The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere
Major element, trace element and Sr–Nd–Pb isotopic data of volcanic rocks from the Madeira Archipelago (eastern North Atlantic) and seamounts of the Madeira hotspot track (Ampère, Coral Patch and Ormonde) are presented in this study. Although the Sr and Nd isotopic ratios are similar to those in nor...
Published in: | Earth and Planetary Science Letters |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2000
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/1646/ https://oceanrep.geomar.de/id/eprint/1646/1/Geldmacher.pdf https://oceanrep.geomar.de/id/eprint/1646/7/Geldmacher_Corrigendum.pdf https://doi.org/10.1016/S0012-821X(00)00266-1 |
id |
ftoceanrep:oai:oceanrep.geomar.de:1646 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:1646 2024-09-30T14:39:28+00:00 The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere Geldmacher, Jörg Hoernle, Kaj 2000 text https://oceanrep.geomar.de/id/eprint/1646/ https://oceanrep.geomar.de/id/eprint/1646/1/Geldmacher.pdf https://oceanrep.geomar.de/id/eprint/1646/7/Geldmacher_Corrigendum.pdf https://doi.org/10.1016/S0012-821X(00)00266-1 en eng Elsevier https://oceanrep.geomar.de/id/eprint/1646/1/Geldmacher.pdf https://oceanrep.geomar.de/id/eprint/1646/7/Geldmacher_Corrigendum.pdf Geldmacher, J. and Hoernle, K. (2000) The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere. Earth and Planetary Science Letters, 183 (1-2). pp. 73-92. DOI 10.1016/S0012-821X(00)00266-1 <https://doi.org/10.1016/S0012-821X%2800%2900266-1>. doi:10.1016/S0012-821X(00)00266-1 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2000 ftoceanrep https://doi.org/10.1016/S0012-821X(00)00266-1 2024-09-04T05:04:40Z Major element, trace element and Sr–Nd–Pb isotopic data of volcanic rocks from the Madeira Archipelago (eastern North Atlantic) and seamounts of the Madeira hotspot track (Ampère, Coral Patch and Ormonde) are presented in this study. Although the Sr and Nd isotopic ratios are similar to those in normal mid ocean ridge basalt, the incompatible element signatures and Pb isotopic compositions (206Pb/204Pb=18.7–19.8) show similarities to the high time integrated 238U/204Pb mantle component. On the 206Pb/204Pb versus 207Pb/204Pb isotope diagram, all samples plot below the Northern Hemisphere reference line (Δ 7/4=−1.0 to −7.2) and form a 430 Ma isochron. The Pb, as well as Sm–Nd, isotope data are consistent with the presence of recycled Paleozoic (≤500 Ma) oceanic crust in the Madeira source. Variations in major element and isotopic geochemistry (e.g. positive correlation between SiO2 and FeOT with Pb isotope ratios in primitive samples) point to a heterogeneous plume source containing upper (primarily hydrothermally altered basaltic) and lower (primarily unaltered gabbroic) ocean crust and lithospheric mantle. The more fertile basaltic crustal component is preferentially sampled during the shield stage of volcanism, whereas the more depleted lower crust and lithospheric mantle components are preferentially sampled during the post-erosional stage. We propose that plume material becomes progressively depleted through melt extraction as it spreads out along the base of the lithosphere in the direction of plate motion. A systematic decrease in 143Nd/144Nd and increase in 207Pb/204Pb isotopic ratios with increasing age along the hotspot track and proximity to the Iberian peninsula are attributed to increased contamination by continental lithosphere. Article in Journal/Newspaper North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Earth and Planetary Science Letters 183 1-2 73 92 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Major element, trace element and Sr–Nd–Pb isotopic data of volcanic rocks from the Madeira Archipelago (eastern North Atlantic) and seamounts of the Madeira hotspot track (Ampère, Coral Patch and Ormonde) are presented in this study. Although the Sr and Nd isotopic ratios are similar to those in normal mid ocean ridge basalt, the incompatible element signatures and Pb isotopic compositions (206Pb/204Pb=18.7–19.8) show similarities to the high time integrated 238U/204Pb mantle component. On the 206Pb/204Pb versus 207Pb/204Pb isotope diagram, all samples plot below the Northern Hemisphere reference line (Δ 7/4=−1.0 to −7.2) and form a 430 Ma isochron. The Pb, as well as Sm–Nd, isotope data are consistent with the presence of recycled Paleozoic (≤500 Ma) oceanic crust in the Madeira source. Variations in major element and isotopic geochemistry (e.g. positive correlation between SiO2 and FeOT with Pb isotope ratios in primitive samples) point to a heterogeneous plume source containing upper (primarily hydrothermally altered basaltic) and lower (primarily unaltered gabbroic) ocean crust and lithospheric mantle. The more fertile basaltic crustal component is preferentially sampled during the shield stage of volcanism, whereas the more depleted lower crust and lithospheric mantle components are preferentially sampled during the post-erosional stage. We propose that plume material becomes progressively depleted through melt extraction as it spreads out along the base of the lithosphere in the direction of plate motion. A systematic decrease in 143Nd/144Nd and increase in 207Pb/204Pb isotopic ratios with increasing age along the hotspot track and proximity to the Iberian peninsula are attributed to increased contamination by continental lithosphere. |
format |
Article in Journal/Newspaper |
author |
Geldmacher, Jörg Hoernle, Kaj |
spellingShingle |
Geldmacher, Jörg Hoernle, Kaj The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere |
author_facet |
Geldmacher, Jörg Hoernle, Kaj |
author_sort |
Geldmacher, Jörg |
title |
The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere |
title_short |
The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere |
title_full |
The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere |
title_fullStr |
The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere |
title_full_unstemmed |
The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere |
title_sort |
72 ma geochemical evolution of the madeira hotspot (eastern north atlantic): recycling of paleozoic (<500 ma) oceanic lithosphere |
publisher |
Elsevier |
publishDate |
2000 |
url |
https://oceanrep.geomar.de/id/eprint/1646/ https://oceanrep.geomar.de/id/eprint/1646/1/Geldmacher.pdf https://oceanrep.geomar.de/id/eprint/1646/7/Geldmacher_Corrigendum.pdf https://doi.org/10.1016/S0012-821X(00)00266-1 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/1646/1/Geldmacher.pdf https://oceanrep.geomar.de/id/eprint/1646/7/Geldmacher_Corrigendum.pdf Geldmacher, J. and Hoernle, K. (2000) The 72 Ma geochemical evolution of the Madeira hotspot (eastern North Atlantic): recycling of Paleozoic (<500 Ma) oceanic lithosphere. Earth and Planetary Science Letters, 183 (1-2). pp. 73-92. DOI 10.1016/S0012-821X(00)00266-1 <https://doi.org/10.1016/S0012-821X%2800%2900266-1>. doi:10.1016/S0012-821X(00)00266-1 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/S0012-821X(00)00266-1 |
container_title |
Earth and Planetary Science Letters |
container_volume |
183 |
container_issue |
1-2 |
container_start_page |
73 |
op_container_end_page |
92 |
_version_ |
1811642072063541248 |