Metasedimentary and igneous xenoliths from Tallante (Betic Cordillera, Spain): Inferences on crust–mantle interactions and clues for post-collisional volcanism magma sources

Bianchini, Gianluca; Braga, Roberto; Langone, Antonio; Natali, Claudio; Tiepolo, Massimo

doi:10.1016/j.lithos.2015.02.011

Cited by 17 publications

(21 citation statements)

References 49 publications

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“…The presence of metasomatic plagioclase indicates equilibration in the shallow mantle was accompanied by reactive melt percolation [ Bianchini et al ., ; Kogarko et al ., ; Rampone et al ., ; Shimizu et al ., ]. The 0.7–0.9 GPa pressure estimation for both the formation of intrusive veins [ Bianchini et al ., ; Rampone et al ., ] and that of Al, Cr, and Ti zoning in pyroxenes [ Kogarko et al ., ] point to an anomalously thin crust of 19–22 km above a hot SCLM at the time of eruption (2–3 Ma ago [ Duggen et al ., ]), which is consistent with the present‐day crust‐mantle boundary at <25 km beneath the region [ Mancilla et al ., ].…”

Section: Provenance Of the Se Iberian Subcontinental Lithospheric Mantlementioning

confidence: 98%

“…The cluster‐bearing xenoliths record minimum pressures of 1.83–1.91 GPa (~ 55–60 km), and the plagioclase‐bearing ones originate at 0.62–0.73 (±0.09) GPa (~ 19–22 km) (Figure ). The calculated stability field of plagioclase lherzolites is consistent with the 0.7–0.9 GPa pressure estimation for both the formation of intrusive veins [ Bianchini et al ., ; Rampone et al ., ] and that of Al, Cr, and Ti zoning in pyroxenes [ Kogarko et al ., ].…”

Section: Geothermobarometrymentioning

confidence: 98%

“…In the sample set we also include two composite xenoliths (LPE‐008 and TAL‐014) that contain several millimeter‐ to centimeter‐wide veins of orthopyroxenite. Similar veins in the area have been interpreted as produced by silica‐rich, subduction‐derived mantle metasomatism [e.g., Rampone et al ., ; Shimizu et al ., , and references therein], which predates the formation of kaersutitic amphibole veins, vein networks, and/or large amphibole‐bearing patches that are also common in the Tallante volcanic center and have been interpreted as the precursors of alkaline basaltic volcanism [ Bianchini et al ., , ; Rampone et al ., ]. Therefore, the selected composite xenoliths might provide relative time constraints between the deformation recorded in peridotite and subduction‐related metasomatism in the area.…”

Section: Sampling Strategymentioning

confidence: 98%

“…The veins in the composite xenoliths (LPE‐008 and TAL‐014) are composed of pyroxenes, olivine, and spinel ± amphibole (Table ), and they crosscut the spinel‐plagioclase host peridotite. Interstitial accessory volatile‐bearing minerals (mostly amphibole and apatite) are present in some samples (Table ) and are similar to those reported in previous studies [e.g., Bianchini et al ., , ; Rampone et al ., ; Shimizu et al ., ].…”

Section: Lithologiesmentioning

confidence: 98%

“…In addition to this Neogene igneous activity, the SEIVP comprises late Miocene to Plio‐Pleistocene shoshonitic igneous rocks and basanites/alkali basalts and their derivatives, often referred in the literature as anorogenic magmatism (Figure b) [e.g., Duggen et al ., , , ; Hoernle et al ., ; Turner et al ., ]. Some alkali basalt volcanic centers contain numerous crustal/mantle high‐grade metamorphic, mafic and ultramafic xenoliths, and megacrysts [e.g., Bianchini et al ., , and references therein].…”

Section: Tectonic Setting and Cenozoic Volcanismmentioning

confidence: 99%

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Flow in the western Mediterranean shallow mantle: Insights from xenoliths in Pliocene alkali basalts from SE Iberia (eastern Betics, Spain)

et al. 2016

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Mantle xenoliths in Pliocene alkali basalts of the eastern Betics (SE Iberia, Spain) are spinel ± plagioclase lherzolite, with minor harzburgite and wehrlite, displaying porphyroclastic or equigranular textures. Equigranular peridotites have olivine crystal preferred orientation (CPO) patterns similar to those of porphyroclastic xenoliths but slightly more dispersed. Olivine CPO shows [100]‐fiber patterns characterized by strong alignment of [100]‐axes subparallel to the stretching lineation and a girdle distribution of [010]‐axes normal to it. This pattern is consistent with simple shear or transtensional deformation accommodated by dislocation creep. One xenolith provides evidence for synkinematic reactive percolation of subduction‐related Si‐rich melts/fluids that resulted in oriented crystallization of orthopyroxene. Despite a seemingly undeformed microstructure, the CPO in orthopyroxenite veins in composite xenoliths is identical to those of pyroxenes in the host peridotite, suggesting late‐kinematic crystallization. Based on these observations, we propose that the annealing producing the equigranular microstructures was triggered by melt percolation in the shallow subcontinental lithospheric mantle coeval to the late Neogene formation of veins in composite xenoliths. Calculated seismic properties are characterized by fast propagation of P waves and polarization of fast S waves parallel to olivine [100]‐axis (stretching lineation). These data are compatible with present‐day seismic anisotropy observations in SE Iberia if the foliations in the lithospheric mantle are steeply dipping and lineations are subhorizontal with ENE strike, implying dominantly horizontal mantle flow in the ENE‐WSW direction within vertical planes, that is, subparallel to the paleo‐Iberian margin. The measured anisotropy could thus reflect a lithospheric fabric due to strike‐slip deformation in the late Miocene in the context of WSW tearing of the subducted south Iberian margin lithosphere.

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