Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin
Major- and trace-element (XRF and INAA) and Nd-isotope analyses are presented on a Jurassic bimodal association of basic greenstones and silicic metavolcanic rocks from the Black Coast, northeast Palmer Land, Antarctic Peninsula. The greenstones are divided into three sub-groups, indistinct in the f...
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ftnerc:oai:nora.nerc.ac.uk:519104 2023-05-15T13:49:34+02:00 Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin Wever, Hein E. Storey, Bryan C. 1992-04 http://nora.nerc.ac.uk/id/eprint/519104/ https://doi.org/10.1016/0040-1951(92)90429-A unknown Elsevier Wever, Hein E.; Storey, Bryan C. 1992 Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin. Tectonophysics, 205 (1-3). 239-259. https://doi.org/10.1016/0040-1951(92)90429-A <https://doi.org/10.1016/0040-1951(92)90429-A> Publication - Article PeerReviewed 1992 ftnerc https://doi.org/10.1016/0040-1951(92)90429-A 2023-02-04T19:46:02Z Major- and trace-element (XRF and INAA) and Nd-isotope analyses are presented on a Jurassic bimodal association of basic greenstones and silicic metavolcanic rocks from the Black Coast, northeast Palmer Land, Antarctic Peninsula. The greenstones are divided into three sub-groups, indistinct in the field, but which have geochemical characteristics of island arc tholeiites (group I), E-type MORB (group II), and continental arc basalts (group III). The tholeiites of group I and II have a similar range of ϵNd values (+3.7 to −1.2) and were produced from a heterogeneous, large ion lithophile element (LILE)-enriched, mantle source. The rocks of group III show a much stronger enrichment in LILE than groups I and II, and were derived from a mantle source with slightly lower ϵNd values (−2.3 to −5.0). The silicic volcanic rocks have low ϵNd values (−7.1 to −8.7) indicating a dominant crustal source, although trace element concentrations show a within-plate affinity. The origin and tectonic setting of this bimodal suite is discussed in relation to Mesozoic subduction along the proto-Pacific margin of the Antarctic Peninsula and southern South America and intra-continental extension associated with the break-up of Gondwana. It is concluded that the mafic greenstones and silicic metavolcanic rocks formed in an ensialic back-arc basin setting where, during a period of continental lithospheric attenuation, the rise of a mantle diapir may have caused widespread bimodal magmatism. The geographical extent of the Palmer Land basin is unknown at present, but it may be part of a much larger Weddell Sea or proto-Weddell Sea back-arc basin system. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Palmer Land Weddell Sea Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Antarctic Peninsula Weddell Sea Pacific Weddell Palmer Land ENVELOPE(-65.000,-65.000,-71.500,-71.500) Black Coast ENVELOPE(-62.500,-62.500,-71.500,-71.500) Tectonophysics 205 1-3 239 259 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
Major- and trace-element (XRF and INAA) and Nd-isotope analyses are presented on a Jurassic bimodal association of basic greenstones and silicic metavolcanic rocks from the Black Coast, northeast Palmer Land, Antarctic Peninsula. The greenstones are divided into three sub-groups, indistinct in the field, but which have geochemical characteristics of island arc tholeiites (group I), E-type MORB (group II), and continental arc basalts (group III). The tholeiites of group I and II have a similar range of ϵNd values (+3.7 to −1.2) and were produced from a heterogeneous, large ion lithophile element (LILE)-enriched, mantle source. The rocks of group III show a much stronger enrichment in LILE than groups I and II, and were derived from a mantle source with slightly lower ϵNd values (−2.3 to −5.0). The silicic volcanic rocks have low ϵNd values (−7.1 to −8.7) indicating a dominant crustal source, although trace element concentrations show a within-plate affinity. The origin and tectonic setting of this bimodal suite is discussed in relation to Mesozoic subduction along the proto-Pacific margin of the Antarctic Peninsula and southern South America and intra-continental extension associated with the break-up of Gondwana. It is concluded that the mafic greenstones and silicic metavolcanic rocks formed in an ensialic back-arc basin setting where, during a period of continental lithospheric attenuation, the rise of a mantle diapir may have caused widespread bimodal magmatism. The geographical extent of the Palmer Land basin is unknown at present, but it may be part of a much larger Weddell Sea or proto-Weddell Sea back-arc basin system. |
format |
Article in Journal/Newspaper |
author |
Wever, Hein E. Storey, Bryan C. |
spellingShingle |
Wever, Hein E. Storey, Bryan C. Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin |
author_facet |
Wever, Hein E. Storey, Bryan C. |
author_sort |
Wever, Hein E. |
title |
Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin |
title_short |
Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin |
title_full |
Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin |
title_fullStr |
Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin |
title_full_unstemmed |
Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin |
title_sort |
bimodal magmatism in northeast palmer land, antarctic peninsula: geochemical evidence for a jurassic ensialic back-arc basin |
publisher |
Elsevier |
publishDate |
1992 |
url |
http://nora.nerc.ac.uk/id/eprint/519104/ https://doi.org/10.1016/0040-1951(92)90429-A |
long_lat |
ENVELOPE(-65.000,-65.000,-71.500,-71.500) ENVELOPE(-62.500,-62.500,-71.500,-71.500) |
geographic |
Antarctic The Antarctic Antarctic Peninsula Weddell Sea Pacific Weddell Palmer Land Black Coast |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Weddell Sea Pacific Weddell Palmer Land Black Coast |
genre |
Antarc* Antarctic Antarctic Peninsula Palmer Land Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Palmer Land Weddell Sea |
op_relation |
Wever, Hein E.; Storey, Bryan C. 1992 Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin. Tectonophysics, 205 (1-3). 239-259. https://doi.org/10.1016/0040-1951(92)90429-A <https://doi.org/10.1016/0040-1951(92)90429-A> |
op_doi |
https://doi.org/10.1016/0040-1951(92)90429-A |
container_title |
Tectonophysics |
container_volume |
205 |
container_issue |
1-3 |
container_start_page |
239 |
op_container_end_page |
259 |
_version_ |
1766251742872207360 |