Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence
International audience The Tertiary Veneto Volcanic Province (VVP; SE Alps, northern Italy) includes Na-rich alkali basalts and basanites hosting many spl-peridotite xenoliths (mg#>88) among the ultramafic nodules which reflect a variably depleted mantle source [e.g. strong Cr/(Cr+Al) ratio incre...
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ftunivnantes:oai:HAL:hal-03953521v1 2023-05-15T17:02:08+02:00 Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence Gasperini, D. Bosch, Delphine Braga, Roberto Bondi, M. Macera, Patrizia Morten, Lauro University of Pisa - Università di Pisa Géosciences Montpellier Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Dipartimento di Scienze della Terra e Geo-Ambientali Alma Mater Studiorum Università di Bologna Bologna (UNIBO) Dipartimento di Scienze della Terra e Geologico Ambientali CORDIS Firenze (Florence), Italy 2004-08-20 https://hal.science/hal-03953521 en eng HAL CCSD hal-03953521 https://hal.science/hal-03953521 Geochimical Society 32nd International Geological Congress (IGC) https://hal.science/hal-03953521 32nd International Geological Congress (IGC), CORDIS, Aug 2004, Firenze (Florence), Italy. pp.A619 [SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/conferenceObject Conference papers 2004 ftunivnantes 2023-01-31T23:58:21Z International audience The Tertiary Veneto Volcanic Province (VVP; SE Alps, northern Italy) includes Na-rich alkali basalts and basanites hosting many spl-peridotite xenoliths (mg#>88) among the ultramafic nodules which reflect a variably depleted mantle source [e.g. strong Cr/(Cr+Al) ratio increase at a slight Mg/(Mg+Fe²+) ratio decrease in spinels] subsequently enriched by different metasomatic processes (e.g. presence of spongy clinopyroxenes; large range of enrichment in LREE, K, Rb, Sr, and P over HREE and HFSE). New geochemical and isotopic (Sr, Nd, Pb, O) data on VVP whole rock xenoliths help evaluating the nature of the geochemical enrichment recorded in the south Alpine subcontinental lithosphere. Compared to various representative world-wide ultramafic xenoliths, the VVP xenoliths show geochemicalsimilarities to those carried by alkaline basalts in tectonic settings dominated by the presence of hot spot magmatism (e.g. Canary and Kerguelen Islands, French Massif Central, Rhon, Eifel). Moreover, most of the enriched xenoliths display significant positive Nb and Ta anomalies, incompatible element ratios, and Sr-Nd-Pb and -O isotopic compositions similar to the host VVP alkaline basalts, thus with a marked OIB-HIMU signature. By contrast, among different agents proposed so-far to explain trace element enrichment in the VVP xenoliths, carbonatite-induced metasomatism does not appear as significantly responsible.Most of the depleted xenoliths are overall characterized by incompatible element patterns (e.g. troughs at Ba, Nb, and Ta) and ratios (e.g. high Rb/Nb, La/Nb, Th/Yb) likely related to a sedimentary component in their source, thus showing Sr-NdPb-O isotopic compositions falling between the field of MORB and altered oceanic crust ± pelagic sediments. Similar features have been observed for ultramafic xenoliths collected in basalts from subduction-related environments (e.g. Marianas, Philippines, and Papua Nuova Guinea). Lack of significant presence of hydrous phases (phlogopite, amphibole) in the ... Conference Object Kerguelen Islands Université de Nantes: HAL-UNIV-NANTES Kerguelen Kerguelen Islands |
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Open Polar |
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Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
spellingShingle |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Gasperini, D. Bosch, Delphine Braga, Roberto Bondi, M. Macera, Patrizia Morten, Lauro Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence |
topic_facet |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
International audience The Tertiary Veneto Volcanic Province (VVP; SE Alps, northern Italy) includes Na-rich alkali basalts and basanites hosting many spl-peridotite xenoliths (mg#>88) among the ultramafic nodules which reflect a variably depleted mantle source [e.g. strong Cr/(Cr+Al) ratio increase at a slight Mg/(Mg+Fe²+) ratio decrease in spinels] subsequently enriched by different metasomatic processes (e.g. presence of spongy clinopyroxenes; large range of enrichment in LREE, K, Rb, Sr, and P over HREE and HFSE). New geochemical and isotopic (Sr, Nd, Pb, O) data on VVP whole rock xenoliths help evaluating the nature of the geochemical enrichment recorded in the south Alpine subcontinental lithosphere. Compared to various representative world-wide ultramafic xenoliths, the VVP xenoliths show geochemicalsimilarities to those carried by alkaline basalts in tectonic settings dominated by the presence of hot spot magmatism (e.g. Canary and Kerguelen Islands, French Massif Central, Rhon, Eifel). Moreover, most of the enriched xenoliths display significant positive Nb and Ta anomalies, incompatible element ratios, and Sr-Nd-Pb and -O isotopic compositions similar to the host VVP alkaline basalts, thus with a marked OIB-HIMU signature. By contrast, among different agents proposed so-far to explain trace element enrichment in the VVP xenoliths, carbonatite-induced metasomatism does not appear as significantly responsible.Most of the depleted xenoliths are overall characterized by incompatible element patterns (e.g. troughs at Ba, Nb, and Ta) and ratios (e.g. high Rb/Nb, La/Nb, Th/Yb) likely related to a sedimentary component in their source, thus showing Sr-NdPb-O isotopic compositions falling between the field of MORB and altered oceanic crust ± pelagic sediments. Similar features have been observed for ultramafic xenoliths collected in basalts from subduction-related environments (e.g. Marianas, Philippines, and Papua Nuova Guinea). Lack of significant presence of hydrous phases (phlogopite, amphibole) in the ... |
author2 |
University of Pisa - Università di Pisa Géosciences Montpellier Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Dipartimento di Scienze della Terra e Geo-Ambientali Alma Mater Studiorum Università di Bologna Bologna (UNIBO) Dipartimento di Scienze della Terra e Geologico Ambientali CORDIS |
format |
Conference Object |
author |
Gasperini, D. Bosch, Delphine Braga, Roberto Bondi, M. Macera, Patrizia Morten, Lauro |
author_facet |
Gasperini, D. Bosch, Delphine Braga, Roberto Bondi, M. Macera, Patrizia Morten, Lauro |
author_sort |
Gasperini, D. |
title |
Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence |
title_short |
Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence |
title_full |
Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence |
title_fullStr |
Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence |
title_full_unstemmed |
Geochemical heterogeneity of South Alpine subcontinental lithosphere: mantle xenoliths evidence |
title_sort |
geochemical heterogeneity of south alpine subcontinental lithosphere: mantle xenoliths evidence |
publisher |
HAL CCSD |
publishDate |
2004 |
url |
https://hal.science/hal-03953521 |
op_coverage |
Firenze (Florence), Italy |
geographic |
Kerguelen Kerguelen Islands |
geographic_facet |
Kerguelen Kerguelen Islands |
genre |
Kerguelen Islands |
genre_facet |
Kerguelen Islands |
op_source |
Geochimical Society 32nd International Geological Congress (IGC) https://hal.science/hal-03953521 32nd International Geological Congress (IGC), CORDIS, Aug 2004, Firenze (Florence), Italy. pp.A619 |
op_relation |
hal-03953521 https://hal.science/hal-03953521 |
_version_ |
1766055390839046144 |