Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts
The Amsterdam-St. Paul (ASP) Plateau is a recent (≤5 Ma) volcanic rise constructed along the Southeast Indian Ridge (SEIR) by the combined effects of a relatively small mantle plume and a mid-oceanic ridge. The Amsterdam and St. Paul islands are located 100 km away from each other and formed during...
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ftunivbruxelles:oai:dipot.ulb.ac.be:2013/123533 2023-05-15T13:53:32+02:00 Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts Doucet, Sonia Weis, Dominique Scoates, James Debaille, Vinciane Giret, André 2004 1 full-text file(s): application/pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/123533 https://dipot.ulb.ac.be/dspace/bitstream/2013/123533/4/56c1eec1-53f3-40cc-b76a-49dde45a4d33.txt en eng uri/info:doi/10.1016/S0012-821X(03)00636-8 uri/info:scp/0942278101 local/VX-004894 https://dipot.ulb.ac.be/dspace/bitstream/2013/123533/4/56c1eec1-53f3-40cc-b76a-49dde45a4d33.txt http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/123533 1 full-text file(s): info:eu-repo/semantics/restrictedAccess Earth and planetary science letters, 218 (1-2 Sciences de la terre et du cosmos info:eu-repo/semantics/article info:ulb-repo/semantics/articlePeerReview info:ulb-repo/semantics/openurl/article 2004 ftunivbruxelles 2022-06-12T21:16:50Z The Amsterdam-St. Paul (ASP) Plateau is a recent (≤5 Ma) volcanic rise constructed along the Southeast Indian Ridge (SEIR) by the combined effects of a relatively small mantle plume and a mid-oceanic ridge. The Amsterdam and St. Paul islands are located 100 km away from each other and formed during the last 0.4 Myr; they are the only subaerial features of the ASP Plateau and the two islands are structurally separated by the presence of a SW-NE transform fault. New geochemical analyses and Hf-Pb-Sr-Nd isotopic compositions of 20 basaltic rocks from Amsterdam and St. Paul Islands constrain the nature and origin of the sources involved in the genesis of the ASP hotspot basalts. Aphyric basalts from St. Paul are mildly alkalic, incompatible element-enriched and highly fractionated; they are distinct from the tholeiitic basalts from Amsterdam, from the recently discovered Boomerang active seamount on the ASP Plateau, and from the Kerguelen Archipelago basalts on the Antarctic Plate. The St. Paul and Amsterdam basalts have very limited isotopic variations with distinct 206Pb/ 204Pb, 207Pb/204Pb, 208Pb/ 204Pb, and 176Hf/177Hf isotopic compositions (19.08±0.07, 15.61±0.02, 39.45±0.12, 0.28313±0.00003 for Amsterdam, and 18.70±0.08, 15.56±0.01, 38.87±0.05, 0.28306±0.00002 for St. Paul, respectively) that are not compatible with any direct contribution of the enriched Kerguelen plume end-member. Pb-Nd-Sr isotopic compositions of the St. Paul basalts appear consistent with simple binary mixtures between heterogeneous ambient upper mantle and a highly radiogenic Pb plume component (the ASP plume end-member), particularly expressed in the isotopic compositions of the Amsterdam basalts. However, the Amsterdam basalts have distinctly higher εHf than the St. Paul basalts (+13 and +10, respectively) for a given εNd (+4) and are inconsistent with such a simple binary mixing scenario. Isotopic systematics in the Amsterdam and St. Paul basalts indicate that the Amsterdam and St. Paul volcanoes were formed by sampling isotopically ... Article in Journal/Newspaper Antarc* Antarctic Paul Islands DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) Antarctic Indian Kerguelen Paul Islands ENVELOPE(-63.716,-63.716,-64.283,-64.283) Southeast Indian Ridge ENVELOPE(110.000,110.000,-50.000,-50.000) The Antarctic |
institution |
Open Polar |
collection |
DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
op_collection_id |
ftunivbruxelles |
language |
English |
topic |
Sciences de la terre et du cosmos |
spellingShingle |
Sciences de la terre et du cosmos Doucet, Sonia Weis, Dominique Scoates, James Debaille, Vinciane Giret, André Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts |
topic_facet |
Sciences de la terre et du cosmos |
description |
The Amsterdam-St. Paul (ASP) Plateau is a recent (≤5 Ma) volcanic rise constructed along the Southeast Indian Ridge (SEIR) by the combined effects of a relatively small mantle plume and a mid-oceanic ridge. The Amsterdam and St. Paul islands are located 100 km away from each other and formed during the last 0.4 Myr; they are the only subaerial features of the ASP Plateau and the two islands are structurally separated by the presence of a SW-NE transform fault. New geochemical analyses and Hf-Pb-Sr-Nd isotopic compositions of 20 basaltic rocks from Amsterdam and St. Paul Islands constrain the nature and origin of the sources involved in the genesis of the ASP hotspot basalts. Aphyric basalts from St. Paul are mildly alkalic, incompatible element-enriched and highly fractionated; they are distinct from the tholeiitic basalts from Amsterdam, from the recently discovered Boomerang active seamount on the ASP Plateau, and from the Kerguelen Archipelago basalts on the Antarctic Plate. The St. Paul and Amsterdam basalts have very limited isotopic variations with distinct 206Pb/ 204Pb, 207Pb/204Pb, 208Pb/ 204Pb, and 176Hf/177Hf isotopic compositions (19.08±0.07, 15.61±0.02, 39.45±0.12, 0.28313±0.00003 for Amsterdam, and 18.70±0.08, 15.56±0.01, 38.87±0.05, 0.28306±0.00002 for St. Paul, respectively) that are not compatible with any direct contribution of the enriched Kerguelen plume end-member. Pb-Nd-Sr isotopic compositions of the St. Paul basalts appear consistent with simple binary mixtures between heterogeneous ambient upper mantle and a highly radiogenic Pb plume component (the ASP plume end-member), particularly expressed in the isotopic compositions of the Amsterdam basalts. However, the Amsterdam basalts have distinctly higher εHf than the St. Paul basalts (+13 and +10, respectively) for a given εNd (+4) and are inconsistent with such a simple binary mixing scenario. Isotopic systematics in the Amsterdam and St. Paul basalts indicate that the Amsterdam and St. Paul volcanoes were formed by sampling isotopically ... |
format |
Article in Journal/Newspaper |
author |
Doucet, Sonia Weis, Dominique Scoates, James Debaille, Vinciane Giret, André |
author_facet |
Doucet, Sonia Weis, Dominique Scoates, James Debaille, Vinciane Giret, André |
author_sort |
Doucet, Sonia |
title |
Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts |
title_short |
Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts |
title_full |
Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts |
title_fullStr |
Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts |
title_full_unstemmed |
Geochemical and Hf-Pb-Sr-Nd isotopic constraints on the origin of the Amsterdam-St. Paul (Indian Ocean) hotspot basalts |
title_sort |
geochemical and hf-pb-sr-nd isotopic constraints on the origin of the amsterdam-st. paul (indian ocean) hotspot basalts |
publishDate |
2004 |
url |
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/123533 https://dipot.ulb.ac.be/dspace/bitstream/2013/123533/4/56c1eec1-53f3-40cc-b76a-49dde45a4d33.txt |
long_lat |
ENVELOPE(-63.716,-63.716,-64.283,-64.283) ENVELOPE(110.000,110.000,-50.000,-50.000) |
geographic |
Antarctic Indian Kerguelen Paul Islands Southeast Indian Ridge The Antarctic |
geographic_facet |
Antarctic Indian Kerguelen Paul Islands Southeast Indian Ridge The Antarctic |
genre |
Antarc* Antarctic Paul Islands |
genre_facet |
Antarc* Antarctic Paul Islands |
op_source |
Earth and planetary science letters, 218 (1-2 |
op_relation |
uri/info:doi/10.1016/S0012-821X(03)00636-8 uri/info:scp/0942278101 local/VX-004894 https://dipot.ulb.ac.be/dspace/bitstream/2013/123533/4/56c1eec1-53f3-40cc-b76a-49dde45a4d33.txt http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/123533 |
op_rights |
1 full-text file(s): info:eu-repo/semantics/restrictedAccess |
_version_ |
1766258716539092992 |