldsurvey and research on Yulonggou intrusive rocks on the process of the project, and obtained the zircon U-Pb age of 442.4±1.6 Ma(MSWD=0.059) rock formation in Yulonggou by ID-TIMS. Its petrology and geochemistry characteristics analysis and regional comparative research showing Yulonggou intrusive rocks is a ferruginous series ultrabasic-basic complex rocks, and has good magmatic differentiation and high abundance of useful elements that Ni、Cu、Co, so it is a favorable ore formation intrusive rocks; The age of 440 Ma, is conversion period from subduction orogeny to collision orogeny in the whole of Qilian Mountains, and into the stage of orogenic with the closure of Laji Mountain small ocean basin, form Yulonggou basic-ultrabasic intrusive rocks in extensional environment of post-collision. Contacting information of other intrusive rocks in Riyushan-Hualong basic-ultrabasic rocks belt, all the intrusive rocks may be formed in the same period, and have specific dynamic mechanism and evolution process. This extensional rifting event has a very close relationship with the mineralization, so the research has very important practical significance.

This study was supported by China Geological Survey project (No. 1212010911032, 1212011121088 and 1212011121092)



2263

Elastic anomalies due to spin state transitions in cobaltate perovskites:

Analogue behaviour for Fe2+ in (Mg,Fe)SiO3

ZHIYING ZHANG1*, JOHANNES KOPPENSTEINER2, WILFRIED SCHRANZ2 AND MICHAEL A. CARPENTER1

1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (*correspondence: [email protected])

2Faculty of Physics, University of Vienna, Strudlhofgasse 4, A-1090, Vienna, Austria (Mg,Fe)(Si,Al)O3 perovskites with orthorhombic Pnma

structure and (Mg,Fe)O are the principal minerals of the Earth’s lower mantle. Fe2+ undergoes spin state transitions at high pressure and high temperature, which have important effects on the physical properties of the lower mantle. Fe2+ in (Mg,Fe)O changes from high spin state to low spin state with increasing pressure, leading to large changes in the bulk modulus and small changes in the shear modulus. However, the influence of spin state transitions on (Mg,Fe)(Si,Al)O3 are less clear. There are still controversies about the nature of the stable spin configuration at high pressure and high temperature, the extent of the effect of spin state transitions on elastic properties and so on. It is hard to investigate the elastic moduli and acoustic dissipation at high pressure and high temperature. Therefore, analogue materials have been made use of. Co3+ is isoelectronic with Fe2+, and undergoes spin state transitions as a function of temperatue at ambient pressure. We have investigated elastic anomalies and acoustic dissipation associated with spin state transitions of Co3+ in NdCoO3 and GdCoO3 perovskites (orthorhombic, Pnma) using resonant ultrasound spectroscopy at high frequencies (0.1-1.5 MHz) and dynamic mechanical analysis at low frequencies (0.1-50 Hz). Strain analysis based on lattice parameter data from the literature shows that the spin state transitions are accompanied by significant variations in shear strain due to the change in ionic radius of Co3+. Spin state/strain coupling via octahedral tilting leads to the renormalization of shear modulus. In NdCoO3, the shear strain is small, and thus the coupling is weak. The temperature dependence of the shear modulus scales semi-quantitatively with an empirical spin order parameter. On the other hand, large shear strain and strong coupling occurs in GdCoO3, and large softening of the shear modulus by up to ~35% has been observed, accompanied by enhanced acoustic dissipation. The large shear strain associated with octahedral tilting in (Mg,Fe)SiO3 at high pressure suggests similar elastic behaviour as in GdCoO3.

Structure and mineralization characteristics of Kangding gold orefield, Sichuan Province, China ZHANG ZHIJUN1 2, DENG JUN1, GONG QINGJIE1 AND

WANG QINGFEI1 1China University of Geosciences, Beijing, 100083 2Tianjin North China Geological Exploration Bureau, Tianjin,

300170 The Kangding gold orefield, located in the north part of

the ‘kangding complex’ block and Sanjiang ore cluster area, has great potential in mineral resources. Based on the geological settings, the gold deposits in the study area are divided into two series!one series is in Kangding complex and the other is in the Xiaojin area with arc-shaped structures. Orefield structure, ore deposit geochemistry and metallogenic model are studied and compared between the two series. The rocks mainly contain amphibolite, granite, granulite, and basic dikes. The Kangding complex has experienced the formation of the basement from Neoarchean to the Paleoproterozoic, the Neoproterozoic magmatic activities (between 860-750Ma.) with the mountain of the main body, Mesozoic Indo-Chinese - Yanshanian magmatic activity, as well as the Cenozoic Himalayan magmatic activities. Magmatic activities are closely related to the formation of gold mineralization. Kangding complex is characterized by two layers which are crystalline basement and fold basement. It is a mixture of metamorphic and magmatic complex, and is the product of regional metamorphism, deformation and partial melting of magmatic rocks since Proterozoic.



2264

Characteristics of metallogenetic fluids and genesis of Nongping gold-copper deposit in Eastern Yanbian,

Northeastern China H.L.ZHAO, Y. S. REN*, N. JU AND H. WANG

College of Earth Sciences, Jilin University, Changchun 130061, China (*correspondence: renys@ jlu.edu.cn)

Nongping is another porphyry deposit besides

Xiaoxinancha large-scale gold-copper deposit in Yanbian area, Northeastern China. It experienced such four stages as sulfides, quartz-sulfides, quartz-sulfides-bismuthinite and quartz-melnikovite-tourmaline stage. And the quartz-sulfide-bismuthinite stage is the main gold mineralizing stage.

The petrographic and microthermometric studies on the fluid inclusions in quartz grains from sulfides-bearing quartz vein formed in the main mineralizing stage show that there are five types of the primary inclusions: (.) gas-liquid, (&) CO2-bearing three-phase, (/) multiple phases, (0) pure gas and (1) pure aqueous phase. The metallogenic fluid is of high-moderate temperature (homogenization temperature ranges from 237.8 to 399.4 ', mainly in the range of 310 ~ 370 '). The salinity of fluid inclusions is 1.39~12.3wt% and 33.32 ~ 42.03wt%. Different types of inclusions are closely accompanied, with roughly accordant homogenization temperatures and significantly different salinity. These characteristics indicate that the metallogenetic fluids experienced fluid boiling. The laser Raman spectroscopic analysis shows that the main components gas phase of the metallogenetic fluids are H2O and CO2, with a small amount of CH4.

Nongping gold-copper deposit and Xiaoxinancha large-scale gold-copper deposit develop the same kinds of inclusions with similar homogenization temperatures, and they both experienced fluid boiling in the formation of deposits [1,2]. Combined with metallogenic geological conditions and mineralization, a conclusion can be drawn that both two deposits are derived from the same magmatic and mineralization events under alike tectonic settings. At the end of the early Cretaceous, thanks to the subduction of the Pacific Ocean slab to the Eurasia plate, large copper-gold mineralization took place under the background of lithospheric extension. [1] Li et al. (1995) Mineral Deposits. 14(2), 151-166. [2] Zhao et al. (2008) Journal of jilin university (earth science edition).38 (3),384-388

High-resolution carbon and oxygen isotopic record through the transition

from OAE1a to ORB1 in the Mudurnu section, central Turkey

KUI-DONG ZHAO1, SHAO-YONG JIANG1*, XIU-MIAN HU1, "SMAIL ÖMER YILMAZ2 AND HONG-FEI LING1

1State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Jiangsu, 210093, P. R. China (*correspondence: [email protected])

2Department of Geological Engineering, Middle East Technical University, 06531 Ankara, Turkey

Change in oceanic sedimentation from Cretaceous black

organic carbon-enriched deposits (Oceanic Anoxic Events) to predominantly oceanic red beds (ORBs) occurred widely in the Tethys. Few attentions have been given to the transition and environmental changes from the Selli Level (OAE1a) to the Oceanic Red Bed 1 (ORB1).

High-resolution carbon and oxygen isotope curves derived from the early Aptian hemipelagic sediments cropping out at Mudurnu, central Turkey, reveals isotopic excursion and recovery through the transition from the OAE1a to ORB1. Comparison with the standard reference (13C curve of the Alpine Tethys shows that the overall character of the excursion through OAE1a is clearly reproduced in central Tethys. A sharp negative (13C excursion (1.5‰) followed by an abrupt and prolonged positive (13C excursion (3.5‰) and black shale deposition through OAE1a. (18O values also show sharp negative excursion synchronous with (13C before OAE1a, implying that the onset of OAE1a might be related with rapid influx of CO2 into the atmosphere from volcanogenic and/or methanogenic sources. Aftermath the OAE1a, (13C values keep high value and last for a long time (>1.0 myr), then decrease gradually to normal values until the appearance of ORB1. The recovery of carbon isotope last for longer than 1myr. Gradually intensifying of bottom circulation and increasing in dissolved oxygen in bottom waters is the most probable the cause for the transition from OAE1a to ORB1.



2265

Component and structure of manganese dominant mineral of Co-rich crusts from West Pacific

ZHAO LEI1 YANG HUA1 AND ZHAO XIAOYI2 1China University of Geosciences (Beijing), 100083

([email protected]) 2Hebei Province Geophysics Investigation Institude

West Pacific is one of the most enriched regions of Co-rich crust. This study selected a multilayered-structure crust, and sampled from an enrichment belt of the main manganese mineral. The component of the manganese- dominant mineral is MnO2 with water and a lot of other element (Fe, Ca, Na, Mg, etc.), its formula can be writing as MnO2 • XH2O (with Fe, Ca, Na, Mg, and other elements). As it is completely different from vernadite, but its structure and stability similar with ( -MnO2 ; for close intergrowth with iron hydroxide, XRD values are larger with the 0.24~0.245 nm and the 0.14~0.143 nm than vernadite. The name is proposed for the marine ( -MnO2 . Marine ( -MnO2 has layer-structure even with tunnel structure, and has good structural stability. When heated to 400 ' , its crystal structure remains basically unchanged. Marine ( -MnO2 changes into Mn2O3 ( 2 -Mn2O3 ) around 550 ' , then changes into Mn3O4 around 804 ' . The temperature of 804 ' is lower 146 ' than the temperature of 950 ' reported by a literature, the structural stability may be related to the metal ions contained. The manganese-dominant mineral of Cobalt-rich crusts in this area is ( -MnO2 , for the three main manganese minerals of todorokite, birnessite and ( -MnO2 in deep seas, ( -MnO2 is the most thorough oxidized mineral, the O/Mn are 1.74~1.87,1.87~2.00,1.99. This shows that the crusts underwent the strong oxidative environments and agrees with the enrichment characteristic of the REE.

Identification of marine manganese minerals should use many means, and the peak of XRD should be determined according to the standard of marine manganese minerals. Considering different stabilities and structures between marine manganese minerals and the terrestrial counterparts, we should use a new naming system for marine manganese minerals: marine 1 nm mineral, marine 0.7 nm manganese mineral marine ( -MnO2.

[1] F. Jean, C. Cachet, L. T. Yu. (1997) Structural changes induced by chemical reduction of various MnO2 species, Journal of Applied Electrochemistry, 27: 635-642

Fe isotope evidence for mantle metasomatism in the lithospheric

mantle of the Eastern China X.M. ZHAO1*, H.F. ZHANG1AND X.K. ZHU2

1State Key Laboratory of Lithopheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China (*correspondence: [email protected], [email protected])

2Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China ([email protected])

To further constrain the iron isotopic composition of the

terrestrial mantle and investigate the behavior of iron isotope during mantle processes, we have determined the Fe isotopic composition of Cenozoic alkali basalts and peridotite xenoliths entrained in Mesozoic and Cenozoic basalts from eastern China by high-resolution MC-ICP-MS.

Results from alkali basalts show a limited Fe isotopic variation, with (57Fe ranging from 0.169‰ to 0.241‰. By contrast, both the mantle peridotites and their mineral separates from the North China Craton exhibit an extremely large Fe isotopic variation with (57Fe ranging from -1.002‰ to 0.258‰. This may reflect heterogeneous Fe isotopic compositions of the lithospheric mantle beneath the North China Craton. An average (57Fe (-0.028‰) calculated from all the mantle xenoliths in this study is obviously lower than the average value (0.198‰) of (57Fe for the Cenozoic alkaline basalts, similar to the previous observation that the basalts generally have heavier Fe isotopes than the mantle peridotites. In individual minerals, (57Fe of the olivines (-0.968 to 0.154‰) are systematically lighter than those of the coexisting pyroxenes (-0.718 to 0.169‰ for orthopyroxene and -0.642 to 0.304‰ for clinopyroxene, respectively). The phlogopite of apparently metasomatic origin has the heaviest iron isotopic composition amongst the mineral phases with (57Fe of 0.302 to 0.376‰. This Fe isotope disequilibrium between mineral phases and an extremely Fe isotope variation in these peridotites, in particularly for the wehrlites, were probably produced by the multistage melt-peridotite interactions, consistent with the petrological observation that some of the xenoliths analyzed such as wehrlites were the products of highly mantle metasomatism. Analogous positive correlations between (57Fe and other major and trace element indicators of metasomatism such as CaO and Rb further support the above suggestion.

These characters suggest that mantle metasomatism or melt-rock interaction can significantly modify Fe isotopes and play an important role in producing Fe isotopic heterogeneity of the lithosphere mantle.



2266

The effect of post-depositional fluids on Edicaran sedimentary carbonate

in South China YAN-YAN ZHAO* AND YONG-FEI ZHENG

School of Earth and space science, University of Science and technology of China, Hefei 230026, China (*correspondence: [email protected])

The post-depositional fluid flow in carbonates can alter the

primary geochemical signatures, leaving detectable signatures in the chemical sedimentary rocks. The geochemistry of veins or cements is essential to understanding the origin of post-depositional fluids. We carried out a detailed study that combines the conventional and laser methods of analyzing C-O isotopes and trace elements in Ediacaran carbonates of the Lantian formation at Piyuancun in South China. Different components of carbonates (calcite, dolomite and bulk carbonate) and different microfacies (wallrock and veins) were analyzed, respectively. The results are used to examine the primary geochemical signatures and geometry of post-depositional fluid flow. All carbonate components show (18O values of -18.48 to -12.78‰ and (13C values of -10.28 to -7.02‰ (both relative to PDB). The (18O values for all carbonate components are almost consistent, but dolomites have slightly higher (13C values than the calcite and bulk carbonate. The different components of carbonate have preserved their primary geochemical signatures based on isotope fractionations between calcite and dolomite. Thus, the dolomite would probably precipitate from the same water as the calcite. The veins can be divided into Groups A and B based on their (18O values of –17.2 to –11.3‰ and –23.7 to –18.1‰, respectively. Nevertheless, (13C values for all the veins and wallrock fall in the same range from –10.6 to –8.9‰. Group A veins have different (18O values and REE patterns from the corresponding wallrock, indicating that these veins and wallrock are not in equilibrium with each other and vein-forming fluids are of external origin. There is no correlation between (18O and (13C values for these veins and wallrock, suggesting that the wallrock was not altered by diagenesis. The low (18O values for these veins indicate that the vein-forming fluids were derived from continental deglacial meltwater subsequent to the Gaskiers iceage. Group B veins have similar (18O and (13C values to the corresponding wallrock. Their REE patterns are almost similar to those of the wallrock except a small difference in HREE. These features indicate that vein-forming fluids are similar to those of wallrock and thus of internal origin. The precipitation water for these veins and wallrock is probably related to seawater. Therefore, the post-depositional effects of diagenetic fluids are recorded by the vein-wallrock compositions.

Zinc isotopes in the Southern Ocean – A tracer of biogeochemical cycling?

Y. ZHAO1*, D. VANCE1 AND W. ABOUCHAMI2 1Bristol Isotope Group, School of Earth Sciences, University

of Bristol, Wills Memorial Building, Bristol BS8 1RJ, UK (*correspondence: [email protected])

2Max Planck Institute for Chemistry, P.O. Box 3060, 55020 Mainz, Germany ([email protected])

Zinc (Zn) is an important trace metal micronutrient in the

marine realm. Dissolved Zn concentrations show extreme variation in the ocean, probably due to both biological uptake and regeneration as well as abiotic processes. Zn isotopes may be useful in tracking this biogeochemical cycling. Here we report the first Zn isotopic data for the Southern Ocean, using a newly developed analytical approach. Our samples derive from the IPY/Geotraces ANT-XXIV/III cruise (Atlantic sector, Southern Ocean), whose main objective was to study the biogeochemistry of trace metals in the Fe-limited Southern Ocean. Our study is focused on the distribution and isotopes of dissolved Zn across the major frontal systems along the Greenwich Zero Meridian, including 3 depth profiles and 11 samples across a surface transect.

Much higher Zn concentrations were found at the surface of the southern ACC and the Weddell Gyre (WG) relative to that of Sub-Antarctic Front (SAF). The WG depth profile showed a local Zn (and Si) concentration maximum in the upper 200m. Zn and Si concentrations show tight linear correlations at any one site. Surface waters, however, showed a monotonically poleward decreasing trend of Zn/Si. Heavy (66Zn was found in the surface waters of the southern ACC and WG. Anomalously low (66Zn at around 50m depth has been noted in two of the three depth profiles in this study. In surface waters (66Zn is fairly constant except for a pronounced fall in at the Polar Front Zone (PFZ) co-incident with a drop in concentration.

These Zn isotope variations are consistent with biological uptake of light isotopes in the photic zone. Isotopically light Zn at around 50m is consistent with findings of similarly light Zn in the shallow sub-surface at other locations, and may highlight the role of shallow recycling of cellular Zn as an important process in the oceanic Zn cycle.



2267

Gas accumulation rules of volcanic rocks of deep formations in Songliao

Basin, Northeast China Z.H. ZHAO1*, G.H. JIAO1, P. SUN1, X.S. JUAN1,

J.X. XIAO2, X.H. JIANG 1 AND H.Q. BAI1 1Langfang Branch of Petroleum Exploration and Development

Research Institute, Petrochina, Langfang 065007 (*correspondence: [email protected])

2School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083 ([email protected])

Deep formations of Songliao basin are defined as between

basement and second member of Quantou formation in lower Cretaceous, including later Jurassic Huoshiling formation, early Cretaceous Shahezi formation, Yincheng formation, Denglouku formation and 1-2 members of Quantou formation. Songliao basin was made up of groups separated fault depressions in Shahezi age of early Cretaceous.

The volcanic rocks in Yincheng formation and Huoshiling formation, are the major reservoirs for deep gas. By the means of systematically analyzing the form conditions, accumulation patterns and exploration prospects of the deep gas, it is suggested that the deep volcanic gas reservoirs are characterized by the short distant migration for gas, locating around main trough and along the fault. The existence of deep volcanic gas pool is controlled by source rocks. High quality volcanic reservoirs controlled by lithology, by lithofacies, by fracture and diagenesis, take controls of the extent of the gas pool. The locations and high production of volcanic gas pools are controlled by faults. Generally, the source rocks, reservoirs and faults all make the contribution to the formation of volcanic gas pool. From the point of view of the forming conditions of deep volcanic gas pools, it is suggested that the beneficial tectonic zone with both development of the source rock and the volcanic reservoir are the favorable exploration zone.

A 4 million year record of paleo-erosion rates from the Qilian Shan,

China ZHIJUN ZHAO1 AND DARRYL E. GRANGER2*

1College of Geographical Sciences, Nanjing Normal University, Nanjing 210046, China ([email protected])

2Dept. of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana, 47907 USA (*correspondence: [email protected])

It has been proposed that mountain erosion rates increased

rapidly at 2-4 Ma due to climate change, based partly on sediment accumulation rates in central Asia [1]. This idea has been recently supported by paleo-erosion rates from the Tien Shan determined from 10Be in basin sediments, which suggest that erosion rates in these mountains doubled near 2 Ma [2]. To test the hypothesis that this represents a regional climatic signal, we constructed a 4 Ma record of paleo-erosion rates from the Qilian Shan, at the northeastern topographic boundary of the Tibetan Plateau.

We analyzed 22 samples for 10Be to determine paleo-erosion rates from the Laojunmiao (LJM) section exposed in an anticline near the city of Yumen. A subset were also analyzed for 26Al. The LJM section has previously been dated by magnetostratigraphy [3]. After accounting for changes in sedimentation rates, we observe no clear change in source area erosion rates from 4 Ma to 1.2 Ma; however, erosion rates increase by an order of magnitude during a discrete interval extending from 1.2-0.8 Ma, subsequently returning to near the background rate. The interval of rapid erosion is found immediately above a regional unconformity.

Our erosion rate record indicates that climate change across the Plio-Pleistocene boundary did not strongly influence erosion in the sparsely glaciated Qilian Shan. Although we cannot exclude that climate change near the Middle Pleistocene transition may have driven the rapid erosion we observe, we prefer the explanation that rapid erosion is a transient response to a tectonic uplift and fault activity near the range front, as evidenced by the regional unconformity. Rapid erosion and sedimentation rates observed elsewhere, such as the Tien Shan [2], may therefore be a local response to either glaciation or uplift, rather than indicators of a global response to climate variability.

[1] Zhang, P., and Molnar, P. (2001) Nature 410, 891-896. [2] Charreau et al. (2011) Earth Plan. Sci. Lett. 304, 85-92. [3] Fang, X.M. et al. (2005) Science in China D 48, 1040-1051.



2268

Origin of postcollisional mafic-ultramafic rocks in the Dabie orogen:

Implications for recycling of the deeply subducted continental crust

Z.-F. ZHAO* AND Y.-F. ZHENG School of Earth and Space Sciences, University of Science

and Technology of China, Hefei 230026, China ([email protected])

Recycling of the deeply subducted continental crust has

bearing on crust-mantle interaction during its subduction to mantle depths, which is known to cause ultrahigh-pressure (UHP) metamorphism in the stability fields of coesite and diamond. UHP metamorphic slices are generally considered as an exhumed product from the mantle depths, which provides a reference to the recycled crust. However, it is critical to find petrological and geochemical records that bear the recycling of deeply subducted continental crust and the consequent crust#mantle interaction in continental subduction zones.

The Dabie orogen was built by the Triassic continental collision between the South and North China Blocks, with subduction of the continental crust to mantle depths. It is intriguing whether the recycled continental crust is recorded in postcollisional mafic igneous rocks. Whole-rock major–trace element and Sr-Nd isotopes and zircon Hf isotopes were determined for postcollisional mafic-ultramafic rocks of Early Cretaceous age in the orogen. The results show arc-like patterns of trace element distribution, high initial 87Sr/86Sr ratios of 0.7065 to 0.7077 and very negative !Nd(t) values of #19.9 to #15.3 for whole-rock. Zircon Hf isotope analyses gave negative !Hf(t) values of #26.3±0.6 to #7.0±0.5 with two-stage Hf model ages of 1.62 to 2.83 Ga. These trace element and radiogenic isotope compositions are similar to those in UHP rocks, suggesting that the mafic-ultramafic rocks were derived from an enriched mantle source with incorporation of crustal component. It may be generated by interaction between the subcontinental lithospheric mantle and the felsic melt derived from the subducting continental crust. In other words, there would be melt-peridotite reactions during the continental deep subduction, forming the orogenic lithospheric mantle composed of peridotite, pyroxenite and hornblendite. Partial melting of the orogenic lithospheric mantle gave rise to the postcollisional mafic-ultramafic rocks, recording the recycling of continental crust in the continental subduction zone.

The evolution of the Tarim Craton in Archean and Proterozoic: Zircon

U–Pb and Hf isotopic evidence from the Kuruktag area, NW China

B.H. ZHENG1*, W.B. ZHU1, L.S. SHU1, H.L. WU1 AND J.W.HE1,

1State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, P.R. China (*correspondence: [email protected])

The Tarim Craton is one of the three major cratons in

China. Compared with Yangtze Craton and North China Craton, only limited age data of the basement rocks in Tarim have been published. Presently, there is still great uncertainty about the formation and crustal growth of the Tarim Craton. Kuluktag Uplift is located in the northeast of Tarim Basin. Basement rocks crop out widely in Kuluktag and are unconformably overlain by Sinian strata. Three Proterozoic detrital zircon samples (F3, F7, F10) and one Neoproterozoic Granite sample (F4) have been collected and LA-ICPMS U-Pb zircon dating as well as Hf isotopic analysis have been carried out. The results show that the granite sample was formed in ca. 832Ma, probably related to the break of Rodinia Supercontinent. The three detrital zircon samples reveal identical age spectra. Two events are recorded: 1) Ca. 2000Ma metamorphism, which caused the reworking of old crustal materials; 2) Tectonic activity between ca. 2350Ma to ca. 2750Ma, which involved both juvenile and old crustal materials. Two stage model ages of all four samples vary from ca. 3.8Ga to ca.2.5Ga, indicating the crustal growth of Tarim Craton lasted from the Paleoarchean to the earliest Palaeoproterozoic, which is comparable with Yangtze and North China Cratons. Figure 1: Diagram of -Hf(t) values vs. 207Pb/206Pb ages for zircons of samples from Kuruktag, NE Tarim in this study.



2269

Influence of major hydraulic projects on saltwater intrusion in the Yangtze

River estuary ZHENG MAOHUI1*, LIU SHUGUANG 1, 2 AND JIANG SIMIN 2 1Shanghai Institute of Disaster Prevention and Relief, Tongji

University, Shanghai 200092, China ( correspondence: [email protected])

2Department of Hydraulic Engineering, Tongji University, Shanghai 200092, China ([email protected])

To understand the influence of the Three Gorges Project

(TGP) and South-to-North Water Diversion Project (SNWDP) on saltwater intrusion in Yangtze River estuary, a depth-averaged 2D numerical model, loosely coupled with geographic information system (GIS), is developed to compute and analyze the hydrodynamics and salinity field about the estuary water. The model is validated through observed data. Then combined simulations under multiple hydrologic conditions considering different regulation schemes of the hydraulic projects as well as varied tidal ranges in the outer sea are carried out. Furthermore, the numerical output is rendered dynamically in GIS environment, and the distribution behaviours and variation trend of salinity are analyzed. The result shows that the salinity of north branch is higher than that of south branch (fig.1), and the change of salnity is mostly affected by river discharge. The maximum water diversion scheme of 1000 m3/s of SNWDP will aggravate saltwater intrusion, while the increased discharge of TGP in dry season will restrain saltwater intrusion in the estuary.

Figure 1: simulated salinity field of Yangtze River estuary in dry season

This study is supported by Key Laboratory of Yangtze River Water Environment, Ministry of Education (YRWEF08003) and partly supported by Nation Natural Science Foundation of China"41001217#.

Methodology and foreground of metalloprotein

PEI-XI ZHENG1 AND YAN ZHOU2

1College of EarthSciences, Jilin University, Changchun China 130061

2Center of Test Science and Experiment Jilin University Changchun China 130026

Metalloproteins is proposed as a new omics to follow

genomics, proteomics and metabolomics. Researchs on metalloproteins not only answer the question of the chemical compose of metals and proteins, but also pioneer a new way for probing into the mechanisms of life substances such as metalloproteins in life activity. In Metalloproteins, metalloenzymes and othe metalcontaining biomolecules are defined as “Metallomes”. Syntheses and metabolic functions of genes and proteins cannot be performed without the aid of various metal ions and metalloproteins. The main research targets of metallomics are to identify the metallomes and elucidate their biological or physiological functions in biosystem. Chemical speciation analysis is a key technology in metalloproteins study.

Some new trends in the study of metalloproteins and metalloenzymes have been described from aspects of metal ions-related diseases (especially the neurodegenerative diseases), the roles of metalions in folding, aggregation and assembly of proteins, the design and reconstruction of metallochaperons and metalloproteins, interactions between metalloproteins and DNA.

Now, metallomics is focused on analytical techniques and methods, particularly the so-called hyphenated techniques which combine a high-resolution separation technique (gel electrophoresis/laser ablation, chromatography or capillary electrophoresis) with a highly sensitive detection method as elemental (inductively coupled plasma, ICP) or molecular (electron spray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI)) mass spectrometry, or nuclear X-ray fluorescence/absorption spectrometry. The applications of these advanced analytical methods in the identification of metallo-/phosphor-/seleno-proteins, probing of relationships between structure and function of metalloproteins, and study of clinically used metallodrugs will be selectively outlined, along with their advantages and limitations.



2270

Nd-isotope evolution in the Cretaceous Gault and chalk seas

(Albian–Maastrichtian) XINYUAN ZHENG1*, HUGH C. JENKYNS1,

GIDEON M. HENDERSON1, DAVID WARD2 AND ANDREW S. GALE3

1Department of Earth Sciences, University of Oxford, South Parks Road, OX1 3AN, UK (*correspondence: [email protected])

2Crofton Court, 81 Crofton Lane, Orpington, Kent, BR5 1HB, UK

3School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Road, PO1 3QL, UK

Nd isotopes recovered from Cretaceous fossil fish teeth

can promote understanding of ocean circulation during this Period [e.g. 1-2], but this goal is limited by the sparsity of available data. This study presents a new time-series of Nd isotopes obtained from fish teeth collected mainly from the Gault Clay and English Chalk in the UK, spanning ~ 110 – ~ 67 Ma.

!Nd values range from ~ -8 to ~ -12.5 in the mid- to Late Cretaceous. The data show a clear decreasing trend from ~ -9 to ~ -10.5 from the early Albian to late Albian. Data from the Cenomanian–Turonian range from ~ -8.5 to ~ -11, and then reach the lowest values of ~ -12.5 in the Santonian and early Campanian, and finally recover to ~ -9 in the Maastrichtian.

Comparison with weathering proxies allows this effect to be deconvolved from circulation changes. For example, the parallel increase in the Nd-isotope and Sr-isotope ratios [3] from the early Campanian to Maastrichtian supports the idea that this increasing trend in the Nd-isotope record reflects the reorganization of ocean circulation; otherwise the enhanced global continental weathering, as indicated by Sr isotopes, should have driven the Nd isotopes in the opposite direction.

Interestingly, the low Nd-isotope values found in the Santonian and early Campanian in our record happened coincidently with major changes in Nd isotopes in the South Atlantic [2]. This coincidence in timing might suggest that changes of ocean circulation patterns in the NW European area are caused not only by local processes, but are also related to large-scale reorganization of ocean circulation induced by global tectonic movements. [1] Pucéat et al. (2005), EPSL 236(3-4), 705-720. [2] Robinson et al. (2010), Geology 38(10), 871-874. [3] McArthur et al. (2001), J. Geol. 109, 155-170.

Growth of zircon and rutile during continental subduction-zone

metamorphism: A case study of UHP eclogite in the Dabie orogen

Y.-F. ZHENG*, X.-Y. GAO, R.-X. CHEN AND T.S. GAO CAS Key Laboratory of Crust-Mantle Materials and

Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China (*correspondence: [email protected])

Both time and temperature of zircon formation can be

directly dated by the U-Pb chronometer and the Ti-in-zircon thermometer, respectively. However, difficulty is encountered for rutile due to the effects of high common Pb on the U-Pb dating and pressure variable on the Zr-in-rutle thermometer. This is particularly so for Dabie-Sulu UHP eclogites of China, which gave consistently lower Zr-in-rutile temperatures than known estimates. Nevertheless, a combined study of zircon and rutile enables tight constraints on P-T-t path of continental subduction-zone UHP eclogites. We measured the Zr content of rutile by both EMP and LA-ICPMS for low-T/UHP eclogit in the Dabie orogen. Zircon U-Pb isotopes and trace elements were analyzed by LA-ICPMS, yielding U-Pb ages of 242±4 Ma and Ti-in zircon temperatures of 713±17°C for Group I zircons, and U-Pb ages of 226±2 Ma and Ti-in-zircon temperatures of 681±12°C for Group II zircons. The Zr-in-rutile temperatures were calculated and interpreted based on possible P-T-t paths for the eclogite. Most inclusion and matrix rutiles yield Zr-in-rutile temperatures of 574 to 658°C at 2.5 GPa and 593 to 680°C at 3.3 GPa. This suggests that these rutiles would grow below and at the peak pressure during continental subduction. A few inclusion rutiles give high temperatures of 719-757°C at 2.0 GPa, consistent with their growth at the peak temperature during HP eclogite-facies recrystallization in response to the “hot” exhumation. Thus, the Zr-in-rutile thermometry is capable of providing metamorphic temperatures for rutile growth provided if petrological and geochronological constraints are available on their P-T-t paths. Although the secondary Zr loss of rutile could be enhanced by fluid-assisted recrystallization, the slow rate of Zr diffusion in rutile makes it impossible as an efficient mechanism for a considerable change in rutile Zr content at the eclogite-facie conditions. Therefore, the remarkable differences in Zr content and thus in temperature between the different occurrences of rutile suggest that many rutiles did not grow at peak P-T conditions. In other words, the Zr-in-rutile temperatures can be used to indicate rutile growth in the different stages of continental subduction-zone metamorphism.



2271

Formation of anhydrous amorphous calcium carbonate and implication

for biomineralization GEN-TAO ZHOU1*, YE-BIN GUAN1 AND QI-ZHI YAO2

1School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, P. R. China (*correspondence: [email protected])

2School of Chemstry and Materials, University of Science and Technology of China, Hefei 230026, P. R. China

Amorphous calcium carbonate (ACC) has been found as a

transiently stabilized precursor in biomineralization in a variety of organisms, and is thought to play a role in the biological control over the subsequent crystallization. However, transient and stable phases of ACC differ in their structure and composition. Stable ACC contains structural water at a ratio of 1:1, while transient ACC is an anhydrous phase, and usually is in a syncytic membrane-delineated environment. Despite the fact that little is known about the formation and stabilization of biogenic ACC, it has been shown that certain macromolecules and/or other additives, such as magnesium and phosphate, may be determinant factors in the processes. To the best of our knowledge, nevertheless, no anhydrous ACC has been successfully synthesize in vitro even in the presence of the macrobiomolecules extracted from biogenic anhydrous ACC. Herein, a biomimetic mineralization process was applied to synthesize CaCO3 by use of phosphatidylcholine (PC) as a model mineralization modifier. The present results show that PC is capable of inducing formation of the unusual anhydrous ACC, and the anhydrous ACC can transform into calcite with the follow-up mineralization. It implies that membrane lipid can exert significant effect on the formation and transient stabilization of anhydrous ACC bound by the membrane. Moreover, an intriguing phenomenon is that there is a large amount of ACC exclusively overlying on the surface of the secondary calcite during the subsequent mineralization. Therefore, the secondary calcite may function as an “organic-inorganic composition substrate”, facilitating ACC deposition to its surface. This finding may indicate that even though the biogenic crystalline CaCO3 and ACC intimately contact each other in organism, it does not means the exclusive origin of the crystalline polymorph from ACC. In contrast, the crystalline polymorph may facilitate the formation of ACC. Our results may provide a new insight into biomineralization mechanism of CaCO3.

Geochemical character and tectonic implication of the Fuling composite pluton in Southern Anhui Province ZHOU JIE1,2, JIANG YAOHUI2 AND XING GUANGFU1

1Nanjing Institute of Geology and Mineral Resource, Nanjing 210016, China

2!State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China

The Fuling composite granite located in the South of

Anhui Province, is one of a tungsten-bearing granites in the east of Jiangnan orogenic belt. It crops out over an area of approximatedly 145km2. The complex intruded into Precambrian to Cambrian siliceous shale, siliceous mudstone and limestones, with NE-SW direction. The complex is composed of 4 rock unites, the earliest units consists of spotted feldspar granite, the earlier units of feldspar granite, the later porphyraceous feldspar granite, and the last fine grain feldspar granite, named Jingkanling body, Yulongchuan body, Xiaochangxi body, and Fanzhengjian body respectively. Petrochemical data show that these granites are metaluminous to peraluminous and have high-silica (SiO2>71%), total alkalis (Na2O+K2O$5.72 to 10.75wt.%), rare elements (total REE$99.14 to 533.86ppm) and Fe*(FeOt/(FeOt+MgO)$0.83 to 0.97). In trace elements, they are enriched in Rb, Th, U, Zr, Hf and depleted in Ba, Sr, and Ti. Compared to the Xiaochangxi pluton and Fanzhengjian pluton, the Jingkanling pluton and Yulongchuan plutons are more depleted in Nb,Ta. (La/Yb)N ratios of the late granite unit lower than the early, average value is 11.93, 7.84, 5.15, 6.92 respectively. New LA-ICPMS zircon U-Pb dating suggests that the crystallization age of the Yulongchuan body is 127Ma, belonging to late Yanshan periods. Isotopically, Fangzhengjian granite has negative -Nd(t)(-5.5~ -5.91), and T2DM values is between 1.35Ga to 1.4Ga. Petrographic, elemental and Sr-Nd isotopic characteristics indicate that the pluton belongs to an A2 type granite. Fuling granite intrusion is enlongated in a NE-SW orientation, which is consistant with the distribution of regional Late Yanshanian granites in the coastal area and is parallel to the NE trending Jixi fault. A-type granites generally form in extensional tectonic environments regardless of the origin of the magma source. Combined with other A-type granites in the NE Yangtze Block, it can be concluded that Fuling A-type granite was derived by partial melting of metasediments in the back-arc extension environment, trigged by the subduction of the Pacific plate.



2272

The comparsion of Mo isotope and paleo-oxygenation parameters in black shales from Upper Yangtze

marine sediments LIAN ZHOU, JIE SU, HU ZHAOCHU, HUANG JUNHUA,

ZHAO LAISHI State Key Laboratory of Geological Processes and Mineral

Resources, China University of Geosciences, Wuhan 430074, China

This paper investigates the high-solution of Mo isotopes

and uses trace-element analyses for fresh and representative black shales and siliceous shales collected from the transition between the Late Ordovician and the Early Silurian at the Wangjiawan section in Yichang and the Late Permian Dalong Formation in the Shangsi Section of Sichuan. The applicability of different geochemical parameters used as paleo-oxygenation indices are also compared. The preliminary results show that V/(V+ Ni), Uauth(auth U), V/Cr, Ceanom and U/Th have a scattered variation range, but most samples plot within the suboxic-anoxic fields. The suboxic-anoxic environment was dominant during the deposition and formation of the two anoxic facies. These redox indicators show little correspondence to the !98Mo values. The U/Mo ratio can be used as a potential proxy for the paleo-redox conditions due to the possibility that Mo is enriched relative to U at different redox gradients during early diagenesis. This evidence is more significant for the euxinicity condition and corresponds to positive !98Mo (>1.5‰) values with low U/Mo ratios. This evidence is likely related to the depositional conditions near the boundary between anoxic and euxinic environments, which are characterised by low bioturbation or water circulation. Other samples reveal a wide scatter of U/Mo ratios and !98Mo <1.5‰. These results are likely due to punctuated improvements in oxygenation with intense bioturbation or water circulation, which led to the redistribution of trace element.

This study has been supported financially by the National Natural Science Foundation of China (Nos. 41073007, 40821061, 90714010) and MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources and the Fundamental Research Funds for the Central Universities.

Study on glaciochemical and microparticle characteristics of three

snow pits in East Antarctica L.Y. ZHOU1*, Y.SH. LI2 AND S. JIANG2

1The key Laboratory of Coast & Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, 210093, China (*correspondence:[email protected])

2Polar Research Institute of China, 200129, China

In the Antarctic summer of 1998/1999, the third Chinese Trans-Antarctic inland glaciological scientific expedition successfully entered Dome A area and extended its research to the site of 79°16'S, 77°00'E, 3,931 m.a.s.l, 1,128km away from Zhongshan station. We present the glaciochemical and microparticle characteristics of three snow pits which were drilled at the 1128km(DAP1), 1000km(DAP2) and 800km(DAP3) site along the investigation route.

From the dating results of the three snow pits, we come to a conclusion that the DAP1 snow pit, which was 3.3m deep, represented the whole sediments from 1987 to 1998; while DAP2 snow pit which was 2.1m deep represented a 7-year long sediment from 1992 to 1998 and DAP3 snow pit of 2.4m deep represented a 8-year long sediment from 1991 to 1998. Comparing the different radius part of the microparticles in the snow pits, we find that they are well linear related which implicates that the main source of the microparticles is the remote continents and the local factors have weak influence on them. The concentration of microparticles also coincides with the accumulation rate, that is, high microparticle concentrations agree with high accumulation.

From the glaciochemical analysis results, we find that the concentration of calcium in the snow pits changes smoothly, which implicates that it is from the deposit of the remote continents and the local influence is not evident. But for DAP3 snow pit, the calcium concentration slightly fluctuates for the unknown local causes. The sulfate in the snow pit exhibits a noticable wave crest for the eruption of Pinatudo volcano in 1991, which verifies the preciseness of the snow pit dating. What’s more, the precipitation calculated by the snow pits well agree with the trend of global warming. The snow pit contains instructive information on the sedimentary characteristics and the climate change.

This study was granted by the National Natural Sciences Foundation of China (No.40703019, 40773074, 40906098).



2273

Instantaneous release nuclide diffusion and migration simulation in

fracture medium N.Q. ZHOU1 S. ZHAO1 AND Y.Q. TANG2

1 Dept. of Hydraulic Engineering, Tongji University, Shanghai, 200092 China ([email protected])

2 Nuclear Industry of China Geotechnical Engineering Co. Ltd, Shijiazhuang, 050021 China

Most nuclear power plants are built on the bedrock

foundations in China. The safety of nuclear power plant is an important matter. A magnitude 9.0 earthquake hit Japan’s northeastern Honshu island on March 11, 2011. Fukushima nuclear power plant was disabled, releasing numerous uranium and radiocative 131I dangerous contaminant into the environment. 131I and 137Ce have been detected in China.

The purpose of this work is to introduce nuclude diffusion and migration in fracture medium. Qian et al once studied contaminants migration in fracture medium [1,2]. Nuclide has its characteristics, such as attenuation, absorption, dilution, and so on. The experiment can be only carried out in laboratory. 131I is used to simulate nuclide migration, its radiocative half-life is 8.3 days. According to the geological conditions of Zhejiang Sanmen Nuclear Plant, China, the lithology is tuff sandstone and andesite basalt on Unit 1 and Unit 2 reactor blocks. The fracture distributions are investigated on the field. Based on the statistical results, random fractures are generated using Monte Carlo method [3]. Li et al studied 85Sr, 134Se and 60Co absorption equilibrium resperctively [4]. Iodine absorption coefficient is measured, then the diffusion and migration equation is established about include instantaneous release.

The research results show that: Instantaneous release of radionuclides in fracture medium is mainly diffusion and adsorption at the preliminary stage. When the adsorption reaches saturation, diffusion and migration of radionuclides play major roles. With the increase of radionuclide migration distance and the lapse of time, the decay will become more obvious and the impact will gradually disappear beyond a certain distance.

This study was supported by the National Science Fund of China (41072208) and Kwang-Hua Fund for College of Civil Engineering, Tongji University. [1] Qian et al.(2007) J. Hydrol. 339: 206-219. [2] Qian et al. (2011) Int. J. Rock Mech. Min. Sci. 48:132-140. [3] Zhou et al. (2004) Int. J. Rock Mech. Min. Sci. 41:402. [4] Li et al. (2003) Radiation protection bulletin. 23(2): 27-31(in Chinese).

Carbon isotope of residual gas in the source and reservoir rocks in the

Northeastern Sichuan Basin S.X. ZHOU1, J. LI 1,2, B.Z. WANG 1,2, S.P. LIU1,2 AND

H.K. ZHANG1,2 1Key Laboratory of Petroleum Resources Research�Institute

of Geology and Geophysics, CAS, Lanzhou, 730000 (*correspondence:[email protected])

2Graduate University of CAS, Beijing, 1000049

There are many large gas fields in the northeastern part of Sichuan Basin, but their origin and source are not clear due to limited information obtained from chemical compositions of accumulated gas. In this study, carbon isotopic signatures of residual hydrocarbon gas and CO2 in different source rocks, reservoir rocks and solid bitumens have been measured and gas-source correlation have been done in this area.

Our results show that various source rocks in different geological period have different isotopic composition of residual gas. Methane in the Precambrian and Cambrian mudstones range from -34.1‰ to -39.4‰ with ethane -27.1‰ to -37.3‰, while other source rocks isotopic signatures are (13CC1=-30.2%-32.6‰ for Ordovician , (13CC1=-30.9% -31.8‰ for Silurian, (13CC1=-35.5‰ for Permian and (13CC1= -34.5‰ for Triassic, and ethane isotopic values in these source rocks lighter than -28‰ indicate that gases in various marine source rocks are derived from sapropelic organic matter except Permian source rock.

Residual gas in Precambrian solid bitumens are -30.6% -34.9‰ for methane and -30.1‰ for ethane, while gas in the Lower Triassic and Upper Permian reservoir formations containing solid bitumens display methane (13C values between -32.5‰ and -36.1‰ lighter than methane values of gas in the reservoirs, ethane (13C values between -20.7‰ and -26‰ heaver than ethane values in natural gas, and (13C values of CO2 between -8.6‰ and -13.6‰. It is conclusion that some natural gases maybe relate to Silurian source rocks, and thermochemical sulfate reduction (TSR) is not obvious in reservoirs.

This work was supported by partly by the Key Project of Chinese Academy of Science (grant KZCX2-YW- Q05-03-05) , the National Special Projects of Science and Technology (2008ZX05018-001-05) and the Chinese National Major Fundamental Research Developing Project (2011CB201103).



2274

Analysis of Poyang Lake water body dissolved inorganic carbon isotopic

tracing and its carbon source contribution

ZHOU WEN-BIN1,2, HU CHUN-HUA1,2*, JIANG JIAN-HUA1,2, GUO CHUN-JING 1,2 AND LOU QIAN 1,2

1School of Environmental and Chemical Engineering, Nanchang University, Nanchang, 330031, China (*correspondence: [email protected])

2Key Laboratory of Lake Poyang Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330029, China In recent decades, intensifying global climate changes

caused by the greenhouse effect have led to recognition of the importance of the global carbon cycle. The key to the research on this phenomenon is the identification of the source of CO2, its variations, and its response to human activities. Lake is sensitively responding to regional and global climate changes, being a rather considerable carbon source [1-2]. During the high- and low-water periods of 2009 and 2010, water samples from the Poyang Lake region and the estuary of five rivers were collected. We analyzed the correlation of the temporal and spatial distribution of dissolved inorganic carbon (DIC). We also examined the carbon flux in the lake and the contribution of its three major carbon sources to the flux. Results show that the DIC content in the high-water period is higher than that during the low-water period. In contrast, the value of (13C DIC is positive in the low-water period and negative in the high-water period; the monthly DIC carbon flux in Poyang Lake is 2.822t–268.428t, and its mean is 135.836t. The largest contributor (73.07% contribution rate) to the carbon flux in Poyang Lake is the CO2 water vapor exchange. The second largest contribution (15.53% contribution rate) is the river input. Weathering of rocks with dissolved carbonate is the major mechanism controlling the DIC source and the (13C DIC composition. The changes in seasonal rainfall runoff are the main factors. [1] Yu H & Li N. (2008) Environmental Science and Technology 21(2), 1-5. (in Chinese). [2] Kling G.W et al. (l99l) Science 251, 298-301.

Predicting CO2 EOR and geological sequestration processes with artificial

noble gas tracers Z. ZHOU1*, M.J. BICKLE2, A. GALY2, H.J. CHAPMAN2, N.

KAMPMAN2, B. DUBACQ2, M. WIGLEY2, O. WARR1, T. SIRIKITPUTTISAK1, P. HANNAH3 AND

C.J. BALLENTINE1 1University of Manchester, M13 9PL, UK

(*correspondence: [email protected]) 2Department of Earth Sciences, University of Cambridge, UK 3Full-Spectrum Monitoring, LLC, USA

Naturally occurring noble gas isotopes provide one of the best tools to study gas-fluid-mineral interaction [1]. By injecting and studying artificial noble gas tracers in CO2 EOR or potential sequestration reservoirs, hydrological modelling can be established to quantify the multi-phase flow of fluids and determine the flow path and flow rate of fluids. This will enable further understanding of gas-aqueous fluid-mineral reactions and kinetics.

We present preliminary results from an artificial noble gas tracer study in a commercial CO2 EOR reservoir located in Wyoming, USA. We constructed a continuous tracer injection system which consisted of two HPLC pumps, three high pressure cylinders and a wireless remote system monitoring temperature, pressure and weight in real time. Over 9 days, we injected 2 STP litres of 3He and 129X each directly into the EOR CO2 injection stream. Based on the analysis of background 3He/4He and 129Xe/132Xe (0.07Ra and 0.98 respectively), our predicted spiked 3He/4He and 129Xe/132Xe ratios for the mass of injected CO2 are 49.54Ra and 11.64 respectively. The wellhead injector fluid and 4 production wells surrounding the injector were sampled from September 2010 to February 2011.

Preliminary results show that the highest 3He/4He and 129Xe/132Xe ratios in the injected CO2 stream reached 49.0Ra and 23.94 respectively and establish the tracer input function. 3He tracer was detected in all producing fluid samples from 4 monitoring wells. Spike breakthrough is consistent with the reservoir geology with the wells updip of the injector seeing tracer arrival earlier than those located downdip of the injector. Spike breakthrough in wells updip of the injector correlated with the well temperature which was an indication of the CO2 breakthrough, but in the wells downdip of the injector spike came through, most probably, dissolved in the water phase. 3He/4He ratio is at a much lower level than the injected ratio and reflect the magnitude of reservoir fluid and CO2 interaction.

[1] Gilfillan et al. (2009) Nature 458, 614-618.



2275

Re-Os geochronology of black shales from the Neoproterozoic Doushantuo

Formation, Yangtze platform, South China

BI ZHU1,2, HARRY BECKER2, SHAO-YONG JIANG1*, DAO-HUI PI1 AND MARIO FISCHER-GÖDDE2

1State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Jiangsu, 210093, P. R. China (*correspondence: [email protected])

2Freie Universität Berlin,Institut für Geologische Wissenschaften, Malteserstr. 74-100, D-12249 Berlin, Germany

Re-Os geochronometer is a useful tool in dating organic-

rich sedimentary rocks like black shale. Precise Re-Os chronology also provides constraints on temporal variation in Os isotopic composition of seawater, which reflects the relative dominance of radiogenic Os from weathering of upper continental crust and unradiogenic Os from alteration of oceanic crust or dissolution of cosmic dust.

In this study, we carried out Re-Os isotopic analysis of black shale samples from the fossil-bearing Miaohe member (Doushantuo Formation IV) at Jiulongwan section and from Doushantuo Formation II at Baiguoyuan section in Three Gorge area, South China. A Re-Os isochron age of 593±17 Ma (MSWD=1.0) with initial Os ratio of 0.88±0.13 for the basal Miaohe Member was obtained by using a CrO3-H2SO4 dissolution technique. This age falls in the range of precise U-Pb zircon ages of 551 Ma from the top and 635 Ma near the base of the Doushantuo Formation, respectively. The minimum age difference of ~25 Ma between the base of the Miaohe member and the 551 Ma old tuff on the top of the Miaohe member means very low sedimentation rates during black shale deposition (< 0.5 m/Ma). By the same technique, samples from Doushantuo Formation II at Baiguoyuan section only gave an imprecise age of 582±58 Ma (MSWD=1.8) with an initial Os of 0.54±0.05, which is comparable to the initial Os (0.62±0.03) for the 608 Ma Ediacaran Old Fort Point Formation in western Canada (Kendall et al. 2004). The increase in initial Os ratio from 0.54 for the lower Doushantuo Formation to 0.88 for the upper Doushantuo Formation is consistent with the secular increase of 87Sr/86Sr in the late Neoproterozoic ocean, and may result from enhanced continental weathering rates during the Ediacaran due to continental convergence of East and West Gondwana and subsequently the formation of a Transgondwana Supermountain.

Recent advances in kinetics of water-rock interaction and applications to

geological carbon sequestration CHEN ZHU1*, FAYE LIU1 AND PENG LU1,2

1Department of Geological Sciences, Indiana Univeristy, Bloomington, IN 474705, USA (*correspondence: [email protected])

2Now at the Carela Corporation

Recent laboratory experiments, field, and modelling studies on the kinetics of water-rock interactions have shown that the rates of dissolution and precipitation reactions are strongly inter-dependent or coupled [e.g., 1, 2, 3]. Numerous laboratory experiments have measured the dissolution rates at conditions far from equilibrium. However, reactions in batch and column experiments and in the field proceed in the near equilibrium region because of the low solubility of aluminosilicates. In the near equilibrium region, the Gibbs free energy term in the rate equations reduce the overall reaction rates. In the case of feldspar dissolution, slow clay precipitation effectively reduces feldspar dissolution rates by orders of magnitude. The implication is that a reaction network is operating, and a system geochemistry approach is necessary for studies of kinetics in geological systems.

When water-rock interaction theories are applied to geological carbon sequestration, the rate of fluid flow also plays a significant role on reaction rates. Recently, we conducted multi-phase reactive flow and transport modelling to simulate large scale CO2 injection (a million tons per year for 100 years) into Mt. Simon sandstone, a major deep saline reservoir in the Midwest of USA [4]. The results indicate that most of the injected CO2 remains within a radius of 2500 m lateral distribution. Four major trapping mechanisms and their spatial and temporal variations are evaluated in our simulations: hydrodynamic, solubility, residual, and mineral trapping. In our model, the replenishing water continues to dissolve CO2 long after the injection, which results in total dissolution of hydrodynamically trapped CO2 at the end of 10,000 years. In contrast, most previous models neglected the regional flow after injection and hence artificially limited the extent of geochemical reactions as if in a batch system. Consequently, a supercritical CO2 plume (hydrodynamic trapping) would persist after 10,000 years.

[1] Zhu ., AE Blum, DR Veblen (2004) WRI-11 (eds. R B Wanty and RRI Seal), v2., pp. 895-899. [2] Zhu, C, and Lu, P, GCA v73, p.3171-3120. [3] Zhu, C, Lu, P, Zheng, Z, Ganor, J, GCA v74, 3963-3983. [4] Liu, F, P Lu, C Zhu, Y Xiao (2011) The International Journal of Greenhouse Gas Control, v.52(2), 294-307.



2276

Kinetic study of brucite carbonation CHEN ZHU1, LIANG ZHAO1*, XIONG GAO1, JUNFENG JI1,

JUN CHEN1 AND H. HENRY TENG1,2 1Department of Earth Sciences, Nanjing University, Nanjing,

Jiangsu, 210093, PRC (*correspondence:[email protected])

2Department of Chemistry, the George Washington University, Washington, DC, 20052, USA

Increasing evidence suggests that the widespread used of

fossil fuels has led to a rapid increase in carbon dioxide concentration in atmosphere. One method to prevent CO2 in the atmosphere from rising to unacceptable levels is carbon dioxide sequestration. Of all the options proposed so far, mineral carbonation is the one that offers advantages in the stablity of the final products and hence the elemination of legacy issues. However, this approach faces the problem of slow reaction kinetics and the difficulty of recycling leaching agents used to extract cations [1].

We present an experimental study of mineral carboation using NH4Cl solution as leaching agent and brucite as raw material. The acidic environment resultant from caused by NH4

+ hydrolysis facilitates mineral dissolution and the release of NH3, which will be collected as a base agent for pH adjustment during the carbonate process and form NH4Cl again. Recycle use of the leaching agent lowers the total cost and increases the commercial potential of the process. Furthermore, most magnesium-rich layer silicon minerals have similar structures and brucite-like magnesium-oxygen octahedral layers exist between silicon-oxgen tetrahedrons, it is reasonable to believe that brucite and magnesium-rich layer silicon minerals have similar dissolution mechanism.

Kinetic experiments show that the convertion-time followed the Avrami model, and that the reaction rate increased with increasing temperature and ammonium chloride concentration, decreasing solid/liquid ratio, and particle size. The following mathematical equation is found to fit the relationship between the reaction constant(k) and various experimental parameters:

k=5.22*105C0.12(S/L)-0.22D-0.31e-5710/T. The reaction activiation energy calculated by the

Arrhenius equation 47.47kJ/mol, in agreement with the reported value for surface controlled brucite dissolution [2]. [1] Sipiläet al. (2008) Greenhouse Issues 90, 3-4. [2] Huang et al. (2009) The Chinese Journal of Process Engineering 9, 1121-1126 (in chinese).

Large area multi-stage quasi-layer petroleum accumulation in

carbonate reservoirs in Tazhong area, Tarim Basin

ZHU GUANGYOU1,2, ZHANG SHUICHANG1,2, WANG YU1,2 AND SU JIN1,2

1Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China

2State Key Lab of Oil Recovery Elevation, Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China

Tazhong area is an important exploration domain in the

Tarim basin with abundant petroleum. Ordovician carbonate reservoir is the major exploration target. The formation and distribution of those reservoirs were major controlled by high energy sedimentary facies, dissolution and faults. Reef-shoal complex in the Lianglitage Formation in Upper Ordovician and karst weathering crust reservoir in the Yingshan Formation in Lower Ordovician were both distributed quasi-layered in large area. The Hydrocarbons were complex accumulated in multi-layer. Those reservoirs were composed of carbonate rocks with low porosity and low permeability, and buried in 4500~6500m depth with intensive heterogeneity. The spatial distribution of effective reservoirs controlled the occurrence of hydrocarbon and accumulated in large area, which showed an integral enrichment characters.

Detailed oil-source rock correlation indicates that the crude oils were mix-oils originated from both Cambrian source rocks and Ordovician source rocks, nevertheless, the natural gases were major oil-crack gases from Middle-Lower Cambrian sources. The analysis of accumulating process shows that the Tazhong area experienced three stages of hydrocarbon accumulation. The first stage occurred in the Late Caledonian tectonic cycle and the hydrocarbons originated from Cambrian-lower Ordovician source rocks, and were severely degraded in the Early Hercynian tectonic movements in large areas. The second stage occurred in the Late Hercynian tectonic cycle which was the most important hydrocarbon charging stage, the oils and gases were from Middle-Upper Ordovician source rocks. The third stage occurred in the late Himalayan tectonic cycle, Cambrian oil-crack gases began to generated in depth, charged into Ordovician reservoirs along faults, gas-washed the oil pools and then formed condensate gas reservoirs which is now extensively occurred in Tazhong area.



2277

Geochronology, geochemistry and ore-forming fluid characteristics of

the Shijinpo gold deposit in Beishan belt, NW China

JIANG ZHU, XINBIAO LV * , CHAO CHEN AND YALONG MO

Faculty of Earth Resources, China University of Geosciences, Wuhan, 430074, China (*correspondence: [email protected])

The Shijinpo gold deposit is one of numerous lode gold

deposits in the Beishan orogenic belt, southern margin of the Altaids, northwestern China. Gold mineralization is hosted in the early Devonian granite and consists primarily of auriferous quartz veins that confined to the EW-trending faults. Ore-related hydrothermal alteration is dominated by sericite + quartz + sulfide assemblages in close proximity of gold veins. Pyrite is the predominant sulfide mineral, variably coexisting with minor amounts of chalcopyrite, sphalerite, and galena. Gold occurs mostly as free gold enclosed in or filling microfractures of pyrite and quartz. Native gold is present coexisting with Au-bearing tellurides consisting mainly of petzite.

Measured (34S values for sulfide minerals range from 8.32‰ to 10.33‰, indicating a deep-seated sulfur source most likely of magmatic origin. Calculated (18O values for the ore fluid range from +2.7‰ to +3.3‰ and the corresponding (D values range from -95‰ to -99 ‰, compatible with mixing of magmatic and meteoric components. Fluid inclusion studies suggest that gold veins were deposited at intermediate temperature conditions (150 to 320°C) from aqueous or aqueous-carbonic fluids with moderate salinity (4.65 to 12.16 wt% NaCl equiv). The ore-forming fluid is assumed to undergo boiling at high temperature triggered by fracturing and then mixed with the ground water. Laser incremental heating 40Ar/39Ar analysis of hydrothermal sericite yield an plateau age at 364.6 ± 3 Ma (2%), suggesting that the gold veining took place in the late Devonian.

Combining these observations with the regional geology we propose that the Shijinpo gold deposit was formed during compressional to transpressional processes in a subduction-related setting.

Mechanisms of nitrogen dissipation in an N-saturated subtropical forest

in Southwest China J. ZHU*, P. DÖRSCH, H. SILVENNOINEN AND

J. MULDER Norwegian University of Life Sciences, 1432 Ås, Norway

(*correspondence: [email protected]) Published N budgets for N-saturated watersheds in

subtropical SW China suggest significant N retention, despite low forest growth, P deficiency and high soil acidity [1]. To characterize mechanisms of N dissipation in these systems, we applied state-of-the-art field and laboratory methodologies to a headwater catchment at Tieshanping (TSP), SW China, (4.04 g N m-2 a-1 atmogenic deposition, 61% of which in form of NH4

+ and 0.57 g N m-2 a-1 effusion in stream water mostly as NO3

-). We explored spatiotemporal patterns of N2O emission and 15N and 18O natural abundances of NO3

- in situ and characterized nitrification and denitrification and their gaseous product stoichiometries by laboratory incubation.

Highest N cycling rates and N2O emissions were found during the wet season (summer), with marked variations between wet and dry years. N2O emissions during summer were driven mainly by rain episodes. Soils on the hillslopes showed higher denitrification and N2O emission rates than a perturbed groundwater discharge zone (GDZ) which had less organic carbon. The spatial pattern of denitrification was consistent with NO3

- concentration profiles and natural abundance signatures. Laboratory experiments confirmed that organic carbon is the limiting factor for N-removal by denitrification in this ecosystem and that the different landscape elements harbour denitrifier communities with distinct N2O product stoichiometries, explaining part of the variation in observed N2O emissions. Nitrification in the hillslopes was found to be unbalanced, producing significant amounts of nitrite which decomposed rapidly to NO and N2O at low native pH (4.0), indicating chemodenitrification from incomplete NH4

+ oxidation as a potentially important additional source for N2O. Estimated annual N2O emission for 2009 and 2010 was 0.29 g N m-2, equivalent to appr. 8.5% of the annual N input. To close the N budget of the watershed, a field 15N labelling experiment was conducted to assess total gaseous losses including N2. [1] Chen XY and Mulder J. (2007). Science of the Total Environment 378: 317-330



2278

The first observation of Chang’E-2 gamma-ray spectrometer

M.H. ZHU1, T. MA2, J. CHANG2, W.-H. IP1,3, Z. TANG1 AND A. A. XU1

1Macau University of Science and Technology, Taipa, Macau 2Purple Mountain Observatory, Nanjing, China 3National Central University, Jhongli, Taiwan

Gamma-ray measurement coming from the lunar surface is a powerful method to infer its composition of material in the top several tens of centimeters. While gamma ray lines are remotely measured in orbit, chemical elements can be identified in light of the energies from which they were emitted, and concentrations can be estimated based on their fluxes.

Chang’E-2 spacecraft was launched to the Moon (100 km, circle polar orbit) at 1st, Oct., 2011, with a gamma-ray spectrometer (CE2-GRS) as one of its scientific payloads. CE2-GRS using a large LaBr3 (Ce) crystal as its main detector is expected to provide global elemental maps of the lunar surface (e.g., Th, K; Mg, O, Al, Ca, Si, Fe, Ti). It employs a big cup-shape CsI (Tl) crystal to suppress the Compton effects and reduce the background gamma rays from the spacecraft materials interacted with GCRs. Gamma-rays are recorded as 512 channel-spectrum every 3 seconds in the range of 0.3 to 10 MeV with the energy resolution of ~ 4% fwhm@662 keV.

CE2-GRS has about 4-days background measurements in its cruise period. The spectrum shows higher quality than that from past scintillation detectors for the lunar gamma-ray remote measurement. From the background spectra, self-activity peaks of LaBr3 crystal (from 138La and 227Ac decay chain generation) can be found clearly. Elements (O, K, Mg, Al, and Ti) from the spacecraft body, the fuels, and instruments were also identified. Potassium map (cps, 5o$5o) was obtained using first three-month measurements. Since the higher spatial resolution (~ 150 km $ 150 km), the derived map can show the potassium distribution on the Moon clearly.

Absolute calibration will be carried out based on the spatial response function. Comparisons with that of Lunar Prospector, Kaguya, and Chang’E-1 will be investigated to see if the new potassium could indicate some interesting, new science.

A Paleoproterozoic tectonothermal event recorded in Precambrian

basement rocks of the Kuluketage uplift, Northeastern Tarim, China

W.B. ZHU, H.L. WU, L.S. SHU AND D.S. MA State Key Laboratory for Mineral Deposits Research,

Department of Earth Sciences, Nanjing University, Nanjing 210093, People’s Republic of China, ([email protected])

The Kuruktag uplift is located to the north of the Tarim

Block. The Neoarchaean to early Neoproterozoic basement rocks are unconformably overlain by the middle Neoproterozoic to Phanerozoic sedimentary cover. The Precambrian basement rocks also crop out in the Korla region, at the western end of the Kuruktag uplift, whose ages are uncertain because of the paucity of reliable isotopic data. These basement rocks, including gneisses, amphibolites, marbles and schists, were subjected strongly deformed and metamorphosed to amphibolite facies.

Four garnet-bearing schists were collected for zircon U–Pb dating and Hf-isotope analyses. CL images display that most zircon grains occur as relatively dark and rounded crystals and are homogeneous in texture, indicative of metamorphic origin. The samples give four metamorphic zircon ages of 1844Ma, 1847Ma, 1850Ma and 1867Ma, respectively. The metamorphic zircon age of ~1.85 Ga obtained in this study indicate that an important tectonothermal event occurred at the end of the Paleoproterozoic in the Tarim Block. Lu–Hf isotopic analysis on these zircons gives Hf model ages ranging from 2.9 to 3.5Ma, indicating that the late Paleoproterozoic metamorphism and tectonism of the Tarim Block represent an overprint on an Archaean basement. These data imply a Paleoproterozoic orogeny in the northern Tarim.

This episode of Precambrian tectonothermal event is broadly coeval with those seen in many continents around the world such as Baltica, Laurentia, Northern Finland, Northern Fennoscandian Shield, Amazonia, North China and India, etc., which is coincident with the timing of the orogeny associated with the amalgamation of the Columbia super-continent suggesting that the Tarim Block was the part of this supercontinent.



2279

Origin and fractionation of heavy metals of sediments in the drinking

water source of Beijing ZHU XIANFANG1 AND JI HONGBING1,2*

1The Key Laboratory of Metropolitan Eco-Environmental Processes, College of Resource Environment and Tourism, Capital Normal University, Beijing 100048 China ([email protected], *correspondence: [email protected])

2State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China

The Miyun Reservoir, the only one surface drinking water

source of Beijing, incepted kinds of pollutants from rivers, agricultural production, mining activity, tailing and so on. Four sediment cores (35cm per core) were collected from Miyun Reservoir and cut into slices of 5 cm each core. Samples were subjected to a total digestion technique and analyzed by ICP-OES for Cr, Pb, Cd, Co, Cu, Mn, Ni, Ti, V and Zn, and by AFS for As and Hg. The seven-step sequential extraction technique was determined the distribution of speciation for heavy metals (except As and Hg). The results revealed the contents of heavy metals were not apparent enrichment compared with the shale standard. Most of heavy metals decreased while the depth increased. The results showed that the main fraction for most of heavy metals was residual phase. Additionally, the extractive phase of Cd was higher and reached 60%, the following was Ni, Co, Zn and Pb.

The origin of heavy metals was identified by multivariate analysis with total content. The results of correlation analysis revealed obvious correlation between heavy metals. Cu, Mn and V were highly correlated among them (r>0.800; p<0.01), Cr and Ni were also identified, whereas As and Ti were less correlated with Cu, Mn and V (r>0.500; p<0.01). The correlation coefficients were not as high as among Hg, Co and other heavy metals. PCA showed there were five principal components. PC1 included Ti, Cd, Cu, Mn and V, PC2 were Cr and Ni, PC3 were As and Zn, PC4 was Hg, and PC5 was Co. Therefore, the five principal components represented five primary origins of heavy metals, which were erosion of rocks, industrial and mining, agricultural production and domestic sewage, atmospheric deposition and secondary pollution of water environment, respectively. The results provided scientific basis for protection of drinking water source of Beijing.

This study was supported by the program of “One Hundred Talented People” of the CAS

Isotope fractionation of transition metals by higher plants

X.K. ZHU1, S.Z. LI1,Y.M. LUO2 AND L.H. WU2

1Lab Isotope Geol., MLR, Inst. Geol., CAGS, Beijing, China ([email protected]; [email protected])

2Inst. Soil Sci., CAS, Nanjing, China

Transition metals such as Fe, Cu and Zn are present as trace elements in organisms, but are essential for life. Thus variations in transition metal isotope composition may be important in tracing the interaction between geosphere and biosphere, to trace the pathways of these elements into and within biological system. A prerequest for these applications is an adequate undersdanding of the the mass fractionation of these isotopes during steps of biological uptake and translocation . Here we report the result of a case study for sotope fractionations of Fe, Cu, Fe and Zn by higher plant using a Cu accumulator Elsholtzia splendens.

Elsholtzia splendens growth-experiments were carried out in green house and in soils with different chemical properties, namely: copper contaminated soil collected from natural envirioment �denoted as CK�, CK with addition of sulphur powder, CK with addition of EDDS, and CK with addition of both EDDS and sulhpur. Soils, roots, stems and leaves were measured for Cu, Fe and Zn isotope ratios using Nu Plasma HR MC-ICPMS after digestion and chemical purification. The results display some prominant features, taking Cu isotopes as an example: 1) relative to soils, the plants show overall lighter isotope enrichment, implying significant isotope fractionation occurred during Cu uptaking of the root from the soil and light Cu isotope were taking preferentially; 2) from soil to root to stem, Cu isotope composition become progressively lighter, indicating stepwise mass fractionation during Cu uptaking and translocating; 3) relative to stems, leaves enrich heavy Cu isotope by ca.0.3‰, suggesting a change in Cu transport mechanism from stems to leaves, and showing that heavy Cu isotope can be preferentially taken at some stage during biological processes; 4) the extent of light isotope enrichment of the plant relative to soil varies with the chemical property of the soil, and the light Cu isotope enrichment is enhanced by the addition of EDDS.

The results presented above enhance our knowledge about mass fractionation proccesses of transition metal isotopes in higher plants significantle.



2280

Mining-induced groundwater environmental impact assessment at Shuyang county, Jiangsu Province,

China X.B. ZHU, J.C. WU, J.F. WU AND X. YUAN

Dept. of Hydrosciences, School of Earth Science and Engineering, Nanjing University ([email protected]) The phosphorite was found at Tangzhuang village,

Shuyang county, Jiangsu province. It is about 2.2km2. It’s can be used and planned to be exploited in the future. Groundwater environment would be impacted heavily by exploiting phosphorite because the phosphorite is deep below the subsurface. The groundwater level should be reduced to the bottom elevation of the phosphorite. So, the huge cone of depression, which result in the subsidence, would be developed.

There is the phreatic aquifer and the confined aquifer in the study area. The hydrogeologic conceptual model was generalized and the numerical model of groundwater flow was built with the MODFLOW module in GMS software. The dewatering of deposit was caculated, 4100m3/d for the upright well used for workers to get inside the exploitation platform and 130543/d for the exploitation channel. The drawdown is computed at the same time. The maximum drawdown is 60m for the confined auqifer and 4m for the phreatic aquifer.

The effect of phosphorite exploitation on the groundwater environment is obvious. Some engineering measures are suggested to be implemented to reduce the effect. Pumping well planned to be built to supply drinking water for people around the study area. Grouting convrete boreholes are suggested to be constructed to cut off the water exchange between the phreatic and the confined aqufer. The effect of exploitation and the subsidence due to dewatering of deposit can be controlled with these engineering measures.

The research was financially supported by National Natural Science Foundation of China (No.40702038 and No. 40725010)

Zircon ages and Hf isotopic feature of Neoproterozoic metamorphosed sedimentary rocks in the South

Qinling terrain, China X.-Y. ZHU 1, 2, F. CHEN 2, S.-Q. LI 2 AND L. YANG 1

1Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China

2School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China The Qinling orogenic belt, being part of the central

orogenic belt in China, was resulted from the North China and South China blocks in early Mesozoic. The Shangnan-Danfeng tectonic zone is an inner suture, which separates this belt into the North and South Qinling terrains. Neoproterozoic sedimentary-volcanic sequences widely distributed in South Qinling have been considered to be basement rocks. Characteristic Neoproterozoic magmatic events (~750 Ma) were recorded in zircons from magmatic and low-grade metamorphic rocks in the South Qinling terrain and the South China block, interpreted as an indicator for close tectonic connection of both terrains in Neoproterozoic [1, 2].

This study presents results of zircon situ Lu-Hf and U-Pb isotopic analysis of low-grade metamorphic sedimentary-volcanic sequences in the South Qinling terrain. Most detrital zircons are euhedral to subhedral, implying a short transportation of material after weathering. Detrital zircon populations with oscillatory zonation of magmatic origin yield U-Pb ages mainly clustering at ~850 Ma and ~1890 Ma. Two zircon groups are characterized by distinguishable Hf isotopic feature, having negative initial -Hf values of around -8.4 and positive initial -Hf values of around +3.6, respectively. The atypical Neoproterozoic magmatic activity of ~850 Ma in the South Qinling terrain basement, similar to those along the northwestern and south eastern margins of South China block, are probably related to an earlier stage of the break-up of Rodinia supercontinent [3, 4]. [1] Chen et al. (2006) JAES 28, 99-115. [2] Yu et al. (2008) Precam. Res 164, 1-15. [3] Ling et al. (2001) Phs. Chem. Earth (A) 26, 805-819 [4] Li et al. (2010) Am. J. Sci 310, 951-980



2281

Abnormal positive !13C values of carbonate in Lake Caohai, Southwest

China and their possible paleoenvironmental significances

Z. ZHU 1,2,3, J. CHEN 1*, S. REN 2 AND Y. LI 2 1The State Key Laboratory of Environmental Geochemistry,

Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China (*correspondence: [email protected])

2Chongqing Key Laboratory of Exogenic Minerallization and Mine Environment, Chongqing Institute of Geology and Mineral Resources, Chongqing 400042, China

3Chongqing Research Center of State Key Laboratory of Coal Resources and Safe Mining 400042, China

Carbon source inputs, CO2 exchanges between atmosphere

and lake water, as well as lacustrine productivity are commonly considered as the main controls on the (13C values of lake authigenic carbonates. Generally, (13C values of carbonates in most lakes are lower than +5‰, few are up to +13‰ [1]. Here, stable carbon isotopes were measured on bulk carbonates from a short sedimentary core in Lake Caohai, Guizhou Province, southwest China. The results showed that (13C values vary between -14.25‰ and +23.10‰, which is the largest carbon isotope variations discovered so far in carbonates from lacusrine sediments, and some (13C values are the most positive values up to +23.10‰, more positive than previously reported values. On the basis of combination with oxygen isotope and carbonate contents proxies, we suggested that the carbon isotope composition of carbonate from Lake Caohai was controlled by photosynthesis/ respiration of aquatic plants, and the input of bacteria to carbon isotope fractionation of organic matter may be responsible for the abnormal positive (13C values in Lake Caohai [2,3]. Therefore, more attention should be paid on the carbon isotope composition of carbonates in Lake Caohai in future research.

This work is financially supported by the National Natural Sciences Foundation (40673068) and the National Key Funds of China 2006CB403201). [1] Blas et al. (1999) Earth Planet. Sci. Lett. 171, 253&&266. [2] Teranes et al. (2005) Limnol. Oceanogr. 50, 914&922. [3] Hollander et al. (2001) GCA 65, 4321&4337

Al diffusion in olivine: An experimental study

IRINA ZHUKOVA*, HUGH O’NEILL AND IAN CAMPBELL Research School of Earth Scuance, National Australian

University, ACT 2000 (*correspondence: [email protected])

Al content in olivine is temperature dependent [1] and

diffusion is thought to be very slow [e.g. 2]. We performed a series of experiments of Al diffusion in

San Carlos olivine and synthetic forsterite at 1300oC and log fO2 = -0.7; -5.7 and atmosphere pressure. In order to provide an inside into mechanism of alumina substitution into olivine, activities of SiO2, MgO and Al2O3 were buffered in all runs. Four mineral associations were used: (a) forsterite – periclase – spinel; (b) forsterite – spinel – sapphirine; (c) forsterite – sapphirine – cordierite; (d) forsterite – cordierite – enstatite and the results analysed by LAICPMS. Each profile was fitted to a one – dimensional diffusion model in a semi-infinite medium with a source reservoir maintained at constant concentration.

The concentration of Al at the interface in equilibrium with the high silica activity buffer (d) is 5 times higher than in case of the low silica activity buffer (a), changing from 50 ± 12 ppm to 220 ± 30 ppm. The solubility of Al in S.C.O. is 2 - 4 times higher than in forsterite (430 ± 50 ppm). These concentrations are 2-4 times lower then those calculated from olivine-spinel geothermometer (940 ± 170 ppm) [1] and obtained by partitioning experiments (755 ± 25 ppm) [3] at temperature of interest.

High rate diffusion of Al in S.C.O. and forsterite was obtained: logDAl/Fo = -15.6 ÷ -13.2 (m2/s) and logDAl/Ol = -15.1 ÷ -14.4 (m2/s). No dependence of Al diffusion rate on oxygen fugacity has been observed. The rate of Al diffusion was strongly controlled by activity of major cations (Si, Mg): there are 2 order of magnitude difference between diffusion coefficients of Al in forsterite in low and high silica activity experiments: logDAl/Fo(a) = -15.5 ± 0.1 (!) (buffer a with activities of aSiO2 = 0.01 and aMgO = 1.00) compare to logDAl/Fo(c) = -13.3 ± 0.1 (!) (buffer d with activities of aSiO2 = 0.58 and aMgO = 0.14). This difference suggests that the mechanism of Al substitution into the olivine lattice requires an ochtohidral site vacansy.

[1] Wan, et. al (2008) American Mineralogist 93, 1142-1147; [2] Spandler & O'Neill (2010) Contrib Mineral Petrolr 159, 791-818; [3] Agee & Walker (1990) Contrib Mineral Petrol 105, 243-254.



2282

The characteristic of lithology and facies and reservoir of volcanic rock

in Songliao Basin, China ZHUO SHENGGUANG1*, WANG XIANBIN2 AND

YANG GUIFANG3 1 Zhuo Shengguang,Northeast University at Qinhuangdao,

China (*correspondence: [email protected]) 2Key Lab of Petrol Resources Research, CAS, Lanzhou

([email protected]) 3Northeast Petroleum University at, Qinhuangdao, China

([email protected])

Yingcheng formation is rich in volcanic rock.in Songliao Basin,China.Volcanic lithofacies consists of eight types; such as fallout facies, effusion facies, base surges facies, pyroclastics flow facies, lahar facies, eruption-sedimentary facies,sub-volcanic rock facis and sub-explosive breccia facies. Volcanic apparatus make up of layered volcano, micro-shield volcano and cone volcano. Lithology of volcanic rock is mainly middle acid volcanic rock (dacite, rhyolite, middle acid brecciated tuff and tuff), belonging to the calc-alka-line series of subalkaline series. The eruptive and overflow facies have better reservoir capacity, the reservoir capacity of volcanic rocks has largely been affected by volcanic condensation diagenesis, tectonism, solution and fluid activity.the volcanic rocks reservoir commonly with the porosity of 6.3%%10.8 % and permeability of about 0.55*10-3$m2%122.0*10-3$m2.The most of effective reservoir are the upper phase or external phase of volcanic facies belts, usually being layers or thin layers of 10-20m.The pores of volcanic reservoir could be classified into four types: 1) primary pores of original rocks, 2) diagenetic pores, 3) diagenetic fractures, 4) secondary tectoclases and weathered fractures. Types 2) and 3) are the most effective reservoir space which were formed in volcanic eruption process of cooling and aftercooling.

U-Pb age, geochemical and Hf-O isotopic constraints on magma source

of the I-type calc-alkaline Baimaxueshan Batholith (SW China): Implications for crustal recycling at a

convergent margin J.-W. ZI1,2*, P.A. CAWOOD1,3, W.-M. FAN2, E. TOHVER1,

Y.-J. WANG2 AND T.C. MCCUAIG1 1School of Earth and Environment, University of Western

Australia, Crawley, WA 6009 Australia (*correspondence: [email protected])

2Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China

3Department of Earth Sciences, University of St. Andrews, KY169AL, Fife, Scotland, UK

The late Permian to Tiassic is a critical period of the

development of the eastern Paleo-Tethys, and corresponds with ocean closure and arc accretion onto the margin of Asia. Mafic enclaves and host granitoids from the Baimaxueshan batholith within the Sanjiang Orogen, SW China, document the tectonomagmatic history of accretion. SHRIMP U-Pb analyses on zircons from the mafic enclaves and host granitoids bracket their crystallization ages into the range of ca. 253-248 Ma, and establish that the mafic and felsic magmas were coeval. The granitoids have calc-alkaline, metaluminous I-type character, and show features of magma mixing between mafic and felsic melts. Whole-rock elemental and Sr-Nd isotopic systematics are compatible with an infracrustal origin for the felsic melt, whereas the mafic enclaves may represent relicts of magmas derived from partial melting of subduction-modified ancient lithospheric mantle triggered by fluids/melts released from the descending slab. The elevated in situ zircon (18O values shown by both the mafic enclaves (9.23 ± 0.2‰ (VSMOW)) and host rocks (8.70 ± 0.09‰) require a considerable input of high-(18O supracrustal components through subduction or underthrusting to the sub-arc mantle wedge, which also explains the enriched Sr-Nd and zircon Hf isotopic ratios (-Hf(t) = -10 ± 1) displayed by the enclave samples. This together with zircon Hf depleted mantle model ages (TDM

C= 1.53 to 2.52 Ga) peaked in the Mesoproterozoic imply that crustal growth processes largely involved reworking of pre-existing lithosphere rather than accretion of juvenile asthenosphere-derived materials.



2283

Application of lithogeochemistry for regional scale mapping of geothermal

prospectivity in Sabalan volcano, North West of Iran

M. ZIAEI, M.ZIAII, A.KAMKAR AND M. ASGHARI Faculty of Mining and Geophysics, Shahrood University of

Technology; Shahrood, Iran, ([email protected])

Many different techniques are suggested for geothermal (convective systems) exploration including geological mapping, magnetic, gravity, hot spring, geochemical sampling, seismic and well logging methods. Geothermal systems are usually characterized by indicative geological features that may not be implied or easily be described by only one analytical method. The methodology presented here provides combined applications of several different methods in order to generate regional scale mapping of geothermal prospectivity in Sabalan volcano located in North West of Iran. The relation of the geothermal occurrences (18 geothermal occurrences used as training points) to evidential maps is assessed by means of the logistic regression as a data driven method. Six evidential maps were used derived from maps of (1) gravity, (2) magnetic, (3) geology, (4) zone proximal to hydrothermal alteration, (5) zones proximal to faults, (6) geochemical multiplicative zonality (Vz). The first five evidential maps are selected based on previous research works. Sixed evidential map is selected based on geochemical zonality anomaly.

According to geochemical studies As, Sb, Hg, Bi and B are typically enriched in geothermal areas. Thus Vz can be introduced as a geochemical evidential map for geothermal exploration.

At least seven sub-areas (in which two areas have been explored and exploited) can be recommended for follow up exploration work based on favorability map. The results indicated that, integration of Vz evidential map with other maps used as spatial evidence is important in filtering-out false selected areas.

[1] Carranze, E.J.M., Wibowo, H., Barritt, S.D. and Sumintadireja, P. (2008) Spatial data analysis and integration for regional-scale geothermal potential mapping, West Java, Indonesia, Geothermics, pp.267-299.

Geochemistry of mantle microxenoliths from Zagadochnaya

kimberlite (Yakutia, Russia) L. ZIBERNA1*, P. NIMIS1, A. ZANETTI2, N.V. SOBOLEV 3

AND A. MARZOLI1 1University of Padua, Department of Geosciences, Italy

(*correspondence: [email protected]; [email protected], [email protected])

2IGG-CNR, Pavia, Italy ([email protected]) 3V.S. Sobolev Institute of Geology and Mineralogy,

Novosibirsk, Russia ([email protected])

The Zagadochnaya kimberlite is a barren type-II kimberlite, which contains Cr-diopside, pyrope garnet (Grt) and spinel xenocrysts, as well as eclogite and grospydite xenoliths [1], but no discrete peridotite xenoliths. We have investigated Grt grains and associated minerals. Some Grts (groups A, B) and associated Cr-diopsides (similar to subgroups IIa, IIb of [2]) show evidence of an early metasomatic event and variations in LHREE/HREE ratios compatible with a model of percolative fractional crystallization of kimberlite melts [3]. Other Grts (group C) exhibit strongly sinusoidal CI-normalized REE patterns, typical for cratonic Grt-peridotites produced by metasomatism of strongly refractory harzburgites. Most of group B and C Grts show secondary domains rich in Cr-diopside + Cr-spinel ± phlogopite. In these domains the Grts are (Ca, Cr)-depleted, are enriched in almost all incompatible elements, and show humped CI-normalized REE patterns (max at Eu). Low Ti/Zr ratios (~ 10) and presence of phlogopite in these domains suggest an origin by reaction with a melt of type-II kimberlite affinity. Based on Ca concentration profiles across Grt zoning, this late-stage event took place less than 104 years before the Zagadochnaya kimberlite eruption, i.e. it was probably related to the same magmatic stage of the host kimberlite.

[1] Sobolev et al. (1968) J Petrol 9, 253-280. [2] Nimis et al. (2009) Lithos 112, 397-412. [3] Burgess & Harte (2004) J Petrol 45, 609-634.



2284

Silicon and oxygen isotopes: The maturation of lacustrine diatoms

K. ZIEGLER1*, J.P. DODD2, Z. D. SHARP2, A.J. BREARLEY2 AND E.D. YOUNG1

1Department of Earth and Space Sciences & Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095, USA. (*correspondence: [email protected]).

2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA.

Oxygen and silicon isotope values of recent (antemortem,

post-mortem) and Pleistocene lacustrine diatoms from the Valles Caldera (New Mexico) provide the opportunity to study 420 ka of opal maturation at the same location.

The "18O (SMOW) values, obtained by laser-fluorination [1], indicate significant reequilibration, with an increase in "18O value from <22‰ to >29‰ within 0.5 yrs after death. This is consistent with growth under oxygen isotopic disequilibrium followed by post-mortem equilibration with lake water. While no structural changes go with the alteration, differences in element compositions also imply exchange between water and diatom. Wholesale reequilibration of "18O ratios requires Si-O bond breaking. We measured the "30Si values of the same diatoms to see if Si also undergoes isotope exchange. "30Si values were obtained by MC-ICPMS [2].

The "30Si values (NBS-28) of all ante-mortem and post-mortem diatoms range from -1.0 to -2.6‰, and -0.4 to -1.9‰, respectively. A specific subset of diatoms was collected in spring, and the same population sampled 0.5 and 1.5 years post-mortem. The "30Si values increase from -2.4 to -1.9 to -0.4‰, indicating a possible maturation trend. The large ante-mortem range can also be explained by variable relative inputs from processes affecting the "30Si values of lake water (diatom [3] and clay [4] formation removes 28Si from water).

Middle Pleistocene (interglacial) lacustrine diatoms from the Valles Caldera have even higher "30Si values of +0.3 to +0.7‰. The trend from low to high "30Si ratios mimics the "18O changes (at a smaller scale). Interglacials correlate with more positive "30Si values in marine diatoms [5]. We infer that Pleistocene Valles Caldera diatoms had higher initial "30Si values than modern ones, and additionally that exchange processes during burial caused further opal maturation.

The combined silicon and oxygen isotope study of such a system improves our understanding of the potential for using Si isotopes as paleoclimate proxies. [1] Dodd & Sharp (2010), GCA 74, 1381-1390. [2] Ziegler et al. (2010), EPSL 295, 487-496. [3] De La Rocha et al. (1997), GCA 61, 5051-5056. [4] Ziegler et al. (2005), GCA 69, 4597-4610. [5] De La Rocha et al. (1998), Nature 395, 680-683.

Silicon and oxygen isotope values of cherts and their precursors K. ZIEGLER1,2*, J. MARIN-CARBONNE1, K.D. MCKEEGAN1 AND E.D. YOUNG1, 2

1Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095, USA. (*correspondence: [email protected]).

2Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095, USA.

We measured "30Si and "18O ratios in two sets of recent

cherts and their precursors in order to evaluate the use of cherts as proxies for environmental conditions at their formation, and to constrain diagenetic transitions. This work has implications for models for Archean cherts formation.

In a handsample from the Miocene Monterey Formation [1, 2], both cristobalitic chert and biogenic, marine opal-A precursor are present. Magadi chert is modern, inorganic, quartzose chert formed from chemically precipitated magadiite [3, 4]. Both precursor-to-chert transitions are due to dissolution-precipitation processes. Monterey chertification is due to later diagenetic water [1, 2], and Magadi chertification occurs at the surface in the same system as magadiite [3, 4].

"30Si values were analyzed by MC-ICPMS (Neptune%), "18O values of cherts by ion microprobe (Cameca 1270), and precursor "18O values were taken from literature [1, 3].

The "18O values of the Monterey opal (37‰) and chert (28-34‰) suggest temperatures of 15°C and 48±8°C, respectively [1]. The "30Si values of the chert and opal are 0.0‰ and 1.4‰, respectively. Diatom formation increases the 30Si/28Si of the aqueous phase [5], and high diatom "30Si values are expected in highly productive oceans. Later chert-forming diagenetic water, equilibrated with Monterey Shale [1], is expected to have more negative "30Si values [6], and explains the lower "30Si value of the chert.

In contrast, the inorganic magadiite and magadi chert have similar "18O (33-38‰ [3, 4] and 38‰, respectively) and "30Si values (-0.2 and -0.5‰, respectively). The isotopic similarity demonstrates that no fractionation attends this chertification, as both phases form from the same silicon and oxygen source (hot springs [3, 4]).

"30Si ratios of cherts record the last chertification event, which can imprint different "30Si values onto its precursor. This needs to be considered for paleoclimate reconstructions.

We thank Jim Boles (UCSB) for providing the samples. [1] Murata et al. (1977), AJS 277, 259-272. [2] Pisciotto (1981), Sedimentology 28, 547-571. [3] O’Neil & Hay (1973), EPSL 19, 257-266. [4] Behr & Röhricht (2000) Int J Earth Sci 89, 268-283. [5] De La Rocha et al. (1997), GCA 61, 5051-5056. [6] Ziegler et al. (2005), GCA 69, 4597-4610.



2285

On the multitude of niches for bacteria and archaea in an acidic

biofilm S. ZIEGLER1, K. DOLCH1, J. MAJZLAN2 AND J. GESCHER1* 1Department of Microbiolgy, Albert-Ludwigs University

Freiburg, Germany (*correspondence: [email protected])

2Department of Mineralogy, Friedrich Schiller University Jena, Germany

We studied a microbial snottite biofilm in an abandoned

pyrite mine. The organisms that build up the biofilm grow at pH about 2.3 and sulphate concentrations of up to 200 mM. The microorganisms are dependent on the oxidative dissolution of pyrite as the primary energy source and on CO2 as the primary carbon source. We assessed the microbial diversity in the consortium using restriction fragment length polymorphism and subsequent sequencing. As expected, organisms belonging to the genera Leptospirillum represented the majority of bacterial species. Interestingly, we could furthermore identify archaeal sequences that are most closely related to the ARMAN (Archaeal Richmond Mine Acidophilic Nanoorganisms) group [1] as well as to so far uncultured members of the Thermoplasmatales. Using oxygen profiling we determined that the high oxygen demand of the microorganisms lead to a drop from 100% to 0% oxygen within 700 µm. Hence the internal part of the biofilm seems to be anoxic. Interestingly, we could show that bacteria populated the biofilm mostly at the oxygenated vicinity. MAR FISH experiments, using 14CO2 revealed that this is also the center of primary production. However, archaea populated the anoxic core only. Currently, we investigate the archaeal niche in the biofilm. [1] Baker et al. (2006) Science 314: 1933-1935.

Developing a comprehensive approach to chamber studies of

secondary organic aerosol formation P. J. ZIEMANN*, A. MATSUNAGA, S. AIMANANT, G. YEH

AND Y. B. LIM Air Pollution Research Center, University of California,

Riverside, CA 92521, USA (*correspondence: [email protected])

Much of what is currently understood about the chemical

and physical processes involved in the atmospheric oxidation of organic gases and particles and the formation of secondary organic aerosol (SOA) has been obtained from experiments carried out in environmental (smog) chambers. Achieving a level of understanding from such studies that is sufficient for extrapolating results to the atmosphere (with confidence) and the development of accurate models of SOA formation requires the acquisition of detailed information on a variety of gas and particle properties and processes, such as gas and particle-phase reaction kinetics, gas and particle composition, particle phase, compound vapor pressures, and gas-particle-wall interactions. Obtaining such data is a challenge, but in this talk I will show examples of studies carried out in our laboratory on selected aerosol-oxidant and VOC-oxidant systems in which this goal is close to being achieved. I will demonstrate that by using a diverse array of measurement techniques including mass spectrometry, nuclear magnetic resonance spectroscopy, gas and liquid chromatography, spectrophotometry (with and without compound derivatization), traditional elemental analysis, pycnometry, temperature-programmed thermal desorption, and scanning mobility particle sizing it is possible to develop full, quantitative mechanisms of organic gas and aerosol chemical reactions and models of SOA formation. Doing so, however, requires a more comprehensive approach to chamber studies that acknowledges the obvious: “The atmosphere does not have walls.”



2286

The hafnium and neodymium isotopic composition of seawater in

the tropical Atlantic Ocean M. ZIERINGER1*, T. STICHEL1,2AND M. FRANK1

1IFM-GEOMAR, Wischhofstrasse 1-3, 24148 Kiel, Germany (*correspondence: [email protected])

2SOEST, University of Hawaii 1680 East-West Rd, Honolulu, HI 96822, USA

The combination of radiogenic isotopes of hafnium (Hf)

and neodymium (Nd) has been used to investigate present and past changes of ocean circulation patterns and continental weathering regimes. We present the first combined full water column Hf and Nd isotopic compositions and concentrations in seawater of the western Atlantic Ocean, as well as Hf and Nd isotopic and concentration data in surface waters of the tropical Atlantic Ocean between the Canary Islands and the northeastern coast of Brazil. Samples were collected during GEOTRACES cruise A11 (Meteor M81/1) from Las Palmas (Canary Islands) to Port of Spain (Trinidad and Tobago) in spring 2010.

Hf concentrations in surface waters range between a maximum of 0.67 pmol/kg north of 20°N off the coast of NW Africa and in the area of the Canary Islands and a minimum of 0.20 pmol/kg off the northeastern coast of Brazil. Surface waters with reduced salinities (< 33.6 psu) due to freshwater input by the Amazon river also show low Hf concentrations. Nd concentrations show a similar distribution pattern with a maximum off the coast of Mauritania (27 pmol/kg) and a minimum in the Amazon plume (14 pmol/kg). Elevated concentrations provide evidence of inputs from partial dissolution of dust from the Sahara region and from ocean island wheathering, which is also reflected in more radiogenic Hf and Nd isotope compositions [1]. Low concentrations of Hf and Nd in the Amazonas plume are most likely caused by particle scavenging induced by high productivity.

Deep-water samples show the highest Hf concentrations in UNADW in the area of the Canary Islands (0.93 pmol/kg), as well as in UNADW in the western basin. Nd concentrations range between a minimum of 12 pmol/kg in SACW and a maximum of 34 pmol/kg in AABW. Lower Hf concentrations in LNADW and AABW indicate an oceanic residence time of Hf shorter than that of Nd.

The isotopic distribution of Hf and Nd in the same samples reflect inputs via dust, the Amazon river, and weathering inputs from the volcanic Canary islands, as well as intermediate and deep water mass mixing.

[1] Rickli et al. (2009), EPSL 280, 118-127.

Connection of atmospheric stability and aerosol and gaseous polutants

concentration N. ZIKOVA1,2* AND V. ZDIMAL1

1Department of Aerosols and Laser Studies, Institute of Chemical Process Fundamentals of the ASCR, Prague, Czech Republic (*correspondence: [email protected])

2Department of Meteorology and Environment Protection, MFF UK, Prague, Czech Republic

Our aim is to find suitable criteria to asses an atmospheric

stability without direct measurements in order to estimate relationships between meteorological conditions and concentration of aerosol particles (measured by SMPS) and gaseous pollutants (O3, NO2 and SO2). An aerological method, a synoptical method and NWP models’ CAPE values are applied.

Aerological method and CAPE were found to be suitable methods for description of atmosperic stability. Synoptical method shows mainly origin of air masses.

The strongest relationships between aerosol particles and stability was found for acumulation mode particles, weaker for particles under 50 nm in diameter.

A negative correlation for acumulation mode particles shows “dilution” of atmosphere during unstable conditions, whereas during stable conditions the aerosol acumulates.

Similar relatioship is between gaseous polutants and stability (apart from concentrations of NO2).

Figure 1: Dependencies between aerosol concentration in different sizes, gaseous pollutants concentrations and atmospheric stability described by the three tested methods.

[1] Zikova N. (2010) WDS'10 Proceedings of Contributed Papers: Part III – Physics, Matfyzpress, pp. 97–102. Ack: GACR P209/11/1342 and SVV-2011-263308.



2287

Possible rhenium fractionation during standard Re-Os dissolution

and chemical separation procedures A. ZIMMERMAN1, S. GEORGIEV1,2, G. YANG1,

H. STEIN1,2 AND J. HANNAH1,2 1AIRIE Program, Colorado State University, USA 2Geological Survey of Norway, 7491 Trondheim

A recent curiosity-driven experiment revealed surprising apparent fractionation of rhenium isotopes during standard Re-Os chemical procedures for Carius tube digestion and elemental separation. A non-standard 185Re/187Re ratio of ~0.602 was measured from a standard Re solution after Carius tube digestion and anion exchange chromotography. A replicate produced a similar, though not identical ratio. These surprising results led to a series of quantitative tests to identify procedure(s) that may have led to Re fractionation.

In the original experiments, Re standard solution, Os standard solution, and inverse aqua regia were digested in Carius tubes at 250 oC for 12 hours. The Os was extracted using chloroform-HBr solvent extraction. The isolated Os underwent microdistillation and was measured for its isotopic composition (IC). Os IC ratios matched expected values. After solvent extraction, the Re was collected via anion exchange chromotography and purified using a single bead clean-up. The final measured 185Re/187Re was 0.601608 versus the expected value of 0.597393. The replicate yielded an IC of 0.599062. Additional tests of Re standard solution loaded directly onto exchange columns and directly onto single beads yielded similarly elevated ratios.

Given such results, a more detailed experiment excluded the Carius tube digestion and loaded diluted Re standard solution directly on the anion exchange columns. One mL fractions were collected as the Re eluted from the column. Half of each 1 mL aliquot was loaded directly onto Pt filaments for IC measurements whereas the second half underwent single bead cleaning prior to IC measurement. Re was only found in the first three of seven 1 mL splits. Only the third 1 mL fraction produced ratios significantly different than the expected ratio. In all cases, the single bead-treated and straight-off-the-column Re IC ratios matched, thereby showing that Re fractionation does not occur during the single bead clean-up procedure.

Given the apparent lack of Re fractionation in the most recent experiment, which bypassed the Carius tube step, a final experiment utilizing the Carius tube digestion along with step-wise column collection is being conducted. This experment should replicate the orignal inquiry and also help identify if and when Re fractionation occurs.

Risk element sorption in soil amended by urban particulate matter

D. ZIMMERMANNOVÁ1, J. SZÁKOVÁ1*, M. KOMÁREK1 AND J. SYSALOVÁ2

1Czech University of Life Sciences, CZ-165 21 Prague 6, Czech Republic (*correspondence: [email protected])

2Institute of Chemical Technology, CZ-166 28 Prague 6, Czech Republic ([email protected])

Introduction

Our previous experiment showed that although the element contents in dust samples exceeded significantly those in soil, the element contents in plants were not affected by single-rate soil amendment with the rural dust sample [1]. Therefore, we tested the potential effect of urban particulate matter (PM) amendment to two soils differring in their physicochemical parameters (rate: 0.6 g of PM per 1 kg of the soil) on sorption characteristics described by Freundlich and Langmuir isotherms. Soil E KL Smax

(mmol/kg) Chernozem 0.978 15.6 86.1 Chernozem+PM 0.959 13.6 81.4 Fluvisol 0.963 1.93 137 Fluvisol+PM 0.939 1.09 165 Table 1. Parameters derived from the fitting of the sorption isotherms of Cd with the Langmuir equation Discussion of the results

Whereas the Freundlich isotherms did not indicate any effect of PM addition to the soils, the Langmuír isotherm allowed us to estimate the potential behavior of the PM in the soil. The results for Cd are summarized in Table 1. The PM added to the Chernozem did not lead to substantial changes in sorption characteristics. On the contrary, the presence of PM in the Fluvisol increased the number of potential sorption sites in the soil. However, the results of the approximation showed a lower affinity of Cd for the Fluvisol and a better stability and a lower bioavailability of Cd in the Chernozem. The results are supported by the decreasing Cd contents in both lettuce and chard biomass growing in PM amended Fluvisol compared to the unamended one.

[1] Száková, J., Sysalová, J., Tlusto3, P.: (2005): Plant Soil Environ. 51, 376. Financial support for these investigations was provided by GA4R Project No. 521/09/1150.



2288

From Archean to Cambrian: Isotopic crustal evolution of the Borborema Province, NE Brazil

S.A. ZINCONE1*, E. WERNICK2 AND T.J.S. SANTOS1 1 Instituto de Geociências, UNICAMP, Campinas, SP, Brazil

(*correspondence: [email protected]) 2 Instituto de Geociências, UNESP, Rio Claro, SP, Brazil

Crustal accretion occurs mainly by the input of calc-alkaline granitoids in the cores of pericontinental and intraoceanic orogens. The added magmas are mainly hybrid, a mixture of a mantle derived component with older crustal rocks as the result of the underplating of major amounts of mafic magma beneath the continental crust. The Santa Quitéria Batholith, Borborema Province, is a good example of the mixing of a juvenile Brasiliano component with older, mainly Paleo-proterozoic, crustal material [1]. One consequence of this growth process must be a systematic change in the crustal isotopic composition through time. This assumption is confirmed by 307 Sm-Nd data for Archean, Paleo- and Neoproterozoic rocks from the northern Borborema Province [1-7] which show a systematic change of the 144Nd/143Nd(t) values with time.

[1] Wernick et al. (2011) MinMag, this volume. [2] Fetter (1999) Ph.D. thesis, KU, USA, 164p. [3] Castro (2004) Ph.D. thesis. USP, Brazil, 221 p. [4] Arthaud (2007) Ph.D. thesis. UNB, Brazil, 164p. [5] Martins (2008) Gondwana Research, 15, 71-85. [6] Torres (2006) Rev. de Geologia, 19(2), 163-176. [7] Nogueira (2004) Ph.D. thesis. UNESP, Brazil, 123p.

Plastic deformations in zircon and their influence on its chemical

"omposition 5.F. ZINGER1, N.S. BORTNIKOV2 AND 6.V. SHARKOV2

1IPGG RAS, St-Petersburg, Russia ([email protected]) 2IGEM RAS, Moscow, Russia ([email protected];

[email protected])

We studied 150 grains of zircon from 8 gabbro samples, dragged at 4 sites in axial part of the MAR, Markov Deep, 6oN, during 10th cruise of R/V “Academic Ioffe” (2001-2002) and 22nd cruise of R/V “Professor Logachev” (2003). This part of the MAR represents typical oceanic core complex (OCC), where altered lower crustal gabbros and serpentinized mantle peridotites expose on seafloor. These rocks were undergone by different tectonic deformations, including plastic flowage. The zircon in gabbros along with host rocks were undergone by plastic creep at 815 to 680oC (Ti-in-zircon thermometry).

During deformations zircon was enriched by diversity of rare elements (U, Th, Hf, Pb, P and Y) and REE. We suggest that it was linked both with appearance of deformation-related crustal-plastic microstructures in zircon, which enhanced diffusion of these components, and circulation of intergranular fluid as demonstrated processes of delution and redeposition of the zircon material with appearance of secondary small pyramidal zircons on another side of the crystal. Nature of this high-temperature fluid is not clear yet: it can be residual fluid, formed under solidification of host-gabbros, or result of involving of fluids, circulated in upper oceanic lithosphere, under it heating by these intrusions; most likely both factors were setting in motion. Introducing U, Th and Hf into zircon crystals can change their original isotopic systematics and influence on results of their isotopic dating.



2289

Chemical models for formation of clay-rich layered rocks in the Mawrth

Vallis region, Mars M.YU.ZOLOTOV1* AND M.V.MIRONENKO2

1School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA (*correspondence: [email protected])

2Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 19 Kosygin Str., Moscow 119991, Russia

Clay minerals have been detected in ancient martian

terrains with the near-infrared orbital spectroscopy [1,2]. In the Mawrth Vallis region, a prospective landing site for the MSL rover in 2012, minerals are observed within the following stratified sequence of layered rocks (from the top): silica and kaolinite, montmorillonite-like Al-rich clays, a Fe2+ phyllosilicate, Mg/Fe smectites, and sulfates [2-6]. We use three numerical models to explore a formation of these rocks through alteration of a fragmented basaltic material by a downward percolation of H2SO4-rich fluids. One model assumes a decrease in the solution to rock ratio with depth. In another model, the downward fluid migration is considered. In both models, fluids reach chemical equilibrium with rocks. In the third model, kinetics of mineral dissolution is considered along with fluid percolation. The modeling is performed for 0 oC and pressure from 0.006 to 1 bar. The system was either open or closed with respect to CO2 and O2.

The modeling reproduces the observed silica-kaolinite-montmorillonite-smectite sequence of dominated minerals. In the models, the sequence reflects neutralization of fluids with depth. Open system models also lead to formation of goethite and/or hematite, and carbonates form in association with smectites (saponite). In closed systems, zeolites and Fe2+-chlorites occur with smectites, and Fe2+-chlorite rich rocks form between layers rich in montmorillonite and smectites. The latter result is consistent with observations, though the upper part of the martian profile also agrees with an open-system acid alteration. Modeled Ca sulfates coexist with clay minerals, and more soluble sulfates could form through evaporation of neutralized fluids accumulated in the lower part of the stratigraphic sequence. [1] Poulet et al. (2005) Nature 438, 623-627. [2] Mustard et al. (2008) Nature 454, 305-309. [3] Wray et al. (2008) Geophys. Res. Lett. 35, L12202. [4] Bishop et al. (2008) Science 321, 830-833. [5] McKeown et al. (2009) J. Geophys. Res. 114, E00D10. [6] Wray et al. (2010) Icarus 209, 416-421.

Study on the phase equilibrium of the quaternary system Cd2+, K+,

Na+//SO42--H2O at 298 K

FANG ZOU1, HUANG YI1, 2*, NI SHIJUN2 AND ZENG YING3 1Department of Geochemistry, Chengdu University of

Technology, Sichuan, PRC (*correspondence: [email protected])

2Applied Nuclear technigues in Groscience Key Laboratory of Sichuan Proviance, PRC

3 College of Materials and Chemistry & Chemical Engineering, Sichuan, PRC

Solid- Liquid Equilibrium of quaternary system Cd2+, K+,

Na+// SO42--H2O at 298 K were studied by an isothermal

solution saturation method. Experimental results indicate that there are five univariant curves E1F1, E1F4, E1E2, E2F2 and E2F3, two invariant points E1, E2 and four crystallization fields in the quaternary system. The system belongs to a quaternary system, and there is a double salt (Na2SO4·3K2SO4) existing. The crystallization zones of equilibrium solid phases are K2SO4 (E1F1MF4 field), Na2SO4·3K2SO4 (E1E2F3F4 field), Na2SO4·10H2O (E2F2AF3 field), and CdSO4·H2O (E2F1BF2 field), respectively. The composition of the invariant point E1 is K2SO4, Na2SO4·3K2SO4 and CdSO4·H2O, respectively. The composition of the invariant point E2 is Na2SO4·3K2SO4, Na2SO4·10H2O and CdSO4·H2O, respectively. The physico-chemical properties of solution in the quaternary system show regular changes along with the increased cadmium concentration. CdSO4 possessed the highest solubility among those three salts, which means a strong transfer of Cd ion and a high pollution risk of soil environment.



2290

Geochemistry and metallogenesis of fluid in Liuju sandstone-bound

copper deposit, Dayao, Yunnan, China

ZOU HIAJUN1,2,*, HAN RUNSHENG2, YAO ZHIHUA1 AND LIU MENGQIONG3

1Yunnan Copper Industry Group, Kunming, Yunnan, P.R.China 650051 (*correspondence: [email protected])

2Kunming University of Science and Technology, Kunming, Yunnan, P.R.China 650093

3Yunnan Architecture Engineering Design Institute, Kunming ,China P.R.China, 650041

11 typical samples are purple or bleached sandstone and

ores, from K2ml1 (main orebody hosting bed), K2ml2, K2md and K1p in Liuju Sandstone-bound Copper Deposit, Dayao, Yunnan, China. Quartz and minor calcite were used for making fluid inclusion tests.

The original inclusions mainly are in vapor-liquid phase. Their generation period features are apparent. The original and secondary inclusions in bleached sandstone respectively represent main metallization stage (forming stratiform chalcocite orebody) and reforming stage. The ones in quartz veins respectively represent minor metallization stage (forming veiny chalcopyrite orebody) and later reforming stage. The ore-forming fluid could be two medium-low salinity fluid of organic material-bearing, medium-temperature to medium-low- temperature, reducing fluid and a little organic material-bearing, oxidizing fluid. 70% uniform temperature numbers of fluid inclusions assemble between 200' and 100'. The fluid belongs to NaCl-H2O system, in which, beside agglutinates, the salinity is less than 12%. The component test results of the original quartz inclusions by La-ICP-MS show the fluid in main metallization stage is of H2O-SO2-CO2-CH4 (C3H8-C2H6)&HSO4

-&HCO3- type, and the

fluid in secondary metallization stage is of H2O-SO2-CO2-N2-CO-CH4- HSO4

- type. Research results indicate the fluid metallogenesis mode

may be described as: the forming and reforming movements of the Daxueshan Anticline provided power and energy (heat energy) for metallization, which drove deep-seated organic matter-bearing and reducing fluid to go up and cycle, with superficial oxidizing infiltrating fluid, to extract ore-forming material from the source beds. Because of the physical-chemical conditions changing in the high permeability and porosity of sandstone beds at the gently inclined wing of the Anticline, oxidation-reduction reactions occurred in the fluids which led to form the deposit.

Robust aerosol indirect effects inferred from remotely-sensed cloud properties acquired during VOCALS

PAQUITA ZUIDEMA1, DAVID LEON2 AND DAVID PAINEMAL3

1U. of Miami/RSMAS, 600 Rickenbacker Cswy, Miami, FL 33149, USA, ([email protected])

2 U of Wyoming, Laramie, WY, 82071, USA ([email protected])

3 U. of Miami/RSMAS, 600 Rickenbacker Cswy, Miami, FL 33149, USA, ([email protected])

One wealth of the VOCALS field experiment in the

southeast Pacific stratocumulus region is a unique dataset on cloud properties acquired through a suite of airborne remote sensors. This includes a lidar, a cloud radar and a radiometer providing cloud liquid water paths. All are valuable individually, but in combination form a powerful suite capable of extending aircraft assessments of aerosol-cloud-precipitation impacts beyond what can be done with in-situ measurements. The cloud liquid water path dataset also allows for the statistically-robust examination of thin clouds, which cloud radars and satellites have difficulty characterizing. For this presentation the new cloud liquid water path dataset is described, compared to adiabatically-derived values, and aerosol indirect effects — co-variations with cloud liquid water path, precipitation, and cloud albedos — are assessed. In keeping with the theme session, comparisons to similarly-derived satellite properties will be made to opine on satellite assessments but done on larger spatial scales.



2291

Effects of grid size in interpolating of geochemical data

RENGUANG ZUO1,2 1State Key laboratory of Geological Process and Mineral

Resources, China University of Geosciences, Wuhan, 430074, China ([email protected])

2State Key laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan, Beijing, 100083, China

Grid size is one of important uncertainty sources in

interpolating of geochemical data. We explore the grid size how to influence geochemical mapping using a case study located in the western Gangdese belt, Tibet (China). This study area measures about 19,375 km2 and comprises of 921 stream sediment samples with a density 0.05 sample point per km2 corresponds to the scale of about 1:500, 000. The selection of grid size is influenced by the density of samples or mapping scale(i.e., The denser the sample points, the larger the scale of mapping, and the smaller the grid size), and the structure of point patterns (i.e., distance between the sampled points, and the range of spatial dependence). Generally, the gird size should be smaller than a given size which makes >95% of the closest point pairs not fall into the same grid. The grid size is also larger than a given grid size because finer grid cell do not make sense as it will be hard to visualize or print them at this scale of work [1]. The resulting of neighbour nearest distance between point pairs shows that the average spacing between the closest point pairs is 2.18 km, and 5% probability smallest distance is 1.09 km, which makes >95% point not fall into the same grid. The original dataset is divided into two parts namely testing dataset and training dataset. The testing dataset contains randomly selected samples, which are 5% of the total number of samples, and the remaining 95% samples are used for interpolating data. Six grid sizes namely 1.1 km, 1.3 km, 1.5 km, 1.7 km, 1.9 km, 2.1 km are selected to interpolate Cu data using inverse distance weighted method (IDW) with the same parameters. The results indicate that 1.7 km is the optimal grid cell size in this study because the interpolating Cu map has the maximum value of standard deviation, and the difference between Cu true value and interpolated value has the lower mean and relative lower standard deviation.

[1] Hengl (2006), Computers & Geosciences 32, 1283-1298.

Technical methods of barriers of near-surface disposal of very low

level radioactive waste RUI ZUO, JINSHENG WANG AND YANGUO TENG

College of Water Sciences, Beijing Normal University, Beijing 100875, China, ([email protected])

The caused environmental pollution problems by nuclear

are very urgent, any country treats it with caution. Under existed technologies, geological disposal is recognized as the most effective method. For security and efficient, the very low level radioactive waste (VLLW) is separated from the medium-low-level radioactive waste, and the design of the repository could meet the environmental requirements without very strict geological condition, however, the barrier material of the VLLW repository still is key to radioactive waste disposal. A candidate site, which was for the disposal of VLLW in Southwestern China, was built in the terraces of alluvial valley. We focused on the multiple geological barrier system on the near-surface geological disposal. The multiple barrier technology is reflected at natural barriers (natural geological body) and engineering barriers (material). For the absorption of the barrier, batch tests and column experiments methods were applied for the influencing factors and mechanism of adsorption.

The disposal site was on a narrow but long river terraces at the interchange of two rivers, the groundwater table in the site was generally 5-6m. 90Sr were selected as the typical nuclides. The barriers in the wall and bottom of repository (basin-shaped) were selected. The fine particle (d<1mm), which is from the site, was used for the barrier material in the wall, attapulgite mixed with gravel was used for the bottom barriers. The sorption characteristics and influencing fators of 90Sr in the two barrier material were measured by batch tests, results show that the selected fine particle (d<1mm) for 90Sr have a certain adsorption, the orders of distribution coefficient in the 102. And from the results, the Kd value of the fine particle and the attapulgite was 40-80 and 100-120, respectively, and there was a great influence of pH value, content of CO3

2-, and initial concentration on sorption. In addition, modified (acid treated, sonicated and baked) attapulgite was researched for the sorption capacity, the concentration of hydrochloric acid at 1M, or ultrasonic time of 10min, or the temperature at 600', the adsorption of nuclear improved significantly.

This study is supported by “the Fundamental Research Funds for the Central Universities”.



2292

Luminescent properties of natural copper and silver iodide

L.A. ZYRYANOVA, N.N. BOROZNOVSKAYA AND K.V. TOLOCHKO

Tomsk State University, Tomsk, Russia

Studies have been performed on the structural characteristics and roentgenoluminescence spectra (RL) of copper and silver iodides from the zone of oxidation of the Rubtsovsk polymetallic deposit (Rudnyi Altai). The investigation on the RL characteristics of the natural Cu and Ag iodides has demonstrated their dependence on the Cu/Ag-ratio and the structural type of a mineral. It has been established that the RL spectra of the cubic marshite (Cu, Ag)I, miersite (Ag, Cu)I and hexagonal iodargyrite (AgI) differ in the intensity and spectral composition of the emission in the wave length range of 400-800 nm. The correlation has been discovered between the silver content entering the minerals of the (Cu, Ag)I - (Ag, Cu)I series and the RL intensity in the range of 600-800 nm. The shift of emission bands in the range of 600-800 nm from iodargyrite to miersite and farther to marshite into the long-wave zone has been established. In the iodargyrite RL spectra, the short-wave RL band (420-450 nm) has been found, the emission character of which coincides with the excitonic luminescence of 2" and 4" polytypes of AgI.

Fig. 1: Roentgenoluminescence spectra (RL) of copper and silver iodides: 1 – marshite, 2 – miersite, 3 – iodargyrite

These researches have been supported by the Ministry of

Education and Science of Russia.

Modeling of column experiments - Goldschmidt Conference Archive

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