Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume
The thick, >20 km, crust of the Kerguelen Archipelago formed as the tectonic setting of the Kerguelen Plume changed from an oceanic ridge-centered location at 43 Ma to its present location beneath the Antarctic plate. The uppermost crust is dominantly flood basalt with a thickness of up to 10 km....
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ftunivbruxelles:oai:dipot.ulb.ac.be:2013/166687 2023-05-15T13:46:28+02:00 Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume Yang, Huai-Jen Frey, Frederic Weis, Dominique Giret, André Pyle, Doug Michon, Gilbert 1998-04 No full-text files http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/166687 en eng uri/info:scp/0031825282 http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/166687 Journal of Petrology, 39 (4 Géographie physique Pétrologie Géochimie Basalt petrogenesis Buffered differentiation Kerguelen Plume Ocean island basalt Plume-lithosphere interaction info:eu-repo/semantics/article info:ulb-repo/semantics/articlePeerReview info:ulb-repo/semantics/openurl/article 1998 ftunivbruxelles 2022-06-12T21:03:29Z The thick, >20 km, crust of the Kerguelen Archipelago formed as the tectonic setting of the Kerguelen Plume changed from an oceanic ridge-centered location at 43 Ma to its present location beneath the Antarctic plate. The uppermost crust is dominantly flood basalt with a thickness of up to 10 km. Inverse isochron 40Ar/39Ar ages for upper and lower lavas in a 630 m section of basalt flows from Mont Bureau are 30.4 and 29.0 Ma; Re-Os isotopic systematics are consistent with this age. Most of the lavas in two stratigraphic sections (Mont Bureau and Mont Rabouillère) from the northern part of the archipelago have Sr, Nd and Pb isotopic characteristics similar to the youngest (Upper Miocene to Pleistocene) lavas erupted in the southeast part of the archipelago, i.e. initial 87Sr/86Sr >0.7050, 143Nd/144Nd <0.5127 and 206Pb/204Pb <18.3. The dominance of this isotopic signature in archipelago lavas for 30 my and its presence in ∼40 Ma gabbros is consistent with the previous interpretation that these are isotopic characteristics of the Kerguelen Plum. Although this component occurs in high (>10%) MgO alkalic lavas in the Southeast Province of the archipelago, in these northern sections it is confined to transitional lavas with <6% MgO. A low plume flux and extensive crustal processing are inferred. In contrast to the plume-derived lavas, ∼15% of the flood basalts in these sections have lower initial 87Sr/86Sr (to 0.70396), higher 143Nd/144Nd (to 0.51289), and they have some compositional characteristics of plagioclase-rich cumulates, i.e. high Sr/Nd and Ba/Th and positive Eu anomalies. However, plagioclase phenocrysts are absent in most of these lavas; therefore a plagioclase-rich component is required in their source. A plausible interpretation is that plagioclase-rich cumulates formed in the lower oceanic crust when the Southeast Indian Ridge was coincident with the plume at ∼43 Ma; subsequently these cumulates were melted by the plume and the melts contributed to a small proportion of the flood ... Article in Journal/Newspaper Antarc* Antarctic Ocean Island DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) Antarctic Indian Kerguelen 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 |
Géographie physique Pétrologie Géochimie Basalt petrogenesis Buffered differentiation Kerguelen Plume Ocean island basalt Plume-lithosphere interaction |
spellingShingle |
Géographie physique Pétrologie Géochimie Basalt petrogenesis Buffered differentiation Kerguelen Plume Ocean island basalt Plume-lithosphere interaction Yang, Huai-Jen Frey, Frederic Weis, Dominique Giret, André Pyle, Doug Michon, Gilbert Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume |
topic_facet |
Géographie physique Pétrologie Géochimie Basalt petrogenesis Buffered differentiation Kerguelen Plume Ocean island basalt Plume-lithosphere interaction |
description |
The thick, >20 km, crust of the Kerguelen Archipelago formed as the tectonic setting of the Kerguelen Plume changed from an oceanic ridge-centered location at 43 Ma to its present location beneath the Antarctic plate. The uppermost crust is dominantly flood basalt with a thickness of up to 10 km. Inverse isochron 40Ar/39Ar ages for upper and lower lavas in a 630 m section of basalt flows from Mont Bureau are 30.4 and 29.0 Ma; Re-Os isotopic systematics are consistent with this age. Most of the lavas in two stratigraphic sections (Mont Bureau and Mont Rabouillère) from the northern part of the archipelago have Sr, Nd and Pb isotopic characteristics similar to the youngest (Upper Miocene to Pleistocene) lavas erupted in the southeast part of the archipelago, i.e. initial 87Sr/86Sr >0.7050, 143Nd/144Nd <0.5127 and 206Pb/204Pb <18.3. The dominance of this isotopic signature in archipelago lavas for 30 my and its presence in ∼40 Ma gabbros is consistent with the previous interpretation that these are isotopic characteristics of the Kerguelen Plum. Although this component occurs in high (>10%) MgO alkalic lavas in the Southeast Province of the archipelago, in these northern sections it is confined to transitional lavas with <6% MgO. A low plume flux and extensive crustal processing are inferred. In contrast to the plume-derived lavas, ∼15% of the flood basalts in these sections have lower initial 87Sr/86Sr (to 0.70396), higher 143Nd/144Nd (to 0.51289), and they have some compositional characteristics of plagioclase-rich cumulates, i.e. high Sr/Nd and Ba/Th and positive Eu anomalies. However, plagioclase phenocrysts are absent in most of these lavas; therefore a plagioclase-rich component is required in their source. A plausible interpretation is that plagioclase-rich cumulates formed in the lower oceanic crust when the Southeast Indian Ridge was coincident with the plume at ∼43 Ma; subsequently these cumulates were melted by the plume and the melts contributed to a small proportion of the flood ... |
format |
Article in Journal/Newspaper |
author |
Yang, Huai-Jen Frey, Frederic Weis, Dominique Giret, André Pyle, Doug Michon, Gilbert |
author_facet |
Yang, Huai-Jen Frey, Frederic Weis, Dominique Giret, André Pyle, Doug Michon, Gilbert |
author_sort |
Yang, Huai-Jen |
title |
Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume |
title_short |
Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume |
title_full |
Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume |
title_fullStr |
Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume |
title_full_unstemmed |
Petrogenesis of the flood basalts forming the northern Kerguelen Archipelago: Implications for the Kerguelen Plume |
title_sort |
petrogenesis of the flood basalts forming the northern kerguelen archipelago: implications for the kerguelen plume |
publishDate |
1998 |
url |
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/166687 |
long_lat |
ENVELOPE(110.000,110.000,-50.000,-50.000) |
geographic |
Antarctic Indian Kerguelen Southeast Indian Ridge The Antarctic |
geographic_facet |
Antarctic Indian Kerguelen Southeast Indian Ridge The Antarctic |
genre |
Antarc* Antarctic Ocean Island |
genre_facet |
Antarc* Antarctic Ocean Island |
op_source |
Journal of Petrology, 39 (4 |
op_relation |
uri/info:scp/0031825282 http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/166687 |
_version_ |
1766243099751743488 |