Multi-stage evolution of the lithospheric mantle beneath the … · 2018. 4. 1. · Multi-stage...

Lithos 276 (2017) 75–89

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Multi-stage evolution of the lithospheric mantle beneath thewesternmost Mediterranean: Geochemical constraints fromperidotite xenoliths in the eastern Betic Cordillera (SE Spain)

Claudio Marchesi a,b,⁎, Zoltán Konc b, Carlos J. Garrido b, Delphine Bosch c, Károly Hidas b,María Isabel Varas-Reus b, Antonio Acosta-Vigil b,d

a Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada, Avenida Fuentenueva s/n, 18002 Granada, Spainb Instituto Andaluz de Ciencias de la Tierra (IACT), CSIC-Universidad de Granada, Avenida de las Palmeras 4, 18100 Armilla, Granada, Spainc Géosciences Montpellier, CNRS-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, Franced Dipartimento di Geoscienze, Università di Padova, Via Gradenigo 6, 35131 Padua, Italy

⁎ Corresponding author at: Departamento de MineraCiencias, Universidad de Granada, Avenida Fuentenueva s

E-mail address: [email protected] (C. Marchesi).

http://dx.doi.org/10.1016/j.lithos.2016.12.0110024-4937/© 2016 Elsevier B.V. All rights reserved.

a b s t r a c t
a r t i c l e i n f o
Article history:Received 31 March 2016Accepted 16 December 2016Available online 23 December 2016

Spinel (±plagioclase) peridotite xenoliths from the Tallante and Los Perez volcanic centres in the eastern Betics(SE Spain) range fromdepleted (clinopyroxene-poor) harzburgites to fertile (clinopyroxene-rich) lherzolites andorthopyroxene-freewehrlites. Significantly, only one harzburgite,which is depleted in heavy rare earth elements(HREE), retains the imprint of ca. 20% ancient melting of an original garnet lherzolite source. In contrast, REEabundances of other harzburgites and lherzolites from the eastern Betics have been increased bymelt-rock reac-tion. The whole-rock and mineral compositions of these mantle rocks are largely controlled by three types ofmodal metasomatism: 1) common clinopyroxene-orthopyroxene addition and olivine consumption which in-creased FeOt, SiO2 and Al2O3, and decreased MgO compared to the refractory melting products; 2) subordinateorthopyroxene dissolution and precipitation of clinopyroxene and olivine, which led to higher FeOt and MgOand lower SiO2 than in common (orthopyroxene-rich) lherzolites; and 3) rare orthopyroxene consumptionand olivine addition that caused higher FeOt and lower SiO2 compared to the original melting residues.These mineral modal and major element variations have been produced mostly by interactions with relativelyFeOt-rich/SiO2-poor melts, likely derived from a peridotite-pyroxenite lithospheric mantle with a highly hetero-geneous isotopic composition. Melting of the lithospheric mantle in thewesternMediterraneanwas triggered byupwelling of the asthenosphere induced by back-arc extension in the Late Oligocene-Early Miocene. Trappingof small fractions of exotic melts in whole-rocks — likely the parental magmas of Miocene back-arc dykes thatintruded the Betic crust — caused local disequilibrium between the trace element signatures and Pb isotopiccompositions of clinopyroxene and whole-rock. Subsequent interaction with SiO2-undersaturated magmas,similar to the parental melts of the Pliocene alkali basalts that host the xenoliths, promoted orthopyroxene con-sumption and clinopyroxene-olivine enrichment at locations close to magma conduits, and finally generatedorthopyroxene-free wehrlites. This event constitutes the last episode of the Cenozoic magmatic evolution ofthe westernmost Mediterranean which is recorded in the mantle xenoliths from the eastern Betics.

© 2016 Elsevier B.V. All rights reserved.

Keywords:Alkaline basaltsMantle metasomatismPyroxenite meltsSr-Nd-Pb radiogenic isotopesWesternmost Mediterranean

1. Introduction

Tectonically-emplaced orogenic peridotitemassifs andmantle xeno-liths in basalts provide key pieces of information that aid the under-standing of the composition, structure, and geodynamic evolution ofthe lithospheric upper mantle (e.g., Bodinier and Godard, 2014;Downes, 2001; Pearson et al., 2014, and references therein). In orogens

logía y Petrología, Facultad de/n, 18002 Granada, Spain.

with a convoluted tectonic history, upper mantle xenoliths in post-orogenic basalts may provide invaluable help in deciphering thetectono-magmatic processes recorded in deep lithospheric mantleroots. In the Alpine Betic-Rif arched belt in the westernmost Mediterra-nean (Fig. 1a), post-orogenic Pliocene alkali basalts in the eastern BeticCordillera entrained numerous mantle xenoliths after a complexgeodynamic evolution that shaped the Gibraltar arc (Bianchini et al.,2011; Duggen et al., 2004, 2005; Rampone et al., 2010; Shimizu et al.,2008). This arc formed during N-S to NW-SE convergence betweenthe African and European plates and contemporaneous Tertiary exten-sion that led to the opening of the Alboran sea basin. The geodynamic

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6W 5W 4W 3W 2W 1W 0 1E35N

36N

37N

38N

Alboran Ridge

African foreland

Iberian foreland

Flysch Trough units

Alpujarride and Malaguidecomplexes (in black, peridotites)

Nevado-Filabride complex

Neogene-Quaternary volcanics ( CA-shoshonitesLREE-enriched Tholeiitic-Calcalkaline LREE-depleted)

Neogene-Quaternary sediments

Normal fault

Reverse fault

South-Iberian paleomargin

Maghrebian paleomargin

Oceanic crust

Magmatic arc crust

Thinned continental crustintruded by

arc magmatism

Algero-Balearic basin

East Alboran basin

West Alboran forearc basin

Alboran domain

Lower to MiddleMiocene thrust belts

Nador

Oran

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Malaga Cabo de Gata

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Tallante/Los Perezvolcanic centres 37°45'N

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Cartagena

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South-eastern IberianSouth-eastern IberianVolcanismVolcanism

High-K calcalkalineHigh-K calcalkaline

UltrapotassicUltrapotassic

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Beni Bouseramassif

Fig. 1. (a) Geological map of the western Mediterranean and the Betic-Rif Cordillera, indicating the distribution of different types of crust and Cenozoic volcanic rocks in the Alboran searegion (CA= calcalkaline volcanism);modified from Booth-Rea et al. (2007). The inset marks the geographic location of the sampling area enlarged in (b). (b) Geological sketch showingthe distribution of different types of volcanic rocks in the South-eastern Iberian Volcanic Province, and in particular the location of the Pliocene alkaline basalt outcrops of Tallante and LosPerez that host the mantle xenoliths studied here; modified from Cebriá et al. (2009).

76 C. Marchesi et al. / Lithos 276 (2017) 75–89

mechanisms proposed to account for this extension are slab rollback,slab detachment, mantle lithosphere delamination, and convectivelithospheric thinning (e.g., Platt et al., 2013, and references therein). Inthis tectonic scenario, subduction-related to intraplate anorogenicmagmatism occurred at different geodynamic stages. Alkali basalts inthe south-eastern Iberian Volcanic Province (Fig. 1b) extruded duringthe youngest volcanic episodes (e.g., Cebriá et al., 2009; Duggen et al.,2004, 2005, 2008). The mantle xenoliths trapped in these basalts

contain valuable information regarding how the Tertiary geodynamicevolution of the Gibraltar arc affected the elemental and isotopiccompositions of the lithospheric mantle beneath the westernmostMediterranean.

In this paper we present a comprehensive study of the majorelement, trace element and Sr-Nd-Pb isotopic compositions of whole-rocks and minerals from the peridotite xenoliths hosted in Pliocenealkali basalts from the Tallante and Los Perez volcanic centres (Fig. 1b).

77C. Marchesi et al. / Lithos 276 (2017) 75–89

This dataset allows us to investigate the nature and geochemical compo-sition of the subcontinental lithospheric mantle beneath the easternBetic Cordillera and its relationships with Alpine and older tectono-magmatic processes that shaped this orogen.

2. Tertiary magmatism in the Betic Cordillera

The Betic-Rif Cordillera in the westernmost Mediterranean acquiredits present-day arched configuration (Fig. 1a) from the collision be-tween the westward migrating Alboran micro-continent and thesouth Iberian and Maghrebian passive margins during the Miocene(e.g., Booth-Rea et al., 2007; Faccenna et al., 2004; Spakman andWortel,2004). During its Tertiary geodynamic evolution, a sequence ofmagmatic events took place in the Betic limb of this orogenic belt. Theearliest igneous activity produced: (i) an Eocene-Early Miocene dykeswarm with an arc-tholeiitic affinity, which is exposed ca. 150 km tothe north of the city of Malaga (Duggen et al., 2004; Turner et al.,1999); and (ii) Late Oligocene andesitic-like pyroxenite dykes that cutthe Ronda peridotites in the western Betic Cordillera (Marchesi et al.,2012). The tholeiitic Malaga dykes were likely generated during earlyback-arc extension in the westernmost part of the Alpine-Betic orogen(Duggen et al., 2004). On the other hand, the andesitic dykes intrudedinto the Ronda tectonites reflect subduction-like magmatism relatedto the underthrusting of theAlboran continental crust beneath an atten-uated back-arc mantle (Varas-Reus et al., 2017-in this issue). The Mid-dle to Late Miocene tholeiitic (central Alboran sea basin) andcalcalkaline volcanic rocks (eastern Betics, Cabo de Gata area, andnorth-western Africa, Fig. 1a) erupted while Tethyan oceanic litho-sphere was being subducted beneath the westward migrating Alborancontinental domain (Duggen et al., 2004, 2008). In the Late Mioceneto Early Pliocene, high-K calcalkaline igneous activity produced mainlyshoshonitic and ultrapotassic (including lamproite) lavas in the easternBetics (Fig. 1). This magmatism is spatially associated with younger(Late Miocene to Quaternary) mantle xenolith-bearing alkali basalts(and their igneous derivatives) (Fig. 1b), produced during the waningmagmatic stages of the Alpine orogeny in the Betic-Rif Cordillera(e.g., Cebriá et al., 2009; Duggen et al., 2005; Turner et al., 1999). LateMiocene to Pliocene Si-K-rich and Quaternary alkali magmatic activityhas been related to lithospheric delamination at continental margins,followed by asthenospheric mantle upwelling (Duggen et al., 2004,2005, 2008; Gill et al., 2004) and/or earlier slab break-off in theAlgerian-Rif margin (Spakman and Wortel, 2004).

3. Sampling and petrography

For this study we sampled 28 mantle xenoliths (~10–15 cm in size)from the Pliocene (2.3–2.9 Ma) alkali basalt volcanic centres of Tallante(Beccaluva et al., 2004; Bianchini et al., 2011; Rampone et al., 2010;Shimizu et al., 2008) and Los Perez near Cartagena (SE Spain)(Fig. 1b). We focus predominantly on spinel (±plagioclase) peridotitexenoliths, excluding subordinate composite rocks with millimetre-scale dykelets of gabbronorite produced by subduction-relatedmetasomatism, and amphibole-bearing pyroxenite veins, which areprecursors of the alkaline basaltic volcanism (Beccaluva et al.,2004; Bianchini et al., 2011; Rampone et al., 2010). Petrographic ob-servations and mass balance calculations based upon anhydrouswhole-rock and mineral compositions indicate that our samples aremostly spinel (±plagioclase) lherzolites (23), spinel harzburgites(3) and wehrlites (2) (Fig. S1, Supplementary material). Amphiboleand phlogopite are absent in all the samples studied here. The com-positions of the peridotite xenoliths from Tallante range fromharzburgites to fertile lherzolites (clinopyroxene ~4–15%) (Fig. S1,Supplementary material). The xenoliths from Los Perez compriselherzolites with more variable olivine/orthopyroxene ratios than inTallante, and rare orthopyroxene-free wehrlites (Fig. S1, Supple-mentary material). These modal compositions overlap with those

of the orogenic peridotites from the Ronda massif, but severalsamples are slightly richer in clinopyroxene at a given olivine/orthopyroxene ratio than the peridotites from Ronda (Fig. S1,Supplementary material).

The samples have porphyroclastic, granular or equigranular textures(Mercier and Nicolas, 1975). Irrespective of texture, some xenoliths con-tain spherical to elongated clusters of coarse orthopyroxene + spinel +clinopyroxene + olivine interpreted as the subsolidus decompressionproducts of former garnet porphyroclasts (Rampone et al., 2010;Shimizu et al., 2008). Minerals in the clusters form coarse, undeformedgrains with straight boundaries, and pyroxenes commonly exhibitexsolution lamellae.

The porphyroclastic peridotites have a bimodal grain size distribu-tionwith large (up to 5mm), rounded orthopyroxene and rare elongat-ed olivine porphyroclasts, embedded in a fine- to medium-grained(~0.5–1.5 mm) matrix of olivine, pyroxenes and spinel. Orthopyroxeneporphyroclasts are normally undeformed. Olivine porphyroclasts havecurvilinear to straight grain boundaries and, with the exception of raresubgrains oriented perpendicularly to the crystal elongation, they gen-erally show no signs of intracrystalline plastic deformation. Exsolutionlamellae of orthopyroxene in clinopyroxene, and clinopyroxene inorthopyroxene are common. Spinel (~1–3 mm) is generally roundedand in places is rimmed by plagioclase.

The granular peridotites consist mostly of uniform (up to 1 cm)grains of olivine, minor orthopyroxene and clinopyroxene, which havecurvilinear to straight boundaries and usually show undulose extinc-tion, subgrains and/or kink bands. Clinopyroxene forms exsolutionlamellae in orthopyroxene and vice versa, and anhedral spinel isscattered between olivine and pyroxenes. Some granular sampleshave textures that are transitional to porphyroclastic, in which olivineand orthopyroxene form dispersed coarser grains.

The equigranular peridotite xenoliths consist of fine- (~0.5 mm) tomedium-grained (~1–3 mm) roughly isometric crystals of olivine andpyroxenes with straight boundaries, often with 120° triple junctions,which define a mosaic-like assemblage. Grains lack intracrystalline de-formation and exsolution lamellae. Dark brown spinel is anhedral andinterstitial between the silicates.

Two types of textural relations between olivine and pyroxenessuggest that the mantle xenoliths from the eastern Betics recorddifferent melt-rock interaction processes. Most samples have lobateand elongated grains of orthopyroxene (Fig. 2a) and clinopyroxene(Fig. 2b) that partly replace curved olivine. In other xenoliths,lobate and interstitial grains of olivine, in places associated withclinopyroxene, corrode large orthopyroxene grains (Fig. 2c, d). Thesemicrostructures suggest that xenoliths reactedwithmeltswith differentsilica activities.

Trace amounts (~1–2%) of plagioclase associated with spinelhave been detected in several samples (TAL-094, TAL-106, TAL-127,TAL-134, LPE-029, LPE-042 and LPE-062), whereas in other xenoliths(TAL-001, TAL-052, TAL-056, LPE-048, LPE-061 and LP08-02)plagioclase occurs in higher amounts (~5%) and mostly forms smallpatches interstitial to olivine and pyroxenes (Fig. 2e, f). The presenceof plagioclase constrains the pressure of final equilibration at ~0.7–0.9 GPa (Beccaluva et al., 2004; Rampone et al., 2010).

4. Analytical methods

4.1. Mineral chemistry

Analyses of major element compositions of minerals were carriedout on a CAMECA SX 100 electron microprobe (EMP) at the Centro deInstrumentación Científica (CIC) of the University of Granada (Spain)and at the “Service Microsonde Sud” of Géosciences Montpellier(CNRS-University of Montpellier, France). Accelerating voltage was15–20 kV, with a sample current of 10–15 nA and a beam diameterof 5 μm. Counting time for each element was 10–30 s. Natural and

Fig. 2. Photographs of microstructures inmantle xenoliths from the eastern Betic Cordillera. (a) Elongated lobate orthopyroxene (Opx) replacing olivine (Ol) porphyroclast; (b) anhedralexsolved clinopyroxene (Cpx) corroding olivine in thematrix; large pointed (c) and interstitial small (d) grains of olivine that replace lobate orthopyroxene porphyroclasts; (e, f) patchesof small plagioclase grains (Pl) interstitial to olivine. Spl: spinel. Black and white bars indicate the scale of each photograph.


synthetic silicate and oxide standards were used for calibration andthe ZAF correction. The results of major element analyses of mineralsare listed in the Supplementary material (Table S1).

Trace elements in clinopyroxene were analysed in ~150 μm thicksections by Laser Ablation Inductively Coupled Plasma Mass Spectrom-etry (LA-ICP-MS). Analyses were conducted at Géosciences Montpellier(France) using a ThermoFinnigan ELEMENT XR sector field ICP-MS,coupled to a Geolas (Microlas) automated laser platform housing a193 nm Complex 102 excimer laser from LambdaPhysik. Ablation wasconducted in a 30 cm3 cell in He atmosphere to enhance signal sensitiv-ity and reduce element fractionation. Signals were acquired by devoting2 min to the measurement of background and 1 min to the measure-ment of sample. The laser was fired at an energy density of 15 J/cm2;frequencies of 6 to 8 Hz and spot diameters of 102 and 122 μm wereemployed. Data reduction was carried out using GLITTER software(van Achterberg et al., 2001) by careful inspection of time-resolvedsignals to check for the stability and homogeneity of signals during ab-lation. Element concentrations were obtained by calibration against therecommended values of Pearce et al. (1997) of the NIST 612 certifiedreference material. Calcium was used as internal standard. The basalticglass BIR-1G was analysed in every procedure as an external referencematerial and shows good agreement with working values for this inter-national standard (Gao et al., 2002). Results of LA-ICP-MS analyses arelisted in the Supplementary material (Table S2).

4.2. Whole-rock major and trace elements

Xenoliths were cut into slabs and remnants of the host basalt werecarefully removed. Slabs were put in plastic bags, crushed with a ham-mer, and representative aliquots of crushates were pulverized in anagate mill. Whole-rock major and transition metal elements (V, Cr, Co,Ni and Zn) were analysed by X-ray fluorescence (XRF) at the CIC(University of Granada, Spain) in fused beads or pressed pellets usinga Philips PW 1401/10 device. Whole-rock trace elements (Rb, Sr, Y, Zr,Nb, Cs, Ba, REE, Hf, Ta, Pb, Th and U) were analysed by an Agilent 7700ICP-MS at the Géosciences Montpellier lab (France). Sample dissolutionwas performed following the HF-HClO4 digestion procedure describedby Ionov et al. (1992). Element concentrations were determined by ex-ternal calibration except for Nb and Ta that were calibrated using Zr andHf as internal standards, respectively. This technique was applied toavoidmemory effects due to the intake of concentrated Nb-Ta solutionsin the instrument and is an implementation for ICP-MS analysis of themethod described by Jochum et al. (1990) for Nb measurementby spark-source mass spectrometry. The compositions of peridotitereference samples JP-1 and UB-N, analysed as unknowns during theanalytical runs, show good agreement with working values of theseinternational standards (Deschamps et al., 2010; Godard et al., 2009).Whole-rock major and trace element data are reported in the Supple-mentary material (Table S3).


4.3. Analyses of Sr-Nd-Pb isotopes in clinopyroxene and whole-rocks

Strontium-Nd-Pb isotopic analyses were performed on b1 g aliquotsof whole-rock powder and aggregates of pure clinopyroxene grains.Clinopyroxene concentrates were obtained from 100 to 150 μm sievedfractions using a Frantz isodynamic separator. Clean clinopyroxenegrainswere hand-picked in alcohol under a zoombinocularmicroscopeavoiding mixed, altered or inclusions-bearing grains. Chemical pro-cessing of mineral concentrates and whole-rocks was performed inthe isotopic clean lab of Géosciences Montpellier (France). Cleanclinopyroxene separates and aliquots of whole-rock powders wereleached with 6 N HCl for 30 min at 80 °C before acid digestion. Leachedgrains and powders were dissolved in Teflon beakers using amixture ofHF and HNO3 for 36–48 h on a hot plate. After evaporation to dryness,1 ml HNO3 was added to the residue and the solution was kept atc. 90 °C in a hot plate for 12–24 h.

Chromatographic separation of Pb was carried out after completeevaporation of HNO3, adding 0.3 ml 8 N HBr and keeping the resultingsolution at 70 °C for 2–3 h before complete evaporation. Pb extractionwas performed in columns filled with anion exchange resin (AG1X8200–400 mesh), in which samples were loaded and initially washedwith 0.5 N HBr. Lead was then eluted using 6 N HCl. Concentrations ofPb in procedural blanks were b40 pg/g, which are negligible contribu-tions to the Pb contents of the samples. Strontium was separatedusing a Sr Eichrom resin and concentratedHNO3 following an extractionchromatographic method modified from Pin et al. (1994). Rare earthelements were extracted by HCl employing AG50WX12 cation ex-change resin, and finally, Nd was eluted with HCl using Teflon HDEHPacid-conditioned columns. The concentrations of Sr and Nd in total pro-cedural blanks were b50 pg/g and 20 pg/g, respectively, which are tinyadditions to the Sr-Nd budgets of the samples.

Lead and Nd isotopic ratios were measured by a VG Plasma 54 or aNuPlasma 500 Multi Collector-ICP-MS at the ENS of Lyon (France).Lead radiogenic isotopic ratios were measured with external precisionof ca. 100–150 ppm using the Tl normalization method of White et al.(2000). Each batch of two samples was bracketed between NBS 981standard splits for Pb analyses, and the ‘Lyon-in-house’ standardfor Nd analyses. Strontium isotopic ratios were measured by ThermalIonization Mass Spectrometry (TIMS) using a ThermoFinnigan TritonT1 mass spectrometer at the Laboratoire de Géochimie Isotopiqueenvironnementale (LABOGIS) of Nîmes (France). Results of theNBS 987 standard yielded average 87Sr/86Sr = 0.710256 ± 10(2σ, n = 22). Mass dependent fractionations were corrected using86Sr/88Sr = 0.1194 and 146Nd/144Nd = 0.7219. Isotopic compositionswere corrected to values at 3 Ma, which is the approximate eruptionage of alkali basalts in the eastern Betics (Duggen et al., 2005); verysimilar present-day values are shown in figures for the samples notanalysed for trace elements. Results of Sr-Nd-Pb isotopic analyses arelisted in the Supplementary material (Table S4).

5. Results

5.1. Whole-rock major and transition metal elements

The whole-rock major element contents of anhydrous (amphibole-,phlogopite-absent) mantle xenoliths from the eastern Betics vary fromdepleted to fertile compositions, with the latter being similar to primi-tive upper mantle (PUM) (Fig. 3). Anhydrous Al2O3 concentrationsspan from ~1.3 to 1.7 wt.% in harzburgites (clinopyroxene ~4%) andfrom ~1.5 to 4.5 wt.% in lherzolites (clinopyroxene ~5–15%). At agiven Al2O3, SiO2 is higher in harzburgites than in lherzolites, and inthe latter SiO2 and Al2O3 are fairly well correlated (Fig. 3a). Al2O3 is neg-atively correlatedwithMgO (~45–36 wt.%) (Fig. 3b) and positively cor-related with CaO (~1–3.5 wt.%) (Fig. 3c) as is often observed in residualand refertilized mantle rocks (e.g., Bodinier and Godard, 2014). MgO isslightly lower in harzburgites than in lherzolites for a given value of

Al2O3 (Fig. 3b). Similar to SiO2, FeOt (~7–10 wt.%) is fairly well corre-lated with Al2O3 and one lherzolite (LPE-062) is notably rich in FeOt(Fig. 3d). Wehrlite (~82–86% olivine, 14–18% clinopyroxene) ischaracterized by particularly low Al2O3-SiO2 and high CaO-FeOt abun-dances (Fig. 3). As seen for modal proportions (Fig. S1, Supplementarymaterial), the whole-rock major element compositions of the easternBetics xenoliths generally overlap with those of the Ronda peridotites(Fig. 3). Cobalt (~115–150 ppm) and, especially, Ni (~1750–2300 ppm)are correlatedwithMgO, and V (~30–100 ppm) is correlatedwith Al2O3

(not shown), in agreement with the main partitioning of Co and Ni inolivine and of V in pyroxenes (Canil, 2004). On the other hand, the Crconcentrations (~2000–3100 ppm) do not show clear correlationswith major elements.

5.2. Whole-rock trace elements

Two analysed harzburgites have subchondritic normalized REE con-centrations that increase slightly from light rare earth elements (LREE)to heavy rare earth elements (HREE) and define relatively flat patternsenriched in La and Ce (Fig. 4a). The most HREE depleted harzburgite(TAL-102) has a different “U-shaped” pattern with high LREEN/middlerare earth elements (MREE)N and low MREEN/HREEN (Fig. 4a). Mostlherzolites have higher REE contents than harzburgites, consistentwith their more fertile major element compositions (Fig. 3), and similarunfractionated patterns enriched in LREE relative toMREE in some sam-ples (Fig. 4b). The FeOt-rich lherzolite LPE-062 has higher REE abun-dances than other lherzolites, and has normalized concentrationssteadily decreasing from LREE to HREE (Fig. 4b). The analysed wehrlitehas REE contents comparable to lherzolite LPE-062 and its normalizedpattern is characterized by a hump-shaped LREE segment (Fig. 4c).

The primitive upper mantle-normalized concentrations of Sr, Zr, Hfand Y in harzburgites are generally lower than in lherzolites, whereasmore incompatible trace elements (Cs, Rb, Ba, Th, U, Nb, Ta and Pb)have similar abundances (Fig. 5a, b). The normalized patterns of bothlithologies show positive spikes of Th, U and Pb and negative anomaliesof Ta, and are enriched in highly incompatible trace elements (fromCs toU in the normalized spider diagrams) relative to more compatible REE(Fig. 5a, b). The pattern of the FeOt- and REE-rich lherzolite LPE-062shows negative spikes of Sr and Zr-Hf, and a more pronounced positiveanomaly of Pb than the other samples (Fig. 5b). Concentrations of Cs, Rb,Ba, Th, U and Nb in LPE-062 are similar to those of other lherzolites,whereas Ta, Pb, Sr, Zr, Hf and Y are more abundant (Fig. 5b), similar toREE (Fig. 4b). Trace elements in the analysed wehrlite are generallyenriched compared with concentrations in the other peridotites, exceptfor Th, U and Nb (Fig. 5c). The normalized incompatible trace elementpattern of wehrlite lacks the positive spike of Pb and has negative Srand Zr-Hf anomalies (Fig. 5c) similar to LPE-062.

5.3. Mineral major elements

Themineral chemistry of the eastern Beticsmantle xenoliths studiedhere is generally consistent with previously published data of theTallante peridotites (Beccaluva et al., 2004; Rampone et al., 2010). Theaverage olivine Mg# [100 × Mg/(Mg + Fe2+)] in lherzolites (88.6–90.5) decreases from refractory (i.e., Al2O3- and REE-poor) to fertile(i.e., Al2O3- and REE-rich) samples, and it is especially low in wehrlites(86.6–86.9) (Fig. S2, Supplementarymaterial). The average NiO contentin olivine varies between 0.36 and 0.40wt.% in lherzolites and it is lowerin wehrlites (0.29–0.31 wt.%). Similar to olivine Mg#, the average Cr#[Cr/(Cr+Al)] of spinel in lherzolites (0.12–0.23) (Fig. S2, Supplementarymaterial) generally decreases from refractory to fertile samples. Higherspinel Cr# (0.18–0.24) at similar olivine Mg# in four samples (Fig. S2,Supplementary material) most likely results from subsolidus re-equilibrationwith plagioclase (Arai, 1994). Co-variation between olivineMg# and spinel Cr# is normally observed in spinel peridotites from dif-ferent tectonic settings (Arai, 1994). In particular, the mantle xenoliths

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WehrliteRonda peridotites

LPE-062

Fig. 3.Whole-rock abundances of Al2O3 versus SiO2 (a), MgO (b), CaO (c) and FeOt (d) in the eastern Betics mantle xenoliths. Green squares: harzburgites; blue triangles: lherzolites; reddiamonds: wehrlites. Compositions of the Ronda orogenic peridotites (white circles) are from Frey et al. (1985), Van der Wal and Bodinier (1996), Lenoir et al. (2001), Bodinier et al.(2008) and Soustelle et al. (2009), and of primitive upper mantle (PUM, light blue star) from McDonough and Sun (1995). All data on anhydrous basis in wt.%.


from the eastern Betics have olivine and spinel compositions that lie inthe relatively high Mg#-low Cr# area of the olivine-spinel mantle array(Fig. S2, Supplementary material) and overlap with compositions ofnormal xenoliths from the subcontinental upper mantle (Arai, 1994).Wehrlites plot to the right of the olivine-spinel mantle array, similar tostrongly metasomatized peridotites and ultramafic cumulates (Arai,1994), and have higher spinel Cr# (0.30–0.33) than lherzolites (Fig. S2,Supplementary material).

The average Mg# of orthopyroxene (89.4–91.0) follows the sametrend of olivine Mg# and decreases from refractory to fertile samples.The TiO2 abundance in orthopyroxene (b0.1–0.16 wt.%) shows theopposite variation. Average Al2O3 (3.36–4.53 wt.%) and CaO (0.60–1.30 wt.%) in orthopyroxene are not correlated with the fertility of thesamples, likely a consequence of subsolidus re-equilibration withclinopyroxene and spinel (Witt-Eickschen and Seck, 1991).

The average clinopyroxene Mg# spans from 91.3 to 92.7 inlherzolites and it is notably lower in wehrlites (87.5–88.7). The TiO2

abundance in clinopyroxene (0.26–0.80 wt.%) increases according tothe fertility of the samples, and the opposite trend is shown by Cr2O3

(0.78–1.20 wt.%). Na2O varies between 0.61 and 0.93wt.% in lherzolitesand has higher concentrations in wehrlites (0.94–1.16 wt.%).

5.4. Trace element composition of clinopyroxene

The trace element composition of clinopyroxene in this study gener-ally overlaps with the results previously published for the Tallante peri-dotite xenoliths (Beccaluva et al., 2004; Rampone et al., 2010; Shimizuet al., 2008). The chondrite-normalized REE pattern of clinopyroxenein harzburgites has a convex-upward shape and shows depletion ofLREE and HREE relative to MREE (e.g., LaN/SmN = 0.5, SmN/YbN =1.5) (Fig. 4a). Clinopyroxene in lherzolites has REE patterns similar to

harzburgites but MREE and HREE concentrations are generally higher,except in TAL-084 and TAL-127 (Fig. 4b); however, REE abundances inclinopyroxene are less variable than in bulk lherzolites. The patterns ofclinopyroxene in samples with significant plagioclase abundancespossess an obvious Eu negative anomaly and tend to have higherMREE and HREE abundances (Fig. 4b), similar to clinopyroxene inimpregnated peridotites from orogenic massifs and ophiolites(Rampone et al., 1993). Clinopyroxene in the FeOt- and REE-richlherzolite LPE-062 has higher LREE concentrations and exhibits a flatREE pattern, similar to the corresponding whole-rock (Fig. 4b).Clinopyroxene in wehrlites has higher LREE and generally lower HREEconcentrations than in lherzolites and displays the same normalizedpattern of whole-rock, i.e. LREE and MREE are enriched relative toHREE (LaN/YbN = 2.9–3.2, SmN/YbN = 2.4) and LREE show a hump-shaped pattern (Fig. 4c).

Concerning trace elements other than REE, clinopyroxene inharzburgites is enriched in Th and U and depleted in Nb, Ta, Zr, Hf andPb compared with adjacent elements in the normalized incompatibletrace element diagram (Fig. 5a). Clinopyroxene in lherzolites has com-positions similar to those found in harzburgites for the most incompat-ible trace elements (from Rb to Ta in the normalized spider diagrams),but Pb showsmore variable negative anomalies, Sr is generally depleted(especially in the samples richer in plagioclase), and Zr, Hf andYhave, ingeneral, higher concentrations (Fig. 5b). The normalized patterns ofclinopyroxene in wehrlites display negative anomalies of Nb, Ta, Pb, SrZr and Hf (Fig. 5c). Three common features of the normalized patternsof the eastern Betics mantle xenoliths are the opposite polarity of Pbspikes, Nb/Ta and Zr/Nb ratios in whole-rocks (Pb positive anomalies,NbN/TaN N 1, ZrN/NbN mostly b1) and clinopyroxene (Pb negativeanomalies, NbN/TaN b 1, ZrN/NbN notably N1) of the same sample(Fig. 5).

Sam

ple/

Cho

ndrit

e

0.1

1

10

Sam

ple/

Cho

ndrit

e

0.1

1

10

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Sam

ple/

Cho

ndrit

e

1

10

(a) HarzburgiteClinopyroxene

Whole-rock

TAL-102

(b)

Lherzolite

Clinopyroxene

Whole-rock

TAL-084

LPE-062

LPE-062

(c)Wehrlite

Clinopyroxene

Whole-rock

Fig. 4. Chondrite-normalized abundances of rare earth elements (REE) in whole-rock(coloured symbols) and clinopyroxene (grey symbols) of mantle xenoliths from theeastern Betics. Symbols as in Fig. 3. Normalizing values from Sun andMcDonough (1989).

Sam

ple/

PU

M

0.01

0.1

1

10

Sam

ple/

PU

M

0.01

0.1

1

10

CsRb

BaTh

UNb

TaLa

CePb

PrSr

NdZr

HfSm

EuGd

TbDy

YHo

ErTm

YbLu

Sam

ple/

PU

M

0.01

0.1

1

10

100

(a) Harzburgite

Clinopyroxene

Whole-rock

TAL-102

(b)

Lherzolite

Clinopyroxene

Whole-rock

(c)

Wehrlite

Clinopyroxene

Whole-rock

LPE-062

Fig. 5. Primitive upper mantle (PUM)-normalized trace element patterns of whole-rock(coloured symbols) and clinopyroxene (grey symbols) of mantle xenoliths from theeastern Betics. Symbols as in Fig. 3. Normalizing values from Sun andMcDonough (1989).


5.5. Sr-Nd-Pb isotopic compositions

Strontium,Nd andPb isotopic ratios ofwhole-rock and clinopyroxenein the eastern Betics mantle xenoliths have been corrected to values at3 Ma (Fig. 6), which is the approximate eruption age of host alkalibasalts (Duggen et al., 2005); present-day values are shown for thesamples not analysed for trace elements. For comparison, in Fig. 6a wealso display the isotopic compositions of the Ronda peridotites fromwestern Betics (Reisberg and Zindler, 1986; Reisberg et al., 1989),and Sr-Nd isotopic data of clinopyroxene separates from the Tallanteperidotite xenoliths analysed by Beccaluva et al. (2004) and Bianchiniet al. (2011). Red dotted tie-lines in Fig. 6 link the age-corrected isotopicratios of whole-rock and clinopyroxene for the samples (i.e., TAL-127and TAL-134) in which both have been analysed for Sr-Nd-Pb isotopesand trace elements.

Lherzolites have 87Sr/86Sr = 0.70226–0.70682 and 143Nd/144Nd =0.51263–0.51327 (Fig. 6a), and the latter generally decreases with in-creasing clinopyroxene abundances. The two samples with a completedataset for age-corrected whole-rock and clinopyroxene (TAL-127 andTAL-134) show very similar Sr-Nd isotopic ratios in both materials.The Sr-Nd isotopic ratios of the analysed wehrlite (87Sr/86Sr =0.70459; 143Nd/144Nd = 0.51269) are similar to those of lherzoliteswith more radiogenic Sr and less radiogenic Nd compositions (Fig. 6a).As a whole, the eastern Betics mantle xenoliths studied here have Sr-Nd isotopic ratios that range from the compositions of the depletedmantle source of mid-ocean ridge basalts (MORB), i.e., Depleted MORBMantle (DMM), to the enrichedmantle 2 (EM2) reservoir (Fig. 6a), sim-ilar to the Tallante xenoliths analysed by Beccaluva et al. (2004) andBianchini et al. (2011). Clinopyroxene-poor lherzolites mostly overlap

0.701 0.703 0.705 0.707 0.709

0.5120

0.5124

0.5128

0.5132

0.5136

17.5 18.0 18.5 19.0 19.5

15.3

15.4

15.5

15.6

15.7

15.8

17.5 18.0 18.5 19.0 19.537.0

37.5

38.0

38.5

39.0

39.5

87Sr/86Sri

143 N

d/14

4 Nd i

206Pb/204Pbi

207 P

b/20

4 Pb i

206Pb/204Pbi

208 P

b/20

4 Pb i

(a) 3 Ma

DMM

TAL-127

HIMU

EM1

EM2

Rondaperidotites

TAL-134Tallante Amph/

Phl-bearing peridotites

Lherzolite whole-rock

Wehrlite whole-rock

Other anhydrousTallante peridotites

Lherzolite clinopyroxene

(b)EM2

DMM 3 Ma

TAL-127

TAL-134

NHRL

(c)

NHRL

3 Ma

EM2

DMM

TAL-127

TAL-134

Fig. 6. Age-corrected (3 Ma) Sr-Nd (a) and Pb (b, c) radiogenic isotope ratios of whole-rock (coloured symbols) and clinopyroxene separates (grey symbols) of mantleperidotites from the eastern Betics. For samples not analysed for trace elements, verysimilar maximum present-day values have been plotted. Symbols as in Fig. 3. Sr-Ndisotopic compositions of other mantle peridotites (prdt.) from Tallante (white circles) in(a) are from Beccaluva et al. (2004) and Bianchini et al. (2011), and of the Rondaorogenic peridotites (dotted area) from Reisberg and Zindler (1986) and Reisberg et al.(1989). Amph = amphibole; Phl = phlogopite. Red dotted tie-lines connect age-corrected compositions of whole-rock and clinopyroxene in the same sample. Theisotopic compositions of mantle reservoirs (light blue stars) are from Zindler and Hart(1986) and Hart (1988). The Northern Hemisphere Reference Line (NHRL) in (b, c) isfrom Hart (1984).


Who

le-r

ock/

Cho

ndrit

e

0.1

1

10


Clin

opyr

oxen

e/C

hond

rite

10

50

2

PUM

Harzburgite Lherzolite

Wehrlite

5% 13% 18%

Whole-rock(a)

Clinopyroxene(b)Spinel peridotite melting

Spinel peridotite melting

5% 13%18%

PUM

TAL-102

Fig. 7. Chondrite-normalizedREE patterns ofwhole-rocks (a) and clinopyroxene (b) of theeastern Betics mantle peridotites compared to curves calculated for non-modal fractionalmelting of primitive upper mantle (PUM, Sun and McDonough, 1989) in the spinellherzolite facies (red lines) [source and melting olivine:orthopyroxene:clinopyroxenemodal proportions 0.54:0.28:0.18 and −0.11:0.59:0.53, respectively (Niu, 1997 at1.5 GPa)]. Symbols as in Fig. 3. Labels indicate partial melting degrees. Partitioncoefficients from Bedini and Bodinier (1999) and Su and Langmuir (2003). Normalizingvalues from Sun and McDonough (1989).


with the compositions of the Ronda peridotites butmore fertile samplesand wehrlite extend to more radiogenic Sr (Fig. 6a).

Except for the particularly unradiogenic Pb isotope ratios ofclinopyroxene in one lherzolite (TAL-127) (Fig. 6b, c), the xenolithsfrom the eastern Betics have relatively homogenous Pb isotopicratios (206Pb/204Pb = 18.38–19.00, 207Pb/204Pb = 15.58–15.70,

208Pb/204Pb=38.37–39.13), especially for 207Pb/204Pb (Fig. 6b). In addi-tion to TAL-127, TAL-134 also has lower Pb isotopic ratios inclinopyroxene than in whole-rock, principally in terms of 207Pb/204Pb(Fig. 6b). The Pb isotopic composition of the analysedwehrlite is similarto those of lherzolites but has lower 207Pb/204Pb (15.58) at a given206Pb/204Pb (Fig. 6c). As seen for the Sr-Nd isotopes, the Pb isotopiccompositions of the eastern Betics mantle xenoliths plot between thecompositions of the DMM and EM2 components, and above the north-ern hemisphere reference line (NHRL) defined by Atlantic MORB(Fig. 6b, c).

6. Discussion

6.1. Record of partial melting and melt-rock reaction

In terms of whole-rock major element contents, the eastern Beticsperidotite xenoliths exhibit linear trends from fertile compositions ofenriched lherzolites, to intermediate and depleted compositions ofmore refractory lherzolites and harzburgites (Fig. 3). In addition,whole-rock HREE concentrations also generally decrease fromlherzolites to harzburgites (Fig. 4). These variations may be explainedby different degrees of partial melting which extracted basaltic meltsfrom an original fertile upper mantle, and progressively depleted themelting residues in incompatible elements (e.g., Downes, 2001;Herzberg, 2004; Niu, 1997; Walter, 2003). Fig. 7a displays the whole-

SiO

2 (w

t.%)

41

43

45

47

MgO (wt.%)

36 38 40 42 44 46

FeO

t (w

t.%)

7

8

9

10

11

Harzburgite Lherzolite Wehrlite

(b)

(a)

Fertile mantle

Fertile mantle

Cpx + Ol additionOpx dissolution

Cpx + Opx additionOl dissolution

Cpx + Opx addition/Ol dissolution

Cpx + Ol addition/Opx dissolution

5 GPa2.5-0.8 GPa

2.5-0.8 GPa

35

3 GPa

Ol additionOpx dissolution


TAL-102

TAL-102

Spinel perid. meltingGarnet perid. melting

2

2 GPa

TAL-047

Fig. 8.Whole-rock abundances of MgO versus FeOt (a) and SiO2 (b) in mantle peridotitesfrom the eastern Betics and curves calculated for melting of different mantle sources(stars) in the spinel peridotite (Niu, 1997, black line) or garnet peridotite field(Herzberg, 2004, grey line). Symbols as in Fig. 3. Labels indicate the pressures (GPa) ofmelt extraction. Coloured arrows illustrate the compositional variations inferred to bedue to modal metasomatism (see Section 6.2 for more details). All data on anhydrousbasis in wt.%.


rock chondrite-normalized REE patterns of the eastern Betics mantlexenoliths and the curves calculated for non-modal fractional meltingof primitive upper mantle (PUM) in the spinel lherzolite facies.Whole-rock LREE and MREE in all samples clearly depart from the pre-dictions of melting models, whereas HREE variations coincide with thepatterns calculated for ~0%–15% melting for lherzolites and 13%–18%for harzburgites. Melting in the garnet peridotite stability field impliesmore fractionated HREE abundances; these are only observed in themost refractory harzburgite (TAL-102).

On the other hand, Fig. 7b shows that the REE compositions ofclinopyroxene are clearly inconsistent with a residual origin. Indeed,HREE in clinopyroxene grains of most lherzolites have higherconcentrations than those in equilibrium with the PUM source(Fig. 7b), similar to clinopyroxene affected by subsolidus re-equilibration with plagioclase, or melt-rock reactions at decreasingmelt volumes (e.g., Rampone et al., 1993). Clinopyroxene inharzburgites has lower HREE contents, but themelting degrees inferredby its compositions (5%–10%) (Fig. 7b) are notably lower than those in-ferred for the corresponding whole-rocks (N10%) (Fig. 7a), and are atodds with the refractory modal abundances of these samples(clinopyroxene ~4%). A residual origin of clinopyroxene by melting inthe garnet peridotite stability field can also be discounted, becauseclinopyroxene in equilibrium with garnet in off-craton garnetperidotites (Pearson et al., 2014, and references therein) is much moredepleted in HREE than the clinopyroxene in these harzburgites. Allthese observations indicate that clinopyroxene in the eastern Beticsmantle xenoliths does not record partial melting butmost likely reflectspost- or syn-melting interaction of the peridotites with percolatingmelts, as recorded in peridotites affected by reactive porous flow(e.g., Rampone et al., 2004). Since clinopyroxene is the main repositoryof REE in anhydrous mantle peridotites, its secondary signature indi-cates that the whole-rock REE contents of these mantle xenoliths in-creased via melt-rock reaction. Therefore, the melting degrees inferredin Fig. 7a are probably significant only for themost depleted harzburgite(TAL-102; ~20%melting). This measure of cumulativemelting likely re-flects several episodes of melt extraction since the Proterozoic(Bianchini et al., 2011; Konc et al., 2012), similar to mantle peridotitesfrom the neighbouring Ronda massif (Marchesi et al., 2010; Reisbergand Lorand, 1995).

Major element abundances in whole-rocks confirm the strong im-print of melt-rock reaction in the eastern Betics mantle xenoliths.MgO-FeOt-SiO2 variations show that, independently of the compositionof the assumed mantle source, only harzburgites and some depletedlherzolites are apparently consistent with melting in the garnet or spi-nel peridotite field (Fig. 8). In particular, sample TAL-102, which betterapproaches the composition of melting residues in terms of HREE(Fig. 7a), has low FeOt and high SiO2, in agreement with melting of anoriginal garnet lherzolite source (Walter, 2003). On the other hand,FeOt and SiO2 in more fertile lherzolites are negatively correlated withMgO, and FeOt has higher abundances than those predicted by meltingmodels of spinel and garnet peridotites (Fig. 8a). This indicates that par-tial melting does not generally control the budget of major elements,which, similar to REE, most likely reflect reactions between depletedmelting residues and percolating melts.

6.2. Modal evidence of mantle metasomatism

The texture and composition of the subcontinental lithosphericmantle commonly record the interaction of peridotites with differenttypes of melt generated in the asthenosphere and/or lithosphere, suchas silicate, sulphide and carbonate melts (e.g., Bodinier and Godard,2014; Bodinier et al., 1990; Garrido and Bodinier, 1999; Ionov et al.,2002; Marchesi et al., 2014, and references therein). This interactionnormally causes mineralogical and/or geochemical modifications —generally referred to as modal or cryptic mantle metasomatism(e.g., Menzies and Hawkesworth, 1987) — manifested as variable

depletion or enrichment in mineral phases, major and trace elements(e.g., Bodinier and Godard, 2014; Downes, 2001; Lenoir et al., 2001;Pearson et al., 2014).

Textural (Fig. 2) and compositional (Figs. 7, 8) evidence of melt-rockreaction suggests that mantle metasomatism may have affected themodal abundances of the eastern Betics peridotite xenoliths. Fig. 9 illus-trates themodal variations of olivine, orthopyroxene and clinopyroxeneagainst Al2O3/SiO2 in these rocks. Al2O3/SiO2 in mantle peridotites isnormally used as a proxy of enrichment (or depletion) from depletedharzburgitic to fertile primitive upper mantle compositions (Jagoutzet al., 1979). Departing from the refractory composition of TAL-102,which better preserves the record of partial melting (Fig. 7a), mosteastern Betics lherzolites show increasing orthopyroxene/olivine,clinopyroxene/olivine and clinopyroxene/orthopyroxene with in-creasing Al2O3/SiO2 (Fig. 9, blue arrow). This suggests that increasingFeOt and SiO2 with decreasing MgO (Fig. 8) and increasing Al2O3

(Fig. 3a, d) in these rocks were produced bymelt-rock reaction, leadingto clinopyroxene-orthopyroxene crystallization and olivine consump-tion at a clinopyroxene/orthopyroxene modal ratio N 1. The partialcorrosion of primary olivine by late poikilitic orthopyroxene andclinopyroxene grains in the Tallante xenoliths (Fig. 2a, b) (Bianchiniet al., 2011; Rampone et al., 2010) provides corroborating evidence forthis conclusion.

One harzburgite (TAL-047) has a notably lower orthopyroxene/olivine ratio than similarly depleted samples, and slightly lowerclinopyroxene/olivine and higher clinopyroxene/orthopyroxene than

Clin

opyr

oxen

e/O

livin

e

0.0

0.1

0.2

0.3

0.4

0.0

0.1

0.2

0.3

0.4

Al2O3/SiO2

0.02 0.04 0.06 0.08 0.100.2

0.4

0.6

0.8

1.0

Ort

hopy

roxe

ne/O

livin

eC

linop

yrox

ene/

Ort

hopy

roxe

ne

(b)

(a)

(c)

PUM

PUM

PUM

Harzburgite

Lherzolite

Wehrlite










TAL-102

TAL-102

TAL-102

TAL-047

TAL-047

TAL-047

Fig. 9. Whole-rock Al2O3/SiO2 versus modal orthopyroxene/olivine (a), clinopyroxene/olivine (b) and clinopyroxene/orthopyroxene ratios (c) in mantle peridotites from theeastern Betics. Symbols as in Fig. 3. Coloured arrows illustrate the modal variationsinferred to be due to metasomatism (see Section 6.2 for more details). The compositionof primitive upper mantle (PUM, light blue star) is from McDonough and Sun (1995).


TAL-102 (Fig. 9, green arrow). These variations are consistentwith the partial replacement of orthopyroxene (±clinopyroxene)porphyroclasts by olivine neoblasts (Fig. 2c) (Rampone et al., 2010),leading to slightly higher FeOt (Fig. 8a) and lower SiO2 (Fig. 8b) thanin TAL-102. Finally, several lherzolites depart from the general positivecorrelations between Al2O3/SiO2 and orthopyroxene and clinopyroxeneabundances (Fig. 9). These samples exhibit decreasing orthopyroxene/olivine, constant clinopyroxene/olivine and strongly increasingclinopyroxene/orthopyroxene ratios with increasing Al2O3/SiO2 (Fig. 9,orange arrow). These modal variations are most likely the product oforthopyroxene dissolution and precipitation of clinopyroxene and

olivine (Fig. 2d) by reaction with low silica melts. This led to higherFeOt-MgO (Fig. 8a) and lower SiO2 (Fig. 8b) compared to the commoncompositions of lherzolites.

6.3. Peridotite reaction with pyroxenite-derived melts

Modal metasomatism in the eastern Betics mantle xenoliths (Fig. 9)generally produced peridotites with higher FeOt and lower SiO2 thanharzburgite TAL-102 (Fig. 8), which approaches the composition oforiginal refractory melting residues (Fig. 7a). This suggests that mantlexenoliths in the eastern Betics reacted with relatively FeOt-rich/SiO2-poor melts similar to alkaline oceanic and continental basalts(e.g., Pilet et al., 2008). Peridotite interactionwith alkali basalts normal-ly causes the dissolution of orthopyroxene (±clinopyroxene) andthe precipitation of olivine (e.g., Morgan and Liang, 2003; Tursackand Liang, 2012). This reaction may explain the modal variation ofharzburgite TAL-047 relative to TAL-102 (Fig. 9, green arrow), but it isinconsistent with the generally increasing orthopyroxene/olivine andclinopyroxene/olivine ratios from harzburgites to lherzolites (Fig. 9,blue arrow). Precipitation of clinopyroxene and orthopyroxene and dis-solution of olivine are predicted by peridotite interaction with evolvedtholeiitic melts (e.g., Kelemen, 1990) or melts derived frommoderatelySiO2-rich pyroxenites (Lambart et al., 2012). Evidence of peridotiteinteraction with melts from hypersthene-normative pyroxeniteshas been documented in the Ronda massif, where extremely fertilepyroxene-rich lherzolites (Marchesi et al., 2013) and olivinewebsterites(Bodinier et al., 2008) were generated by the impregnation of perido-tites by melts with a garnet pyroxenite component. This event hasbeen related to melting at ~1.5 GPa of an extremely attenuated litho-sphere induced by asthenospheric upwelling in the Late Oligocene-Early Miocene (Lenoir et al., 2001). Mantle xenoliths from the easternBetics, which are less fertile than these peculiar Ronda peridotites andpyroxenites (Fig. S1, Supplementary material), may represent interme-diate products of this process.

On the other hand, orthopyroxene dissolution and addition ofclinopyroxene (and olivine) occur in peridotites reacting with meltsfrom silica-deficient (nepheline-normative) pyroxenites (Lambartet al., 2012). These pyroxenites are common in the Beni Bousera perido-titemassif in the southern limbof theBetic-Rif Cordillera (Lambart et al.,2012) and their melts are characterized by relatively high FeOt and lowSiO2, similar to alkaline basalts (e.g., Lambart et al., 2013). Reactionwiththis type of melt, or with melts similar to the parental magmas of hostalkaline basalts (see Section 6.5), may explain the modal variations inseveral lherzolites (Fig. 9, orange arrow).

Constraints on the geochemical signature of melts that interactedwith anhydrous (amphibole-, phlogopite-free) mantle xenoliths in theeastern Betics have been obtained through inspection of their Sr-Nd iso-topic compositions and the calculation of the REE contents of melts inequilibrium with clinopyroxene. In particular, Beccaluva et al. (2004)and Bianchini et al. (2011) proposed that (i) clinopyroxene-poorperidotites reacted with Permo-Triassic alkaline lamprophyres, and(ii) clinopyroxene-rich (plagioclase-bearing) peridotites interactedwith Jurassic MORB-like basalts. On the other hand, Rampone et al.(2010) ascribed modal metasomatism to reactions at different litho-spheric levels with subalkaline tholeiitic melts, which were similar tothe Eocene-Miocene subduction-related lavas extruded in the Alboranregion. Anhydrous lherzolite xenoliths from the eastern Betics normallyshow decreasing Nd isotopic ratios with increasing clinopyroxene abun-dances (Fig. 10). This suggests that clinopyroxene (and plagioclase) en-richment from harzburgites to lherzolites is mostly due to interactionwith an enriched isotopic component, and not with depleted JurassicMORB-like basalts as maintained by Bianchini et al. (2011), who reporthigher Nd isotopic ratios in clinopyroxene-rich samples. Cenozoicsubduction-related rocks, especially the Eocene-Mioceneback-arcMalagadykes, have more radiogenic Sr and less radiogenic Nd than Jurassictholeiitic basalts, and partly overlap with the isotopic compositions of

Clinopyroxene (%)4 6 8 10 12 14 16

0.5124

0.5126

0.5128

0.5130

0.5132

0.513414

3 Nd/

144 N

d i

Wehrlite

Lherzolite

TAL-127 LPE-046

Fig. 10. Modal abundances of clinopyroxene (%) in peridotite xenoliths from the easternBetics versus whole-rock age-corrected (3 Ma) Nd radiogenic isotope ratios. Symbols asin Fig. 3. 0.702 0.704 0.706 0.708 0.710 0.712 0.714

0.5120

0.5124

0.5128

0.5132

0.5136

87Sr/86Sri

143 N

d/14

4 Nd i

Jurassic tholeiitic basalts


Wehrlite whole-rock

Cenozoic tholeiitic dykes


Orogenic grt pyroxenites

Orogenicperidotites

Al-Augite pyroxenites

Miocenetholeiitic lavas

SiO2-pooralkaline lavas

(a)

3 Ma

TAL-127

18.0 18.5 19.0 19.5 20.0 20.5 21.015.40

15.45

15.50

15.55

15.60

15.65

15.70

15.75


Orogenic peridotites

Miocene tholeiitic lavas

3 Ma

(b)

TAL-127

206Pb/204Pbi

207 P

b/20

4 Pb i

18.0 18.5 19.0 19.5 20.0 20.5 21.037.6

38.4

39.2

40.0

206Pb/204Pbi

208 P

b/20

4 Pb i


3 Ma

Miocenetholeiitic lavas

Al-Augite pyroxenites

Orogenicperidotites

(c) Cenozoic tholeiitic dykes

Orogenic garnet pyroxenites

TAL-127

DMM

EM2

DMM

EM2

EM2

DMM

+Cpx

+Cpx

+Cpx

TAL-134

+Cpx

+Cpx

+Cpx

Al-Augitepyroxenites


Wehrlite whole-rock

Cenozoic tholeiitic dykes


Orogenic grt pyroxenites

LPE-046

Fig. 11. Age-corrected (3 Ma) Sr-Nd (a) and Pb (b, c) radiogenic isotope ratios of whole-rock (coloured symbols) and clinopyroxene separates (grey symbols) of mantleperidotites from the eastern Betics. For samples not analysed for trace elements, verysimilar maximum present-day values have been plotted. Symbols as in Fig. 3. Dotted tie-lines connect age-corrected compositions of whole-rock and clinopyroxene in the samesample. Data of orogenic peridotites (green area), Al-Augite pyroxenites (pink area) andgarnet (grt) pyroxenites (light blues circles) are from Pearson et al. (1993), Becker(1996), Le Roux et al. (2009), and Bodinier and Godard (2014) and references therein.Data of Cenozoic tholeiitic Malaga dykes (small yellow squares), (LREE-depleted)tholeiitic lavas (yellow area) and SiO2-poor alkaline lavas (brown area) from thewestern Mediterranean (all corrected to 3 Ma for comparison) are from Turner et al.(1999), Gill et al. (2004) and Duggen et al. (2004, 2005, 2008). Strontium-Nd isotopiccompositions of Jurassic tholeiitic basalts from the Betics (small white diamonds) arefrom Gómez-Pugnaire et al. (2000). The compositions of the depleted MORB mantle(DMM) and enriched mantle 2 (EM2) are from Zindler and Hart (1986) and Hart (1988).


lherzolites (Fig. 11). Peridotite reactionwith the parental melts of thesedykes may therefore explain the isotopic signature of pyroxene-richmantle xenoliths in the eastern Betics (Rampone et al., 2010).

However, two moderately fertile lherzolites (TAL-127 and LPE-046)have relatively high bulk 143Nd/144Nd (Fig. 10) and clinopyroxene inTAL-127 has very depleted Sr-Nd (Fig. 11a) and Pb (Fig. 11b, c) isotopicsignatures. This indicates that clinopyroxene enrichment in these sam-ples was not due to interaction with Cenozoic subduction-relatedmagmas but with an isotopically depleted melt (Fig. 11). The verydifferent isotopic compositions ofmelts that interactedwith the easternBetics mantle xenoliths, from depleted DMM to enriched EM2 compo-sitions, are difficult to reconcile solely with contamination of theirsources by subduction-related fluids/melts. This important variabilityis better explained by derivation of melts from a reservoir with avery heterogeneous isotopic signature. Mantle peridotites and pyroxe-nites in orogenic massifs have very variable Sr-Nd-Pb isotopic compo-sitions (Fig. 11) that reflect their different time-integrated evolutions.We thus favour the hypothesis that the very heterogeneous isotopiccompositions of lherzolite xenoliths from the eastern Betics (Fig. 11)are mostly due to interaction with melts issued from a heterogeneouspyroxenite-peridotite veined mantle. These melts were possibly pro-duced by Late Oligocene-Early Miocene melting of the thinned litho-spheric mantle, induced by upwelling of the asthenosphere beneathan extended back-arc basin in the western Mediterranean (Garridoet al., 2011; Lenoir et al., 2001).

6.4. Capture of percolating exotic melts

Very incompatible trace elements, such as large-ion lithophile ele-ments (LILE: Rb, Ba), LREE, Sr, and high field strength elements (HFSE:Nb, Ta), are distributed in spinel peridotites between the main mineralphases, melt/fluid/solid inclusions in minerals, glassy films coating thegrain-boundaries, and microphases (i.e., Ti-rich oxides, phlogopite,amphibole) constituting reaction rims on mineral surfaces (Bedini andBodinier, 1999; Bodinier et al., 1996; Garrido et al., 2000). Micrometricrepositories of trace elements in the mantle may derive from differentsources, such as trapped melts in equilibrium with the main silicatesor exotic small melt fractions rich in volatiles (Bedini and Bodinier,1999).

Clinopyroxene is the main host of REE in anhydrous mantle perido-tites, so its normalized REE pattern normally mimics that of the corre-sponding whole-rock (e.g., Garrido et al., 2000, and referencestherein). Different REE fractionations (Fig. 4a, b), Nb/Ta ratios and Pbspikes in the normalized patterns of clinopyroxene and whole-rock(Fig. 5a, b) indicate that trace elements in mantle xenoliths from theeastern Betics are hosted by repositories other than clinopyroxene,


Sam

ple/

Cho

ndrit

e

0.1

1

5

Harzburgite Lherzolite

Analysed whole-rock compositions

Calculated whole-rock compositions

Fig. 12. Whole-rock chondrite-normalized abundances of REE in representative mantleperidotites from the eastern Betics (black solid lines) compared with their theoreticalcompositions that take into account only the main silicates (grey dashed lines). Thelatter were calculated using the clinopyroxene REE contents analysed by LA-ICP-MS,modal abundances of olivine, orthopyroxene and clinopyroxene, and inter-mineraldistribution coefficients relative to clinopyroxene (DOl/Cpx, DOpx/Cpx) computed from themineral/melt partition coefficients of Bedini and Bodinier (1999) and Su and Langmuir(2003). Symbols as in Fig. 3. Normalizing values from Sun and McDonough (1989).


Sam

ple/

PU

M

1

10

100 Melts in equilibrium withclinopyroxene in wehrlites

SiO2-poor alkaline lavas fromthe westernmost Mediterranean

Fig. 13. Primitive upper mantle (PUM)-normalized abundances of REE in calculatedmeltsin equilibriumwith clinopyroxene inwehrlites (black lines) comparedwith the SiO2-pooralkaline lavas from the westernmost Mediterranean (grey lines) (Duggen et al., 2005;Turner et al., 1999). Partition coefficients of clinopyroxene with SiO2-undersaturatedmelts are from Vannucci et al. (1998). Symbols as in Fig. 3. Normalizing values from Sunand McDonough (1989).


and possibly other than the main silicates. Fig. 12 compares the whole-rock normalized REE patterns of representative peridotite xenolithsfrom the eastern Betic Cordillera with their theoretical compositionscalculated using the clinopyroxene REE contents, modal abundancesand inter-mineral distribution coefficients calculated from publishedmineral/melt partition coefficients. The calculated compositions are de-pleted in LREE compared with their corresponding analysed concentra-tions (Fig. 12), suggesting that anhydrous mantle xenoliths from theeastern Betics contain small amounts of trapped melt in disequilibriumwith the main silicates (e.g., Kourim et al., 2014). This is confirmed bythe more radiogenic Pb isotopic ratios of whole-rock relative toclinopyroxene in two lherzolites (TAL-127 and TAL-134) (Fig. 6b, c),suggesting that whole-rocks captured small fractions of exotic meltswith an isotopic signature different from that of melts in equilibriumwith clinopyroxene. On the other hand, Sr and Nd isotopes in thesame samples have coincident ratios in clinopyroxene and whole-rock(Fig. 6a), and our whole-rock data reproduce the isotopic variability ofclinopyroxene separates previously analysed in peridotites fromTallante (Beccaluva et al., 2004; Bianchini et al., 2011). Disequilibriumof Pb but not of Sr-Nd radiogenic isotopesmay reflect the higher incom-patible character of Pb compared to Sr and Nd and its higher abundancein the percolating exotic melts, which may hamper the re-equilibrationof Pb with the peridotite matrix more effectively than for Sr-Nd (Navonand Stolper, 1987). Interaction between the SiO2-poor alkaline basaltsthat host the xenoliths and the xenoliths themselves, manifested asb50 μm glassy fractures along grain boundaries or crosscutting themain minerals (Rampone et al., 2010), may have influenced the traceelement budget of these peridotites. However, the general resemblanceof thewhole-rock Pb isotopic compositions of the eastern Betics perido-tites, including TAL-127 and TAL-134, to those of the EarlyMiocene tho-leiitic Malaga dykes (Fig. 11b, c) suggests that these back-arc magmas,and not the silica-poor alkaline host basalts, mostly affected thewhole-rock trace element compositions of peridotite xenoliths. EarlyMiocene back-arc magmas were likely trapped after reaction withpyroxenite-derived melts, and possibly crystallized the interstitialaggregates of plagioclase ± olivine and/or orthopyroxene observed insome samples (Rampone et al., 2010). Reaction with small fractions ofpercolating melts may also explain the positive NbN/TaN and negativeZrN/NbN in whole-rocks compared to opposite values in clinopyroxene(Fig. 5a, b). Indeed, this process may form micrometric rims of rutileand phlogopite coating spinel surfaces (Bedini and Bodinier, 1999;

Bodinier et al., 1996), which preferentially incorporate Nb over Ta andZr (e.g., Pearson et al., 2014).

6.5. Wehrlite formation by late peridotite interaction with alkaline basalts

Wehrlites sampled in suites of mantle xenoliths are commonly gen-erated by clinopyroxene-forming melt-rock reactions induced by mi-gration of carbonatite or alkaline silicate melts (e.g., Ionov et al., 2005;Raffone et al., 2009; Yaxley et al., 1991). In particular, thewehrlite xeno-liths from the eastern Betics resemble the products of reaction betweenmantle peridotites and alkaline basalts. Contrary to wehrlites related tocarbonatites (e.g., Raffone et al., 2009; Yaxley et al., 1991), these rocksare rich in FeOt (Fig. 3d) and have low clinopyroxene and olivine Mg#and relatively high spinel Cr# (Fig. S2, Supplementary material), typicalof mantle wall-rocks that interacted with evolved basaltic melts rela-tively close to magma conduits or porous flow channels (Bodinieret al., 1990; Ionov et al., 2005). Moreover, the hump-shaped LREE-richpattern of clinopyroxene (Fig. 4c) and its relatively high Ti/Eu ratios(~2500–4600) normally characterize clinopyroxene equilibrated withalkaline silicate melts (e.g., Bodinier et al., 1987; Coltorti et al., 1999).These rocks therefore likely formed as a result of a large, time-integrated flux of SiO2-undersaturated alkaline melts, which replacedorthopyroxene with olivine and clinopyroxene in their protoliths. Thisis also confirmed by similar mineral crystal preferred orientations inwehrlites and lherzolites from this xenolith suite (Hidas et al., 2016).One fertile lherzolite (LPE-062) is particularly rich in FeOt (Fig. 3d)and has whole-rock and clinopyroxene trace element compositionssimilar to wehrlites (Fig. 4). This sample thus probably records local re-actions between alkaline silicate melts and wall-rock peridotites afterLate Oligocene-Early Miocene refertilization by pyroxenite-derivedmelts.

The last (Late Miocene to Quaternary) magmatic event in the west-ernmost Mediterranean produced SiO2-poor alkaline lavas includingthe host basalts of the mantle xenoliths studied here (Duggen et al.,2005; Turner et al., 1999). Duggen et al. (2005) proposed that primi-tive SiO2-poor magmas in the westernmost Mediterranean derivedfrom a plume-contaminated asthenosphere and interacted with themetasomatized lithospheric mantle during ascent, leading to increasing87Sr/86Sr and decreasing 143Nd/144Nd and 206Pb/204Pb. The computedmelts in equilibrium with clinopyroxene in wehrlites, calculated usinga set of partition coefficients for SiO2-undersaturated melts, have REEnormalized patterns that display considerable overlap with the SiO2-poor alkaline basalts from the westernmost Mediterranean (Fig. 13).Similar conclusions have been inferred by Rampone et al. (2010) and


Bianchini et al. (2011) for olivine—amphibole-bearing clinopyroxenitesenclosed in the Tallante peridotites. Intrusion of these pyroxenitesproduced a clinopyroxene-rich reaction zone at the contact with thehost peridotite (Rampone et al., 2010), which has REE composition(Bianchini et al., 2011) similar to the wehrlites studied here. Moreover,these wehrlites have higher 87Sr/86Sr and lower 143Nd/144Nd and206Pb/204Pb than most of the SiO2-poor lavas (Fig. 11), and the Tallantehost basalts in particular, which may reflect significant interaction ofSiO2-poor melts with enclosing metasomatized peridotites (Duggenet al., 2005). All these observations strongly suggest that the wehrlitexenoliths in the eastern Betics were produced by interaction betweensubcontinental lithosphericmantle peridotites and the parental alkalinemagmas of the enclosing Pliocene basalts.

7. Conclusions

Peridotite xenoliths in Pliocene alkali basalts from the eastern BeticCordillera include spinel (±plagioclase) harzburgites and lherzolites,and spinel wehrlites. These peridotites derive from residues of around20% partial melting and experienced different types of mantle metaso-matism. In most samples, reaction with melt caused the addition ofclinopyroxene and orthopyroxene and dissolution of olivine, whichled to higher FeOt, SiO2, Al2O3 and REE and lower MgO compared tothe original melting residues. Modal metasomatism in other xenolithspromoted the consumption of orthopyroxene and the enrichment inclinopyroxene and olivine, which increased FeOt and MgO and de-creased SiO2 relative to common (orthopyroxene-rich) lherzolites.Higher FeOt and lower SiO2 abundances in one sample than thosefound in refractory melting products reflect the addition of olivine anddissolution of orthopyroxene. Thesemodal and compositionalmodifica-tionsweremostly induced by reactions of the peridotiteswith relativelyFeOt-rich/SiO2-poor melts produced by melting of a pyroxenite-peridotite veined lithosphere with highly heterogeneous Sr-Nd-Pb iso-topic compositions. Melting of the lithospheric mantle in the westernMediterranean was caused by upwelling of the asthenosphere relatedto back-arc extension in the Late Oligocene-Early Miocene. Small frac-tions of back-arc tholeiitic magmas, finally crystallized in the EarlyMiocene tholeiitic Malaga dykes, were trapped in peridotites leadingto a divergence between the trace element and Pb isotopic signatures ofclinopyroxene and whole-rock. Late melt-mantle reactions close to per-colation conduits of SiO2-poor alkaline magmas replaced orthopyroxenewith olivine and clinopyroxene, producing wehrlites. These meltswere similar to the parental magmas of the Late Miocene-Quaternaryalkaline basalts extruded in the westernmost Mediterranean, which in-clude the Pliocene lavas that host the xenoliths. Interaction with thesemelts constitutes the last magmatic episode of the Cenozoic evolutionof the westernmost Mediterranean recorded in the mantle xenolithsfrom the eastern Betics.

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.lithos.2016.12.011.

Acknowledgements

We thank the Guest editor M. Matusiak-Małek, E. Rampone andV. Cvetković for their constructive reviews of the submitted version ofthe manuscript. We are grateful to J. Harvey for the revision of theEnglish text. R. Reyes-González (Instituto Andaluz de Ciencias de laTierra, IACT, Spain), O. Bruguier and B. Galland (GéosciencesMontpellier,France) are thanked for sample preparation and assistance during ICP-MS analyses and chemical separation in the lab, and A. Caballero (IACT)for his help in drawing thefigures. C.M. acknowledges funding byRamóny Cajal Fellowship RYC-2012-11314 and K.H. by Juan de la CiervaPostdoctoral Fellowship FPDI-2013-16253, both granted by the Spanish“Ministerio de Economía y Competitividad” (MINECO). A.A.-V acknowl-edges a research contract from IACT and a Piscopia—Marie Curie Fellow-ship (funded under GA No. 600376) from the Università di Padova

(Italy). Z.K. and M.I.V.R research have been supported by two JAE-PreDoc fellowships funded by theCSIC.We further acknowledge fundingfrom the MINECO (grants CGL2013-42349-P and CGL2016-81085-R),“Junta de Andalucía” (research group RNM-131 and grant P12-RNM-3141), and the International Lithosphere Program (CC4-MEDYNA).This research has benefited from EU Cohesion Policy funds from theEuropean Regional Development Fund (ERDF) and the European SocialFund (ESF) in support of human resources, innovation, research capaci-ties, and research infrastructures.

References

Arai, S., 1994. Characterization of spinel peridotites by olivine-spinel compositionalrelationships: review and interpretation. Chemical Geology 113, 191–204.

Beccaluva, L., Bianchini, G., Bonadiman, C., Siena, F., Vaccaro, C., 2004. Coexistinganorogenic and subduction-related metasomatism in mantle xenoliths from theBetic Cordillera (southern Spain). Lithos 75, 67–87.

Becker, H., 1996. Crustal trace element and isotopic signatures in garnet pyroxenites fromgarnet peridotite massifs from Lower Austria. Journal of Petrology 37, 785–810.

Bedini, R.M., Bodinier, J.-L., 1999. Distribution of incompatible trace elements between theconstituents of spinel peridotite xenoliths: ICP-MS data from the East African Rift.Geochimica et Cosmochimica Acta 63, 3883–3900.

Bianchini, G., Beccaluva, L., Nowell, G.M., Pearson, D.G., Siena, F., 2011. Mantle xenolithsfrom Tallante (Betic Cordillera): insights into the multi-stage evolution of the southIberian lithosphere. Lithos 124, 308–318.

Bodinier, J.L., Godard, M., 2014. Orogenic, ophiolitic, and abyssal peridotites. In: Carlson,R.W. (Ed.), The Mantle and CoreTreatise on Geochemistry vol. 3. Elsevier,pp. 103–167.

Bodinier, J.-L., Garrido, C.J., Chanefo, I., Bruguier, O., Gervilla, F., 2008. Origin of pyroxenite-peridotite veined mantle by refertilization reactions: evidence from the Ronda peri-dotite (southern Spain). Journal of Petrology 49, 999–1025.

Bodinier, J.-L., Guiraud, M., Fabriès, J., Dostal, J., Dupuy, C., 1987. Petrogenesis of layeredpyroxenites from the Lherz, Freychinède and Prades ultramafic bodies (Ariège,French Pyrénées). Geochimica et Cosmochimica Acta 51, 279–290.

Bodinier, J.-L., Merlet, C., Bedini, R.M., Simien, F., Remaidi, M., Garrido, C.J., 1996. Distribu-tion of niobium, tantalum, and other highly incompatible trace elements in the lith-ospheric mantle: the spinel paradox. Geochimica et Cosmochimica Acta 60, 545–550.

Bodinier, J.-L., Vasseur, G., Vernieres, J., Dupuy, C., Fabries, J., 1990. Mechanisms of mantlemetasomatism: geochemical evidence from the Lherz orogenic peridotite. Journal ofPetrology 31, 597–628.

Booth-Rea, G., Ranero, C.R., Martínez-Martínez, J.M., Grevemeyer, I., 2007. Crustal typesand Tertiary tectonic evolution of the Alborán sea, westernMediterranean. Geochem-istry, Geophysics, Geosystems 8, Q10005.

Canil, D., 2004. Mildly incompatible elements in peridotites and the origins of mantlelithosphere. Lithos 77, 375–393.

Cebriá, J.M., López-Ruiz, J., Carmona, J., Doblas, M., 2009. Quantitative petrogenetic con-straints on the Pliocene alkali basaltic volcanism of the SE Spain Volcanic Province.Journal of Volcanology and Geothermal Research 185, 172–180.

Coltorti, M., Bonadiman, C., Hinton, R.W., Siena, F., Upton, B.G.J., 1999. Carbonatite meta-somatism of the oceanic upper mantle: evidence from clinopyroxenes and glasses inultramafic xenoliths of Grande Comore, Indian Ocean. Journal of Petrology 40,133–165.

Deschamps, F., Guillot, S., Godard, M., Chauvel, C., Andreani, M., Hattori, K., 2010.In situ characterization of serpentinites from forearc mantle wedges: timing ofserpentinization and behavior of fluid-mobile elements in subduction zones. Chemi-cal Geology 269, 262–277.

Downes, H., 2001. Formation and modification of the shallow sub-continental litho-spheric mantle: a review of geochemical evidence from ultramafic xenolith suitesand tectonically emplaced ultramafic massifs of Western and Central Europe. Journalof Petrology 42, 233–250.

Duggen, S., Hoernle, K., Klügel, A., Geldmacher, J., Thirlwall, M., Hauff, F., Lowry, D., Oates,N., 2008. Geochemical zonation of the Miocene Alborán Basin volcanism (western-most Mediterranean): geodynamic implications. Contributions to Mineralogy andPetrology 156, 577–593.

Duggen, S., Hoernle, K., Van Den Bogaard, P., Garbe-Schönberg, D., 2005. Post-collisionaltransition from subduction- to intraplate-type magmatism in the westernmostMediterranean: evidence for continental-edge delamination of subcontinentallithosphere. Journal of Petrology 46, 1155–1201.

Duggen, S., Hoernle, K., van den Bogaard, P., Harris, C., 2004. Magmatic evolution of theAlboran region: the role of subduction in forming the western Mediterranean andcausing the Messinian Salinity Crisis. Earth and Planetary Science Letters 218,91–108.

Faccenna, C., Piromallo, C., Crespo-Blanc, A., Jolivet, L., Rossetti, F., 2004. Lateral slab defor-mation and the origin of the western Mediterranean arcs. Tectonics 23, TC1012.

Frey, F.A., Suen, C.J., Stockman, H.W., 1985. The Ronda high temperature peridotite:geochemistry and petrogenesis. Geochimica et Cosmochimica Acta 49, 2469–2491.

Gao, S., Liu, X., Yuan, H., Hattendorf, B., Günther, D., Chen, L., Hu, S., 2002. Determination offorty two major and trace elements in USGS and NIST SRM glasses by laser ablation-inductively coupled plasma-mass spectrometry. Geostandards Newsletter 26,181–196.

Garrido, C.J., Bodinier, J.-L., 1999. Diversity of mafic rocks in the Ronda peridotite:evidence for pervasive melt–rock reaction during heating of subcontinental litho-sphere by upwelling asthenosphere. Journal of Petrology 40, 729–754.



http://refhub.elsevier.com/S0024-4937(16)30444-3/rf0005






































































Garrido, C.J., Bodinier, J.-L., Alard, O., 2000. Incompatible trace element partitioning andresidence in anhydrous spinel peridotites and websterites from the Ronda orogenicperidotite. Earth and Planetary Science Letters 181, 341–358.

Garrido, C.J., Gueydan, F., Booth-Rea, G., Precigout, J., Hidas, K., Padrón-Navarta, J.A.,Marchesi, C., 2011. Garnet lherzolite and garnet-spinel mylonite in the Rondaperidotite: vestiges of Oligocene backarc mantle lithospheric extension in thewestern Mediterranean. Geology 39, 927–930.

Gill, R.C.O., Aparicio, A., El Azzouzi, M., Hernandez, J., Thirlwall, M.F., Bourgois, J., Marriner,G.F., 2004. Depleted arc volcanism in the Alboran Sea and shoshonitic volcanism inMorocco: geochemical and isotopic constraints on Neogene tectonic processes. Lithos78, 363–388.

Godard, M., Awaji, S., Hansen, H., Hellebrand, E., Brunelli, D., Johnson, K., Yamasaki, T.,Maeda, J., Abratis, M., Christie, D., Kato, Y., Mariet, C., Rosner, M., 2009. Geochemistryof a long in-situ section of intrusive slow-spread oceanic lithosphere: results fromIODP site U1309 (Atlantis massif, 30°N mid-Atlantic-ridge). Earth and PlanetaryScience Letters 279, 110–122.

Gómez-Pugnaire, M.T., Ulmer, P., López Sánchez-Vizcaíno, V., 2000. Petrogenesis of themafic igneous rocks of the Betic cordilleras: a field, petrological and geochemicalstudy. Contributions to Mineralogy and Petrology 139, 436–457.

Hart, S.R., 1984. A large-scale isotope anomaly in the southern hemispheremantle. Nature309, 753–757.

Hart, S.R., 1988. Heterogeneous mantle domains: signatures, genesis and mixingchronologies. Earth and Planetary Science Letters 90, 273–296.

Herzberg, C., 2004. Geodynamic information in peridotite petrology. Journal of Petrology45, 2507–2530.

Hidas, K., Konc, Z., Garrido, C.J., Tommasi, A., Vauchez, A., Padrón-Navarta, J.A., Marchesi,C., Booth-Rea, G., Acosta-Vigil, A., Szabó, C., Varas-Reus, M.I., Gervilla, F., 2016.Flow in the western Mediterranean shallow mantle: insights from xenoliths inPliocene alkali basalts from SE Iberia (eastern Betic Cordillera, Spain). Tectonics 35:2657–2676. http://dx.doi.org/10.1002/2016TC004165.

Ionov, D.A., Bodinier, J.-L., Mukasa, S.B., Zanetti, A., 2002. Mechanisms and sources of mantlemetasomatism: major and trace element compositions of peridotite xenoliths fromSpitsbergen in the context of numerical modelling. Journal of Petrology 43, 2219–2259.

Ionov, D.A., Chanefo, I., Bodinier, J.-L., 2005. Origin of Fe-rich lherzolites and wehrlitesfrom Tok, SE Siberia by reactive melt percolation in refractory mantle peridotites.Contributions to Mineralogy and Petrology 150, 335–353.

Ionov, D.A., Savoyant, L., Dupuy, C., 1992. Application of the ICP-MS technique to trace-element analysis of peridotites and their minerals. Geostandards Newsletter 16,311–315.

Jagoutz, E., Palme, H., Baddenhausen, H., Blum, H., Cendales, M., Dreibus, G., Spettel, B.,Lorenz, V., Wanke, H., 1979. The abundances of major, minor and trace elements inthe Earth's mantle as derived from primitive ultramafic nodules. Geochimica etCosmochimica Acta 11, 2031–2050.

Jochum, K.P., Seufert, H.M., Thirwall, M.F., 1990.Multi-element analysis of 15 internationalstandard rocks by isotope-dilution spark source mass spectrometry (ID-SSMS).Analytical Chemistry 331, 104–110.

Kelemen, P.B., 1990. Reaction between ultramafic rock and fractionating basalticmagma I.Phase relations, the origin of calc-alkalinemagma series, and the formation of discor-dant dunite. Journal of Petrology 31, 51–98.

Konc, Z., Marchesi, C., Garrido, C.J., González-Jiménez, J.M., Griffin,W.L., Alard, O., Hidas, K.,O'Reilly, S.Y., Pearson, N., 2012. Provenance and evolution of the western Mediterra-nean lithospheric mantle beneath the eastern Betics (S. Spain): insights from in-situanalyses of Os isotopes and platinum-group elements in sulphides from the Tallantemantle xenoliths. Geophysical Research Abstracts 14, EGU2012–EG12929.

Kourim, F., Bodinier, J.-L., Alard, O., Bendaoud, A., Vauchez, A., Dautria, J.-M., 2014. Natureand evolution of the lithospheric mantle beneath the Hoggar Swell (Algeria): a recordfrom mantle xenoliths. Journal of Petrology 55, 2249–2280.

Lambart, S., Laporte, D., Provost, A., Schiano, P., 2012. Fate of pyroxenite-derived meltsin the peridotitic mantle: thermodynamic and experimental constraints. Journal ofPetrology 53, 451–476.

Lambart, S., Laporte, D., Schiano, P., 2013. Markers of the pyroxenite contribution inthe major-element compositions of oceanic basalts: review of the experimentalconstraints. Lithos 160-161, 14–36.

Le Roux, V., Bodinier, J.-L., Alard, O., O'Reilly, S.Y., Griffin, W.L., 2009. Isotopic decouplingduring porous melt flow: a case-study in the Lherz peridotite. Earth and PlanetaryScience Letters 279, 76–85.

Lenoir, X., Garrido, C.J., Bodinier, J.-L., Dautria, J.-M., Gervilla, F., 2001. The recrystallizationfront of the Ronda peridotite: evidence for melting and thermal erosion of subconti-nental lithospheric mantle beneath the Alboran Basin. Journal of Petrology 42,141–158.

Marchesi, C., Dale, C.W., Garrido, C.J., Pearson, D.G., Bosch, D., Bodinier, J.-L., Gervilla, F.,Hidas, K., 2014. Fractionation of highly siderophile elements in refertilized mantle:implications for the Os isotope composition of basalts. Earth and Planetary ScienceLetters 400, 33–44.

Marchesi, C., Garrido, C.J., Bosch, D., Bodinier, J.-L., Gervilla, F., Hidas, K., 2013. Mantlerefertilization by melts of crustal-derived garnet pyroxenite: evidence from the Rondaperidotite massif, southern Spain. Earth and Planetary Science Letters 362, 66–75.

Marchesi, C., Garrido, C.J., Bosch, D., Bodinier, J.-L., Hidas, K., Padrón-Navarta, J.A., Gervilla,F., 2012. A Late Oligocene suprasubduction setting in the westernmost Mediterra-nean revealed by intrusive pyroxenite dikes in the Ronda peridotite (southernSpain). The Journal of Geology 120, 237–247.

Marchesi, C., Griffin, W.L., Garrido, C.J., Bodinier, J.-L., O'Reilly, S.Y., Pearson, N., 2010.Persistence of mantle lithospheric Re–Os signature during asthenospherizationof the subcontinental lithospheric mantle: insights from in situ isotopic analysis ofsulfides from the Ronda peridotite (southern Spain). Contributions to Mineralogyand Petrology 159, 315–330.

McDonough, W.F., Sun, S.-s., 1995. The composition of the Earth. Chemical Geology 120,223–253.

Menzies, M.A., Hawkesworth, C.J., 1987. Mantle Metasomatism. Academic Press, London;Orlando (472 pp.).

Mercier, J.C.C., Nicolas, A., 1975. Textures and fabrics of upper-mantle peridotites as illus-trated by xenoliths from basalts. Journal of Petrology 16, 454–487.

Morgan, Z., Liang, Y., 2003. An experimental and numerical study of the kinetics ofharzburgite reactive dissolution with applications to dunite dike formation. Earthand Planetary Science Letters 214, 59–74.

Navon, O., Stolper, E., 1987. Geochemical consequences of melt percolation-the uppermantle as a chromatographic column. The Journal of Geology 95, 285–307.

Niu, Y., 1997. Mantle melting and melt extraction processes beneath ocean ridges:evidence from abyssal peridotites. Journal of Petrology 38, 1047–1074.

Pearce, N.J.G., Perkins, W.T., Westgate, J.A., Gorton, M.P., Jackson, S.E., Neal, C.R., Chenery,S.P., 1997. A compilation of new and publishedmajor and trace element data for NISTSRM 610 and NIST SRM 612 glass reference materials. Geostandards Newsletter 21,115–144.

Pearson, D.-G., Canil, D., Shirey, S.B., 2014. Mantle samples included in volcanic rocks:xenoliths and diamonds. In: Carlson, R.W. (Ed.), The Mantle and CoreTreatise onGeochemistry vol. 3. Elsevier, Oxford, pp. 169–253.

Pearson, D.G., Davies, G.R., Nixon, P.H., 1993. Geochemical constraints on the petrogenesisof diamond facies pyroxenites from the Beni Bousera peridotite massif, NorthMorocco. Journal of Petrology 34, 125–172.

Pilet, S., Baker, M.B., Stolper, E.M., 2008. Metasomatized lithosphere and the origin ofalkaline lavas. Science 320, 916–919.

Pin, C., Briot, D., Bassin, C., Poitrasson, F., 1994. Concomitant separation of strontium andsamarium-neodymium for isotopic analysis in silicate samples, based on specificextraction chromatography. Analytica Chimica Acta 298, 209–217.

Platt, J.P., Behr, W.M., Johanesen, K., Williams, J.R., 2013. The Betic-Rif arc and its orogenichinterland: a review. Annual Review of Earth and Planetary Sciences 41, 313–357.

Raffone, N., Chazot, G., Pin, C., Vannucci, R., Zanetti, A., 2009. Metasomatism in the litho-spheric mantle beneath Middle Atlas (Morocco) and the origin of Fe- and Mg-richwehrlites. Journal of Petrology 50, 197–249.

Rampone, E., Piccardo, G.B., Vannucci, R., Bottazzi, P., Ottolini, L., 1993. Subsolidusreactions monitored by trace element partitioning: the spinel- to plagioclase-faciestransition in mantle peridotites. Contributions to Mineralogy and Petrology 115,1–17.

Rampone, E., Romairone, A., Hofmann, A.W., 2004. Contrasting bulk and mineral chemis-try in depleted mantle peridotites: evidence for reactive porous flow. Earth andPlanetary Science Letters 218, 491–506.

Rampone, E., Vissers, R.L.M., Poggio, M., Scambelluri, M., Zanetti, A., 2010. Melt migrationand intrusion during exhumation of the Alboran lithosphere: the Tallante mantlexenolith record (Betic Cordillera, SE Spain). Journal of Petrology 51, 295–325.

Reisberg, L., Lorand, J.-P., 1995. Longevity of sub-continental mantle lithosphere fromosmium isotope systematics in orogenic peridotite massifs. Nature 376, 159–162.

Reisberg, L., Zindler, A., 1986. Extreme isotopic variations in the upper mantle: evidencefrom Ronda. Earth and Planetary Science Letters 81, 29–45.

Reisberg, L., Zindler, A., Jagoutz, E., 1989. Further Sr and Nd isotopic results from perido-tites of the Ronda ultramafic complex. Earth and Planetary Science Letters 96,161–180.

Shimizu, Y., Arai, S., Morishita, T., Ishida, Y., 2008. Origin and significance of spinel–pyroxene symplectite in lherzolite xenoliths from Tallante, SE Spain. Mineralogyand Petrology 94, 27–43.

Soustelle, V., Tommasi, A., Bodinier, J.-L., Garrido, C.J., Vauchez, A., 2009. Deformation andreactive melt transport in the mantle lithosphere above a large-scale partial meltingdomain: the Ronda peridotite massif, southern Spain. Journal of Petrology 50,1235–1266.

Spakman, W., Wortel, R., 2004. A tomographic view on western Mediterraneangeodynamics. In: Cavazza, W., Roure, F., Spakman, W., Stampfli, G.M., Ziegler, P.(Eds.), TheTRANSMEDAtlas, theMediterranean Region fromCrust toMantle. Springer,pp. 31–52.

Su, Y., Langmuir, C.H., 2003. Global MORB Chemistry Compilation at the Segment Scale.(PhD thesis). Department of Earth and Environmental Sciences, Columbia University,New York.

Sun, s.-S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes. In: Saunders, A.D., Norry, M.J.(Eds.), Magmatism in the Ocean Basins. Geological Society of London Special Publica-tions 42, pp. 313–345.

Turner, S.P., Platt, J.P., George, R.M.M., Kelley, S.P., Pearson, D.G., Nowell, G.M., 1999.Magmatism associated with orogenic collapse of the Betic-Alboran Domain, SESpain. Journal of Petrology 40, 1011–1036.

Tursack, E., Liang, Y., 2012. A comparative study of melt-rock reactions in the mantle:laboratory dissolution experiments and geological field observations. Contributionsto Mineralogy and Petrology 163, 861–876.

van Achterberg, E., Ryan, C.G., Jackson, S.E., Griffin, W., 2001. Data reduction softwarefor LA-ICP-MS. In: Sylvester, P.J. (Ed.), Laser Ablation ICP-MS in the Earth Science.Mineralogical Association of Canada 29, pp. 239–243.

Van der Wal, D., Bodinier, J.-L., 1996. Origin of the recrystallisation front in the Rondaperidotite by km-scale pervasive porous melt flow. Contributions to Mineralogyand Petrology 122, 387–405.

Vannucci, R., Bottazzi, P., Wulff-Pedersen, E., Neumann, E.-R., 1998. Partitioning of REE, Y,Sr, Zr and Ti between clinopyroxene and silicate melts in the mantle under La Palma(Canary Islands): implications for the nature of the metasomatic agents. Earth andPlanetary Science Letters 158, 39–51.

Varas-Reus, M.I., Garrido, C.J., Marchesi, C., Bosch, D., Acosta-Vigil, A., Hidas, K., Barich,A., Booth-Rea, G., 2017. Sr-Nd-Pb isotopic systematics of crustal rocks from the























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western Betics (S. Spain): implications for crustal recycling in the lithosphericmantle beneath the westernmost Mediterranean. Lithos 276, 45–61 (inthis issue).

Walter, M.J., 2003. Melt extraction and compositional variability in mantle lithosphere.In: Carlson, R.W. (Ed.), The Mantle and CoreTreatise on Geochemistry vol. 2. Elsevier,pp. 363–394.

White, M.W., Albarède, F., Télouk, P., 2000. High precision analysis of Pb isotopic ratios bymulti-collector ICP-MS. Chemical Geology 167, 257–270.

Witt-Eickschen, G., Seck, H.A., 1991. Solubility of Ca and Al in orthopyroxene from spinelperidotite: an improved version of an empirical geothermometer. Contributions toMineralogy and Petrology 106, 431–439.

Yaxley, G.M., Crawford, A.J., Green, D.H., 1991. Evidence for carbonatite metasomatismin spinel peridotite xenoliths from western Victoria, Australia. Earth and PlanetaryScience Letters 107, 305–317.

Zindler, A., Hart, S., 1986. Chemical geodynamics. Annual Review of Earth and PlanetarySciences 14, 493–571.

















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