Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism
Several spinel peridotite xenoliths from Spitsbergen have Sr-Nd isotopic compositions that plot to the right of the 'mantle array' defined by oceanic basalts and the DM end-member (depleted mantle, with low 87 Sr/86 Sr and high 143Nd/144 Nd). These xenoliths also show strong fractionation...
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ftunivbruxelles:oai:dipot.ulb.ac.be:2013/198714 2023-05-15T18:50:54+02:00 Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism Ionov, Dimitri Mukasa, Samuel S.B. Bodinier, Jean-Louis 2002-12 No full-text files http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/198714 en eng uri/info:scp/0036927638 http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/198714 Journal of Petrology, 43 (12 Géographie physique Pétrologie Géochimie Lithospheric mantle Metasomatism Radiogenic isotopes Spitsbergen Theoretical modelling info:eu-repo/semantics/article info:ulb-repo/semantics/articlePeerReview info:ulb-repo/semantics/openurl/article 2002 ftunivbruxelles 2022-06-12T20:34:28Z Several spinel peridotite xenoliths from Spitsbergen have Sr-Nd isotopic compositions that plot to the right of the 'mantle array' defined by oceanic basalts and the DM end-member (depleted mantle, with low 87 Sr/86 Sr and high 143Nd/144 Nd). These xenoliths also show strong fractionation of elements with similar compatibility (e.g. high La/Ce), which cannot be produced by simple mixing of light rare earth element-depleted peridotites with ocean island basalt-type or other enriched mantle melts. Numerical simulations of porous melt flow in spinel peridotites applied to Sr-Nd isotope compositions indicate that these features of the Spitsbergen peridotites can be explained by chemical fractionation during metasomatism in the mantle. 'Chromatographic' effects of melt percolation create a transient zone where the host depleted peridotites have experienced enrichment in Sr (with a radiogenic isotope composition) but not in Nd, thus producing Sr-Nd decoupling mainly controlled by partition coefficients and abundances of Sr and Nd in the melt and the peridotite. Therefore, Sr-Nd isotope decoupling, earlier reported for some other mantle peridotites worldwide, may be a signature of metasomatic processes rather than a source-related characteristic, contrary to models that invoke mixing with hypothetical Sr-rich fluids derived from subducted oceanic lithosphere. Pb isotope compositions of the Spitsbergen xenoliths do not appear to be consistently affected by the metasomatism. SCOPUS: ar.j info:eu-repo/semantics/published Article in Journal/Newspaper Ocean Island Spitsbergen DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
institution |
Open Polar |
collection |
DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
op_collection_id |
ftunivbruxelles |
language |
English |
topic |
Géographie physique Pétrologie Géochimie Lithospheric mantle Metasomatism Radiogenic isotopes Spitsbergen Theoretical modelling |
spellingShingle |
Géographie physique Pétrologie Géochimie Lithospheric mantle Metasomatism Radiogenic isotopes Spitsbergen Theoretical modelling Ionov, Dimitri Mukasa, Samuel S.B. Bodinier, Jean-Louis Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism |
topic_facet |
Géographie physique Pétrologie Géochimie Lithospheric mantle Metasomatism Radiogenic isotopes Spitsbergen Theoretical modelling |
description |
Several spinel peridotite xenoliths from Spitsbergen have Sr-Nd isotopic compositions that plot to the right of the 'mantle array' defined by oceanic basalts and the DM end-member (depleted mantle, with low 87 Sr/86 Sr and high 143Nd/144 Nd). These xenoliths also show strong fractionation of elements with similar compatibility (e.g. high La/Ce), which cannot be produced by simple mixing of light rare earth element-depleted peridotites with ocean island basalt-type or other enriched mantle melts. Numerical simulations of porous melt flow in spinel peridotites applied to Sr-Nd isotope compositions indicate that these features of the Spitsbergen peridotites can be explained by chemical fractionation during metasomatism in the mantle. 'Chromatographic' effects of melt percolation create a transient zone where the host depleted peridotites have experienced enrichment in Sr (with a radiogenic isotope composition) but not in Nd, thus producing Sr-Nd decoupling mainly controlled by partition coefficients and abundances of Sr and Nd in the melt and the peridotite. Therefore, Sr-Nd isotope decoupling, earlier reported for some other mantle peridotites worldwide, may be a signature of metasomatic processes rather than a source-related characteristic, contrary to models that invoke mixing with hypothetical Sr-rich fluids derived from subducted oceanic lithosphere. Pb isotope compositions of the Spitsbergen xenoliths do not appear to be consistently affected by the metasomatism. SCOPUS: ar.j info:eu-repo/semantics/published |
format |
Article in Journal/Newspaper |
author |
Ionov, Dimitri Mukasa, Samuel S.B. Bodinier, Jean-Louis |
author_facet |
Ionov, Dimitri Mukasa, Samuel S.B. Bodinier, Jean-Louis |
author_sort |
Ionov, Dimitri |
title |
Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism |
title_short |
Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism |
title_full |
Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism |
title_fullStr |
Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism |
title_full_unstemmed |
Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism |
title_sort |
sr-nd-pb isotopic compositions of peridotite xenoliths from spitsbergen: numerical modelling indicates sr-nd decoupling in the mantle by melt percolation metasomatism |
publishDate |
2002 |
url |
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/198714 |
genre |
Ocean Island Spitsbergen |
genre_facet |
Ocean Island Spitsbergen |
op_source |
Journal of Petrology, 43 (12 |
op_relation |
uri/info:scp/0036927638 http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/198714 |
_version_ |
1766244655439020032 |