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SOCIETÀ PALEONTOLOGICA ITALIANA

MODENA - 2009

TIME AND LIFE IN THE SILURIAN:A MULTIDISCIPLINARY APPROACH

SUBCOMMISSION on

SILURIAN

STRATIGRAPHY in

SARDINIA

Fieldmeeting4 - 11 June 2009

S4

Time and life in the Silurian: a multidisciplinary approach

Subcommission on Silurian Stratigraphy Field Meeting 2009

Abstracts

I

Rendiconti della Società Paleontologica Italiana

3(III)

Time and Life in the Silurian:a multidisciplinary approach

Subcommission on Silurian Stratigraphy Field Meeting 2009Sardinia, June 4-11, 2009

Abstracts

Edited byMaria G. Corriga

Sergio Piras

Società Paleontologica Italiana2009

II

REFERENCES TO THIS VOLUME

It is recommended that reference to the whole or part of this volume be made in one ofthe following forms, as appropriate:

CORRIGA M.G. & PIRAS S., eds. (2009). Time and Life in the Silurian: a multidisciplinary approach.Abstracts. Rendiconti della Società Paleontologica Italiana, 3 (3): 106 pp.

BARRICK J.E., KLEFFNER M.A., GIBSON M.A., PEAVEY F.N. & KARLSSON H.R. (2009). The LauPrimo-Secundo Oceanic Event and Mid-Ludfordian Isotope Excursion (Ludlow, Silurian) inSouthern Laurentia. In Corriga M.G. & Piras S. (Eds.), Time and Life in the Silurian: amultidisciplinary approach. Abstracts. Rendiconti della Società Paleontologica Italiana, 3(3): 267-268.

THE ITALIAN PALAEONTOLOGICAL SOCIETY

The Association named Società Paleontologica Italiana was founded in 1948 to promoteresearch in palaeontology and related sciences. Membership is open to institution and to anyoneis interested in palaeontology, wheather as a professional scientist or as amateur. Membershipfees for year 2009 are:Ordinary membership (European Union) 35 EuroOrdinary membership (extra E.U.) 45 EuroJunior membership (under 30) 21 EuroIstitutional membership 70 Euro

Since 1960 the Society publishes the Bollettino della Società Paleontologica Italiana, aninternational journal with scientific papers dealing on any branch of palaeontology. In year 2000,it also started to publish PaleoItalia, a half-yearly booklet written in Italian, mainly addressedto amateur palaeontologists.

The Rendiconti della Società Paleontologica Italiana is a series of volumes groupingdocuments of scientific meetings (abstracts and proceedings) and field trips guidebooks.

For further informations: www.spi.unimo.it

EDITORS ADDRESSES

Maria G. CorrigaDipartimento di Scienze della Terra, Università di Cagliarivia Trentino 51, I-09127 Cagliari (Italy); [email protected]

Sergio PirasDipartimento di Scienze della Terra, Università di Cagliarivia Trentino 51, I-09127 Cagliari (Italy); [email protected]

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ORGANIZING COMMITTEE

Carlo Corradini Università di Cagliari, Italy

Annalisa Ferretti Università di Modena e Reggio Emilia, Italy

Petr Storch Czech Academy of Sciences, Czech Republic

Sebastiano Barca Università di Cagliari, Italy

Maria G. Corriga Università di Cagliari, Italy

Myriam Del Rio Università di Cagliari, Italy

Maurizio Gnoli Università di Modena e Reggio Emilia, Italy

Kathleen Histon Università di Modena e Reggio Emilia, Italy

Francesco Leone Università di Cagliari, Italy

Alfredo Loi Università di Cagliari, Italy

Gian Luigi Pillola Università di Cagliari, Italy

Sergio Piras Università di Cagliari, Italy

Paola Pittau Università di Cagliari, Italy

Paolo Serventi Università di Modena e Reggio Emilia, Italy

SCIENTIFIC COMMITTEE

Stanley Finney California State University Long Beach, Long Beach, CA, U.S.A.

Michael J. Melchin St. Francis Xavier University, Antigonish, Canada

Juan Carlos Gutiérrez-Marco Universidad Complutense de Madrid, Madrid, Spain

Charles H. Holland Trinity College, Dublin, Ireland

Jiri Kriz Czech Geological Survey, Prague, Czech Republic

Peep Männik Tallinn Technical University, Tallin, Estonia

Florentin Paris Université de Rennes 1, Rennes, France

Jiayu Rong Chinese Academy of Sciences, Nanjing, China

Hans Peter Schönlaub Austrian Academy of Sciences, Vienna, Austria

Enrico Serpagli Università di Modena and Reggio Emilia, Modena, Italy

Jacques Verniers Ghent University, Ghent, Belgium

Time and life in the Silurian: a multidisciplinary approachSubcommission on Silurian Stratigraphy field meeting 2009

Sardinia, June 4-11, 2009

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SPONSORING INSTITUTIONS

Università di CagliariUniversità di Modena e Reggio EmiliaFacoltà di Scienze MM.FF.NN., Università di CagliariComune di GoniComune di Silius

Università degli Studi Università degli Studidi Cagliari di Modena e Reggio Emilia

UNDER THE PATRONAGE OF

Il Magnifico Rettore dell’Università degli Studi di CagliariIl Magnifico Rettore dell’Università degli Studi di Modena e Reggio EmiliaIl Preside della Facoltà di Scienze MM.FF.NN., Università di CagliariIl Presidente della Società Paleontologica Italiana

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The Lau Primo-Secundo Oceanic Event and Mid-Ludfordian Isotope Excursion (Ludlow, Silurian) insouthern Laurentia

JAMES E. BARRICK, MARK A. KLEFFNER, MICHAEL A. GIBSON, F. NICOLE PEAVEY,HARALDUR R. KARLSSON

J.E. Barrick - Department of Geosciences, Texas Tech University, Lubbock, TX 79409-1053 (U.S.A.); [email protected]. Kleffner - School of Earth Sciences, Division of Geological Sciences, The Ohio University at Lima, Lima, OH

45804 (U.S.A.).M.A. Gibson - Department of Geology, Geography & Physics, University of Tennessee at Martin, Martin, TN 38238-

5039 (U.S.A.).F.N. Peavey - Texas Tech University, Lubbock, TX 79409-1053 (U.S.A.).R.H. Karlsson - Texas Tech University, Lubbock, TX 79409-1053 (U.S.A.).

The Lau Primo-Secundo Oceanic Event and the mid-Ludfordian Isotope Excursionhave been recognized in three regions in southern Laurentia: the Arbuckle Mountains insouthern Oklahoma (2 sections), the western Illinois Basin in eastern Missouri (1 section),and the western valley of Tennessee (5 sections).

Pre-Lau strata in southern Oklahoma comprise the brownish argillaceous, siltywackestones and shales with poorly preserved graptolites of the lower HenryhouseFormation. A diverse Dapsilodus-dominated fauna includes species characteristic of theHavdlem Primo Episode in moderate abundance: Polygnathoides siluricus, Oulodussiluricus, Ozarkodina confluens, Walliserodus sp., Kockelella sp. and Panderodusrecurvatus. These species disappear at a bedding surface, to be replaced by a faunacharacterized by Ozarkodina snajdri and abundant Wurmiella excavata and Dapsilodus.Clay and silt content declines abruptly at the faunal break and more resistant skeletalwackestones appear slightly higher, with Pedavis latialata and O. auriformis. Values ofδ13C dip from +1 to –0.5‰ below the faunal break, rise to near +4.0‰ in the W. excavatafauna, and fall to +1.0‰ in the overlying resistant wackestones. The lower Henryhousesilty wackestones and shales have been removed by erosion over much of southernOklahoma, and the post-Lau skeletal wackestones lie at the base of the HenryhouseFormation at many sections.

In eastern Missouri, pre-Lau strata of the Bainbridge Formation comprise mottled redargillaceous wackestones and shales yielding a Panderodus equicostatus-dominated fauna,with P. recurvatus, less common O. confluens, Walliserodus, and rare Polygnathoidessiluricus. Above this lies a thin, >1 m, argillaceous greenish gray carbonate mudstonefrom which only a few elements of Pseudooneotodus have been recovered. Above thismudstone are interbedded reddish shales and thin limestones, in which an abundantDapsilodus and W. excavata fauna appears. This is overlain by a clean, more resistantskeletal wackestone with O. snajdri and O. auriformis. Values of δ13C dip from +1.0 to–3.5‰ in the base of the greenish-gray mudstone, rise to near +5.0‰ in the top of themudstone, and fall to +1.0‰ in the shale and thin limestones below the resistant wackestoneunit.

Rendiconti della Società Paleontologica Italiana, 3 (3), 2009: 267-268

Time and Life in the Silurian: a multidisciplinary approachSardinia, Italy - June 4-11, 2009

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Pre-Lau strata in the Brownsport Formation in western Tennessee comprise green tobrown fossiliferous shales and argillaceous skeletal wackestones of the Beech RiverMember, which may grade upward into an echinoderm grainstone facies, the Bob Member.The Beech River and Bob members are characterized by a sparse Panderodus equicostatus/P. recurvatus conodont fauna that includes small numbers of O. confluens, P. siluricus,and rare other species. In the more western sections, darker gray argillaceous carbonatemudstones, packstones and shales overlie the Beech River-Bob section, near the base ofwhich the mid-Ludfordian Excursion appears, which extends through 5 m of section andreaches values of δ13C greater than +6‰. In the more eastern sections, however, theExcursion appears near the base of, and ranges through a 4- to 5-m section of, coarse-grained echinoderm grainstones that rest directly on Beech River-Bob lithofacies. Maximumvalues of δ13C reach only as high as +5‰ in these grainstones. The pre-Lau Panderodus-dominated conodont fauna disappears as the values of δ13C start to rise from a shortinterval of negative values in both areas. At the base of the grainstones, a conodont faunawith W. excavata, Dapsilodus, Decoriconus, and rare O. snajdri is present, with rare P.recurvatus. In both areas, strata that comprise the Mid-Ludfordian Excursion yield only afew isolated elements of W. excavata, Dapsilodus or Pseudooneotodus. The LobelvilleMember, the upper shaly member of the Brownsport with a unique coral fauna, is post-Lau in age in its type area in the east, but may include the Lau Event at its base to thewest.

The Lau Event and mid-Ludfordian Excursion in southern Laurentia represent aninterval of time during which a major reorganization of conodont faunas occurred, butwith few lineage extinctions. The major rearrangement of shallow water lithofacies inwestern Tennessee, shifts in deeper water carbonate lithofacies in eastern Missouri and inOklahoma, and an erosional unconformity in Oklahoma all indicate the presence of asignificant sequence boundary that was the product of a major middle Ludfordian fall andrise in eustatic sea level.

Subcommission on Silurian Stratigraphy field meeting 2009 - Abstract book

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Early Palaeozoic palaeogeography of SevernayaZemlya, Arctic Russia (with new data on the Silurian)

OLGA K. BOGOLEPOVA, ALEXANDER P. GUBANOV

O.K. Bogolepova - CASP, Cambridge University, 18 a Huntingdon Road, Cambridge, CB3 0DH (United Kingdom);[email protected]

A.P. Gubanov - CASP, Cambridge University, 18 a Huntingdon Road, Cambridge, CB3 0DH, (United Kingdom);[email protected]

Our research in recent years has been focused on the palaeontology, biostratigraphyand palaeogeography of the Severnaya Zemlya Archipelago of Arctic Russia. This area,together with northern Taimyr, belongs to the Kara Terrane, palaeogeography of whichduring the early Palaeozoic remains problematic; it may have been an independentmicrocontinent, a part of separate microcontinent Arctida, or contiguous with Baltica(Gee & Pease, 2004; Metelkin et al., 2005, and references therein).

The Cambrian trilobites, brachiopods, molluscs and microfossils of Severnaya Zemlyashow affinity to Baltica and Siberia (Bogolepova et al., 2001). The Ordovician macro-and microfossil assemblages contain elements typical of both Siberian and Baltic bioticprovinces (Bogolepova et al., 2006).

New data on the Silurian faunas provide some unique information on their similaritiesto those of Baltica and Laurentia. The evidence from the ostracodes Entomozoe aff. E.tuberosa indicates connection between Severnaya Zemlya and eastern North Greenland(Siveter & Bogolepova, 2006). One more example of these affinities can be shown withregard to conodonts, which occur commonly in the Early Silurian successions of SevernayaZemlya). Several taxa characteristic of the Telychian faunas of the eastern (Timan-Pechora)and western (Estonia) parts of Baltica (e.g. Apsidognathus cf. milleri, Distomodus cf.staurognathoides and Pterospathodus eopennatus) were found in the region for the firsttime. Moreover, on Severnaya Zemlya, Pterospathodus eopennatus occurs together withAspelunda aff. expansa and Ozarcodina broenlundi, known from Peary Land of easternNorth Greenland (Männik et al., 2009).

Thus, a probable palaeogeographic scenario is that the Kara Terrane was locatedbetween Baltica and Siberia during the Late Cambrian and Ordovician. The entire regionwas covered by shallow seas, with no deep-water seaways, allowing easy faunal exchangebetween Baltica and Siberia. The presence of common benthic taxa throughout theCambrian suggests that Iapetus was a rather narrow seaway even when it reached itsmaximum size during the Early Ordovician (Gubanov & Tait, 1998). The Iapetus Oceanbegan to narrow through the rest of the Ordovician and was closed in late Silurian byrelatively orthogonal collision between Laurentia and Baltica (Roberts & Gee, 1985); thisgave an increasing number of taxa of the Laurentian affinity into Kara.

REFERENCESBOGOLEPOVA O.K., GUBANOV A.P. & RAEVSKAYA E.G. (2001). The Cambrian of Severnaya Zemlya Archipelago,

Russia. Newsletters on Stratigraphy, 39 (1): 73-91.



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BOGOLEPOVA O.K., GUBANOV A.P. & PEASE V. (2006). The Ordovician of Severnaya Zemlya Archipelago.Newsletters on stratigraphy, 42 (1): 1-21.

GEE D.G. & PEASE V.L. eds. (2004). The Neoproterozoic Timanide Orogeny of Eastern Baltica. GeologicalSociety, London, Memoirs, 30, 249 pp.

GUBANOV A.P. & TAIT J. (1998). Maclurites (Mollusca) and Ordovician palaeogeography. Schriften desStaatlichen Museums für Mineralogie und Geologie zu Dresden, 9: 140-142.

MÄNNIK P., BOGOLEPOVA O.K., POLDVERE A. & GUBANOV A.P. (2009). New data on Ordovician-Silurian conodontsand stratigraphy of the Severnaya Zemlya Archiopelago, Russian Arctic. Geological Magazine [inpress]

METELKIN D.V., VERNIKOVSKY V.A., KAZANSKY A.YU., BOGOLEPOVA O.K. & GUBANOV A.P. (2005). Paleozoichistory of the Kara microcontinent and its relation to Siberia and Baltica: paleomagnetism, palaeogeographyand tectonics. Tectonophysics, 398: 225-243.

ROBERTS D. & GEE D.G. (1985). An introduction to the structure of the Scandinavian Caledonides. In: GeeD.G., Sturt B.A. (Eds.),The Caledonide Orogen - Scandinavia and Related Areas. Wiley, Chichester, 55–68

SIVETER D.J. & BOGOLEPOVA O.K. (2006). The myodocope ostracod Entomozoe from the early Silurian ofSevernaya Zemlya, Russian Arctic. Norwegian Journal of Geology, 86: 51-58.


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Trilobites from the Scyphocrinites limestone (Pridoli)of the Sierra Norte of Seville Natural Park, southernSpain

RODRIGO CASTAÑO, ISABEL RÁBANO, GRACIELA N. SARMIENTO

R.Castaño - Instituto Geológico y Minero de España (Spanish Geological Survey); Avda. Real 1, 24006 León (Spain);[email protected]

I. Rábano - Instituto Geológico y Minero de España (Spanish Geological Survey); Ríos Rosas, 23, 28003 Madrid(Spain); [email protected]

G.N. Sarmiento - Instituto de Geología Económica (CSIC-UCM), Ciudad Universitaria s/n, 28040 Madrid (Spain);[email protected]

Two of the more complete and representative Silurian sections of the Ossa-MorenaZone of the SW Iberian Massif are located in the Sierra Norte of Seville Natural Parkwithin the cores of the Valle and Cerrón del Hornillo synclines (Robardet & Gutiérrez-Marco, 2004). The Silurian succession of this area has a reduced thickness and displays atripartite stratigraphy reminiscent of the “Thuringian triad” of the northern margin ofGondwana, being composed of graptolitic black shales with an intermediate carbonateunit, the “Scyphocrinites limestone” (Jaeger & Robardet, 1979).

The “Lower graptolitic shales” represent a complete succession of Llandovery, Wenlockand Ludlow age, recorded by 20 graptolitic biozones (Jaeger & Robardet, 1979; Robardet& Gutiérrez-Marco, 2004).

The “Scyphocrinites limestone” consists of 10-15 meters of alternating dark limestonesand calcareous shales with abundant scyphocrinoid remains (columnals, crowns and lobolithsof Scyphocrinites and Camarocrinus), as well as some brachiopods, trilobites, cephalopods,bivalves, gastropods, ostracods, cornulitids, hyolitids, machaeridians, solitary corals,graptolites, conodonts and siliceous sponge spicules.

The “Upper graptolitic shales” of latest Pridoli to Lochkovian age contains in its basal5-6 meters calcareous nodules with latest Silurian graptolites and molluscs and, accordingto Oczlon (1989), also the trilobite Cromus aff. bohemicus (Barrande), not relocated byus.

The trilobite assemblage reported here was collected from marly intercalations of the“Scyphocrinites limestone” and includes the following taxa: Cromus cf. krolmusi Chlupác,C. aff. leirion Šnajdr, Cromus n. sp. 1, Cromus n. sp. 2, Crotalocephalus cf. transiens(Bou´ek), Bohemoharpes (Unguloharpes) sp., Denkmanites sp. and Leonaspis sp. Thisassociation has a distinct Bohemian character, but Cromus n. sp. 1 resembles Cromusrialpensis von Gaertner, which occurs in Ludlow strata in the Pyrenees.

The “Scyphocrinites limestone” correlates entirely with the Pridoli. The graptolites ofthe lower part of this unit belong to the lower Pridoli Neocolonograptus parultimus- N.ultimus Biozone, and those from the top of the limestone, as well as those recorded fromthe calcareous nodules at the base of the “Upper graptolitic shales”, indicate correlationwith the uppermost Pridoli Istrograptus transgrediens Biozone (Piçarra et al., 1998).The conodont assemblages found in the same beds of both formations belong to the



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Ozarkodina remscheidensis interval Zone (Pridoli), as indicated by the occurrence ofOulodus elegans (Walliser), Pseudooneotodus beckmanni (Bischoff & Sannemann),“Ozarkodina” remscheidensis (Ziegler), “O.” confluens (Branson & Mehl),“O.”eosteinhornensis (Walliser) and “O.” excavata (Branson & Mehl).

Of paleogeographic importance is the close affinity of the trilobite association of the“Scyphocrinites limestone” with Bohemian faunas, so far unknown in the coeval“Ockerkalk” of the typical Thuringian facies from Germany and southeastern Sardinia.In addition to SW Iberia, some of the Bohemian trilobite taxa are geographically widespread,occurring in Pridolian limestones of an intermediate Thuringian-Bohemian facies, asindicated by its possible occurrence in several localities of N Africa and the Pyrenees.

This work is a contribution to the PATRIORSI project (CGL2006-07628/BTE) of theSpanish Ministry of Science and Innovation.

REFERENCESJAEGER H. & ROBARDET M. (1979). Le Silurien et le Dévonien basal de la Province de Séville (Espagne).

Geobios, 12: 687-714.OCZLON M. (1989). Fazies und fauna im Silur und Devon des “Valle” (Provinz Sevilla, SW-Spanien).

Diplomarbeit Universität Heidelberg. 86 pp. (Unpublished).PIÇARRA, J.M., GUTIÉRREZ-MARCO, J.C., LENZ, A.C., ROBARDET, M. (1998). Pridoli graptolites from the Iberian

Peninsula: a review of previous data and new records. Canadian Journal of Earth Sciences, 35: 65-75.ROBARDET M. & GUTIÉRREZ-MARCO J.C. (2004). The Ordovician, Silurian and Devonian rocks of the Ossa-

Morena Zone (SW Iberian Peninsula, Spain). Journal of Iberian Geology, 30: 73-92.


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Looking for a late Silurian Standard ConodontZonation: still a long way to go

CARLO CORRADINI

C. Corradini - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);[email protected]

In the last forty years several conodont zonation schemes were proposed for theSilurian, but none has been widely accepted up to now.

The first conodont zonation for the Silurian was proposed by Walliser (1964), whobased his scheme primarily on the Cellon Section (Carnic Alps, Austria), taking in accountalso data from Bohemia and Spain. The author defined twelve successive appearancezones spanning the Silurian and the lowermost Devonian. Several of these zones havebeen widely recognized, but the difficulties of applying the complete scheme in otherparts of the world have led to the development of many local zonations, mainly for theLlandovery, which is not completely exposed in Cellon.

Aldridge & Schönlaub (1989), considering all the available data, provided a new scheme,which is a “step on the path to the development of a reference biozonation” (p. 275).Their global zonation has been reported also in the Newsletter of the Subcommission ofSilurian Stratigraphy (Silurian Times n°1; 1993). Two years later, a new Conodont GlobalZonation chart appeared (Silurian Times n°3; Nowlan, 1995), significantly different fromthe others, but never fully justified or discussed.

Corradini & Serpagli (1998, 1999) proposed a new scheme, based on Sardinian data:the authors proved that the Sardinian conodont zonation is widely usable worldwide andclaimed that it is “of practical use for Silurian biostratigraphy, and therefore more generallyuseful than extremely detailed schemes, sometimes based on not yet defined or endemictaxa” (Corradini & Serpagli, 1999, p. 270). Following these considerations, the sameauthors (Corradini & Serpagli, 2000) proposed their scheme as a Standard SilurianConodont Zonation for the Wenlock-Pridoli time span.

Finally, Ogg et al. (2008) published a scheme intermediate between those introducedby Nowlan (1995) and Corradini & Serpagli (1999), but with some problems still open,mainly the occurrence of a “not zoned” interval in the lower Ludlow.

Other unsolved problems arose recently from the taxonomic revision of someOzarkodinids carried on by a few authors in the last five years (Murphy et al., 2004;Carls et al., 2005, 2007), who left without a home several morphotypes previously identifiedas Oz. remscheidensis. We agree that those taxa may represent several different specieswithin the Genus Zieglerodina, but it is necessary to conclude soon the revision at aspecies level (and not at genus level), in order to avoid the big taxonomic chaos that wecan observe now. All specimens figured by different authors in the last decades should beincluded and discussed in this revision. In fact, it is not acceptable simply to write thatseveral previous taxonomic determinations and all previous biostratigraphic schemes forthe Pridoli are wrong (Carls et al., 2007), without providing any alternative.

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The proposal by Corriga & Corradini (2009) and Corriga et al. (2009) to rename theformer “remscheidensis interval Zone” as “eosteinhornensis s.l. interval Zone” withoutchanging the meaning of the zone and the definition of its boundaries is a temporarysolution and can be accepted only until that taxonomic work will be concluded. Then, anew zonation for the Pridoli should be proposed.

REFERENCESALDRIDGE R.J. & SCHÖNLAUB H.P. (1989). Conodonts. In Holland C.H. & Bassett M.G. (Eds.), A Global

Standard for the Silurian System. National Museum of Wales, Geological Series, 9: 274-279.CARLS P., SLAVIK L. & VALENZUELA-RIOS J.I. (2005). A new Ludlow (Late Silurian) Spathognathodontidae

(Conodonta) from Bohemia with incipient alternating denticulation. Neues Jahrbuch für Geologie undPaläontologie Monatshefte, 2005-H9: 547-565.

CARLS P., SLAVIK L. & VALENZUELA-RIOS J.I. (2007). Revision of conodont biostratigraphy across the Silurian-Devonian boundary. Bulletin of Geosciences, 82 (2): 145-164.

CORRADINI C. & SERPAGLI E. (1998). A Late Llandovery-Pridoli (Silurian) conodont biozonation in Sardinia. InSerpagli E. (Ed.), Sardinia Field-trip Guide-book, ECOS VII. Giornale di Geologia, 60, Spec. Issue: 85-88.

CORRADINI C. & SERPAGLI E. (1999). A Silurian conodont zonation from late Llandovery to end Pridoli inSardinia. Bollettino della Società Paleontologica Italiana, 38 (2-3): 255-273.

CORRADINI C. & SERPAGLI E. (2000). A new (standard?) Silurian conodont zonation. Silurian Times, 8: 25-28.CORRIGA M.G. & CORRADINI C. (2009). Upper Silurian and Lower Devonian conodonts from the Monte Cocco

II Section (Carnic Alps, Italy). Bulletin of Geosciences, 84 (1): 155-168.CORRIGA M.G., CORRADINI C. & FERRETTI A. (2009). Silurian conodonts from Sardinia: an overview. Rendiconti

della Società Paleontologica Italiana 3 (1): 95-107.MURPHY M.A., VALENZUELA-RIOS J.I. & CARLS P. (2004). On Classification of Pridoli (Silurian)-Lochkovian

(Devonian) Spathognathodontidae (Conodonts). University of California, Riverside Campus MuseumContribution, 6: 1-25.

NOWLAN G.S. (1995). Left Hand Column for Correlation Charts: Silurian Times, 3: 7-8.OGG J.G., OGG G. & GRADSTEIN F.M. (2008). The Concise Geologic Time Scale. 177 pp., Cambridge University

Press.WALLISER O. (1964). Conodonten des Silurs. Abhandlungen des Hessischen Landesamtes für

Bodenforschung zu Wiesbaden, 41: 1-106.

Fig. 1 - Comparison of main late Silurian conodont zonation schemes.


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Rendiconti della Società Paleontologica Italiana, 3 (3), 2009: 275


Silurian-Lower Devonian conodonts from the RifugioLambertenghi Fontana III Section (Carnic Alps, Italy)

MARIA G. CORRIGA, CARLO CORRADINI

M.G. Corriga - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);[email protected]

C. Corradini - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);[email protected]

The Carnic Alps, located at the Italian-Austrian border, expose one of the most completePalaeozoic sedimentary successions, documenting almost continuously a Late Ordovicianto Permian Age.

Silurian and Lower Devonian sediments are irregularly distributed within the CarnicChain from the Monte Cocco area, at the East, to Lake Wolayer, at the West.

The Rifugio Lambertenghi Fontana III (RLF III) Section is located just South of LakeVolayer. The area is well known for the abundant Silurian and Devonian sediments exposedin the area.

The RLF III Section, recently discovered, exposes about 15 m of grey-reddish“Orthoceras limestones”. The abundant macrofauna, mainly crinoids, brachiopods,nautiloids and trilobites, indicates a shallow water environment.

In order to achieve a precise age placing for the section, seventeen conodont sampleswere collected and processed with the conventional formic acid technique. All theinvestigated levels were productive and about 1200 conodont elements were recovered.The state of preservation is generally quite good, even if a few elements are broken orslightly deformed. In general the Silurian part of the section is richer (up to 96 elements/kg), whereas abundance strongly decreases in the upper part, in connection with a shallowingdepositional environment. The conodont colour is dark brown, corresponding to a ColorAlteration Index of 3.5-4. Twenty taxa, belonging to ten genera (Belodella, Coryssognathus,Dapsilodus, Icriodus, Oulodus, Ozarkodina, Panderodus, Pseudooneotodus, Wurmiellaand Zieglerodina) were discriminated. Wurmiella excavata and Panderodus unicostatusare very abundant in the lower part of the section. Belodella, both B. anomalis and B.resima are constantly present.

It is difficult to precisely locate the Silurian/Devonian Boundary, due to the scarcity ofthe fauna in the upper part of the section. Icriodus hesperius, the taxon normally used toindicate a Devonian age, occurs only at very top of the section; however, it is possible tosuppose that the boundary is about 3.5 m below, between the last occurrence of Ozarkodinaconfluens and the entry of Zieglerodina remscheidensis.

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Integrated high-resolution chronostratigraphy of theTelychian and Sheinwoodian stages: conodonts,graptolites, isotopes, and the future of Paleozoicchronostratigraphy

BRADLEY D. CRAMER, DAVID K. LOYDELL, CHRISTIAN SAMTLEBEN, AXEL MUNNECKE,DIMITRI KALJO, PEEP MÄNNIK, TÕNU MARTMA, LENNART JEPPSSON, MARK A.KLEFFNER, JAMES E. BARRICK, MATTHEW R. SALTZMAN

B.D. Cramer - Division of Geological Sciences, School of Earth Sciences, The Ohio State University, Columbus, Ohio43210 (U.S.A.).

D K. Loydell - School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth P01 3QL (UnitedKingdom).

C. Samtleben - Institut für Geowissenschaften, Universität Kiel, D-24118 Kiel (Germany).A. Munnecke - GeoZentrum Nordbayern, Fachgruppe Paläoumwelt, Universität Erlangen, D-91054 Erlangen

(Germany).D. Kaljo - Institute of Geology at Tallinn University of Technology, 19086 Tallinn (Estonia).P. Männik - Institute of Geology at Tallinn University of Technology, 19086 Tallinn (Estonia).T. Martma - Institute of Geology at Tallinn University of Technology, 19086 Tallinn (Estonia).L. Jeppsson - Department of Geology, GeoBiosphere Science Centre, Lund University, SE-223-62 Lund (Sweden).M A. Kleffner - Division of Geological Sciences, School of Earth Sciences, The Ohio State University at Lima, Lima,

Ohio 45804 (U.S.A.).J.E. Barrick - Department of Geosciences, Texas Tech University, Lubbock, Texas 79409 (U.S.A.).M.R. Saltzman - Division of Geological Sciences, School of Earth Sciences, The Ohio State University, Columbus,

Ohio 43210 (U.S.A.).

The resolution and reliability of global chronostratigraphy is directly related to the timeperiod under investigation. Whereas Cenozoic strata can often be correlated with a precisionof a few thousand to a few hundred thousand years, Paleozoic global chronostratigraphiccorrelation is frequently practiced with error bars of ±1 million years or worse. Thegeneral lack of Paleozoic deep-sea sediments and orbitally-tuned data series combinedwith the incomplete epicontinental stratigraphic record have engendered a prevailing wisdomamong the comparatively small Paleozoic community that suggests resolving the Paleozoictimescale to the level achieved for the Cenozoic was either impractical or simply impossible.

Here we integrate conodont and graptolite biostratigraphic and carbonate carbon isotopicdata from seven of the chronostratigraphically best-constrained sections from Baltica,Avalonia and Laurentia, and demonstrate global chronostratigraphic control for upperLlandovery through middle Wenlock (Telychian-Sheinwoodian) strata with precisionapproaching 100 kyr. Some intervals require further study to delineate such small timeslices, but this study helps demonstrate that it is possible to produce a Paleozoic timescalecomparable to that of younger eras.



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Late Silurian Ostracodes from the Hazro Anticline (SETurkey)

CLAUDIA DOJEN

C. Dojen - Westfälische Wilhelms-University, Institute for Geology and Palaeontology, Corrensstr. 24, D-48149 Muenster(Germany); [email protected]

A new ostracode fauna recently has been discovered from the Fetlika Valley in theHazro Anticline (SE Turkey), some 75 km northeast of the city of Diyarbakir. The area issituated south of the Assyrian suture, at the northern border of the Arabian platform.Here, adjacent to the northern margin of Gondwana, late Silurian to early Devoniansediments of the Dadas and Hazro Formation were deposited in a marine shorelineenvironment. The base of the Dadas Formation consists of biocalcarentic limestonesdeposited in a mid to outer shelf position.

The studied ostracodes are taken around the transition between the middle and upperDadas Formation, where the Silurian/Devonian boundary was supposed. But accordingto Stolle (2008) palynomorph records indicate a late Silurian age for the lower part of theupper Dadas Formation, which corresponds well with the ostracodes.

The ostracode associations consist mainly of beyrichioids represented by several newtaxa of the subfamily Amphitoxitidinae. The occurring taxa resemble strongly genera suchas Hobergiella, Juviella, Hemsiella, and Macrypsilon which are well known from thelate Silurian from Gotland and partly also from South America. Thus far, no certainidentification of these beyrichioids was possible as very few heteromorphs have beenfound. Additionally, the ostracodes specimens show only comparatively small sizes forbeyrichioids (between 0.5 an 1.0 mm), indicating that only larval stages are represented.Due to the outer shelf position, a turbiditic deposit is suggested. Besides these beyrichioidssome new beyrichiomorph and primitiopsiomorph taxa, e.g., with affinities toLimbinariella, as well as some new binodicope and podocope taxa have been found.

The occurrence of beyrichioid ostracodes at the northern border of Gondwana in LateSilurian times is remarkable, as the distribution of this ostracode group and their assumedabsence from Gondwana before the Emsian has been one of the main arguments for theRheic Ocean. However, the pre-Emsian occurrence of beyrichioids not only on the Arabianplatform, but also in South America and most probably in North Africa evidence against amature ocean which separates Gondwana from Baltica-Avalonia from the late Silurianonward. Other possibilities like island hoping, dispersal via other marine hosts, or transportby whirlwinds is unlikely because of the assumed large distances between the land masses.Recent palaeogeographic reconstructions consider for the late Silurian a width of about2500 km of the Rheic Ocean, with no rifting anymore but subduction zones, which wouldfunction as a barrier for benthic faunas. Other palaeontological evidence such as thedistribution of shallow marine brachiopods corroborate the opinion of a wide shallowmarine area instead of alare Rheic ocean.



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ACKNOWLEDGEMENTI am thankful to David Siveter (University of Leicester, Great Britain) and Roger Schallreuter (University

Greifswald, Germany) for many information concerning the ostracode fauna.

REFERENCESSTOLLE E. (2008). Upper Silurian to Middle Devonian stratigraphy of the Dada_ section, Hazro area, SE

Turkey. In: Königshof, P. & Linnemann, U. (Eds.), From Gondwana and Laurussia to Pangea: Dynamicsof Oceans and Supercontinents. 20th International Senckenberg-Conference and 2nd Geinitz-Conference.Final Meeting of IGCP 497 and IGCP 499. Abstract & Programme: 39-40.


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Conodonts of the Silurian-Devonian boundary beds inPodolia, Ukraine

DANIEL DRYGANT, HUBERT SZANIAWSKI

D. Drygant - State Museum of Natural History, National Academy of Sciences of Ukraine, Teatralna 18, Lviv 79008(Ukraine); [email protected]

H. Szaniawski - Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa (Poland);[email protected]

Upper Silurian and Lower Devonian sediments are well exposed at many localitiesalong the banks of Dniester and its tributaries. They are composed of continuous marinesedimentary sequence formed since the late Llandovery to the late Lochkovian. Thicknessof the Silurian deposits is about 340 m. and of the marine Devonian (Lochkovian) about500 m. The marine Lochkovian pass gradualy into terrigenous Old Red facies.

Lower part of the Pridoli series (50 m.) is composed of limestones of various lithologictype with the bioherms and biostroms, as well as dolomites and dolomitic marls. Conodontsare rare; represented mainly by Ozarkodina typica and some wide-spread species ofPanderodus. Upper part of the series (20 m.) is build mainly of nodular limestone withrich assemblages of fauna. The limestone is rich also in conodonts. Comparatively abundantare: Ozarkodina typica, Parazieglerodina eosteinhornensis, Wurmiella excavata andPanderodus unicostatus. Rarely occur also Delotaxis detorta and Belodella resima(Drygant 1984). Some of the species are important for identification of the S/D boundary.O. typica and W. excavata curvata do not occur higher than 1,4 m. below the boundaryand P. eosteinhornensis disappear just below the boundary. The boundary is establishedon the first occurence of graptolite Monograptus uniformis angustidens, which is knownin Podolia from the outcrops in the villages Dinstrove (Volkovtsy) and Rashkiv (NikiforovaPredtechenskij 1968). The lowermost part of the Lochkovian stage, the KhudykivtsiFormation (57 m), is developed in form of the clayey limestones interbedded with shales.40 cm below the S/D boundary appears Zieglerodina remscheidensis and 60 cm above itthe first representative of the genus Caudicriodus, the C. hesperius. We can not confirmthe earlier reports about occurence of Caudicriodus specimens below the boundary.Higher part of the Lochkovian – the Mytkiv Fm. (about 125 m) is composed of darkshales with rare and thin lenses of coquilla limestone, composed mainly of the brachiopodshells. Occurrences of graptolites, Monograptus uniformis uniformis at 55 to 130 mabove the S/D boundary and M. uniformis brevis at 160 m above the boundary (Koren1973), correlates well with the distribution of conodonts. Caudicriodus hesperius andZieglerododina remscheidensis disappear on about the same level as the graptolites. Itsuggest that stratigraphic range of the conodont horizon C. hesperius corresponds to therange of the graptolite horizon M. uniformis.

REFERENCESDRYGANT D. (1984). Correlation and conodonts of the Silurian - Lower Devonian deposits of Volyn and

Podolia. Naukova Dumka, Kiev, pp. 1-192 (in Russian).



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KOREN T.( 1973). Lower Devonian biostratigraphy of Pai-Khoi, Polar Urals and Podolia on Graptolites.Stratigrafija nizhniego i sredniego devona. Trudy III Mezhdunarodnogo simpoziuma po granice silura idevona i stratigrafii nizhniego i sredniego devona (in Russian). T. 2. Nauka, Leningrad: 142-148.

NIKIFOROVA O.I., PREDTECHENSKIJ N.N. (1968). A guide to the geological excursion on Silurian and LowerDevonian deposits of Podolia (Middle Dniestr River). In: Proceedings of the 3rd international symposiumon Silurian-Devonian boundary and Lower and Middle Devonian stratigraphy. Leningrad: 1-58.


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Geobiodiveristy Database and its application ingraptolite research

JUNXUAN FAN, DAN GOLDMAN, FENG CHEN, HUA ZHANG

J. Fan - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

D. Goldman - Department of Geology, University of Dayton, Dayton (U.S.A.); [email protected]. Chen - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,

Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]. Zhang - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,

Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

The Geobiodiversity Database (GBDB) Project (http://www.geobiodiversity.com) isdedicated to the construction and maintenance of a web-enabled taxonomic, stratigraphic,and geographic database for information gathered from the fossil record. Its goal is tofacilitate regional and global scientific collaborations focused on studying the history,diversity, geography, and environmental context of life on Earth. The key elements ofGBDB are data, analyzing tools and web services.

The GBDB is structured around several independent subsets or tables, such asbibliographic reference, geography (locality or section), taxonomy (fossil classification),stratigraphy, and fossil collection. Each record of these subsets can be linked to a recordor records in other subsets. For example, one reference may contain several sections,each containing a lithostratigraphic description and hundreds of fossil collections. Thereference subset is compatible with Endnote and has the available function of uploading astandardized reference list (text format, such MS word or rtf). In the taxonomy subset,the user can input general taxonomic information from the rank of phylum down tospecies or subspecies. In the collection subset, the user can relate geographic,chronostratigraphic, lithostratigraphic, or taxonomic information as well as the isotopicage and paleogeographic information of any fossil collection by simply searching in differentsubsets.

The GBDB also provides a powerful text-searching engine. For example, the user cansearch collection subsets by using any combination of 22 fields, such as fossil name,locality and biozone. Results are viewable on present-day geographic and satellite maps atpresent. The statistical tools and related functions, such as data visualization (e.g.,rangechart, data visualization on reconstruction maps), diversity statistics (e.g., diversitycurve, origination and extinction rates), and linkage to Geographic Information Systems(GIS) software will be soon be available. The integration of GBDB with GIS will providepowerful tools for the analysis of spatial data from the fossil record. The server of GBDB,which is hosted in the State Key Laboratory of Palaeobiology and Stratigraphy, NanjingInstitute of Geology and Palaeontology, Chinese Academy of Sciences, is supported bythe institute and the laboratory, and will provide stable, long-term, free access.

The GBDB online database is an important tool in graptolite research, facilitatingstudies on paleogeographic distribution, biodiversity trends, systematics, and regional and/or global correlations. A preliminary study on the biogeographic evolution of graptolite



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faunas in South China during the Late Ordovician to Early Silurian extinction and recoveryinterval was recently conducted with the graptolite data from the GBDB. A stepwiseshrinking of graptolite distribution from the pre-Hirnantian to the early Hirnantian followedby a subsequent expansion in the earliest Silurian can be recognized – a pattern thatseems to coincide with simultaneous icesheet and sea-level changes.

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Biostratigraphy and geography of the Ordovician-Silurian Lungmachi black shales in South China

JUNXUAN FAN, MICHAEL J. MELCHIN, XU CHEN, YI WANG, YUANDONG ZHANG, QING

CHEN, FENG CHEN

J. Fan - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology andPalaeontology, Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

M. J. Melchin - Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova ScotiaB2G 2W5 (Canada); [email protected]

X. Chen - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology andPalaeontology, Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

Y. Wang - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology andPalaeontology, Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

Y. Zhang - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology andPalaeontology, Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

Q. Chen - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology andPalaeontology, Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

F. Chen - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology andPalaeontology, Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

Based on the new material of seven sections investigated recently, together withpreviously published data, the authors analyze the tempo and spatial distributions of theLungmachi black shales, a key petroleum source bed widely distributed in South China.

The Lungmachi black shales range in age from the Normalograptus persculptus Biozoneof the uppermost Ordovician to the Spirograptus guerichi Biozone of the lower Telychian,and ten graptolite biozones can be recognized within this unit (Fig. 1). The basal andupper contacts of the Lungmachi black shales are diachronous. The basal contact rangesfrom the N. persculptus to the Coronograptus cyphus biozones, a span of five graptolitebiozones over two stages. The upper contact ranges from the D. pectinatus-M. argenteus

Fig. 1 - Temporal and spatial distribution of the Lungmachi black shales in South China.



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Biozone to the Spirograptus guerichi Biozone, which spans four graptolite biozonesover two stages.

The Yichang Uplift resulted in the formation of the Hunan-Hubei Submarine High inthe border area of Hubei, Hunan, and Chongqing. This is supported by a break insedimentation in this area spanning all or part of the Hirnantian, and in many areasextending into the underlying Katian and overlying Rhuddanian. Comparison of thedistribution of the Katian to Rhuddanian strata in this area indicates a growth and subsequentreduction in area of the Hunan-Hubei Submarine High particularly in the Hirnantian toearly Rhuddanian, which may partly represent the influence of the process of formationand melting of ice sheet in Ordovician South Pole and consequent sea level change.


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Cephalopod limestone biofacies in the Silurian of theCarnic Alps, Austria

ANNALISA FERRETTI, KATHLEEN HISTON

A. Ferretti - Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia, largo S. Eufemia 19, I-41100Modena (Italy); [email protected]

K. Histon - Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia, largo S. Eufemia 19, I-41100Modena (Italy); [email protected]

Cephalopod limestones represent one of the most peculiar biofacies that developed inSilurian times along the northern margin of Gondwana. The presence and relativeabundance of fossils, clearly visible in the field, enabled a taxonomic study of the mainfossil groups since the end of the eighteenth century. Together with the most evidentcephalopods, also bivalves, brachiopods and trilobites were studied in detail in differenttimes. A good stratigraphic assignment either with graptolites or with conodonts wasmade of most sections. Paleoecological studies, on the contrary, were not so definite.Cephalopod limestones from North Gondwana are often referred to as a single unit, andthe same paleoecologic-environmental conclusions driven in an area are borrowed andextended to other regions.

Key-stratigraphic sections (Rauchkofel Boden, Cellon, Rauchkofel Boden torl, ValentinTörl, Seewarte, Seekopf) representing distinctive paleogeographic/paleoenvironmentalsettings were taken into consideration and studied in detail in this work, paying particularattention to observe taphonomical information (abundance, dimension, orientation, colour,preservation, etc.) of all organisms composing the fauna. The study aimed to fit even theCarnic Alps cephalopod limestone biofacies into a more general picture of the Silurian. Inparticular, a precise depositional environment and an improved sequence-stratigraphicalframe for the Silurian of the Carnic Alps in Austria based on a sedimentological,lithostratigraphical, biostratigraphical and microfacial approach was achieved (Brett et al.,in press).

Furthermore, analysis of “ooidal pockets” and “stromatolite-like” structures within thePt. celloni – Pt. a. amorphognathoides conodont zones is also discussed with regard totheir paleoenvironmental implications. Similar studies in other sectors (Oggiano & Mameli,2006 from the Ordovician/Silurian of northern Sardinia), for this stratigraphical intervalhighlight that knowledge to date regarding these peculiar carbonate facies is still quitelimited. In-depth studies in key areas to recognise these markers may shed light on therelative positions of microterranes along the North Gondwana margin.

REFERENCESBRETT C., FERRETTI A., HISTON K., SCHÖNLAUB H.P. Silurian Sequence Stratigraphy of the Carnic Alps, Austria.

Palaeogeography, Palaeoclimatology, Palaeoecology (in press).OGGIANO G., MAMELI P. (2006). Diamictite and oolitic ironstones, a sedimentary association at Ordovician–

Silurian transition in the north Gondwana margin: New evidence from the inner nappe of Sardinia Variscides(Italy). Gondwana Research, 9: 500-511.

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Palaeozoic black shales: how much should we trust theRecent to reconstruct the Past?

ANNALISA FERRETTI, ALESSANDRA NEGRI, THOMAS WAGNER, PHILIP A. MEYERS

Annalisa Ferretti - Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia, largo S. Eufemia 19,I-41100 Modena (Italy); [email protected]

Alessandra Negri - Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); [email protected]

Thomas Wagner - School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, NE17RU (United Kingdom); [email protected]

Philip A. Meyers - Department of Geological Sciences, The University of Michigan, Ann Arbor, Michigan 48109-1005(U.S.A.); [email protected]

Organic-carbon-rich sediments were widely deposited during multiple intervals ofMesozoic and Palaeozoic time or even earlier; on the contrary, sediments rich in organiccarbon are today restricted to small areas along continental margins and have rarelyaccumulated during the Cenozoic. Global marine deposits document that episodes ofaccumulation of OC-rich sediments occurred in different regions and at different times.These episodes were linked to climatic and palaeoceanographic perturbations that resultedin massive fluctuations in hydrologic and nutrient cycles and in ocean chemistry and thatrecurred throughout geologic time.

The whole Palaeozoic is punctuated by a profusion of episodes of black shale depositionthat represent a common and not unusual sediment for that time. Furthermore, theabundance of organic matter does not, per se, imply black shales. The Palaeozoic, in fact,is also characterized by fossiliferous OC-rich limestones, e.g. the Silurian–Devonian“Orthoceras limestones” bordering northern Gondwana. However, the paucity of survivingPalaeozoic and earlier black shale sections makes it difficult to impossible to recognizethe internal structure of global events that are common in younger OC-rich sedimentarysequences. Going ever deeper into the past, in fact, two factors appear playing a moreand more fundamental role: preservation and time resolution. OC-rich sediments, eitherin form of black shales or limestones, do not necessarily reflect periods of elevateddeposition of high organic matter but may paradoxically simply represent times of betterorganic matter preservation. Then, even well-dated sequences do not offer the high-resolution records needed to fully document or delineate short-time processes. In thePalaeozoic the length of individual biozones is generally on the order of millions of years,which is in the same range as third-order sea-level changes. Thus, an important questionin Palaeozoic sequences is whether episodes occur at different scales or belong to cyclesof diverse order.

Also according to this premise, too often was exasperate the use of the uniformitarianismprinciple in which models or opinions derived from recent examples are simplisticallyapplied to any of the older “timeboxes”. In actuality, physical and biological conditions(e.g., oxygen and CO

2) have strongly varied through time. Palaeozoic black shales were

clearly deposited in a CO2-dominated setting (see Berner, 1994, 1998), whereas younger

deposits reflect a lower concentration of the same gas. Again, the nature of primaryproducers is not yet completely defined for pre-Jurassic production of organic matter.

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Furthermore, palaeogeographic scenarios reveal completely different worlds in terms ofland masses, oceans, palaeolatitudes, etc. According to this, any attempt to model thedeposition of OC-rich sediments through the Phanerozoic must necessarily be tuned withall these variables. Another relevant point is that some of the Phanerozoic OC-rich sedimentsare defined as global events, like the Cretaceous OAE1a and OAE2, but some othersappear to have had a more restricted and even localized significance. These differencesrequire the application of different approaches in search of possible interpretations andperhaps diverse mechanisms leading to the deposition of OC-rich sequences.

Finally, many of the most significant black shale episodes in the Palaeozoic strictlymatch with major crises in the history of life. Understanding what drives global diversitymay be used to explain processes, such as mass extinctions, that control diversity andturnover at a variety of geographic and temporal scales.

The main issues described here need to be further investigated and are certainly worthanswering. The Scientific Community must come to a multiple-time scale approach andto a constructive dialogue that better integrates data and models in order to be even moresuccessful. These efforts, with an emphasis on the upscaling/downscaling of processesand effects/feedbacks, will lead to the identification of methodologies that may be useduniformly in the Palaeozoic, Mesozoic and Cenozoic. In that case the scientific communitywill be able to test the validity of processes in the recent as well as its application in thepast, to obtain real progress in the knowledge of OC-rich sediments, and to gain credibilityfor delineating true perspectives for the future.

REFERENCESBERNER R.A. (1994). GEOCARB II: a revised model for atmospheric CO

2 over Phanerozoic time. American

Journal of Science, 294: 56-91.BERNER R.A. (1998). The carbon cycle and CO

2 over Phanerozoic time: the role of land plants. Philosophical

Transactions of the Royal Society of London, B 353: 75-82.NEGRI A., FERRETTI A., WAGNER T. & MEYERS P.A. (2009). Organic-carbon-rich sediments through the

Phanerozoic: Processes, progress, and perspectives. Palaeogeography, Palaeoclimatology,Palaeoecology, Special Issue, 273 (3-4): 197 pp.


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Nautiloid Cephalopods from the Silurian of the CarnicAlps – New evidences

MAURIZIO GNOLI, PAOLO SERVENTI, LUCA SIMONETTO

M. Gnoli - Dipartimento di Scienze della Terra , Università di Modena e Reggio Emilia, Largo Sant’Eufemia 19, I-41100 Modena, (Italy); [email protected]

P. Serventi - Dipartimento del Museo di Paleobiologia e dell’Orto Botanico, Università di Modena e Reggio Emilia,via Università 4, I-41100 Modena (Italy); [email protected]

L. Simonetto - Museo Friulano di Storia Naturale, via Marangoni 39-41, I-33100 Udine (Italy); [email protected]

Nautiloid Cephalopods from the Carnic Alps are the most frequent macrofossils foundin Silurian limestones. They have been described by Italian, German and Austrianpaleontologists since the 18th century (see Frech, 1888; Gortani & Vinassa de Regny,1909; Heritsch, 1929). After the Second World War, apart from Ristedt’s (1968) taxonomicrevision on the Order Orthocerida and on juvenile stages and protoconchs, in the ninetiesresearches were resumed mainly revising Universities and Museums major collections(Gnoli & Histon, 1998, Histon, 1999, Gnoli et al., 2000). The reviewed fauna is dominatedby orthoconic shells belonging to the Order Orthocerida (Families Orthoceratidae,Geisonoceratidae and Pseudorthoceratidae), but also Orders Oncocerida and Barran-deocerida (Families Oncoceratidae, Barrandeoceratidae, Uranoceratidae and Lechritro-chceratidae).

The present research deals with new material collected during several field trips, thanksto the cooperation between the Museum of Natural History of Udine and the Universityof Modena and Reggio Emilia. The new genus and species Serpaglioceras forojuliensehas been created (Gnoli & Serventi, 2008). The new taxon presents a very characteristicgrid-like outer adornment and “actinoceroid-type” recumbent septal necks, but the lackof the endosiphuncular system does not allow the attribution to the Order Actinocerida.

Taxa belonging to the Order Actinocerida had been described on the basis of theircharacteristic inner features, even if the poor state of preservation does not permit adefinitive specific attribution; the species identified are: Huroniella? sp. ind.; Ormocerassp. ind. A; Elrodoceras sp. ind. A. Furthermore, the species Nucleoceras cf. obelus isfound for the first time outside Bohemia, its type-area.

REFERENCESFRECH F. 1888. Uber das Devon des Ostalpen, nebst Bemerkungen uberdas Silur und einem

paläontologischen Anhang. Zeitschrift Deutsche Geophysikalische Gesellschaft, Berlin: 659-738.GORTANI M. & VINASSA DE REGNY P. 1909. Fossili neosilurici del Pizzo di Timau e dei Pal nell’Alta Carnia.

Memorie della Reale Accademia dell’Istituto di Scienze, Bologna: 183-217.GNOLI M. & HISTON K. 1998. Silurian Nautiloid cephalopods from the Carnic Alps: a preliminary investigation.

Bollettino della Società Paleontologica Italiana, 36: 311-330.GNOLI M. & SERVENTI P. 2008. A new Cephalopod from the early Silurian of the Carnic Alps (Italian side).

Rivista Italiana di Paleontologia e Stratigrafia, 114 (2): 171-178.GNOLI M., HISTON K. & SERVENTI P. 2000. Revision of Silurian cephalopods from the Carnic Alps: the Gortani

and Vinassa de Regny collection, 1909. Bollettino della Società Italiana, 39 (1): 3-12.HERITSCH F. 1929. Faunen aus dem Silur der Ostenalpen. Abhandlungen der Geologischen Bundesanstalt,

23(2): 1-183.

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HISTON K. 1999. Revision of Silurian nautiloid Cephalopods from the Carnic Alps (Austria) - The Heritsch(1929) Collection in the Geological Survey of Austria. Abhandlungen der Geologischen Bundesanstalt,56 (1): 229-258.

RISTEDT H. 1968. Zur Revision der Orthoceratidae. Abhandlungen der Mathematisch-Naturwissenschaftlichen. Akademie der Wissenschaften und Literatur in Mainz, Klasse, 68 (4): 212-287.


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The Silurian of the southern Siberian Platform

ALEXANDER P. GUBANOV, OLGA K. BOGOLEPOVA, JAMES P. HOWARD,MELISE B. HARLAND, MARCELA GOMEZ-PEREZ

A.P. Gubanov - CASP, Cambridge University, 18 a Huntingdon Road, Cambridge, CB3 0DH (United Kingdom);[email protected]

O.K. Bogolepova - CASP, Cambridge University, 18 a Huntingdon Road, Cambridge, CB3 0DH (United Kingdom);[email protected]

J.P. Howard - CASP, Cambridge University, 18 a Huntingdon Road, Cambridge, CB3 0DH (United Kingdom);[email protected]

M.B. Harland - previously CASP, now GETECH, Leeds (United Kingdom); [email protected]. Gomez-Perez - CASP, Cambridge University, 18 a Huntingdon Road, Cambridge, CB3 0DH (United Kingdom).

The Silurian rocks of the southern part of Siberian Platform are poorly exposed andstudied.

During fieldwork in 2008 in the Tayshet Region of East Siberia, previously unknownSilurian exposures of the Kezhem Formation were described and sampled forpalaeontology, petrography and provenance studies. At these new localities the strata arerepresented by siliciclastic rocks. The succession does not contain fossils that will enabledating of the strata, but by lithological comparison with the type section on Kezhem River(Komarevsky & Zhukov, 1966) and the section on Chuna River (Tesakov et al., 2000),we suggest a preliminary correlation of these strata. The Kezhem River sequence is up to100 m thick and lies conformably on Late Ordovician strata. It consists of basalconglomerate, and quartz sandstone interbedded with claystone. The Chuna Riversiliciclastic sequence yields lingulids, gastropods, cephalopods, acanthodians and thelodontsof Early Silurian age. The sequence is interpreted as inshore to lagoonal deposits.

A detailed paleogeography of this region will be presented.

REFERENCESKOMAREVSKY V.T. & ZHUKOV N.V. (1966). Explanatory notes to the geological map 1961, sheet N-47-II.

Moscow, Nedra,:1-73 (in Russian)TESAKOV YU.I., PREDTECHENSKY N.N., LOPUSHINSKAYA T.V., KROMYCH V.G., BAZAROVA L.S., BERGER A.YA., &

KOVALEVSKAYA E.O. (2000). Stratigraphy of Oil and Gas Basins of Siberia. Silurian of Siberian Platform.403 pp. GEO, Novosibirsk (in Russian with English summary).



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Upper Silurian nautiloid faunas from the Eggenfeldsection (Graz, Austria)

KATHLEEN HISTON, BERNHARD HUBMANN


B. Hubman - Institute for Earth Sciences (Geology & Palaeontology), University of Graz, Heinrichstrasse 26, A-8010Graz (Austria); [email protected]

The preliminary results of a systematic investigation of the nautiloid faunas from theUpper Silurian (Pridoli) sections of the Graz Palaeozoic are presented. The aim of thepresent study is to add a further contribution to the systematic description of Siluriannautiloid cephalopods within a well defined biostratigraphic framework in order to elaboratetheir use as a tool for biostratigraphic correlation and palaeobiogeographic reconstructions.

The presence of the common Circum Mediterranean ‘Orthoceras’ Limestone andScyphocrinites Communities (Vai 1999) and the Dualina nigra-Patrocardia bivalvesubcommunity (Kriz 1999) within the latest Pridoli of the Carnic Alps sections demonstratesthat faunal exchange was taking place during this interval between the North Gondwanaterranes and Baltica.

Unfortunately there are few age comparable faunas described for considering exchangeof the nautiloid faunas between the North Gondwana terranes during the Pridoli assystematic revision, particularly of the Bohemian fauna, is still lacking. Gnoli (1990) hasshown links between the Sardinian and Bohemian Silurian nautiloid faunas within a broadstratigraphic framework while Histon (2002) concluded that the more shallow water faciesrestricted nautiloid species described from the Carnic Alps were common to both areaspossibly reflecting closeness to Bohemia where these forms are common in the Ludlow /Pridoli series while the more pelagic faunas in common reflected the exchange betweenthe various North Gondwana terranes, Baltica and the Urals due to currents.

The preliminary data presented for the faunas from the Graz Palaeozoic- increase and add to the existing documentation of Silurian nautiloid faunas and thusmake a further contribution towards the palaeobiogeographic knowledge of the positionof this fragment of the North Gondwana terranes at a precise stratigraphic interval, thelatest Pridoli.- provide more data in support of the idea of faunal exchange between North Gondwanaterranes such as the Carnic Alps and Sardinia, and Baltica.- are of great importance as they place the the nautiloid faunas from the Graz Silurianwithin a global scenario. The results of the proposed study of the systematics andpaleobiogeography of the fossil nautiloids will provide important information on regionalpaleogeography and possible migrational pathways for pelagic organisms. This will yieldfurther insights into the positioning of paleocontinents and paleooceangraphy during theSilurian.



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REFERENCESGNOLI M. (1990). New evidence of faunal links between Sardinia and Bohemia in Silurian time on the basis of

nautiloids. Bollettino della Societé Paleontologica Italiana, 29 (3): 289-307.HISTON K. (2002). A nautiloid assemblage from the Upper Silurian (Pridoli) of the Carnic Alps, Austria. In:

Wyse Jackson P.N., Parkes M.A. & Wood R. (eds), Studies in Palaeozoic Palaeontology and biostratigraphyin honour of Charles Hepworth Holland, Special Papers in Palaeontology, 67: 115-133.

KRIZ J. (1999). Silurian and Lowermost Devonian Bivalves of Bohemian Type from the Carnic Alps. InLobitzer and Grecula (eds) Geologie ohne grenzen - Festschrift 150 Jahre Geologische Bundesanstalt.Abhandlungen der Geologische Bundesanstalt, 56: 259-316.

VAI G.B. (1999). Wenlockian to Emsian communities of the Carnic Alps (Austria and Italy). In Boucot A.J.& Lawson J.D. (eds) Paleocommunities - a case study from the Silurian and Lower Devonian: 282-304.


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The Cellon Section: a Review of the Stratotype Sectionfor the Southern Alps (1894-2009)

KATHLEEN HISTON, HANS PETER SCHÖNLAUB, ANNALISA FERRETTI


H.P. Schönlaub - Austrian Academy of Science, Center for Geosciences, Vienna (Austria); [email protected]. Ferretti - Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia, largo S. Eufemia 19, I-41100

Modena (Italy); [email protected]

Among the many geological sections located in the Central and Southern Alps theCellon Section represents one of the most important as it serves as a reference section forthe Upper Ordovician and the Silurian. There is no other profile which has beed visited sooften or has attracted so many Earth scientists for basic or comparative studies. In fact,the long lasting history of research started with a mapping report of the area by Geyer(1894) which served as a basis for further studies. Geyer correlated the section with theupper Silurian in the former terminology of the 19th century. After the Great War scientistsfrom both Austria and Italy worked in the area. Of particular importance is thecomprehensive study carried out by von Gaertner who focused his work on the Cellonsection and introduced a formal lithostratigraphic subdivision which has partly been in useuntil the present. In the late 1950s Otto H. Walliser studied the conodont biostratigraphyfor the Upper Ordovician, Silurian and lowermost Devonian portion of the Cellon Section.Based on more than 250 samples he collected almost 35,000 conodont elements which heassigned to 11 Silurian conodont zones. This zonation (Walliser, 1964) has served formany years as a standard for global correlation of Silurian strata. An Hirnantian conodontfauna has also now been documented (Ferretti & Schönlaub, 2001). In recent times,however, some additions and amendments from other sections have provided a moredetailed zonation. Other studies on chitinozoans (Priewalder, 1997) and graptolites (Jaeger,1975: Storch pers. comm. - presence of Glyptograptus persculptus) have added furtherimportant data so the section is now fully defined biostratigraphically using threestandardarized zonations. Over the last four decades a variety of systematic palaeontologicalresearch by diverse authors has been carried out in the Cellon Section, e.g. on bivalves,brachiopods, nautiloids, graptolites, agglutinated foraminifers, ostracods, acritarchs,chitinozoans, trilobites and most recently even corals. Detailed studies have been done ofthe microfacies and faunal taphonomy in addition to studies of the sedimentology,geochemistry and application of C and O isotope analysis methods for the whole section.More recently, bentonite-bearing horizons in the Late Ordovician, upper Llandovery andWenlock have been correlated with coeval occurrences in other parts of Europe. The ashlayers originated from a subduction-related volcanism of an active plate margin and wasdominated by calcalcalic mafic lavas of a volcanic arc setting with andesitic-rhyodacitic/dacitic magmatism, data of important significance with relation to geodynamics andpalaeogeographical reconstructions of the Peri-Gondwanan terranes (Histon et al., 2007).Finally, sequence stratigraphic methods were applied to the Silurian part of the Cellon



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Section by a team headed by Carl Brett which highlighted eustatic changes which may betraced across four palaeocontinents (Brett et al., in press).

Present and Future - A valuable multidisciplinary data set is now available with regardto the Cellon Section which may be used for subdivision, to discriminate minute time-lapses and to recognize short or long-lasting events in Earth’s history which occursimultaneously in other parts of the world. A short overview of the research done to dateand present/future projects regarding faunal response to eustatic changes will be presentedso as to highlight the still outstanding importance of this standard section.

REFERENCESBRETT C.E., FERRETTI A., HISTON K. & SCHÖNLAUB H.P. (in press). Silurian sequence stratigraphy of the

Carnic Alps (Austria). Palaeogeography, Palaeoclimatology, Palaeoecology.FERRETTI A. & SCHÖNLAUB H.P. (2001). New conodont faunas from the Late Ordovician of the Central

Carnic Alps, Austria. Bollettino della Società Paleontologica Italiana, 40: 3-15.HISTON K., KLEIN P., SCHÖNLAUB H.P. & HUFF W.D. (2007). Lower Paleozoic K-bentonites from the Carnic

Alps, Austria. Austrian Journal of Earth Sciences, 100: 26-42.JAEGER H. (1975). Die Graptolithenführung im Silur/Devon des Cellon-Profils (Karnische Alpen). Carinthia

II, 165 (85): 111-126.PRIEWALDER H. (1997). The distribution of the chitinozoans in the Cellon section (Hirnantian – lower Lochkovian)

- A preliminary report. Berichte der Geologischen Bundesanstalt, 40: 74-85.WALLISER O.H. (1964). Conodonten des Silurs. Abhandlungen des Hessischen Landesamtes für

Bodenforschung, 41: 1-106.


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Does “Lilliput Effect” of brachiopod exist in SouthChina after the late Ordovician mass extinction?

BING HUANG, DAVID A. T. HARPER, JIAYU RONG, RENBIN ZHAN

B. Huang - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

D.A.T. Harper - Geological Museum, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen (Denmark);[email protected]

J. Rong - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China).

R. Zhan - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China).

Body size is a key morphological parameter that has many implications for the behaviour,ecology and morphological development of an animal. In the immediate aftermath ofmass extinction fossil organisms are typically much smaller at species level than those ofpre-event times. This evolutionary phenomenon is termed “Lilliput Effect” (Urbanek,1993).

The Lilliput Effect describes significant size reduction within species-level taxa thatsurvive the extinction events and is usually a temporary phenomenon confined to thesurvival interval. However the continued discovery of new miniaturized faunas hasexpanded the definition of the Lilliput Effect far beyond Urbanek’s (1993) original concept.Recently, two types of the Lilliput Effect have been recognized through a series of detailedcase studies: 1) a specific effect, following the original definition which affects specieslevel taxa, related to deteriorated environments, and 2) a more general effect, apparent inhigher rank above the species level (e.g. Twtichett, 2007).

To date, case studies of the Lilliput Effect have concentrated mainly on the aftermathof the end Permian event. The body size change of brachiopods across the end Ordovicianmass extinction is poorly known. In this study, the body sizes of brachiopods from southeastChina through the Ordovician and Silurian transition (late Katian, Hirnantian, earliestRhuddanian) are compared at generic, superfamilial, ordinal, and class levels.

Implicit in the Lilliput model is that the miniaturized faunas are in some way dwarfedor stunted. To avoid this, the size frequency and survivorship curves for Levenea andLeptaena were produced, and results of both genera from different taxonomic classes canbe compared with the normal population of the brachiopod Lepidocyclus capax fromOrdovician strata.

To focus on macroevolutionary trends within a defined environmental setting, all fossilcollections were restricted to BA3, which include normally-oxygenated, shallow-waterenvironments. Analyses were also limited to the assemblages from silty mudstones ormudstones. The width and length of all complete and nearly complete specimens (juvenilespecimens are excluded from the analyses) were measured. Instead of the traditional 90%or 95% confidence interval estimate, the IQR (Inter Quartile Range) which morerepresentative than the standard deviation (Hampel, 1974) is adopted for estimates of thespread of the body size data.



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Some preliminary conclusions are as follows.1) Trends in the fluctuations of body size of taxa at lower taxonomic ranks are highlyvariable, which is more in line with Urbanek’s (1993) original definition and very differentfrom the Lilliput Effect occurred after the end Permian mass extinction. A possibleexplanation is that the intensity of the terminal Ordovician extinction event was much lessthan that of the end Permian mass extinction.2) Representatives of Orthida and Strophomenida both increased their body sizes duringthe latest Ordovician extinction but suffered significant losses after the crisis; but those ofPentamerida and Rhynchonellida, which decreased their body size, diversified rapidlyafter the extinction in the earliest Silurian. These contrasting trends in body size change atthe ordinal level and dominance suggest that these two major groups adopted quite differentsurvival strategies.

REFERENCESHAMPEL F.R. (1974). The influence curve and its role in robust estimation. Journal of the American Statistical

Association, 69: 383-393.TWITCHETT R.J. (2007). The Lilliput effect in the aftermath of the end-Permian extinction event.

Palaeogeography, Palaeoclimatology, Palaeoecology, 252: 132-144.URBANEK A. (1993). Biotic crises in the history of Upper Silurian graptoloids: a palaeobiological model. Historical

Biology, 7: 29-50.


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Origin and diversification of the Early Silurianvirgianid brachiopods

JISUO JIN, PAUL COPPER

J. Jin - Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7 (Canada); [email protected]. Copper - Department of Earth Sciences, Laurentian University, Sudbury, Ontario P3E 2C6 (Canada);

[email protected]

Late Ordovician virgianid brachiopods (Order Pentamerida), which developedconspicuously large shells and thrived in the shallow tropical seas of Laurentia, Baltica,Kazakhstan, Siberia, North China, South China, and their surrounding microplates andterranes, virtually disappeared during the latest Ordovician (Hirnantian) mass extinctions.Only two Late Ordovician genera of the Suborder Pentameridina survived into the EarlySilurian: Holorhynchus which originated in the latest Katian, and Brevilamnulella in theHirnantian.

During the earliest Silurian, the virgianids constituted a major component of the post-extinction recovery brachiopod faunas in the paleocontinents of North America (includingGreenland), Siberia, Baltica, and Kazakhstan. But the origin of the large-shelled virgianids(as well as the stricklandiids and clorindids) during the earliest Silurian (Rhuddanian) hasbeen a puzzle because neither Holorhynchus nor Brevilamnulella appear to have beenlikely ancestors on the basis of previously known fossil record.

A series of intermediate forms between Brevilamnulella and Virgiana has now beenfound in the lower Rhuddanian (basal Llandovery) carbonate strata of Anticosti Island,strongly suggesting that either the Virgiana lineage originated from Brevilamnulella, orthat the two lineages were sister groups. Several morphological modifications have beenobserved in a morpho-series from the Hirnantian Brevilamnulella to the early RhuddanianViridita and then to the middle-late Rhuddanian Virgiana.

1. Shell size and shape (outline and convexity). Increasing shell size, fromequidimensional to elongate; from nearly equibiconvex to strongly ventribiconvex. InViridita lenticularis, shells are slightly wider than long, and transversely subelliptical.Some shells may become equidimensional with equal length and width. The stronglytransverse shell of Viridita becsciensis appears to be a rare and extreme case among thevarious forms of genus on Anticosti Island. A more advanced but yet undescribed form(Viridita n. sp.) from the upper Fox Point Member of the Becscie Formation is intermediatebetween typical Viridita lenticularis and early Virgiana barrandei in its larger, morestrongly convex shell, with some specimens showing a tendency towards acceleratedlongitudinal growth.

2. Umbonal height. In relatively small shells of V. lenticularis, the ventral and dorsalumbones are low (1-2 mm above hinge line) and of similar height, with the ventral umboslightly higher in larger specimens.

3. Shell costae. Brevilamnulella has a largely smooth shell. In Viridita, the shellschange from quasi-smooth in small forms to weakly costate antero-medially in adults.Contrary to common belief, Virgiana barrandei, the type species of mid-Rhuddanian

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age, is only faintly costate, with the ribs clearly visible only with the help of coating andproper lighting in some specimens. Stronger and distinct costae are not developed untilthe late Rhuddanian, in such species as V. mayvillensis.

4. Fold and sulcus. Brevilamnulella of Hirnantian age lacks a fold and sulcus. This istrue also for the early growth stage (up to 5 mm length) of Viridita lenticularis in theearly Rhuddanian. At later growth stages, a ventral sulcus and a dorsal fold of variablestrength are developed and extend to the anterior margin to produce a uniplicatecommissure. In Viridita n. sp., the fold and sulcus have a tendency to become flattenednear the anterior margin, concomitant with the a moderate increase in shell size andconvexity. The result is a rectimarginate anterior commissure, although the coarse costaemake the margin denticulate.

A flattening of the dorsal valve and development of an antero-medial depression,together with a notable shell elongation, mark the origin of the true Virgiana, representedby Virgiana barrandei that first appears in early middle Rhuddanian strata of the BecscieFormation. In V. barrandei, the uniformly convex state (or the Brevilamnulella state),without a fold or sulcus, is confined to apical 2 mm. From 2 mm to about 20 mm length,a dorsal fold and a ventral sulcus are well defined, usually with a single costa in thesulcus. This can be referred to as the Viridita state. The fold and sulcus disappear moreanteriorly – the dorsal fold inverts into a gentle medial depression that broadens towardsthe anterior margin, whereas the corresponding antero-medial carina in the ventral valveis usually less well delimited than the medial depression of the dorsal valve. The result isa weakly sulciplicate anterior commissure in relatively large shells of V. barrandei. Withontogeny, therefore, the anterior commissure of a Virgiana shell may change fromrectimarginate to uniplicate, to rectimarginate, and then to gently sulciplicate.


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Tracking Silurian eustasy: Alignment of empiricalevidence or pursuit of deductive reasoning?

MARKES E. JOHNSON

M.E. Johnson - Department of Geosciences, Williams College, Williamstown, Massachusetts 01267 (U.S.A.);[email protected]

Sea level is not static, but liable to fluctuations due to addition or subtraction of waterin the world’s oceans, as well as changes to the shape and holding capacity of oceanbasins. Relative changes in sea level are well supported by the rock record on a regionalscale. Whether or not global (eustatic) changes are evident and how frequently theyoccurred during any given interval of time is a matter of contention among stratigraphers.Opinions have evolved over the last century with arguments based on refinements inbiostratigraphy, chemostratigraphy, radiometric dating, and conceptual advances in sequencestratigraphy derived from technological advances in seismic stratigraphy. The PulsationTheory of A.W. Grabau (1936) attributed to Paleozoic strata a global history of 11highstands distributed through a sequence with 21 subdivisions. In 1977, Peter Vail andassociates from the Exxon Production Research Company independently interpreted asimilar Paleozoic history showing 10 second-order highstands but distributed over 19subdivisions. The approach of Vail et al. (1977) was model-based and followed a deductivepath, while Grabau’s was based on inductive reasoning. Recent refinements in a Paleozoicsea-level curve by Haq & Schutter (2008) are based on the same deductive approachtaken by the Vail group, but pinned to patterns in sequence stratigraphy. Drawing on theSilurian System as a Paleozoic sample, this contribution compares the timing, frequency,and magnitude of sea-level highstands deduced by Haq & Schutter (2008) with thosepromulgated by the author from the mid-1980s onward using empirical evidence more inline with Grabau’s methodology (Johnson 2006). Both apply the concept of geographicreference areas, but Haq & Schutter (2008) identify many more Silurian highstands overan interval lasting 27.7 million years. Eight out of 10 Silurian highstands identified by thisauthor (Johnson 2006) match or overlap 8 out of 15 highstands recognized by Haq &Schutter (2008). At issue is which, if any, qualify as eustatic signals with respect tocurrent databases for biostratigraphic and chemostratigraphic correlation. Evaluation isbased on paleontological and biostratigraphic evidence reviewed from Iowa, New York,Norway, Estonia, and Austria in the paleogeographic context of three separate Siluriancontinents. All sequences are compared using the Silurian time scale and biostratigraphiczonations from Ogg et al. (2008).

REFERENCESGRABAU A.W. (1936). Oscillation or pulsation?. International Geological Congress, Report of the 16th session,

United States of America 1933, 1: 539-553.HAQ B.U. & SCHUTTER S.R. (2008). A chronology of Paleozoic sea-level changes, Science, 322: 64-68.JOHNSON M.E. (2006). Relationship of Silurian sea-level fluctuations to oceanic episodes and events, GFF,

128: 115-121.



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OGG J.G., OGG G. & GRADSTEIN F.M. (2008). The Concise Geologic Time Scale. Cambridge University Press,Cambridge, UK, 177 pp.

VAIL P.R., MITCHUM R.M., JR. & THOMPSON S., III (1977). Seismic stratigraphy and global changes of sealevel, Part 4: Global cycles of relative changes of sea level. In Payton C.E. (Ed.), Seismic Stratigraphy –Applications to Hydrocarbon Exploration, American Association of Petroleum Geologists Memoir, 26:83-97.


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Additions to the carbon isotope trend of Podolia(Ukraine) with a summary and evaluation of theSilurian chemostratigraphy

DIMITRI KALJO, VOLODYMIR GRYTSENKO, TÕNU MARTMA

D. Kaljo - Institute of Geology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); [email protected]. Grytsenko - Geological Museum of State Natural History Museum of National Academy of Sciences, 15 B. Khmelnitsky

Str., 01030 Kyiv (Ukraine); [email protected]. Martma - Institute of Geology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia);

[email protected]

Silurian chemostratigraphy has been progressing rather rapidly during the last twodecades. Many papers have been published concerning Silurian carbon isotope trendsmainly of Baltica and Laurentia, but also Australia, China, Avalonia and Barrandia. Ourteam at the Institute of Geology started these studies in the mid-1990s, in later yearsinvolving colleagues from elsewhere. Since then we have been publishing about Ordovicianand Silurian carbon isotope chemostratigraphy, mainly of the Baltic area sensu stricto(Estonia, Latvia and Lithuania), but also of Gotland, Norway and Podolia. Here only theSilurian is discussed.

Podolia is known as a classical area of Silurian rocks. The succession begins with thetopmost Llandovery, ranging up to the very end of the Pridoli and continuing into thelower Devonian. In Kaljo et al. (2007) three global δ13C excursions were revealed in thelower and upper Wenlock and upper Ludlow of Podolia. The Pridoli was left out of thatstudy. Recently, however, we took a series of samples from a drill core made in theTernopil area at Katuzhiny village. The drilling partly penetrated very shallow waterfacies (upper Ludlow to lower Pridoli), represented by dolomitic rocks with gypsuminterbeds and obvious gaps. Higher in the Pridoli facies became gradually more marine,as evidenced by limestones, marlstones and even argillites with graptolites appearing inthe lowermost Devonian. It means that after a sea level low stand in the late Ludlow/earliest Pridoli, later during the latter epoch the Podolian basin experienced a continuedtransgression and deepening. The Grinchuk Formation (Fm.), lying just below the mid-Ludfordian δ13C excursion, shows in the Katuzhiny section the same plateau of valuesaround 0‰ as observed earlier in outcrops. The mid-Ludfordian peak is missing in theIsakovtsy and lower Prigorodok Fms of the core; instead there occurs a large negativeexcursion with a maximum value (–5‰) measured in the lowermost Pridoli (lower VarnitsaFm.). Higher in the Varnitsa Fm. values remain below 0‰, and in the Trubchin Fm.around 0, but below 1‰ except in a few samples at the top. These samples show thebeginning of a new δ13C excursion with the highest value of 4.5‰ in the DzwinogorodFm. The falling limb of this excursion is rather steep and may refer to a gap at this level.A new recovery of the curve reaches a value of 2.8‰ in the lowermost Devonian (TainaFm.).

Summarizing the new Podolian data, we note a major δ13C excursion in the upperPridoli and a medium one at the very beginning of the Devonian on the background of



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relatively low values and several gaps in the section. Comparing these data with the Balticones, we see several minor coincidences in trends, but none of the positive excursionsnoted above is observed due to specificity of these sections. However, Andrew et al.(1994) found a major δ13C shift at the bottom of the Devonian in Australia, proving aglobal value of this excursion.

The topmost Ordovician major δ13C excursion, peaking in the mid-Hirnantian slightlybelow the O/S boundary, is a good starting point for discussions about Silurianchemostratigraphy. Some negative δ13C excursions might appear to be very characteristic,but here we consider only positive shifts of medium and major sizes, which are mosttrusted in chemostratigraphy. The following seven excursions have been established: mid-Aeronian and early Telychian in the Llandovery, early Sheinwoodian and late Homerianin the Wenlock, late Gorstian (?) and mid-Ludfordian in the Ludlow, and one excursion inthe late Pridoli. The Silurian/Devonian boundary is marked by a clear shift as describedabove. Most of these excursions are well defined also biostratigraphically and are thushighly useful for Silurian stratigraphy.

The study was partly supported by the Estonian target funding projects SF 0140020s08and 320080s07.

REFERENCESANDREW A.S., HAMILTON P.J., MAWSON R., TALENT J.A. & WHITFORD, D.J. (1994). Isotopic correlation tools in

the mid-Paleozoic and their relation to extinction events. Australian Petroleum Exploration AssociationJournal, 34: 268-277.

KALJO D., GRYTSENKO V., MARTMA T. & MÕTUS M.A. (2007). Three global carbon isotope shifts in the Silurianof Podolia (Ukraine): stratigraphical implications. Estonian Journal of Earth Sciences, 56: 205-220.


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Silurian sea level variations based on SiO2/Al

2O

3 and

K2O/Al

2O

3 ratios from Priekule drill core section,

Latvia, and comparison with redox conditionscarbonate precipitation and global δδδδδ13C changes

TARMO KIIPLI, ENLI KIIPLI, DIMITRI KALJO

T. Kiipli - Institute of Geology, Tallinn University of Technology, Ehitajate 5, 19086 Tallinn (Estonia); [email protected]. Kiipli - Institute of Geology, Tallinn University of Technology, Ehitajate 5, 19086 Tallinn (Estonia); [email protected]. Kaljo - Institute of Geology, Tallinn University of Technology, Ehitajate 5, 19086 Tallinn (Estonia); [email protected]

Eustatic sea level responds sensitively to the climatic changes due to the growth andretreat of continental ice sheets at high latitudes (McKerrow, 1979). Long range variationsin global sea level may be caused by plate tectonic processes and global distribution ofcontinents (Haq & Shutter, 2008). These sea level falls and rises can be read from thefacies movements, breaks in sedimentation and changes in benthic faunal communities insedimentary sections on stable platforms (Johnson, 1996).

Here we propose independent method for establishing sea level high and low stands bythe SiO

2/Al

2O

3 and K

2O/Al

2O

3 ratios. This bases on aluminium concentration preferably

in clay minerals forming the major part of fine grained pelitic fraction of terrigenousmaterial. In contrary, silicon and potassium concentrate in quartz and potassium feldspar,which are abundant in coarser fractions. Therefore these element ratios reflect grain sizeof siliciclastic material depending on the intensity of water movement and sea depth. TheWest-Latvian Priekule drill core section from the Silurian deep shelf was investigated.Deep shelf environment is favourable for study of sea level fluctuations by this methodbecause of steady sedimentation without breaks. Specific aspect, compared with shallowwater sections, is that only large changes in sea level are recorded. Correlation of sectionbases on finds of zonal graptolites, and the published δ13C curve (Kaljo et al., 1997).

In more than 400 m thick shale and marlstone section from Telychian to Ludfordianthe SiO

2/Al

2O

3 ratio is 3.4 in average. In Lower Sheinwoodian, Upper Homerian and

Lower Ludfordian the ratio rises to the 3.8–4.0. This corresponds to the content of 40–50% of coarse silt fraction and indicates sea level fall. Probably the fall leads to seadepths less than 120 m, the depth of surface mixing zone in shelves open to the ocean.Lower values of the SiO

2/Al

2O

3 ratio (2.7–3.3) are characteristic to the Telychian, Middle

Wenlock, Gorstian and Upper Ludfordian indicating greater sea depths than mixing zone.K

2O/Al

2O

3 ratio behaves similarly to SiO

2/Al

2O

3 confirming these depth changes. Positive

δ13C excursions identified in many studies worldwide reflect global events. Good correlationof increased values of SiO

2/Al

2O

3 and K

2O/Al

2O

3 ratio with positive δ13C excursions

indicates that they all correspond to the global sea level changes. Changes in redox conditionsin sediments can be described on the basis of sulphur content. Sulphur fixation intosediment depends on the reduction of sulphate in pore water, depending on organic mattercontent. Higher sulphur contents in the Priekule section exceeding 1% occur in the intervalsof sea level low stand. Enhanced flux of organic matter into sediments can be caused by



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about two times decrease of water depth, although contribution from higher bioproductivityis also possible. Higher contents of carbonates occur in the intervals corresponding to thesea level low stands as well. This can be caused by shifting of sedimentation area fromsuboxic pH minimum zone to the shallower seawater mixing zone during the fall of sealevel. All five described geochemical signatures correlate in general, but at different levelsmay have temporal differences: e. g. some sea level low stands start earlier and lastlonger, than δ13C positive excursions.

Three lowstands and four highstands described herein in deep shelf Priekule sectionreflect large most important changes in sea level. Present study suggests that the amplitudeof many sea level changes recorded in previous more detailed studies needs to be re-estimated.

REFERENCESHAQ B.U. & SHUTTER S.R. (2008). A chronology of Paleozoic sea level changes. Science, 322: 64-68.JOHNSON M. E. (1996). Stable cratonic sequences and a standard for Silurian eustasy. In Witzke B.J., Ludvingson

G.A. & Day J.E. (Eds.), Paleozoic Sequence Stratigraphy: Views from the North American Craton.Geological Society of America Special Paper, 306: 203-211.

KALJO D., KIIPLI T. & MARTMA T. (1997). Carbon isotope event markers through the Wenlock-Pridoly sequenceat Ohesaare (Estonia) and Priekule (Latvia). Palaeogeography, Palaeoclimatology Palaeoecology,132: 211-223.

MCKERROW W.C. (1979). Ordovician and Silurian changes in sea level. Journal of the Geological SocietyLondon, 136: 137-145.


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Aeronian and lower Telychian retiolitid graptolites,Arctic Canada

ALFRED LENZ, MICHAEL MELCHIN, ANNA KOZLOWSKA

A. Lenz - Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7 (Canada);[email protected]

M. Melchin - Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia B2G 2W5 (Canada);[email protected]

A. Kozlowska - Institute of Paleobiology, Polish Academy of Sciences, 51/55 ul. Twarda, PL-00 818 Warszawa (Poland);[email protected]

Aeronian and lower Telychian retiolitid graptolites have been relatively poorly knownor understood, due largely to their morphologic complexity and mode of preservation.The recovery of isolated, uncompressed and beautifully preserved material from ArcticCanada contributes to a much better understanding of their morphology and theevolutionary development of retiolitids as a whole. Retiolitids, first represented byPseudoretiolites, appeared in the basal Aeronian, and by mid-Aeronian (convolutusBiozone) at least six species of retiolitids were in existence. The earliest members of thegenus Pseudoretiolites, presumably the ancestors to later-appearing members, but ofwhich no complete specimen has yet been recovered, preserve a complete sicula as wellas a partially preserved theca 11. By contrast, the sicular preservation of those occurringin the convolutus Biozone ranges from a complete metasicula, partial metasicula, prosiculaonly, or non-preservation. This variation exists even within the same species, althoughmost representatives of each species preserve at least the prosicula. Two other taxa,Eorograptus and “Eorograptus” also occur in the convolutus Biozone; both possess ashallow, bowl-shaped ancora umbrella that is weakly spiralled, and both generally preserveat least a prosicula. The former genus possesses pleural lists but no thecal ventral lists,whereas the latter, most probably a new genus and species, possesses no pleural lists, butcomplete thecal ventral lists; the latter taxon is similar to the younger (early Telychian)genus Rotaretiolites in possessing complete thecal ventral lists. Rotaretiolites andPseudoplegmatograptus occur in the earliest Telychian guerichi Biozone. The apparentproliferation of retiolitid taxa in the convolutus Biozone and to a lesser extent in theguerichi Biozone appear to be real in that the underlying and overlying biozones, with theexception of the sedgwickii Biozone, have yielded ample occurrences other graptolites,and furthermore, the diversification surges in retiolitids correspond to global peaks inother graptolites (Melchin et al., 1998).

REFERENCEMELCHIN M.J., KOREN’ T. N. & STORCH P. (1998). Global diversity and survivorship patterns of Silurian graptoloids.

In Landing E. & Johnson M.E. (Eds.), Silurian Cycles. New York State Museum Bulletin 491: 165-182.



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Occurrence and 3D-preservation of Llandoverygraptolites in the Criadero Quartzite of the Almadénmining district (Spain)

SATURNINO E. LORENZO, JUAN C. GUTIÉRREZ-MARCO

S.E. Lorenzo - Departamento de Ingeniería Geológica y Minera, Escuela Universitaria Politécnica, Universidad deCastilla-La Mancha, E-13400 Almadén (Ciudad Real) (Spain); [email protected]

J.C. Gutiérrez-Marco - Instituto de Geología Económica (CSIC-UCM), José Antonio Novais 2, E-28040 Madrid(Spain); [email protected]

The Criadero Quartzite is one of the most distinctive Paleozoic formations of theIberian Massif because it hosts the famous mercury mineralization of Almadén (Central-Iberian Zone), where mining started more than 2,000 years ago and has since accountedfor one third of the cumulative world mercury production (Ortega Gironés & HernándezSobrino, 1992). The Criadero Quartzite has been traditionally considered as “basal Silurian”,correlating with the entire Llandovery or possibly the Llandovery and Wenlock. However,a low-diversity Hirnantia Fauna indicates that its basal part spans the Ordovician/Silurianboundary (García Palacios et al., 1996; Villas et al., 1999). Previously, graptolites possiblyof Aeronian age were reported from the uppermost beds of a lateral equivalent of theCriadero Quartzite, located east of the Almadén syncline (Gutiérrez-Marco & PinedaVelasco, 1988; García Palacios et al., 1996).

The Criadero Quartzite displays important variations in thickness and lithologies in thesouthern flank (65-70 m) of the Almadén syncline in comparison with sections in thenorthern flank (0-30 m), which have been related to shallower environments of blanketsandstones deposited by tidal currents prevailing in the south (Gallardo-Millán et al.,1994).

The graptolite locality described here lies in the upper part of the Criadero Quartziteon the northern flank of the syncline, about 11 Km NE of the Almadén mine. Thegraptolites occur in an alternating sequence (7-8 m thick) of dark micaceous sandstonesand shales from a bed of sandstone with weathered pyrite nodules that is 4 m above thetop of the coquinoid quartzite bearing the Late Ordovician Hirnantia Fauna described byVillas et al. (1999). The monospecific assemblage comprises abundant specimens of abiserial graptolite provisionally identified here as Normalograptus scalaris (Hisinger),which is a widespread species ranging from the middle Aeronian Pribylograptus leptothecaor Lituigraptus convolutus biozones to the lowest Spirograptus turriculatus Biozone(lower Telychian). The most interesting aspect is, however, the extraordinary three-dimensional preservation of the specimens, which occur as empty rhabdosomes with theperiderm apparently replicated by iron-oxides and with a minor proportion of phyllosilicates.This preservation may be explained by multiphase pyritization of the graptolites, similarto some samples described by Underwood & Bottrell (1994). In this sense, the framboidalpyrite that mineralized the periderm during very early diagenesis was remarkably resilientnot only to subsequent deformation, but also to the differential weathering of the massiveoverpyrite that constitute the nodules that wholly enclosed rhabdosomes.



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The occurrence of pyrite nodules within the Criadero Formation was reported bySaupé (1971) from a single horizon of black quartzites at the base of the Upper Quartzitemember (8-10 m). This basal horizon of the San Francisco ore body, may be even alateral equivalent of the bed here studied on the northern flank of the syncline, which afurther search of graptolites at the Almadén mine could clarify.

This work is a contribution to the project CGL2006-07628/BTE of the Spanish Ministryof Science and Innovation.

REFERENCESGALLARDO-MILLÁN J.L., HIGUERAS P. & MOLINA J.M. (1994). Análisis estratigráfico de la “Cuarcita de Criadero”

en el Sinclinal de Almadén. Boletín Geológico y Minero, 105: 135-145.GARCÍA PALACIOS A., GUTIÉRREZ-MARCO J.C. & HERRANZ ARAÚJO P. (1996). Edad y correlación de la “Cuarcita

de Criadero” y otras unidades cuarcíticas del límite Ordovícico-Silúrico en la Zona Centroibérica meridional(España y Portugal). Geogaceta, 20: 19-22.

GUTIÉRREZ-MARCO J.C. & PINEDA VELASCO A. (1988). Datos bioestratigráficos sobre los materiales silúricos delsubsuelo de El Centenillo (Jaén). Comunicaciones II Congreso Geológico de España, Granada, 1: 91-94

ORTEGA GIRONÉS E. & HERNÁNDEZ SOBRINO A. (1992). The mercury deposits of the Almadén syncline, Spain.Chronique de la Recherche Minière, 506: 3-24.

SAUPÉ F. (1971). Stratigraphie et pétrographie du «Quartzite du Criadero» (Valentien) à Almadén (province deCiudad Real, Espagne). Mémoires du Bureau des Recherches Géologiques et Minières, 73: 139-147.

UNDERWOOD C.J. & BOTTRELL S.H. (1994). Diagenetic controls on multiphase pyritization of graptolites. GeologicalMagazine, 131: 315-327.

VILLAS E., LORENZO S. & GUTIÉRREZ-MARCO J.C. (1999). First record of a Hirnantia Fauna from Spain, and itscontribution to the Late Ordovician palaeogeography of northern Gondwana. Transactions of the RoyalSociety of Edinburgh: Earth Sciences, 89: 187-197.


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Silurian geoheritage of the Almadén Mining Park(central Spain)

SATURNINO E. LORENZO, JUAN C. GUTIÉRREZ-MARCO, ISABEL RÁBANO

S.E. Lorenzo - Departamento de Ingeniería Geológica y Minera, Escuela Universitaria Politécnica, Universidad deCastilla-La Mancha, E-13400 Almadén (Ciudad Real) (Spain); [email protected]

J.C. Gutiérrez-Marco - Instituto de Geología Económica (CSIC-UCM), José Antonio Novais 2, E-28040 Madrid(Spain); [email protected]

I. Rábano - Museo Geominero, Instituto Geológico y Minero de España, Ríos Rosas 23, E-28003 Madrid (Spain);[email protected]

The Almadén mining district (Central-Iberian Zone of the Iberian Massif) constitutesthe largest geochemical mercury anomaly in the Earth’s crust. Mercury ore bodies arehosted by uppermost Ordovician, Silurian and Upper Devonian sedimentary and volcanicrocks. In the Almadén-type mineralization, cinnabar and native Hg stratabound orebodiesare distributed throughout the uppermost Ordovician to lower Silurian Criadero Quartzite.The Almadén mine ceased operation in 2001 after having produced approximately 200,000metric tons of mercury during more than 2,000 years of uninterrupted mining by Romans,Arabs and Christians. The mine were transferred to the Spanish crown in the 16th centurywhen mercury became a strategic metal used in the amalgamation of the gold and silverproduced in the American territories of the Spanish Empire.

With the great decrease international market price because of declined use of mercurydue to its environmental problems, the Almadén mine is now a legacy, yet it retainsnotable interest from the geological, paleontological and mining perspective. Operativesince 2006, the Almadén Mining Park transformed the mining enclosures, the undergroundmine and the metallurgical facilities into an area for culture, education and quality tourism,where visitors can enjoy the magnificent scientific, industrial and technological heritage ofone of the oldest mines in the world adapted to modern times through centuries oftechnological innovation.

Also planned for the Almadén Mining Park is an Interpretation Centre for understandingthe geology and mining activities in the district, which will include information on thestratigraphy and paleontology of the Silurian succession and also on the probable deep-seated (mantle derived mafic magma) source of mercury.

Before the mining activities ended, the present authors (helped by Petr Storch, J.M.Piçarra and F. Palero) collected graptolites between the 10th and 12th floors of theunderground mine (about -300 m) from black shales directly above the Criadero Quartzite.A big part of the graptolite collection belongs to the Monoclimacis griestoniensis andTorquigraptus tullbergi biozones (mid-Telychian) with abundant specimens (other thanthe named species) of Metaclimacograptus flamandi (Legrand), Parapetalolithusmeridionalis Legrand, Monograptus priodon (Bronn), M. juancarlosi Storch andCochlograptus veles (Richter), a.o. Older Telychian beds belonging to the Rastritestlinnaei Biozone are known through old samples coming from the mine, now preserved inmuseums, as well from a number of outcrops located north and south of the Almadénmine that expose the contact among the Criadero Quartzite and the basal graptolite shales.



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Silurian graptolites were discovered in the Almadén mine by Kuss (1878) and Malaise(1897), and after the work of Hernández Sampelayo (1926) and Haberfelner (1931) themining district became a classical reference for Silurian paleontology in central Spain withsome widespread species defined there (for instance Parapetalolithus hispanicus).

Besides the projected museum displays on Silurian fossils within the Almadén MiningPark, we are proposing a Silurian geo-route for further demonstration of the stratigraphyand paleontology of the area. Starting at the Interpretation Centre, it will lead visitors toselected Silurian outcrops in the vicinity of the mining park (Lápiz stream, Chillón railway,El Entredicho open pit).

This work is a contribution to the project CGL2006-07628/BTE of the Spanish Ministryof Science and Innovation.

REFERENCESHABERFELNER E. (1931). Eine Revision der Graptolithen der Sierra Morena (Spanien). Abhandlungen der

senckenbergischen naturforschenden Gesellschaft, 43: 19-66.HERNÁNDEZ SAMPELAYO P. (1926). Yacimientos de graptolítidos en la zona de Almadén. Boletín de la Real

Sociedad Española de Historia Natural, 26: 251-262.KUSS H. (1878). Mémoire sur les mines et usines d’Almadén. Annales des Mines [7], 13: 39-151.MALAISE C. (1897). Découverte de graptolithes à Almaden, province de Ciudad Real, Espagne. Bulletin de la

Société Géologique de Belgique, 24: 26.


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Nitrogen Isotopes in Paleozoic ChemostratigraphicStudies: Contrasting Examples from the Hirnantianand early Wenlock

MICHAEL J. MELCHIN, CHRIS HOLMDEN

M. J. Melchin - Department of Earth Sciences, St. Francis Xavier University, PO Box 5000, Antigonish, Nova ScotiaB2G 2W5 (Canada); [email protected]

C. Holmden - Saskatchewan Isotope Laboratory, Department of Geological Sciences, University of Saskatchewan,114 Science Place, Saskatoon, Saskatchewan S7N 5E (Canada); [email protected]

Integrated paleoenvironmental and bioevent studies in the Ordovician and Siluriansystems have commonly employed O and C isotopes for chemostratigraphic analysis,although isotopes of Sr, S, Os, and Nd are also leading to valuable insights. LaPorte et al.(in press) showed that variations in N isotopes from organic matter in Late Ordovicianstrata in Nevada may be interpreted in terms of changes in ocean state and patterns of N-cycling from pre-Hirnantian into Hirnantian, peak glacial times. Their model proposesthat during times of greenhouse climate, development of widespread denitrification zonesin the world’s oceans resulted in a low upwelling flux of recycled ‘fixed’ nitrogen to thephotic zone. Algal productivity then depended on the presence of a significant biomass ofnitrogen-fixing cyanobacteria within the photic zone, leading to relatively low δ15N valuesin the produced organic matter. In contrast, during glacial times, increased oceanic ventilationresulted in reduction in the oceanic dentrification zones and an increased supply of fixednitrogen transported to the surface waters, which could be directly utilized by algal plankton.This would lead to higher δ15N values in organic matter. The LaPorte et al. (in press)model was developed using data from a section that preserved only the preglacial toHirnantian glacial rise in δ15N values; postglacial strata were not preserved at that section.

The present study provides new δ15N data on organic matter from two sections inArctic Canada that span the pre-Hirnantian to post-Hirnantian stratigraphic succession.The Hirnantian glacial interval in these sections has already been well characterized interms of biostratigraphy, lithostratigraphy, and C-isotope chemostratigraphy (Melchin &Holmden, 2006). Both sections show a strong (~3‰), positive δ15N excursion that isrestricted to the strata representing the Hirnantian glacial interval, providing strong supportfor the Laporte et al. model. Our interpretation of these new data suggests that prior tothe Hirnantian interval of peak glaciation, substantial denitrification zones were widespreadaround the paleotropical margins of Laurentia during late Katian times but were dramaticallyreduced by glacially-induced oceanic ventilation during the early Hirnantian. In addition,the end of the glacial episode saw a rapid return to preglacial conditions of oceanicdenitrification. The coincidence of the change in δ15N values with dramatic drops ingraptoloid biodiversity and abundances during the early Hirnantian supports the widelyaccepted hypothesis that the preferred graptoloid habitat was closely linked with thepresence of oceanic denitrification zones.

The lower Wenlock strata in Arctic Canada show a significant, positive carbon isotopeexcursion in both the organic and inorganic carbon fractions of the sediments (the Ireviken



316

Event). Although the Ireviken Event shows many similarities with the early Hirnantianglacial event, there are some important differences. Most notably, this sequence showscontinuous deposition of graptolite-bearing black shales through the C-isotope excursioninterval, which is generally not the case for the Hirnantian interval in similar faciesworldwide. Moreover, we have found no significant positive shift in δ15N values. Together,these lines of evidence suggest that Ireviken excursion was not accompanied by a profoundincrease in ocean ventilation and reduction in denitrification, at least on the northernmargin of Laurentia. This suggests that the Ireviken and Hirnantian events may havebeen significantly different in terms of the scale and/or nature of the processes that wereresponsible for the observed paleoenvironmental and biodiversity changes.

REFERENCESLAPORTE D.F., HOLMDEN C. PATTERSON W.P., LOXTON J.D., MELCHIN M.J., MITCHELL C.E., FINNEY S.C. & SHEETS

H.D. (in press). Carbon and nitrogen cycling during the Hirnantian glaciation: implications for epeiric seagradients, productivity and calcite dust deposition. Palaeogeography, Palaeoclimatology,Palaeoecology.

MELCHIN,M.J. & HOLMDEN C. (2006). Carbon isotope chemostratigraphy in Arctic Canada: sea-level forcingof carbonate platform weathering and implications for Hirnantian global correlation. Palaeogeography,Palaeoclimatology, Palaeoecology, 234: 186-200.


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The Upper Ordovician to lower Silurian Tihangesections, Condroz Inlier: a litho- and biostratigraphicalstudy with chitinozoans combined with carbon isotopes

JAN MORTIER, DAVID A.T. HARPER, JAN A. ZALASIEWICZ, PHILIPPE CLAEYS,JACQUES VERNIERS

J. Mortier - Research Unit Palaeontology, Department of Geology and Soil Science, Ghent University, Krijgslaan 281building S8, B-9000 Ghent (Belgium); [email protected]

D.A.T. Harper - Natural History Museum of Denmark (Geological Museum), University of Copenhagen, Øster Voldgade5-7, DK-1350 Copenhagen K (Denmark); [email protected]

J.A. Zalasiewicz - Department of Geology, University of Leicester, University Road, Leicester LE1 7RH (UnitedKingdom); [email protected]

P. Claeys - Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium);[email protected]

J. Verniers - Research Unit Palaeontology, Department of Geology and Soil Science, Ghent University, Krijgslaan281 building S8, B-9000 Ghent (Belgium); [email protected]

Five lithostratigraphical units, exposed in a series of outcrops in Tihange (central CondrozInlier, Belgium) range from the middle Upper Ordovician to the lowermost Silurian. Twoare only known from these outcrops. One newly discovered unit may be dated bybrachiopods and another is dated using graptolites. Forty seven samples from the fiveunits in a 112 m thick composite section contain chitinozoans, but these are often long-ranging forms. Preliminary results from carbon isotope studies on the organic materialwill be presented.

The lowest unit, the Vitrival-Bruyère Formation consists of dark grey, medium grainedsiltstone. It belongs to the Rue de Courrière Member (uppermost member of the Vitrival-Bruyère Formation) although the facies is slightly different from the type area. It wasdeposited during the Burrelian to middle Streffordian (Caradoc, upper Sandbian to lowerKatian) based on the occurrence of Spinachitina bulmani, Desmochitina juglandiformisand possibly Desmochitina nodosa.

The following Bois de Presles Member (lower member of the Fosses Formation)contains brownish grey siltstone and limestone nodules. It was probably deposited duringthe Pusgillian to early Rawtheyan (middle Ashgill, upper Katian) based on lithostratigraphicalcorrelation with the type area of that member, where it was dated by chitinozoans.

The Faulx-les-Tombes Member (middle member of the Fosses Formation) consists ofgreyish green to grey, fine siltstone with characteristic, dark grey, fusiform to ellipticbioturbation traces of a few mm diameter (“schistes mouchetés” in litteris ). Towardsthe top, it becomes darker grey with the appearance of small rusty spheres to ellipses(maximum 1 mm in diameter). It is thought to have been deposited during the Rawtheyan(middle Ashgill, upper Katian) based on lithostratigraphical correlation with the type areaof that member, where it was dated with chitinozoans.

The Tihange Member (the new upper member of the Fosses Formation) can be dividedinto two. The lower part consists of dark grey, fine siltstone with millimetric rusty spheresto ellipses prominent and larger in comparison with the top of the underlying unit. Its age

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probably ranges from latest Rawtheyan to Hirnantian. The upper part consists of lightgrey, fine siltstone that quickly coarsens upwards into coarse siltstone with laminationsand irregular yellow patches (possibly caused by weathering). This is followed by a rapidfining upwards into fine siltstone with a slightly darker colour and the occurrence of rustyspheres to ellipses identical to those in the lower part of the member. This newly discoveredmember, only occurring in the eastern Condroz Inlier, has correlated with the Hirnantianbased on a newly discovered brachiopod fauna: the first evidence of this stage in theCondroz Inlier.

The highest unit, the Bonne Espérance Formation (a new name) consists of darkgreen to dark grey, finely laminated shales with the occurrence of white clayey layers ofpossibly volcanic origin. It is deposited during the middle Rhuddanian based on theoccurrence of graptolites belonging to the upper part of the Parakidograptus acuminatusbiozone and the Atavograptus atavus biozone. The occurrence of Belonechitinapostrobusta is in agreement with this age.


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New biostratigraphic and chemostratigraphic datafrom the lower Chicotte Formation (Llandovery) onAnticosti Island (Quebec, Canada)

AXEL MUNNECKE, PEEP MÄNNIK

A. Munnecke - GeoZentrum Nordbayern, Fachgruppe Paläoumwelt, Loewenichstr. 28, D-91054 Erlangen Germany);[email protected]

P. Männik - Institute of Geology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia);[email protected]

The sequence on Anticosti with its excellent coastal-cliff and river-valley outcropsrepresents one of the best-preserved exposures of upper Ordovician–lower Silurian shallow-water carbonates. The youngest rocks exposed on Anticosti are represented by the 80-90m thick Chicotte Formation, which consists of crinoidal limestones, interpreted as inner-ramp shoal deposits, and reefs. The formation is considered to be Llandovery in age.Conodonts of the I. inconstans and lowermost P. a. amorphognathoides zones havebeen identified from the lower part of the formation (Uyeno and Barnes 1983). Earlierstable isotope data from Anticosti Island did not show much variation in the δ13C valuesin Llandovery, and scatter around +1‰ (Azmy et al. 1998). An increase is observed fromca. +0.5‰ in the upper part of the Jupiter Formation to about 1.5‰ in the overlyingChicotte Formation.

Recently, 19 brachiopod shells and 7 micrite samples from the lower part of theChicotte Formation (below the major unconformity reported by Desrochers 2006) weremeasured for stable isotopes and four samples were processed for conodonts. Based onour studies, the mean δ13C values show an increase from about 1.0‰ in the uppermostJupiter Formation (upper part of Pavillon Member) to 2.8‰ in the lower part of theChicotte Formation, with peak values of > 3.1‰. In the youngest sample studied thevalues decrease back to around 1.4‰. Similar small positive δ13C excursion was recognizedin the Viki core section, western Estonia (Kaljo et al. 2003; our new data). In the lastsection the δ13C values increase from ca. 0.1‰ in the lower Rumba Formation (? uppermostAeronian) up to values between 2 and 3‰ in the interval spanning the uppermost P.eopennatus ssp. n. 1 Zone to the lower Upper P. eopennatus ssp. n. 2 Subzone (lowerVelise Formation). Towards the top of the P. eopennatus ssp. n. 2 Zone the values of˜ 13C decrease gradually and remain +/- constant around 2‰ in the lower part of thesucceeding P. a. angulatus Zone.

The conodont data available suggest that the δ13C excursions recognized in the lowerChicotte Formation on Anticosti and in the lower Velise Formation in the Viki core sectionare of the same age. Also on Anticosti Island the δ13C values reach maximum below theappearance of P. a. angulatus in the sequence. In summary, the stratigraphic position ofthe lower part of the Chicotte Formation (below the major unconformity) ranges from theP. eopennatus ssp. n. 1 Zone to the P. a. angulatus Zone. This time interval is not onlyrepresented by a minor extinction period for conodonts (Valgu Event, Männik 2007) butis also characterised by significant changes in depositional environments. In the Viki core,



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the interval spanning the isotope excursion shows frequent intercalations of micriticlimestones, marls and claystones with reddish or brownish colours, and on AnticostiIsland the Chicotte Formation is built by pure crinoidal limestones and reefs.

REFERENCESAZMY K., VEIZER J., BASSETT M.G. & COPPER P. (1998). Oxygen and carbon isotopic composition of Silurian

brachiopods: Implications for coeval seawater and glaciations. GSA Bulletin, 110 (11): 1499-1512.DESROCHERS A. (2006). Rocky shoreline deposits in the Lower Silurian (upper Llandovery, Telychian) Chicotte

Formation, Anticosti Island, Québec. Canadian Journal of Earth Sciences, 43: 1205-1214.KALJO D., MARTMA T., MÄNNIK P. & VIIRA V. (2003). Implications of Gondwana glaciations in the Baltic late

Ordovician and Silurian and a carbon isotopic test of environmental cyclicity. Bulletin de la SocieteGeologique de France, 174: 59-66.

MÄNNIK P. (2007). Some comments on the Telychian-Early Sheinwoodian conodont faunas, Events andstratigraphy. Acta Palaeontologica Sinica, 46: 305-310.

UYENO T.T. & BARNES C.R. (1983). Conodonts of the Jupiter and Chicotte formations (lower Silurian), AnticostiIsland, Québec. Geological Survey of Canada Bulletin, 355: 49 pp.


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Silurian of the Barrancos-Hinojales domain of SWIberia: a contribution to the geological heritage of theBarrancos area (Portugal) and the Sierra de Aracena-Picos de Aroche Natural Park (Spain)

JOSÉ M. PIÇARRA, JUAN C. GUTIÉRREZ-MARCO, GRACIELA N. SARMIENTO,ISABEL RÁBANO

J.M. Piçarra - Laboratório Nacional de Energia e Geologia, Ap. 104, P-7801-902 Beja (Portugal);[email protected]

J.C. Gutiérrez-Marco - Instituto de Geología Económica (CSIC-UCM,) José Antonio Novais 2, E-28040 Madrid(Spain); [email protected]

G.N. Sarmiento - Instituto de Geología Económica (CSIC-UCM,) José Antonio Novais 2, E-28040 Madrid (Spain);[email protected]

I. Rábano - Museo Geominero, Instituto Geológico y Minero de España, Ríos Rosas 23, E-28003 Madrid (Spain);[email protected]

Fossiliferous Silurian strata crop out extensively in the Barrancos-Hinojales region ofthe Ossa-Morena Zone (SW Iberia), where the structural complexity often makes precisestratigraphic studies difficult. The Silurian succession of this region differs from theThuringian-like facies of the eastern Ossa-Morena areas (Sierra Norte of Seville) by theabsence of the “Scyphocrinites limestone”, the greater lateral variation of clastic units,the relatively less diverse graptolite record and by the scarcity of benthic faunas.

The localities of Barrancos in Portugal, and of Encinasola and Hinojales river in Spain,are the sections more complete and representative of the Silurian stratigraphic andpalaeontological development in the studied domain. All of them lie in natural areas protectedby regional laws; such is the case of the Sierra de Aracena-Picos de Aroche Natural Parkfor the Spanish localities.

The Silurian of Barrancos corresponds to a condensed succession (80 m) of lydites,black shales and dark shales and siltstones. Within it, 19 graptolite biozones ranging fromthe lower Rhuddanian Parakidograptus acuminatus Biozone to the Pridoli Monograptusbouceki Biozone have been recognized (Piçarra in Robardet et al., 1998).

The Encinasola sections, direct extensions of the outcrops at Barrancos, also haveabundant Rhuddanian to Gorstian graptolites, but post-Ludlow strata are virtuallyunfossiliferous (Giese et al., 1994).

The Silurian strata of the Hinojales area are middle Aeronian to lower Sheinwoodiangraptolite black shales; Wenlock-Ludlow strata lack graptolites and are identify bypalynomorphs (Mette, 1987, 1989).

These sections characterize a unique Silurian realm unknown in other parts of theIberian Peninsula that are important for the paleogeographic reconstruction of northernGondwana. Also the partly continuous graptolite succession documents critical episodeson marine life related with global climatic changes (Gutiérrez-Marco et al., 1996).

Therefore, these Silurian sections should be recognized as important geosites thatgenerate added value for the natural areas to which belong and which were originally



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established to protect biodiversity in their original ecosystems and landscapes. But at themoment this geological heritage is not appreciated as a scientific resource of internationalinterest by the local government agencies.

In our opinion, these Silurian geosites should be reserved for scientific study becauseof their rarity and fragility, although the dissemination of scientific information in Barrancoscould be provided by an interpretation center such as that being planned by the town hall,or by the new walking track created as a georoute by the private Noudar Nature Park inthe same area.

This work is a contribution to the PATRIORSI project (CGL2006-07628/BTE) of theSpanish Ministry of Science and Innovation.

REFERENCESGIESE U., HOEGEN R. VON, HOLLMANN G. & WALTER R. (1994). The Palaeozoic of the Ossa Morena Zone north

and south of the Olivenza-Monesterio Anticline (Huelva province, SW Spain). Neues Jahrbuch fürGeologie und Paläontologie, Abhandlungen, 192: 293-331.

GUTIÉRREZ-MARCO J.C., LENZ A.C., ROBARDET M. & PIÇARRA J.M. (1996). Wenlock-Ludlow graptolitebiostratigraphy and extinction: a reassessment from the southwestern Iberian Peninsula (Spain and Portugal).Canadian Journal of Earth Sciences, 33: 656-663.

METTE W. (1987). Geologische und biostratigraphische Untersuchungen im Altpaläozoikum westlichvon Cala, westliche Sierra Morena. Diplomarbeit Institut und Museum für Geologie und Paläontologie,Universität Göttingen, 174 p. (unpublished).

METTE W. (1989). Acritarchs from Lower Paleozoic rocks of western Sierra Morena, SW-Spain andbiostratigraphic results. Geologica et Palaeontologica, 23: 1-19.

ROBARDET M., Piçarra J.M., Storch P., Gutiérrez-Marco J.C. & Sarmiento G.N. (1998). Ordovician andSilurian stratigraphy and faunas (graptolites and conodonts) in the Ossa Morena Zone of the SW IberianPeninsula (Portugal and Spain). Temas Geológico-Mineros, ITGE, 23: 289-318.


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Silurian stratigraphy and paleontology of the Valongoanticline and Arouca-Tamames syncline, Central-Iberian Zone (Portugal and Spain)

JOSÉ M. PIÇARRA, ARTUR A. SÁ, PETR STORCH, JUAN C. GUTIÉRREZ-MARCO


A.A. Sá - Departamento de Geologia, Universidade de Trás-os-Montes e Alto Douro, Ap. 1013, P-5001-801 Vila Real,(Portugal); [email protected]

P. Storch - Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojova 269, 165 02 Praha 6, CzechRepublic; [email protected]

J.C. Gutiérrez-Marco - Instituto de Geología Económica (CSIC-UCM) José Antonio Novais 2, E-28040 Madrid(Spain); [email protected]

Silurian rocks crop out intermittently in a narrow belt, 320 km long, extending fromthe NW corner of Portugal to south of Salamanca, Spain. Although graptolitic shales havebeen known from many localities since the 19th Century, detailed knowledge on theirstratigraphy and fossils is very limited and comes mainly from the classical Valongo andTamames areas. The Silurian succession comprises three units that, in ascending order,are: a) ca. 100 m of black shales and lydites (lower “Xistos Carbonosos”); b) dark shaleswith alternating siltstones and lydites (upper “Xistos Carbonosos”, of unknown thickness)and c) about 200 m of sandstones and siltstones (Sobrado Formation). The highest unitmay include the Silurian-Devonian boundary or may be entirely Devonian on the basis ofthe Middle Devonian age of El Castillo volcanic rocks in the Spanish outcrops (Gutiérrez-Alonso et al., 2008).

Published graptolite data (Thadeu, 1956; Waterlot, 1965; Romariz, 1962, 1969 andreferences cited therein) allowed the lower black shales to be correlated to the Llandoveryand the upper dark shales to the Wenlock. However, available graptolite lists show aremarkable inconsistency by the identification of some Aeronian, Telychian, Sheinwoodianor even Ordovician graptolite species from the same horizons, and sometimes associatedon a single slab. The Wenlock graptolite assemblages of the upper shale unit were relatedto the so-called “Sardic faunas”; among them, 25 new species and “varieties” weredescribed in the Valongo region (Monograptus duriensis, Monoclimacis lusitanica,Pristiograptus valongensis, a.o.: Romariz, 1962; Waterlot, 1965). This “Sardic fauna”was later reviewed by Piçarra and Gutiérrez-Marco (2001), who showed that all theselocal taxa are based upon highly deformed graptolites, unrecognizable at specific or evengeneric level.

The present authors examined most of the original material collected by the earlierworkers from the Valongo and Tamames regions, as well as new localities sampled in theArouca Geopark. Our results allow the preliminary identification of the AeronianDemirastrites pectinatus-D. triangulatus, Lituigraptus convolutus and ?Stimulograptussedgwickii biozones, as well as the Telychian Rastrites linnaei, ?Monoclimacisgriestoniensis, ?Torquigraptus tullbergi and ?Oktavites spiralis biozones within the lower“Xistos Carbonosos”. However, the best material comes from old localities presently



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inaccessible (closed mines, urbanized areas). A good fossiliferous section needs to belocated.

Graptolite-rich beds from the upper “Xistos Carbonosos” have also yielded, otherthan the unrecognizable “Sardic faunas”, some assemblages indicating the presence ofthe Sheinwoodian Cyrtograptus rigidus-Monograptus belophorus Biozone and HomerianCyrtograptus lundgreni Biozone including its Cyrtograptus radians Subzone withoutany doubt. The youngest graptolite records are of imprecise Gorstian age, as indicated bythe occurrence of Bohemograptus bohemicus in the Tamames area.

This work is a contribution to the projects CGL2006-07628/BTE (Spain) and PTDC/CTE-GEX/64966/2006 (Portugal).

REFERENCESGUTIÉRREZ-ALONSO G., MURPHY J.B., FERNÁNDEZ-SUÁREZ J. & HAMILTON M.A. (2008). Rifting along the northern

Gondwana margin and the evolution of the Rheic Ocean: A Devonian age for the El Castillo volcanicrocks (Salamanca, Central Iberian Zone). Tectonophysics, 461: 157-165.

PIÇARRA J.M. & GUTIÉRREZ-MARCO J.C. (2001). Revisão preliminar dos graptólitos silúricos portugueses detipo “sardo”. Publicaciones del Seminario de Paleontología de Zaragoza, 5: 434-440.

ROMARIZ C. (1962). Graptolitos do Silúrico Português. Revista da Faculdade de Ciências de Lisboa, 2ªSérie C, 10: 115-312.

ROMARIZ C. (1969). Graptolitos silúricos do Noroeste Peninsular. Comunicações dos Serviços Geológicosde Portugal, 53: 107-155.

THADEU D. (1956). Note sur le silurien beiro-durien. Boletim da Sociedade Geológica de Portugal, 12: 1-38.

WATERLOT G. (1965). Découverte d’une faune graptolitique géante dans le Llandovérien et le Tarannonieninférieur des environs de Porto (Portugal). Annales de la Société Géologique du Nord, 85 : 159-169.


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New data on Silurian graptolites from the Rio Ollastuvalley (SE Sardinia)

SERGIO PIRAS

S. Piras - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);[email protected]

The Silurian graptolites in southeastern Sardinia are well documented from the LowerGraptolitic Shales, an informal lithostratigraphic unit recognized in the “Sarrabus tectonicUnit” and in the “Gerrei tectonic Unit”. A series of graptolite biozones ranging from lowerLlandovery to lower Ludlow are documented in the unit (Storch & Piras, 2009).

The Riu Ollastu valley is located in the Sarrabus subregion (SE Sardinia), betweenBurcei and San Vito villages. Helmcke (1973) and Barca & Jaeger (1990) reported graptolitesfrom the Lower Graptolitic Shales in this area and brought evidence on the followinggraptolite biozones of the zonal scheme presented by Storch & Piras (2009): ascensus-acuminatus, vesiculosus, cyphus, triangulatus-pectinatus, lepthotheca-convolutus,linnaei, turriculatus-crispus, tullbergi, spiralis, lundgreni-testis, ludensis-gerhardi andnilssoni-colonus.

New field researches in the Rio Ollastu valley revealed a few, previously unstudiedoutcrops of the Lower Graptolitic Shales. Among those, the one at Sarcilloni locality is ofparticular importance. Two highly fossiliferous levels of black siliceous and argillaceousshales, rich in graptolites of Cyrt. lapworthi and Cyrt. insectus biozones, have beendetected in this outcrop. Graptolite association includes: Retiolites angustidens Elles &Wood, Monograptus pseudocultellus Boucek, Monoclimacis geinitzi (Boucek), Oktavitesspiralis (Geinitz), Oktavites falx? (Suess) and Cyrtograptus lapworthi (Tullberg) in thelapworthi Biozone, and Retiolites geinitzianus (Barrande), Pristiograptus largus (Perner),Mediograptus cf. vittatus Storch, Mediograptus ?morleyae Loydell & Cave, Mediograptussp., Monograptus priodon (Bronn), Monograptus praecedens Boucek, Monograptuspseudocultellus Boucek, Monoclimacis geinitzi (Boucek), Cyrtograptus insectus Boucekand Barrandeograptus pulchellus (Tullberg) in the insectus Biozone.

REFERENCESBARCA S. & JAEGER H., (1990). New geological and biostratigraphical date on the Silurian in the SE-Sardinia.

Close affinity with Thuringia. Bolletino della Società Geologica Italiana 108, 565-580.HELMCKE D. (1973). Schichtgebundene NE-Metall- und F-Ba-Lagerstätten im Sarrabus-Gerrei-Gebiet, SE-

Sardinien. II. Bericht: Zur Stratigraphie des Silur und Unterdevon der Lägerstättenprovinz Sarrabus-Gerrei. Neues Jahrbuch für Geologie und Paläontologie. Monatshefte 1973, 529-544.

STORCH P. & PIRAS S. (2009). Silurian graptolites of Sardinia: assemblages and biostratigraphy. Rendicontidella Società Paleontologica Italiana, 3 (1), 77-93.

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Silurian chitinozoan biostratigraphy of Sardinia

PAOLA PITTAU, MYRIAM DEL RIO

P. Pittau - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);[email protected]

M. Del Rio - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);[email protected]

Silurian chitinozoan assemblages and biozones of southeastern Sardinia are wellcalibrated against graptolite biozones, whereas those deriving from isolated blocks of theFluminimaggiore Fm of southwestern Sardinia have less precise biochronologic constraints.

An attempt to arrange, into a regional frame, the up to now known chitinozoanassemblages according to the stratigraphic significance of index species, allow to discriminateeight biozones from Llandovery to lowermost Lochkovian; however not all the timeintervals are documented. One biozone, Conochitina emmastensis, is recognized in theAeronian - Telychian of the Rio Ollastu section. Three chitinozoan biozones: C. goniensis-C. subcyatha, Sphaerochitina jaegeri, S. serpaglii are correlated from the belophorous-rigidus to the lundgreni-testis graptolite biozones. One chitinozoan biozone, C.pachycephala, calibrated against vulgaris-gerhardi graptolite biozone and fittingecostratigraphically within the Cardiola docens-C. donigala bivalves community.Angochitina cf. elongata biozone ecostratigraphycally encompassing the Cardiola docenscommunity; Urnochitina urna and Eisenackitina bohemica ecostratigraphically correlatingrespectively with Cheiopteria-Patrocardia-Cardiolinka, Patrocardia evolvens evolvens-Panenka bivalves communities and Pterinopecten-Cybele nesiotes and Patrocardiaevolvens evolvens-Panenka communities that encompass Pridoli and Lochkovian.

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Wenlock bentonites from the Midland Platform,England: geochemistry, sources and correlation

DAVID RAY

D. Ray - School of Earth & Environmental Sciences, University of Portsmouth, Burnaby Building, Burnaby Road,Portsmouth PO1 3QL (United Kingdom); [email protected]

Forty-two bentonites have been sampled from the Wenlock Series (Silurian) strata ofthe Eastnor Park and Lower Hill Farm boreholes, and from outcrops at Coates Quarry,Harley Hill (Wenlock Edge, Shropshire) and Wren’s Nest Hill (Dudley, West Midlands).The composition of the sand and clay size fractions of each bentonite has been establishedby XRD, heavy liquid separation and microscopy. In addition primary volcanogenic apatitegrains have proven sufficiently abundant in fifteen bentonites to allow for chemicalfingerprinting. Based upon the rare earth element (REE) and yttrium concentrations ofthese apatite grains the chemical similarity between ash fall events and the nature of thesource magma has been established. The REE compositions of the bentonites indicate anevolving subduction related magmatic source that becomes increasingly granitic withindecreasing age. Furthermore comparisons with Wenlock bentonites from Gotland, Swedenindicate a close affinity with samples SW10, SW11 and SW12 (Batchelor & Jeppsson1999), possibly reflecting the same source region. Finally two bentonite horizons, constrainedby five samples, have been shown to be regionally traceable. The lower of the bentonitehorizons occurs within the uppermost Woolhope Limestone and Buildwas Formation(Eastnor Park and Lower Hill Farm boreholes) and is probably contained within thelower riccartonensis Biozone (Ray 2007). The upper bentonite occurs in the MuchWenlock Limestone Formation at Coates Quarry, Harley Hill and Wren’s Nest Hill and iscontained within the ludensis Biozone. Such correlations provide important WenlockSeries time-lines between the type area and the remainder of the Midland Platform.

REFERENCESBATCHELOR R. A. & JEPPSSON L. (1999). Wenlock metabentonites from Gotland, Sweden: geochemistry,

sources and potential as chemostratigraphic markers. Geological Magazine, 136 (6): 661-669RAY D.C. (2007). The correlation of Lower Wenlock Series (Silurian) bentonites from the Lower Hill Farm

and Eastnor Park boreholes, Midland Platform, England. Proceedings of the Geologists’ Association.118 (2): 175-185.



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Sequence stratigraphy of the Wenlock Series of theMidland Platform, England

DAVID RAY, OWEN SUTCLIFFE

D. Ray - Neftex Petroleum Consultants Ltd. 97 Milton Park, Abingdon, Oxfordshire OX14 4RY (United Kingdom);[email protected]

O. Sutcliffe - Neftex Petroleum Consultants Ltd. 97 Milton Park, Abingdon, Oxfordshire OX14 4RY (United Kingdom);[email protected]

The Wenlock Series of the Midland Platform, England has been studied via boreholerecords and a limited number of outcrops. Based upon new data and a re-evaluation oflithological and palaeontological data from the Lower Hill Farm borehole and outcropswithin the type Wenlock area (Bassett et al., 1975; Swire 1993) an assessment of relativesea-level change has been made. Broadly the Wenlock Series consists of two shallowwater carbonates separated by terrigenous sediments. Within this framework two majordepositional sequences have been recognised along with higher-order cycles. The sequenceboundary of sequence-1 straddles the Llandovery-Wenlock boundary (amorphognathoidesconodont Biozone) and probably represents a depositional hiatus. The overlying stratainitially consists of argillaceous sediment with the basal limestones of the Wenlock(Buildwas, Woolhope and Barr Limestone formations) becoming established (centrifugusBiozone) and prograding during a minor regressive-transgressive cycle. As the rate oftransgression increased limestone production was halted giving way to the deposition ofthe Coalbrookdale Formation and highest relative level-sea (dubius Biozone of Zalasiewiczand Williams, 1998). Sequence-2 is characterised a gradual infilling of the accommodationspace by argillaceous sediments followed by extensive limestone development. Within theargillaceous portion of sequence-2 are two additional transgressive-regressive cycles thatare associated with the deposition of sandstones within the southern Midland Platform(rigidus-lundgreni biozones of Zalasiewicz and Williams, 1998). The maximum regressivesurface of sequence-2 is within the upper lundgreni Biozone and is identified by themaximum progradation of sandstones. The overlying transgressive-regressive cycle ischaracterised by the gradual reestablishment of limestone production culminating in theonset of the Much Wenlock Limestone and Farley Member (of the CoalbrookdaleFormation) (uppermost lundgreni Biozone). The limestones of sequence-2 are characterisedby the development of two prominent limestone bands separated by a more nodular andargillaceous interval associated with the maximum flooding surface (nassa Biozone). Anadditional minor regression is also widely identifiable at the top of the lower limestone(nassa Biozone). The upper sequence boundary is contained within the uppermost MuchWenlock Limestone Formation (uppermost ludensis Biozone) and is overlain bytransgressive limestones and then argillaceous sediments marking the base of the LudlowSeries.

REFERENCESBASSETT M.G., COCKS L.R.M., HOLLAND C.H., RICKARDS R.B. & WARREN P.T. (1975). The type Wenlock Series. Institute of

Geological Sciences Report no. 75/13: 1-19.



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SWIRE P.H. (1993). The palynology of the Lower Wenlock of the Wenlock type area, Shropshire, England. Palaeontology,48: 97-109.

ZALASIEWICZ J. & WILLIAMS M. (1998). Graptolite biozonation of the Wenlock Series (Silurian) of the Builth Wells district,central Wales. Geological Magazine, 136: 263-283


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Discovery of a latest Ordovician deep waterbrachiopod fauna at Yuhang, Hangzhou, Zhejiang,East China

JIAYU RONG, RENBIN ZHAN, BING HUANG, DAVID A.T. HARPER

J.Rong - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China).

R. Zhan - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China); [email protected]

B.Huang - State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008 (China).

D.A.T. Harper - Geological Museum, University of Copenhagen, Copenhagen (Denmark).

The formation of the continental glaciations in northern Africa during the Hirnantian(latest Ordovician) caused a dramatic drop of global sea level and the widespread of cooland shallow water benthic regimes within which benthic shelly faunas are well-developedand essentially different from those of pre-Hirnantian. Most of the documented Hirnantianshelly faunas around the world are shallow water in nature, and little is known about thedeep water benthic faunas of this time interval. During the field seasons of 2007 and2008, a moderately diverse brachiopod and trilobite assemblage, the Leangella-Dalmanitnia (Songxites) Assemblage, was found in the upper Yankou Formation(Hirnantian, probably equivalent to the top Normalograptus persculptus Biozone) atShizi Hill, Yuhang, west of Hangzhou, northern Zhejiang, East China. The brachiopodsare moderately rich in abundance, characterized by minute, thin shells with small bodycavities (mostly less than 8 mm in width), preserved in silty mudstone as external andinternal moulds. Preliminary study reveals that the taxonomic composition of thisassemblage includes Paracraniops sp., Skenidioides sp., Dolerorthis sp., Ravozetinasp., dalmanellid indet., ?Jezercia sp., Epitomyonia sp., Aegiromena planissima (Reed),Anisopleurella sp., Eoplectodonta sp., Leangella cf. scissa (Davidson), Brevilamnulellasp., and ?Alispira sp. Taking into account of those accompanied fossils (e.g., trilobitesDalmanitina (Songxites) cf. wuningensis (Lin) and Niuchangella sp., gastropods Holopeasp., machaeridid Lepidocoleus, cystoids, and stems of crinoids), sedimentary features ofthe rocks and the regional geology of this area, this unique brachiopod fauna may haveinhabited quiet, deep-water and dysaerobic slope environments with low levels of nutrients,equivalent to Benthic Assemblage 5. Most genera were adapted for life in deep water.The slope environments were recolonised from outer shelf and upper slope communitiesduring the early Hirnantian after the first phase of the end Ordovician mass extinctions.Relatively isolated biotas may have survived in deeper-water habitats by reducing theirindividual size, population size and diversity during the crisis. The Leangella-Dalmanitina(Songxites) Assemblage, slightly younger than most of the representatives of the Hirnantia-Dalmanitina Fauna, provides a unique Hirnantian window through which we can monitorthe changes in the deep-water biofacies following the first phase of the extinctions. Itbridges the gap between the normal Hirnantia Fauna and the earliest Silurian shelly



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faunas (Fig. 1). Significantly, it may indicate that parts of the deep water marineenvironments may have survived the end Ordovician mass extinctions.

Fig. 1 - Correlation chart showing the stratigraphic position of the Leangella-Dalmanitina(Songxites) Assemblage and its coeval strata.


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P-rich nodules and “hollow graptolites” in the upperSilurian of the Moncorvo synclinorium, north Portugal

ARTUR A. SÁ, JOSÉ M. PIÇARRA, JUAN C. GUTIÉRREZ-MARCO,GRACIELA N. SARMIENTO

A.A. Sá - Departamento de Geologia, Universidade de Trás-os-Montes e Alto Douro, Ap. 1013, P-5001-801 Vila Real(Portugal); [email protected]


J.C. Gutiérrez-Marco - Instituto de Geología Económica (CSIC-UCM,) José Antonio Novais 2, E-28040 Madrid(Spain); [email protected]

G.N. Sarmiento - Instituto de Geología Económica (CSIC-UCM,) José Antonio Novais 2, E-28040 Madrid (Spain);[email protected]

The Moncorvo synclinorium in the Trás-os-Montes region of N Portugal is located inthe northern Central-Iberian Zone. The core of the synclinorium includes a 300-600 mthick Silurian succession of strongly tectonized and sparsely fossiliferous shales withsome limestone intercalations. Sarmiento et al. (1999) described the Silurian successionas a relatively condensed sequence that is much thinner and stratigraphically similar toSilurian successions of the Ossa-Morena Zone, SE Sardinia and parts of north Africa.Their distal shelf characteristics resemble the “Thuringian triad” by the presence, towardsthe upper part, of a Ludlow-Pridoli scyphocrinoid limestone correlated by conodonts.

We report here the graptolite taphonomy of silico-phosphatic nodules (up to 15 cm indiameter) found ESE from Moncorvo in a metric bed of alum shale below thescyphocrinoid limestone. From these nodules we recorded a Sheinwoodian assemblage of3D-specimens of Pristiograptus dubius (Suess), Monograptus cf. flemingii (Salter),Monoclimacis cf. flumendosae (Gortani), and Retiolites sp. They occur as “hollow”

Fig. 1 - A) Equatorial section of a nodule, showing concentric rims (x 0.7); B) detail of phosphategrains (x 2.7); C) longitudinal sections of rhabdosomes (x 2.1); D) transverse sections ofrhabdosomes (x 2.4); E) pseudo-stalactites of phosphatic minerals inside a rhabdosome (x11.3); F) phosphatic overgrowth in both sides of the graptolite periderm (hollow space, arrowed)(x 116); G) geopetal silica (arrowed) at the base of an interthecal septum (x 66).



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moulds in a siliceous matrix with coarse phosphatic grains. The organic periderm is notpreserved, but features such as the fusellar tissue are finely replicated by phosphaticovergrowths that coated the inner and outer surfaces of the rhabdosome. Occasional“stalactites” of phosphatic minerals and colloidal silica partially occupied the empty spaces.A later alteration of the dispersed iron sulphides favoured the ferruginous impregnation ofsome rhabdosomes.

Our results corroborate the correlation between these Wenlock strata and the bedswith “phosphoritknollen” that occur towards the middle part of the Lower GraptoliticShales in Thuringia and SE Sardinia (Jaeger, 1976), being restricted to these Thuringianfacies developed in offshore settings in northern Gondwana.

This work is a contribution to the projects CGL2006-07628/BTE (Spain) and PTDC/CTE-GEX/64966/2006 (Portugal).

REFERENCESJAEGER H. (1976). Das Silur und Unterdevon vom thüringischen Typ in Sardinien und seine regionalgeologische

Bedeutung. Nova Acta Leopoldina, n.F., 45, 224: 263-299.SARMIENTO G.N., PIÇARRA J.M., REBELO J.A., ROBARDET M., GUTIÉRREZ-MARCO J.C., STORCH P. & RÁBANO I.

(1999). Le Silurien du synclinorium de Moncorvo (NE du Portugal): biostratigraphie et importancepaléogéographique. Geobios, 32: 749-767.


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Howellellid branches at the Silurian/Devonianboundary interval and their importance fordelthyridoid spiriferid evolution

MENA SCHEMM-GREGORY

M. Schemm-Gregory - Senckenberg Forschungsinstitut und Naturmuseum, Paläozoologie III, Senckenberganlage25, D-60325 Frankfurt am Main (Germany); [email protected]

The cosmopolitan genus Howellella Kozlowski, 1946 is regarded as the root of severalbranches of delthyridoid spiriferids, a group of coarsely plicated and mostly alatebrachiopods. During the Silurian and Early Devonian taxa of Howellella were globallydistributed and closely related to each other. Within the Early Devonian faunal isolationbegan resulting in endemic brachiopod provinces and realms each with its own evolutionarybranch of brachiopods. Extinctions events followed by re-settlements of brachiopodcommunities characterised each region.

The type species of Howellella, H. elegans Muir-Wood, 1925, occurs in the Wenlockof Gotland, Sweden, and is characterized by a very small specimens with two to threeribs on each flank and a fimbriate micro-ornamentation consisting of single rows of micro-spines at the edge of each growth lamella. Younger species, however, show an increase insize and amount of ribs as well as development of other forms of micro-ornamentation,capillate with and without micro-spines or fimbriate with more than one row of micro-spines at the edge of each growth lamella.

Several phylogenetic lineages are recognisable coming out of Howellella, e.g., thevanuxemi-cycloptera-murchisoni lineage in eastern North America or the cortazari-salicamensis-arduennensis-mosellanus lineage in Western and Central Europe.

All taxa of Howellella seem very similar on first sight but already Carls (1985) andCarls et al. (1993) showed that Howellella can be subdivided into subspecies in Europe.

It is remarkable that all lineages under consideration are characterized by an increasein size of specimens, one of the most spectacular example is the ratio of size in Howellellaand Euryspirifer Wedekind, 1926. However, it is remarkable that with Quiringites Struve,1992 a Howellella-like morphotype occured for a short time again within the Eifelian(early Middle Devonian).

According to Johnson & Hou (2006) in the revised “Treatise on InvertebratePaleontology”, descendants of Howellella survived until the early Middle Devonian inAsia with the genus Xenospirifer Hou & Xian, 1975. After detailed comparison withother delthyridoid spiriferids it has turned out that Xenospirifer belongs to a different andnew family within the Delthyridoidea of the “Asian delthyridoid spiriferid clade” (Schemm-Gregory 2009), but originating also from Howellella.

REFERENCESCARLS P. (1985). Howellella (Hysterohowellella) knetschi (Brachiopoda, Spiriferacea) aus dem tiefen Unter-

Gedinnium Keltiberiens. Senckenbergiana lethaea, 65: 297-326.



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CARLS P., MEYN H. & VESPERMANN J. (1993). Lebensraum, Entstehung und Nachfahren von Howellella(Iberohowellella) hollmanni n. sg., n. sp. (Spiriferacea; Lochkovium, Unter-Devon). Senckenbergianalethaea, 73: 227-267.

JOHNSON J.G. & HOU H. (2006). Delthyridoidea. In Kaesler R.L. (Ed.), Treatise on Invertebrate Paleontology,Part H, Brachiopoda 5 (revised). Geological Society of America & University of Kansas, Lawrence,Kansas: 1825-1847.

KOZLOWSKI R. (1946). Howellella, a new name for Crispella Kozlowski, 1929. Journal of Paleontology,20: 295.

MUIR-WOOD H.M. (1925). Notes on the Silurian braciopod genera Delthyris, Uncinulus, and Meristina.Annals and Magazine of Natural History, series 9, 15: 83-95.

SCHEMM-GREGORY M. (2009). A new spiriferid genus and ist phylogenetic position within the Delthyridoidea(Brachiopoda, Lower Devonian). Neues Jahrbuch für Geologie und Paläontologe, 252: 53-70.

STRUVE W. (1992). Neues zur Stratigraphie und Fauna des rhenotypen Mittel-Devon. Senckenbergianalethaea, 71: 503-624.

WEDEKIND R. (1926). Die devonische Formation. In Salomon W. (Ed.), Grundzüge der Geologie 2,Erdgeschichte. Schweizerbart’sche Verlagsbuchhandlung (Nägele), Stuttgart: 194-226.


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The Silurian of the Goldsteintal (RheinischesSchiefergebirge, Germany)

MENA SCHEMM-GREGORY, ULRICH JANSEN

M. Schemm-Gregory - Senckenberg Forschungsinstitut und Naturmuseum, Paläozoologie III, Senckenberganlage25, D-60325 Frankfurt am Main (Germany); [email protected]

U. Jansen - Senckenberg Forschungsinstitut und Naturmuseum, Paläozoologie III, Senckenberganlage 25, D-60325Frankfurt am Main (Germany); [email protected]

At the classic locality in the idyllic Goldsteintal (“Golden Stone Valley”) near Wiesbadenin the Taunus Hills of the southern Rheinisches Schiefergebirge and at other localitiesnearby, the Kellerskopf Formation (= Graue Phyllite or „Grey Phyllites“ in former works)crops out yielding a small fauna consisting of corals, brachiopods, trilobites, crinoidalremains, bryozoans, and bivalves (Struve, 1973). Due to strong tectonic deformation andeven gentle metamorphosis of this succession during the Variscan orogeny, most of thefossils are poorly preserved. Accordingly, the age of this stratum has been controversalfor a long time; it has been dated either as late Silurian (Dahmer, 1946) or earliest Devonian(Fuchs, 1929; Shirley, 1962; Struve, 1973). New finds confirm the identification of thebrachiopod Dayia shirleyi Alvarez & Racheboeuf, 1986, allowing a correlation with thelowermost Noulette Formation of Artois (France), the Köbbinghausen Formation of theEbbe Anticline (N Rheinisches Schiefergebirge, Germany) and the lower Muno Formationof the Ardennes (cp. Godefroid, 1995; Godefroid & Cravatte, 1999). As for these strata,a late Silurian (Pridolian) age is suggested for the faunas of the Kellerskopf Formation, asthe genus Dayia has never been observed to cross the Silurian/Devonian boundary. Thepresence of Quadrifarius dumontianus (de Koninck, 1876) and Shaleria rigida (deKoninck, 1876) support this assignment, whereas the presence of Platyorthis wouldrather plead for an Early Devonian age. The two taxa mentioned first allow a correlationwith the Weismes Formation (= Grès de Gdoumont) of the Hautes Fagnes and the SilbergFormation of the Müsen Horst (N Rheinisches Schiefergebirge). The finds in theGoldsteintal fit well in a scenario of a vast “dumontianus Shelf” (Carls, 2001) duringPridolian time, representing the first transgression after the Caledonian orogeny in theRheinisches Schiefergebirge and marking the onset of the Variscan cycle.

REFERENCESALVAREZ F. & RACHEBOEUF P.R. (1986). Sous-famille Dayiinae Waagen 1883. In Racheboeuf P.R. (Ed.), Le

Groupe de Liévin. Pridoli-Lochkovien de L‘Artois (N. France). Sédimentologie - Paléontologie -Stratigraphie - Biostratigraphie du Paléozoique, 3: 128-131.

CARLS P. (2001). Kritik der Plattenkinematik um das Rhenohercynikum bis zum frühen Devon.Braunschweiger geowissenschaftliche Arbeiten, 24: 27-108.

DAHMER G. (1946). Gotlandium mit Dayia navicula im Taunus. Seine Beziehungen zu den Köbbinghäuser(Dayia-) Schichten des Ebbe- und Remscheider Sattels und zu den Schichten von Weismes.Senckenbergiana, 27: 76-84.

FUCHS A. (1929). Die unteren Gedinneschichten der Gegend von Wiesbaden. Jahrbuch des NassauischenVereins für Naturkunde, 80 (2): 74-86.



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GODEFROID J. (1995). Dayia shirleyi Alvarez & Racheboeuf, 1986, un brachiopode silurien dans les ”Schistesde Mondrepuis” à Muno (sud de la Belgique). Bulletin de l’Institut Royal des Sciences Naturelles deBelgique: Sciences de la Terre, 65: 269-272.

GODEFROID J. & CRAVATTE T. (1999): Les brachiopodes et la limite Silurien/Dévonien à Muno (sud de laBelgique). Bulletin de l’Institut Royal des Sciences Naturelles de Belgique: Sciences de la Terre, 69: 5-26.

KONINCK L. (1876). Notice sur quelques fossiles recueillis par G. Dewalque dans le système Gédinnien de A.Dumont. Annales (le la Société géologique de Belgique, 3: 25-52.

SHIRLEY J. (1962). Review of the correlation of the supposed Silurian strata of Artois, Westphalia, the Taunusand Polish Podolia. In Erben H.K. (Ed.), Symposium Silur/Devon-Grenze 1960: 234-242.

STRUVE W. (1973). Die ältesten Taunus-Fossilien. Natur und Museum, 103: 349-359.


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Silurian Nautiloid Cephalopods from the Cabrièresarea (Montagne Noire, France): a preliminary report

PAOLO SERVENTI, RAYMUND FEIST

P. Serventi - Dipartimento del Museo di Paleobiologia e dell’Orto Botanico, Università di Modena e Reggio Emilia,via Università 4, I-41100 Modena (Italy); [email protected]

R. Feist - Institut des sciences de l’évolution, Université Montpellier 2 – CNRS, Place Eugène Bataillon, F-34095Montpellier (France); [email protected]

This preliminary report deals on a nautiloid cephalopod fauna collected on the northernslope of the Plateau de Falgairas, a few km south of Cabrières. The Silurian-LowerDevonian succession of the area mainly consists of isolated exposures (Feist, 2002) andwas described by Feist & Schönlaub (1974). Biostratigraphic data were provided on thebasis of conodonts (Feist & Schönlaub, 1974) and chitinozoans (De Bock, 1982).

Silurian nautiloid cephalopods from the Montagne Noire were illustrated by Ristedt(1968), who described five taxa from this area.

The studied material have been collected from some blocks along the path from LaRoquette to Col de l’Orte. The association consists of four species: Orthocycloceras?fluminese (Meneghini), Michelinoceras (Michelinoceras) michelini (Barrande),Arionoceras submoniliforme (Meneghini) and Arionoceras canonicum (Meneghini).Several protoconchs referable to subfamily Michelinoceratinae, have been collected, too.

Some specimens have been dated to Pridoli, thanks to conodonts found in the nautiloid-bearing blocks.

REFERENCESDE BOCK F. (1982). Présence de chitinozaieres dans le passage siluro-dévonien de la Montagne Noire sud-

orienatale. Geobios, 15 (6): 845-871.FEIST R. (2002). The Palaeozoic of the Montagne Noire, Southern France. ECOS VIII Guidebook to the

Field Excursion: 85 pp.FEIST R. & SCHÖNLAUB H.P. (1974). Zur Silur/Devon-Grenze in der östlichen Montagne Noire Süd-Frankreichs.

Neues Jahrbuch für Geologie und Paläontologie Monatshefte, 1974-H4: 200-219.RISTEDT H. 1968. Zur Revision der Orthoceratidae. Abhandlungen der Mathematisch-

Naturwissenschaftlichen. Akademie der Wissenschaften und Literatur in Mainz, Klasse, 68(4): 212-287.



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Gondwanan tectonics and European events in theSilurian of Australasia

LAWRENCE SHERWIN

L. Sherwin - Geological Survey of New South Wales, Dept of Primary Industries, Locked Bag 21, Orange, New SouthWales 2800 (Australia); [email protected]

Silurian biostratigraphic events defined in north-west Europe correspond with intervalsof marked tectonic activity in Australasia (north-east Gondwana) but the accuracy incorrelation is not such that a European biostratigraphic event can be tied to a specificAustralasian tectonic event. Problems remain in a strict application of European Silurianzonation schemes in Australasia (Strusz, 2007). In the eastern margin of Australasia theearlier part of the Silurian (Llandovery - early Wenlock?) is represented mostly by deepwater siliciclastic sediments with few calcareous beds in the Lachlan Fold Belt (LFB).Events of any kind are difficult to recognise within the Llandovery in the eastern part ofthe LFB near Goulburn because of later structural complications, particularly theimbrication of Late Ordovician and Early Silurian fault slices which nonetheless havevery similar lithologies.

Silurian strata are structurally simpler in the western part of the LFB near Forbeswhere the pre Wenlock is represented by fairly uniform laminate quartzose siltstone ofthe Cotton Formation. Here, the graptolitic sedgwickii bioevent coincides with a minorchange in lithology that results in sedgwickii and guerichi graptolite faunas (Sherwin,1974; Loydell et al., 1993) being associated with distinctly more prominent outcrops.Above the guerichi fauna the base of the Forbes Group is marked by a poorly datedpolymictic carbonate cemented cobble conglomerate (Bocobidgle Conglomerate),succeeded by approximately 300m of generally massive olive grey silty mudstone(Mumbidgle Formation). About the middle of this unit is an horizon with a ludensis-sherrardae fauna but without any marked change in lithology from the remainder of theMumbidgle Formation. The marked change in lithology from the Cotton Formation to theForbes Group is associated with an hiatus of uncertain duration but is interpreted asencompassing the lapworthi and murchisoni graptolitic bioevents and the Ireviken, Bogeand Valleviken conodont bioevents. This hiatus is also apparent in the eastern part of theLFB in the Yass and Goulburn districts (Thomas & Pogson, in press). The Forbes Groupis overlain with a low angle unconformity by the non graptolitic Derriwong Group. Thebasal unit of the Derriwong Group is a pebbly sandstone lacking age diagnostic fossils butoverlying the sandstone is a felsic volcanic sequence with interbedded limestones whichcontain a remscheidensis zone conodont fauna, although one sample indicates a possiblecrispa zone age (Pickett & Ingpen, 1990). The indicated hiatus thus spans much of theLudlow and overlaps with the timespan covering the Linde and Lau conodont bioevents.In the eastern part of the LFB there is more or less continuous sedimentation, withnotable olistostromes in the Pridoli (Sherwin, 1971, Thomas & Pogson, in press),corresponding to the hiatus during the Ludlow in the western LFB.

Published with the permission of the Director, Geological Survey of New South Wales.



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REFERENCESLOYDELL D.K., STORCH P. & MELCHIN M.J. (1993). Taxonomy, evolution and biostratigraphical importance of

the Llandovery graptolite Spirograptus. Palaeontology, 36, 909-926.PICKETT J.W. & INGPEN I.A. (1990). Ordovician and Silurian strata south of Trundle, New South Wales.

Geological Survey of New South Wales, Quarterly Notes, 100, 1-7.SHERWIN L. (1971). Stratigraphy of the Cheesemans Creek district, New South Wales. Geological Survey of

New South Wales, Records, 13, 199-237.SHERWIN L. (1974). Llandovery graptolites from the Forbes district, New South Wales. Special Papers in

Palaeontology, 13, 149-175.STRUSZ D.L. (2007). The Silurian timescale – an Australian perspective. Memoirs of the Association of

Australasian Palaeontologists, 34, 157-171.THOMAS O.D. & POGSON D.J. (in press). Goulburn 1:250000 Geological Sheet, 2nd edition. Explanatory

Notes. Geological Survey of New South Wales, Maitland.


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Problematic fossil remains from the Silurian KokFormation in the type area (Carnic Alps, Italy)

LUCA SIMONETTO, PAOLO SERVENTI, MONICA PONDRELLI, CARLO CORRADINI

L. Simonetto - Museo Friulano di Storia Naturale, via Marangoni 39-41, I-33100 Udine (Italy); [email protected]. Serventi - Dipartimento del Museo di Paleobiologia e dell’Orto Botanico, Università di Modena e Reggio Emilia,

via Università 4, I-41100 Modena (Italy); [email protected]. Pondrelli - International Research School of Planetary Sciences, Dipartimento di Scienze, Università d’Annunzio,

viale Pindaro 42, I-65127 Pescara (Italy); [email protected] - Dipartimento di Scienze della Terra, Università di Cagliari, via Trentino 51, I-09127 Cagliari (Italy);

[email protected]

This report is one of the outcomes of a broader research project which aim is tosurvey the geology of the Silurian Orthoceras Limestone cropping out in the Italian sideof the Carnic Alps (North-Eastern Italy). The former researches on this subject date infact from the first half of the twentieth century.

The Silurian Orthoceras Limestone crop out through all the Carnic Alps, but thecomplex tectonic assemblage of the area, due to compressional as well as extensionaldeformative phases, makes the unravelling of the depositional setting quite complex.Moreover, this unit is generally only few meters thick. As a consequence the outcrops areusually small and scattered.

A revision of the macrofossils preserved in the Silurian limestone of the study area hasbeen undertaken. The Carnic Alps, in fact, have been known since the end of the nineteenthcentury for the abundance and variety of Silurian fossils. Orthoconic cephalopods are,doubtless, the most frequent remains, followed by trilobite fragments (usually isolatedpygidiums and cephalons), bivalves, gastropods and crinoids; the latter are quite frequentas isolated articles, forming at places true encrinite levels. Brachiopods, corals and ostracodsremains are rarer.

In the eastern part of the chain Silurian fossils are particularly abundant in the MonteCocco area, North of Ugovizza village. Important mining activities have been documentedin this area, since sixteenth century, digging out iron and manganese from cephalopodlimestone. The mined non-mineralized limestone was spread outside the gallery entrances;as a consequence, a lot of fossiliferous rocks are available in spite of the relative scarcityof wide outcrops, most of which being hidden by wood or debris.

Large collections of Silurian fossils from Monte Cocco are stored in the Museo Friulanodi Storia Naturale, in Udine. That material and newly collected samples from the lateLlandovery-lower Ludlow Kok Formation have been investigated in order to obtain newdata on the Silurian faunas of the Carnic Alps. Conodonts allow to date most of theseremnants at the amorphognathoides Zone.

Beside representatives of common fossil groups, the study of thousands of samplesevidenced the presence of several small-sized remains whose interpretation turn out to bedifficult, although having characteristic shape. Beside other less common shapes, threedifferent morphologies are relatively abundant in the examined material: a sub-triangularwith sigmoidal ornamentation (Fig. 1a), a subcircular with a concentric ornamentation



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(Fig. 1b) and an elongate with chessboard thin costae. It should be noted that representativesof these morphs are constant is size.

Moreover, a few fossil fragments can be ascribed to the artropods but have no trilobitefeatures. We hypothesize that these samples could be parts of eurypterids but the remainsare so poorly preserved that the determination is quite tricky. Furthermore, eurypteridsremains have never been reported in literature for this area, so their eventual detectionmust be carefully evaluated.

Fig. 1 - Problematic fossil microremains from Monte Cocco. Both from block “Tamer-BK 1”(amorphognathoides Zone). a) Subtriangular plate with sigmoidal ornamentation. b) Subcircularplate with a irregular concentric ornamentation.


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Carbon isotope data and graptolite record in the lowerSilurian (Llandovery) of northern peri-Gondwana –exemplified by Barrandian area, Czech Republic

PETR STORCH, JIRI FRYDA

P. Storch - Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojova 269, 165 02 Praha 6 (CzechRepublic); [email protected]

J. Fryda - Czech Geological Survey, Klarov 3, 118 21 Praha 1, and Faculty of Environmental Sciences, CULS, 165 21Praha 6 (Czech Republic); [email protected]

Late Ordovician and Silurian carbon isotope record exhibits a series of positive excursionswhich coincide with sea-level changes and mass faunal extinctions. The δ13C

org values

from the uppermost Hirnantian to lower Telychian strata of the Barrandian area arecompared with data on graptolite faunal dynamics based on a high resolution graptolitebiostratigraphy.

Significant negative shift in δ13Corg

from late Hirnantian baseline values to ca. 31 ‰ isassociated with graptolite-rich black shale that appears just below the base of the SilurianAkidograptus ascensus Biozone. Further increase in the organic carbon content coincideswith a magnificent adaptive radiation among graptolites and gradual increase of δ13C

org.

This trend extends from A. ascensus, through Parakidograptus acuminatus to Cystograptusvesiculosus biozones in Repy and Hlasna Treban sections. A prominent gap insedimentation, embracing upper A. ascensus – Coronograptus cyphus biozones, wasdocumented in Radotin tunnel section. A sequence boundary expressed by this stratigraphicunconformity (Storch, 2006) coincides with a sudden rise in organic carbon content andminor positive shift in δ13C

org in Radotin tunnel. The δ13C

org values fluctuate between 28

and 30 ‰ during early and middle Aeronian Demirastrites triangulatus – Lituigraptusconvolutus biozones, whereas maximum TOC values of the late Rhuddanian C. cyphusBiozone and early Aeronian D. triangulatus Biozone decline through to the lower part oflate Aeronian Stimulograptus sedgwickii Biozone. Rich and diverse mid-Aeronian graptolitefauna vanished from the black shale at about the top of the convolutus Biozone, hencethe lower part of the sedgwickii Biozone, remarkable by silty fraction and abundantpyrite, exhibits few graptolite rhabdosomes.

Pyrite-rich interval is overlain by a heavily mottled, silty/sandy-micaceous bed. Rapidsea-level drawdown, supposed by Loydell (1998) manifests itself by increased input ofthe silty/sandy-micaceous fraction, that correlates with a gap in sedimentation elsewherein Barrandian and abroad. Siliciclastic signal is compatible with low organic content andheavy bioturbation in this particular level and further coincides with a strong positivecarbon isotope excursion. Positive excursion, recorded also in Dob‘s Linn, Scotland andCornwallis Island of Arctic Canada (Melchin & Holmden, 2006), is rather short-term,perhaps incomplete in the Barrandian area. It clearly postdates, however, the major phaseof graptolite extinction known as sedgwickii Event. Lithology, sequence architecture,organic carbon content, isotope record, as well as graptolite faunal dynamics, are consistentwith a conception of short term advance in continental glaciation in Gondwana.



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The level with positive δ13C excursion is overlain by micaceous black shale characterizedby a rapid return to normal δ13C

org values, rapid increase in TOC, and rapid proliferation

of low diversity-high abundance graptolite fauna belonging to the middle part of the S.sedgwickii Biozone.

Though the anoxic black shale is intercalated with pale-coloured marlstones in thesucceeding lowermost Telychian Rastrites linnaei and Spirograptus turriculatus biozones,and TOC values fluctuate, the δ13C

org record is steady.

REFERENCESLOYDELL D.K. (1998). Early Silurian sea-level changes. Geological Magazine, 135: 447-471.MELCHIN M.J. & HOLMDEN C. (2006). Carbon isotope chemostratigraphy of the Llandovery in Arctic Canada:

implications for global correlation and sea-level change. GFF, 128: 173-180.STORCH P. (2006). Facies development, depositional settings and sequence stratigraphy across the Ordovician-

Silurian boundary: a new perspective from the Barrandian area of the Czech Republic. GeologicalJournal, 41: 163-192.


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Paleoenvironment of the Siluro-Devonian sequence insouthern Burgenland (Austria)

THOMAS J. SUTTNER

T.J. Suttner - Commission for the Palaeontological and Stratigraphical Research of Austria c/o University of Graz,Institute of Earth Sciences (Geology and Palaeontology), Heinrichstrasse 26, A-8010 Graz (Austria);[email protected]

Late Silurian to Lower Devonian deposits of southern Burgenland (Austria) are knownfrom an ancient quarry south of the village of Kirchfidisch and near Sulz, where a severaltens of meters thick sequence is exposed (Pollak, 1962). From the base to the top, theunit consists of phyllitic shale (8 m), white carbonaceous marl (8 m), laminated limestone(17.5 m), even bedded serpulid tube-bearing limestone which is intercalated by thin siltlayers (2 m), and dolomitic limestone and dolomite (4 m). Due to the evidence that onlythe upper 6 meters of the unit yield fossils, geochemical analysis were used to gainadditional information on the rock composite for a better interpretation of the depositsaccording to paleoenvironmental conditions and settings. In general the fauna consists ofspiculae, gastropods, serpulids, ostracods, brachiopods, crinoids and conodonts (Suttner& Lukeneder, 2004).

Until now it is not clear, whether the basal phyllitic shale is overlain by the marlsconformably or if a hiatus separates them. The development above the shale seems to bemore or less continuous. According to the facies, different lithologies like dark bituminouslaminated limestones, dolomites or the serpulid bearing limestones, hint to shallow marineconditions. This is supported by the conodont fauna, which is dominated by icriodontids(Suttner, 2009). Earlier speculations that the ancient serpulid-tube build ups were relatedto cold seeps could be disproved as geochemical data of carbon isotopes and trace elementsdo not show values distinctive for such environments.

Taphonomic analyses of serpulid bearing limestone beds conclude allochthonousdeposition. The accumulated trochospiral and helical tubes are not erected within thelimestone beds. Single tubes and re-deposited tube-aggregates show no orientation; theyare ‘floating’ in the limestone matrix. Fragmentation of tubes and accompanying fauna islow which suggests that the accumulated tubes must have been deposited proximal to theancient build up. An in situ serpulid bioherm which was constructed by similar tube-morphotypes is known from Devonian strata of Arizona (Beus, 1980). In dolomiticlimestones above the serpulid bearing beds, thin shell layers alternate with fine laminatedlimestone layers, which finally are overlain by unfossiliferous dolomite. From the dolomiticlimestone beds some fused conodont clusters are known.

In general, shallow to subtidal settings are proposed to be dominating paleoenvironment,where calm periods (indicated by the growth of microbial mats, or deposition of thinbrownish silt layers) alternate with more turbulent, possibly storm induced periods resultingin accretion of serpulid tubes or shell layers. Even though the serpulid beds and thepreservation of conodont clusters might hint to special conditions for this interval - howfar can it justify whether this small outcrop accords to restricted lagoonal deposits or not?



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Additionally it remains unclear whether this sequence was deposited during temperatecool or subtropical warm conditions.

REFERENCESBEUS S.S. (1980). Devonian serpulid bioherms in Arizona. Journal of Paleontology, 54: 1125-1128.POLLAK W. (1962). Untersuchungen über Schichtfolge, Bau und tektonische Stellung des österreichischen

Anteils der Eisenberggruppe im südlichen Burgenland. 108 pp. unpublished Ph.D. thesis, University ofVienna.

SUTTNER T.J. (2009). Lower Devonian conodonts of the “Baron von Kottwitz” quarry (Southern Burgenland,Austria). In Over D.J. (Ed.) Conodont Studies Commemorating the 150th Anniversary of the First ConodontPaper (Pander, 1856) and the 40th Anniversary of the Pander Society, Palaeontographica Americana,62: 75-87.

SUTTNER T. & LUKENEDER A. (2004). Accumulations of Late Silurian serpulid tubes and their palaeoecologicalimplications (Blumau-Formation; Burgenland; Austria). Annalen des Naturhistorischen Museums inWien, 105 A: 175-187.


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Siluro-Devonian biodiversification of trilete spores andcryptospores from Tunisia: palaeophytogeographic andpalaeoclimatic implications

MARCO VECOLI, AMALIA SPINA

M. Vecoli - Université Lille 1, UMR 8157 “Géosystèmes” CNRS, F-59655 Villeneuve d’Ascq (France).A. Spina - Dipartimento di Scienze della Terra, Università di Perugia, I-06124 Perugia (Italy).

A detailed study on miospore assemblages from Ludlow-Lochkovian time interval inSouthern Tunisia (MG-1 borehole, Ghadamis Basin) permits a comparison with coevalassociations from other Gondwanan and Euramerican localities and to better define thepalaeoclimatic changes across this time span.

Four palynological assemblages have been established and assigned respectively toupper Gorstian-Ludfordian, Ludfordian-lower Pridoli, Pridoli and Lochkovian. TheGorstian-Ludfordian assemblage is mainly characterised by the presence of patinate formswith verrucate sculpture (e.g., S. verrucatus), and laevigate trilete spores with equatorialcrassitude such as Ambitisporites avitus, and occurrence of retusoid spores (Retusotrileteswarringtonii). The Ludfordian-lower Pridoli assemblage mainly consists of abundantornamented trilete spores such as Chelinospora poecilomorpha, Amicosisporitessplendidus, Synorisporites libycus, and less abundant cryptospores. The Pridoli associationis mainly characterised by interradial tripapillate spores recorded both in Gondwana andLaurussia domains, co-occurring with laevigate trilete spores (i.e. Archeozonotriletes,Ambitisporites, etc.), present in all Silurian record. In the upper part of the assemblage,the microflora is characterized by a bloom of Aneurospora spp., abundantly present alsoin the overlying Lochkovian assemblage. Most cryptospore and trilete spore species firstappearing during the Pridoli, range through the Silurian-Devonian boundary and commonlyoccur during the Lochkovian. This pattern is recognized in Gondwanan as well as inEuramerica. In addition, Lochkovian assemblages are characterized by the appearanceand diversification of tripapillate spores, distally sculptured with grana, coni, and spinae,such as Streelispora newportensis, which appears to be palaeogeographically widespreadduring the Early Devonian. These data suggest that the Silurian-Devonian transition is notcharacterised by pronounced floristic turnover. With the exception of some minor localdifferences probably due to the endemism of some species, the close similarities ofmicroflora recorded both from Gondwana and Europe reflect palaeogoegraphical proximityas well as broadly uniform climatic conditions between Gondwana and Laurussia duringthe Silurian-Devonian transition.

The diversification of cryptospores and trilete spores from MG-1 borehole has beencompared with that recorded from Gondwana and Euramerica. Over 60 selectedpublications have been used to draw a trilete spores and cryptospores biodiversity curvefor the Wenlock-Lochkovian time interval of both Gondwanan and Euramerican domain.Trilete spore and cryptospore have been plotted as average diversity per geologic stage.The cryptospores biodiversity curve shows the same trend for both Euramerican and



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Gondwanan domain, although in this latter they are less diversified. In comparison withthe trilete spores, generally the cryptospores disappear progressively from the Wenlock-Ludlow to Lochkovian, although they are slightly more abundant in the Early Devonianthan in the Pridoli. On the contrary, the diversification of trilete spore continues fromWenlock to Lochkovian. Nevertheless, the Euramerican trilete spores are less diversifiedthan those from Gondwana. The MG-1 biodiversity curve shows the same trend recordedin Gondwana. The biodiversity of these sporomorphs could be correlated with thetransgressive-regressive trend recorded in both domains from Wenlock to Lochkovian.


353

Discovery of a new Llandovery-Wenlock boundarysection in Bajiaokou, Ziyang, China

JIAN WANG, LI-PU FU, YONG MENG, RONG-SHE LI, HONG-PING HUANG

J. Wang - Xi’an Institute of Geology and Mineral Resoures; Xi’an 71005 (China); [email protected]. Fu - Xi’an Institute of Geology and Mineral Resoures; Xi’an 71005 (China); [email protected]. Meng - Xi’an Institute of Geology and Mineral Resoures; Xi’an 71005 (China); [email protected] Li - Xi’an Institute of Geology and Mineral Resoures; Xi’an 71005 (China); [email protected]. Huang - Xi’an Institute of Geology and Mineral Resoures; Xi’an 71005 (China).

A biostratigraphic study of the Silurian sections of Ziyang was carried out in the courseof 1:50000 scale geological mapping. A new, highly fossiliferous section with particularlywell developed Llandovery-Wenlock boundary interval was encountered in Bajiaokou.Great numbers of complete rhabdosomes of Cyrtograptus insectus Boucek and C.centrifugus Boucek have been collected in this section. Present material of the formerzonal index species originated from 9 different beds, material of the latter species camefrom 6 beds. Five graptolite biozones were identifiend in the section, in the ascendingorder: C. sakmaricus Biozone 1.16 m above the base of the section, C. insectus Zone1.16-3.10 m above the base, C. centrifugus Zone at 3.1-6.3 m, C. murchisoni Zone at6.3-11.1 m, and Monograptus riccartonensis Zone at 11.1 m above the base.



355

The Silurian-Devonian Boundary in West Qinling ofSouth China – Evidence from Chemostratigraphy andmicrovertebrate remains across the Silurian/Devoniantransition

WEN-JIN ZHAO, ULRICH HERTEN, NIAN-ZHONG WANG, ULRICH MANN, MIN ZHU,ANDREAS LÜCKE

W.-j. Zhao - Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology andPaleoanthropology (IVPP), Chinese Academy of Sciences, PO Box 643, Beijing 100044 (China);[email protected]

U. Herten - Institute of Chemistry and Dynamics of the Geosphere ICG-V: Sedimentary Systems, Research CenterJuelich GmbH, D-52425 Juelich (Germany); [email protected]

N.-z. Wang - Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology andPaleoanthropology (IVPP), Chinese Academy of Sciences, PO Box 643, Beijing 100044 (China);[email protected]

U. Mann - Institute of Chemistry and Dynamics of the Geosphere ICG-V: Sedimentary Systems, Research CenterJuelich GmbH, D-52425 Juelich (Germany); [email protected]

M. Zhu - Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology andPaleoanthropology (IVPP), Chinese Academy of Sciences, PO Box 643, Beijing 100044 (China);[email protected]

A. Lücke - Institute of Chemistry and Dynamics of the Geosphere ICG-V: Sedimentary Systems, Research CenterJuelich GmbH, D-52425 Juelich (Germany); [email protected]

Many biostratigraphic attempts have been made so far to define the exact level of theSilurian/Devonian (S/D) Boundary in West Qinling of South China (XIGMR and NIGPAS,1987; Rong et al., 1987). Because the comparisons to the S/D index fossils like thegraptolite Monograptus uniformis and the trilobite Warburgella rugulosa rugosa or diagnosticchitinozoans from the GSSP Klonk (Czech Republic) are not feasible in the Putonggouand Yanglugou sections, there exist many issues regarding the biostratigraphy of the UpperSilurian – Lower Devonian in West Qinling, the S/D Boundary in particular. The firstisotope curve based on organic carbon for the SDB sequence from GSSP (Mann et al.,2001) shows the distinct positive excursion of δ13C

org from uppermost Silurian to lowermost

Devonian is directly related to the high bioproductivity, mass burial of organic carbon andtransgression - regression of 3rd order, and represents a global bioproductivity event.Subsequently, the distinct positive shifts in the isotopic composition of organic carbonacross SDB were confirmed at several global locations including the sections from Ukraine,Turkey, USA, Morocco and Poland (Mann et al., 2001; Buggisch & Mann, 2004; Hertenet al., 2004). This distinct change trend from the isotopic composition of organic carbonacross SDB potentially offers a good means to exactly correlate and define the SDB fromdifferent sedimentary facies. In addition, the study on microvertebrate remains since theperforming of IGCP328 showed that microvertebrates have played an important role inthe Silurian-Devonian Stratigraphy. The detailed geochemical analyses, as well as theresearch of microvertebrate assemblage sequences, may throw new lights on the study ofthe S/D Boundary in West Qinling. Recently, we focused on the two sections in WestQinling, and applied the Chemostratigraphy (including the content of carbonate and total



356

organic carbon, stable isotopic ratios of carbonate and organic carbon versus depth, etc.)and Biostratigraphy (including microvertebrate assemblage sequences) as a tool to identifythe Silurian/Devonian Boundary and set up the accurate Late Silurian – Lower Devoniansequence framework in the region. Our newest results suggested that the variations ofδ13C

org exhibited at SDB in two sections from West Qinling can be correlated to the

representative curve of the SDB at Klonk in Czech Republic (GSSP), and in spite of theabsence of some index fossil, the exact level of the Silurian/Devonian (S/D) Boundary inWest Qinling can be located at the upper part of Yanglugou Formation (between ZY-06and ZY-07) in Yanglugou Section and the lower part of Xiaputonggou Formation (betweenZP-09 and ZP-10) in the Putonggou section, which helped to study the early diversificationof vertebrates and land plants, and explore the interaction between the geosphere and thebiosphere.

REFERENCESBUGGISCH W. & MANN U. (2004). Carbon isotope stratigraphy of Lochkovian to Eifelian limestones from the

Devonian of central and southern Europe. International Journal of Earth Science, 93: 521-541.HERTEN U., MANN U. & YALÇIN M.N. (2004). Chemostratigraphic localization of the Silurian/Devonian Boundary

in the Palaeozoic of Istanbul (Esenyali, pendik-Istanbul) by stable carbon isotope composition. Proceedingsof International Symposium on Earth System Sciences 2004, Istanbul – Turkey: 321-334.

MANN U., HERTEN U., KRANENDONCK O., POELCHAU H.S., STROETMANN J., VOS H., WILKES H., SUCHÝ V., BROCKE

R., WILDE V., MULLER A., EBERT J., BOZDOGAN N., SOYLU C. EL-HASSANI A. & YALÇIN M.N. (2001).Dynamics of the Silurian/Devonian boundary sequence: sedimentary cycles vs. organic matter variation.Terra Nostra, (4): 44-48.

RONG J.Y., ZHANG Y. & CHEN X.Q. (1987). Pridolian and Lochkovian brachiopods from Luqu-Tewo area ofWest Qinling Mts., China. In Xi’an Institute of Geology and Mineral Resources (XIGMR) & NanjingInstitute of Geology and Palaeontology, Chinese Academy Sciences(NIGPAS) (eds.), Late Silurian-Devonian strata and fossils from Luqu-Tewo area of west Qinling Mountains, China, Vol. 2: 1-94.

Xi’an Institute of Geology and Mineral Resources (XIGMR) & Nanjing Institute of Geology and Palaeontology,Chinese Academy Sciences(NIGPAS), eds. (1987). Late Silurian-Devonian strata and fossils from Luqu-Tewo area of west Qinling Mountains, China, Vol. 1. 305pp. Nanjing University Press, Nanjing.


357

The Xiaoxiang Fauna (Ludlow, Silurian) - a window toexplore the early diversification of jawed vertebrates

MIN ZHU, WEN-JIN ZHAO

M. Zhu - Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology andPaleoanthropology (IVPP), Chinese Academy of Sciences, PO Box 643, Beijing 100044 (China);[email protected]

W.-j. Zhao - Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology andPaleoanthropology (IVPP), Chinese Academy of Sciences, PO Box 643, Beijing 100044 (China);[email protected]

Gnathostomes, or jawed vertebrates, can be divided into four major clades: thePlacodermi, the Acanthodii, the Chondrichthyes (cartilaginous fishes) and the Osteichthyes(actinopterygians and sarcopterygians). Despite the earliest record of gnathostomes possiblyextends to the Late Ordovician, the Silurian gnathostome remains had been few andfragmentary for a long time, thus leaving the early evolutionary history of jawed vertebratesenigmatic.

The Xiaoxiang Fauna, characterized by the early diversification of gnathostomes, isknown from the Ludlow of Qujing, Yunnan Province, southwestern China. The marineSilurian strata in Qujing are subdivided into four formations in ascending order, theYuejiashan, Kuanti, Miaokao and Yulungssu formations (Ting & Wang, 1937; Fang et al.,1985; Rong et al., 1990). Early fishes (mainly microremains) are recorded from thesequence in association with rich invertebrates such as corals, brachiopods, cephalopods,ostracods, bryozoans and trilobites (Fang et al., 1985), and include Psarolepis and anindeterminable osteichthyan from the Yulungssu Formation (Gagnier et al., 1989; Zhuand Schultze, 1997) and two “actinopterygians” Naxilepis gracilis and Ligulalepisyunnanensis from the Miaokao and Kuanti formations (Wang & Dong, 1989). From themuddy limestone of the Kuanti Formation immediately beneath the first appearance pointof Ozarkodina crispa (Walliser & Wang, 1989; Wang, 2001) at a locality near XiaoxiangReservoir in the suburb of Qujing, we have recently found rich fish remains including theoldest near-complete jawed vertebrate Guiyu oneiros (Zhu et al., 2009). The discoveryof Guiyu, with the accurate dating based on Silurian conodont zonation (Walliser &Wang, 1989), provides not only the near-complete restoration of a primitive fish withmosaic gnathostome characters, but also a new minimum date for the sarcopterygian –actinopterygian split. In addition to Guiyu and other osteichthyan forms, the XiaoxiangFauna includes agnathan galeaspids and diversified placoderms and acanthodians understudy. The research on the Xiaoxiang Fauna will significantly improve our understandingof early diversification of gnathostomes, and the rise of osteichthyans from other primitivegnathostomes in particular.

REFERENCESFANG R.-S., JIANG N.-R., FAN J.-C., CAO R.-G. & LI D.-Y., et al. (1985). The Middle Silurian and Early

Devonian Stratigraphy and Palaeontology in Qujing District, Yunnan. 171 pp. Yunnan People’s PublishingHouse, Kunming.



358

GAGNIER P.Y., JAHNKE H. & SHI Y. (1989). A fish fauna of the Lower Yulongsi Formation (Upper Silurian) ofQujing (E. Yunnan, S. W. China) and its depositional environment. Courier ForschungsinstitutSenckenberg, 110: 123-135.

RONG J.-Y., CHEN X., WANG C.-Y., GENG L.-Y., WU H.-J., DENG Z.-Q., CHEN T.-E. & XU J.-T. (1990). Someproblems concerning the correlation of the Silurian rocks in South China. Journal of Stratigraphy, 14:161-177.

TING V.-K. & WANG Y.-L. (1937). Cambrian and Silurian Formations of Malung and Chutsing Districts,Yunnan. Bulletin of the Geological Society of China, 16: 1-28.

WALLISER O.H. & WANG C.-Y. (1989). Upper Silurian stratigraphy and conodonts from the Qujing District,East Yunnan, China. Courier Forschungsinstitut Senckenberg, 110: 111-121.

WANG C.-Y. (2001). Age of the Guandi Formation in Qujing District, E. Yunnan. Journal of Stratigraphy, 25:125-127.

WANG N.-Z. & Dong Z.-Z. (1989). Discovery of Late Silurian microfossils of Agnatha and fishes fromYunnan, China. Acta Palaeontologica Sinica, 28: 192-206.

ZHU M. & SCHULTZE H.P. (1997). The oldest sarcopterygian fish. Lethaia, 30: 293-304.ZHU M., ZHAO W.-J., JIA L.-T., LU J., QIAO T. & QU Q.-M. (2009). The oldest articulated osteichthyan reveals

mosaic gnathostome characters. Nature. (doi: 10.1038/nature07855) (To be published on March 26,2009).


359



Stable oxygen isotope stratigraphy using conodontbiogenic apatite from the Pridolof the Baltic Basin

ZIVILE ZIGAITE, MICHAEL M. JOACHIMSKI, OLIVER LEHNERT

Z. Zigaite - University of Lille 1, Laboratory of Palaeozoic Palaeontology and Palaeogeography, CNRS UMR 8014,F-59655 Villeneuve d’Ascq cedex (France) and Department of Geology and Mineralogy, Vilnius University,M.K.Ciurlionio 21/27, Vilnius (Lithuania); [email protected]

M.M. Joachimski - Institute of Geology and Mineralogy, University of Erlangen-Nurnberg, Schlossgarten 5, D-91054Erlangen (Germany); [email protected]

O. Lehnert - Institute of Geology and Mineralogy, University of Erlangen-Nurnberg, Schlossgarten 5, D-91054 Erlangen(Germany); [email protected]

Phosphatic conodont microfossils, originating from Upper Silurian (Pridolian) sectionsof Lithuania, have been studied for their oxygen isotope composition. The 18O/16O ratiosof conodont apatite have been measured in order to obtain Silurian seawaterpalaeotemperatures, if the phosphates are well-preserved and not alterated by diageneticprocesses. Diagenetic overprinting of the isotopic record has been aimed to be avoided byselecting conodonts of less than 1.5 colour alteration index, which was the case for thematerial examined, reflecting minor thermal alteration of the Upper Silurian strata in thispart of the Baltic Basin.

ä18Oapatite

values obtained ranged from 17.7 to 19.2‰ V-SMOW, perfectly fitting inthe general Silurian conodont apatite ä18O value range of 17.5 to 19.5‰ V-SMOW,proposed by Joachimski et al. (2003). Therefore the ä18O record appeared to be applicablefor the palaeobasin seawater temperatures reconstructions. The proper conodont apatiteä18O record also provides supplementary evidence for the low diagenetic alteration of theSilurian strata of the Baltic Basin.

We present the first ä18Oapatite

curve from a Pridolian section in the eastern BalticBasin (Gëluva-99 borehole), which is located in the central facies belt of the Silurian ofLithuania. The position of a positive shift in the curve perfectly matches a facies changebetween the lower Pridoli (Vievis Fm.), and the upper Pridoli (Lapës Fm.). The positiveexcursion, indicating drop of palaeoseawater temperature, also corresponds to thelithologically recorded and interpreted as an abrupt sea level drop in between Vievis andLapës Formations, in the middle Pridoli of the Baltic Basin (Paskevicius, 1997; Lazauskieneet al., 2003). This formation boundary has been also recorded biostratigraphically, followingthe significant change in faunal composition (Karatajute-Talimaa & Brazauskas, 1994).Regarding this new chemostratigraphical ä18O

apatite record of conodont apatite, the formation

boundary can now be supported. Palaeoenvironmental climate interpretations of ä18Odata might indicate a cooling event (Lehnert et al., 2007) associated with this middlePridoli sea level drop in the Baltic Basin.

REFERENCESJOACHIMSKI M.M., HORACEK S., BREISIG S. & BUGGISCH W. (2003). The oxygen isotopic composition of biogenic

apatite - no evidence for a secular change in seawater ä18O. European Geophysical Society, GeophysicalResearch Abstracts, 5: 10792.

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KARATAJUTE-TALIMAA V. & BRAZAUSKAS A. (1994). Distribution of vertebrates in the Silurian of Lithuania.Geologija, 17: 106-114.

LAZAUSKIENE J., SLIAUPA S., BRAZAUSKAS A. & MUSTEIKIS P. (2003). Sequence stratigraphy of the Baltic Siluriansuccession: tectonic control on the foreland infill. In McCann T. & Saistot A. (eds.). Tracing TectonicDeformation Using the Sedimentary Record. Geological Society, London, Special Publications, 208:95-115.

LEHNERT O., ERIKSSON M.J., CALNER M., JOACHIMSKI M.M. & BUGGISH W. (2007). Concurrent sedimentary andisotopic indications for global climatic cooling in the Late Silurian. Acta Palaeontologica Sinica, 46(Suppl.): 249-255.

PASKEVICIUS J. (1997). The Geology of the Baltic Republics. Geological Survey of Lithuania, Vilnius, pp.387.


361

Barrick James E. 267, 277Bogolepova Olga K. 269, 293

Castano Rodrigo 271Chen Feng 283, 285Chen Qing 285Chen Xu 285Claeys Phillippe 317Copper Paul 301Corradini Carlo 273, 275, 345Corriga Maria G. 275Cramer Bradley D. 277

Del Rio Myriam 327Dojen Claudia 279Drygant Daniel 281

Fan Junxuan 283, 285Feist Raymund 341Ferretti Annalisa 287, 289, 297Fryda Jiri 347Fu Li-pu 353

Gibson Michael A. 267Gnoli Maurizio 291Goldman Dan 283Gomez-Perez Marcela 293Grytsenko Volodymir 305Gubanov Alexander. P. 269, 293Gutierrez-Marco Juan C. 311, 313, 321, 323,

335

Harland Melise B. 293Harper David A.T. 299, 317, 333Herten Ulrich 355Histon Kathleen 287, 295, 297Holmden Chris 315Howard James P. 293Huang Bing 299, 333Huang Hong-ping 353Hubmann Bernhard 295

Jansen Ulrich 339Jeppsson Lennart 277Jin Jisuo 301Joachimski Michael M. 359Johnson Markes E. 303

Kaljo Dimitri 277, 305, 307Karlsson Haraldur R. 267

Kiipli Enli 307Kiipli Tarmo 307Kozlowska Anna 309Kleffner Mark A. 267, 277

Lenz Alfred 309Lehnert Oliver 359Li Rong-she 353Lorenzo Saturnino E. 311, 313Loydell David K. 277Lucke Andreas 355

Mann Ulrich 355Mannik Peep 277, 319Martma Tonu 277, 305Melchin Michael J. 285, 309, 315Meng Yong 353Meyers Philip A. 289Mortier Jan 317Munnecke Axel 277, 319

Negri Alessandra 289

Peavey F. Nichole 267Picarra Josè 321, 323, 335Piras Sergio 325Pittau Paola 327Pondrelli Monica 345

Ray David 329, 331Rabano Isabel 271, 313, 321Rong Jiayu 299, 333

Sa Artur. A. 323, 335Saltzman Matthew R. 277Samtleben Christian 277Sarmiento Graciela. N. 271, 321, 335Schemm-Gregory Mena 337, 339Schönlaub Hans Peter 297Serventi Paolo 291, 341, 345Sherwin Lawrence 343Simonetto Luca 291, 345Spina Amalia 351Storch Petr 323, 347Sutcliffe Owen 331Suttner Thomas J. 349Szaniawski Hubert 281Vecoli Marco 351Verniers Jacques 317

Index of authors

362

Wagner Thomas 289Wang Jian 353Wang Nian-zhong 355Wang Yi 285

Zalasiewicz Jan. A. 317

Zhan Renbin 299, 333Zhang Hua 283Zhang Yuandong 285Zhao Wen-jin 355, 357Zhu Min 355, 357Zigaite Zivile 359

363

Table of contents

J.E. BARRICK, M.A. KLEFFNER, M.A. GIBSON, F.N. PEAVEY, H.R. KARLSSON - The LauPrimo-Secundo Oceanic Event and Mid-Ludfordian Isotope Excursion (Ludlow,Silurian) in Southern Laurentia .................................................................................... p. 267

O.K. BOGOLEPOVA, A.P. GUBANOV - Early Palaeozoic palaeogeography of SevernayaZemlya, Arctic Russia (with new data on the Silurian) ............................................... p. 269

R. CASTAÑO, I. RÁBANO, G.N. SARMIENTO - Trilobites from the Scyphocriniteslimestone (Pridoli) of the Sierra Norte of Seville Natural Park, southern Spain ..... p. 271

C. CORRADINI - Looking for a late Silurian Standard Conodont Zonation: still a longway to go ....................................................................................................................... p. 273

M.G. CORRIGA, C. CORRADINI - Silurian-Lower Devonian conodonts from theRifugio Lambertenghi Fontana III Section (Carnic Alps, Italy) .................................. p. 275

B.D. CRAMER, D.K. LOYDELL, C. SAMTLEBEN, A. MUNNECKE, D. KALJO, P. MÄNNIK,T. MARTMA, L. JEPPSSON, M.A. KLEFFNER, J.E. BARRICK, M.R. SALTZMAN -Integrated High-Resolution Chronostratigraphy of the Telychian andSheinwoodian Stages: Conodonts Graptolites, Isotopes, and the Future ofPaleozoic Chronostratigraphy ..................................................................................... p. 277

C. DOJEN - Late Silurian Ostracodes from the Hazro Anticline (SE Turkey) .................. p. 279

D. DRYGANT, H. SZANIAWSKI - Conodonts of the Silurian-Devonian boundary bedsin Podolia, Ukraine ...................................................................................................... p. 281

J. FAN, D. GOLDMAN, F. CHEN, H. ZHANG - Geobiodiveristy Database and itsapplication in graptolite research ................................................................................ p. 283

J. FAN, M.J. MELCHIN, X. CHEN, Y. WANG, Y. ZHANG, Q. CHEN, F. CHEN - Bio-stratigraphy and geography of the Ordovician-Silurian Lungmachi black shalesin South China .............................................................................................................. p. 285

A. FERRETTI, K. HISTON - Cephalopod limestone biofacies in the Silurian of theCarnic Alps, Austria ...................................................................................................... p. 287

A. FERRETTI, A. NEGRI, T. WAGNER, P.A. MEYERS - Palaeozoic black shales: how muchshould we trust the Recent to reconstruct the Past? ................................................... p. 289

M. GNOLI, P. SERVENTI, L. SIMONETTO - Nautiloid Cephalopods from the Silurian ofthe Carnic Alps – New evidences ................................................................................ p. 291

A.P. GUBANOV, O.K. BOGOLEPOVA, J.P. HOWARD, M.B. HARLAND, M. GOMEZ-PEREZ -The Silurian of the southern Siberian Platform .......................................................... p. 293

K. HISTON, B. HUBMANN - Upper Silurian Nautiloid Faunas from the EggenfeldSection (Graz, Austria) ................................................................................................. p. 295

K. HISTON, H.P. SCHÖNLAUB, A. FERRETTI - The Cellon Section: a Review of theStratotype Section for the Southern Alps (1894-2009) ............................................. p. 297

B. HUANG, D.A.T. HARPER, J. RONG., R. ZHAN - Does “Lilliput Effect” of brachiopodexist in South China after the late Ordovician mass extinction? ................................ p. 299

J. JIN, P. COPPER - Origin and diversification of the Early Silurian virgianidbrachiopods .................................................................................................................. p. 301

364

E.M. JOHNSON - Tracking Silurian eustasy: Alignment of empirical evidence orpursuit of deductive reasoning? ................................................................................... p. 303

D. KALJO, V. GRYTSENKO, T. MARTMA - Additions to the Carbon Isotope trendof Podolia (Ukraine) with a summary and evaluation of the Silurianchemostratigraphy ........................................................................................................ p. 305

T. KIIPLI, E. KIIPLI, D. KALJO - Silurian sea level variations based on SiO2/Al

2O

3 and

K2O/Al

2O

3 ratios from Priekule drill core section, Latvia, and comparison with

redox conditions carbonate precipitation and global δ13C changes ........................... p. 307

A. LENZ, M. MELCHIN, A. KOZLOWSKA - Aeronian and lower Telychian retiolitidgraptolites, Arctic Canada ............................................................................................ p. 309

S.E. LORENZO, J.C. GUTIÉRREZ-MARCO - Occurrence and 3D-preservation ofLlandovery graptolites in the Criadero Quartzite of the Almadén mining district(Spain) .......................................................................................................................... p. 311

S.E. LORENZO, J.C. GUTIÉRREZ-MARCO, I. RÁBANO - Silurian geoheritage of theAlmadén Mining Park (central Spain) ......................................................................... p. 313

M. J. MELCHIN, C. HOLMDEN - Nitrogen Isotopes in Paleozoic ChemostratigraphicStudies: Contrasting Examples from the Hirnantian and early Wenlock ................... p. 315

J. MORTIER, D.A.T. HARPER, J. A. ZALASIEWICZ, P. CLAEYS, J. VERNIERS - The UpperOrdovician to lower Silurian Tihange sections, Condroz Inlier: a litho- andbiostratigraphical study with chitinozoans combined with carbon isotopes ............. p. 317

A. MUNNECKE, P. MÄNNIK - New biostratigraphic and chemostratigraphic data fromthe lower Chicotte Formation (Llandovery) on Anticosti Island (Quebec, Canada) . p. 319

J.M. PIÇARRA, J.C. GUTIÉRREZ-MARCO, G.N. SARMIENTO, I. RÁBANO - Silurian of theBarrancos-Hinojales domain of SW Iberia: a contribution to the geologicalheritage of the Barrancos area (Portugal) and the Sierra de Aracena-Picos deAroche Natural Park (Spain) ........................................................................................ p. 321

J.M. PIÇARRA, A.A. SÁ, P. STORCH, J.C. GUTIÉRREZ-MARCO - Silurian stratigraphy andpaleontology of the Valongo anticline and Arouca-Tamames syncline, Central-Iberian Zone (Portugal and Spain) ............................................................................... p. 323

S. PIRAS - New data on Silurian graptolites from the Rio Ollastu valley (SE Sardinia) .. p. 325

P. PITTAU, M. DEL RIO - Silurian chitinozoan biostratigraphy of Sardinia ....................... p. 327

D. RAY - Wenlock bentonites from the Midland Platform, England: geochemistry,sources and correlation ................................................................................................ p. 329

D. RAY, O. SUTCLIFFE - Sequence stratigraphy of the Wenlock Series of the MidlandPlatform, England ......................................................................................................... p. 331

J. RONG, R. ZHAN, B. HUANG, D.A.T. HARPER - Discovery of a latest Ordovician deepwater brachiopod fauna at Yuhang, Hangzhou, Zhejiang, East China .......................... p. 333

A.A SÁ, J.M. PIÇARRA, J.C. GUTIÉRREZ-MARCO, G.N. SARMIENTO - P-rich nodulesand “hollow graptolites” in the upper Silurian of the Moncorvo synclinorium,north Portugal ............................................................................................................... p. 335

M. SCHEMM- GREGORY - Howellellid branches at the Silurian/Devonian Boundaryinterval and their importance for Delthyridoid Spiriferid evolution ......................... p. 337

M. SCHEMM-GREGORY, U. JANSEN - The Silurian of the Goldsteintal (RheinischesSchiefergebirge, Germany) .......................................................................................... p. 339

365

P. SERVENTI, R. FEIST - Silurian Nautiloid Cephalopods from the Cabrières area(Montagne Noire, France): a preliminary report ........................................................ p. 341

L. SHERWIN - Gondwanan tectonics and European events in the Silurian ofAustralasia .................................................................................................................... p. 343

L. SIMONETTO, P. SERVENTI, M. PONDRELLI, C. CORRADINI - Problematic fossilremains from the Silurian Kok Formation in the type area (Carnic Alps, Italy) ........ p. 345

P. STORCH, J. FRYDA - Carbon isotope data and graptolite record in the lower Silurian(Llandovery) of northern peri-Gondwana – exemplified by Barrandian area,Czech Republic ............................................................................................................. p. 347

T.J. SUTTNER - Paleoenvironment of the Siluro-Devonian sequence in southernBurgenland (Austria) .................................................................................................... p. 349

M. VECOLI, A. SPINA - Siluro-Devonian biodiversification of trilete spores andcryptospores from Tunisia: palaeophytogeographic and palaeoclimaticimplications .................................................................................................................. p. 351

J. WANG, L. FU, Y. MENG, R.S. LI, H.P. HUANG - Discovery of a Llandovery-Wenlockboundary section in Bajiaokou, Ziyang, China ............................................................ p. 353

W.J. ZHAO, U. HERTEN, N.Z WANG, U. MANN, M. ZHU, L. ANDREAS - The Silurian-Devonian Boundary in West Qinling of South China – Evidence from Chemo-stratigraphy and microvertebrate remains across the Silurian/Devonian transition .. p. 355

M. ZHU, W.J. ZHAO - The Xiaoxiang Fauna (Ludlow, Silurian) - a window to explorethe early diversification of jawed vertebrates ............................................................. p. 357

Z. ZIGAITE, M.M. JOACHIMSKI, O. LEHNERT - Stable oxygen isotope stratigraphy usingconodont biogenic apatite from the Pridolof the Baltic Basin .................................. p. 359

Index of Authors ................................................................................................................. p. 361

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