Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting
Syenogranites and monzogranites of Edward VII Peninsula, Marie Byrd Land, represent magmatism associated with continental rifting and the separation of New Zealand from W Antarctica in the mid-Cretaceous. These coarse-grained, leucocratic, subsolvus biotite granites occur as five small plutons cutti...
Published in: | Earth and Environmental Science Transactions of the Royal Society of Edinburgh |
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Royal Society of Edinburgh
1992
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Online Access: | http://nora.nerc.ac.uk/id/eprint/519103/ https://doi.org/10.1017/S0263593300007963 |
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ftnerc:oai:nora.nerc.ac.uk:519103 2023-05-15T13:49:34+02:00 Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting Weaver, S.D. Adams, C.J. Pankhurst, R.J. Gibson, I.L. 1992-01 http://nora.nerc.ac.uk/id/eprint/519103/ https://doi.org/10.1017/S0263593300007963 unknown Royal Society of Edinburgh Weaver, S.D.; Adams, C.J.; Pankhurst, R.J.; Gibson, I.L. 1992 Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting. Transactions of the Royal Society of Edinburgh: Earth Sciences, 83 (1-2). 281-290. https://doi.org/10.1017/S0263593300007963 <https://doi.org/10.1017/S0263593300007963> Earth Sciences Publication - Article PeerReviewed 1992 ftnerc https://doi.org/10.1017/S0263593300007963 2023-02-04T19:46:02Z Syenogranites and monzogranites of Edward VII Peninsula, Marie Byrd Land, represent magmatism associated with continental rifting and the separation of New Zealand from W Antarctica in the mid-Cretaceous. These coarse-grained, leucocratic, subsolvus biotite granites occur as five small plutons cutting Lower Palaeozoic metasediments. Petrographic features include the predominance of microcline perthite over albite, bipyramidal smoky quartz, red-brown biotite and accessory ilmenite, zircon, apatite, monazite and fluorite. Enclaves are absent and miarolitic cavites are rare.The granites are a weakly peraluminous, potassic, and highly fractionated suite with high concentrations of Rb, Nb, Y, HREE and F in the most evolved compositions. REE patterns vary from LREE-enriched (CeN/YbN = 8·4), to flat REE patterns (CeN/YbN = 1·1) with large negative Eu anomalies (Eu/Eu* = 0·02). Initial 87Sr/86Sr ratios are 0·7116-0·7206 and initial εNd values are −5·5 to −7·7. Generalised fractionation trends for the suite are explicable in terms of the modal mineralogy. Monazite crystallisation exerted a predominant control on LREE concentrations.The geochemistry of the Edward VII Peninsula granites suggests an infracrustal I-type source, and regionally available Devonian-Carboniferous I-type granodiorites and tonalites satisfy the isotopic constraints. The granites classify as A-type (preferred term A-subtype) and Within-Plate Granites on standard diagrams, but the least fractionated rocks clearly indicate the I-type, Volcanic Arc Granite geochemical signatures of their inferred crustal sources. Article in Journal/Newspaper Antarc* Antarctic Antarctica Marie Byrd Land W. Antarctica Natural Environment Research Council: NERC Open Research Archive Antarctic New Zealand Byrd Marie Byrd Land ENVELOPE(-130.000,-130.000,-78.000,-78.000) Edward VII Peninsula ENVELOPE(-155.000,-155.000,-77.667,-77.667) Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83 1-2 281 290 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Weaver, S.D. Adams, C.J. Pankhurst, R.J. Gibson, I.L. Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting |
topic_facet |
Earth Sciences |
description |
Syenogranites and monzogranites of Edward VII Peninsula, Marie Byrd Land, represent magmatism associated with continental rifting and the separation of New Zealand from W Antarctica in the mid-Cretaceous. These coarse-grained, leucocratic, subsolvus biotite granites occur as five small plutons cutting Lower Palaeozoic metasediments. Petrographic features include the predominance of microcline perthite over albite, bipyramidal smoky quartz, red-brown biotite and accessory ilmenite, zircon, apatite, monazite and fluorite. Enclaves are absent and miarolitic cavites are rare.The granites are a weakly peraluminous, potassic, and highly fractionated suite with high concentrations of Rb, Nb, Y, HREE and F in the most evolved compositions. REE patterns vary from LREE-enriched (CeN/YbN = 8·4), to flat REE patterns (CeN/YbN = 1·1) with large negative Eu anomalies (Eu/Eu* = 0·02). Initial 87Sr/86Sr ratios are 0·7116-0·7206 and initial εNd values are −5·5 to −7·7. Generalised fractionation trends for the suite are explicable in terms of the modal mineralogy. Monazite crystallisation exerted a predominant control on LREE concentrations.The geochemistry of the Edward VII Peninsula granites suggests an infracrustal I-type source, and regionally available Devonian-Carboniferous I-type granodiorites and tonalites satisfy the isotopic constraints. The granites classify as A-type (preferred term A-subtype) and Within-Plate Granites on standard diagrams, but the least fractionated rocks clearly indicate the I-type, Volcanic Arc Granite geochemical signatures of their inferred crustal sources. |
format |
Article in Journal/Newspaper |
author |
Weaver, S.D. Adams, C.J. Pankhurst, R.J. Gibson, I.L. |
author_facet |
Weaver, S.D. Adams, C.J. Pankhurst, R.J. Gibson, I.L. |
author_sort |
Weaver, S.D. |
title |
Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting |
title_short |
Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting |
title_full |
Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting |
title_fullStr |
Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting |
title_full_unstemmed |
Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting |
title_sort |
granites of edward vii peninsula, marie byrd land: anorogenic magmatism related to antarctic-new zealand rifting |
publisher |
Royal Society of Edinburgh |
publishDate |
1992 |
url |
http://nora.nerc.ac.uk/id/eprint/519103/ https://doi.org/10.1017/S0263593300007963 |
long_lat |
ENVELOPE(-130.000,-130.000,-78.000,-78.000) ENVELOPE(-155.000,-155.000,-77.667,-77.667) |
geographic |
Antarctic New Zealand Byrd Marie Byrd Land Edward VII Peninsula |
geographic_facet |
Antarctic New Zealand Byrd Marie Byrd Land Edward VII Peninsula |
genre |
Antarc* Antarctic Antarctica Marie Byrd Land W. Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Marie Byrd Land W. Antarctica |
op_relation |
Weaver, S.D.; Adams, C.J.; Pankhurst, R.J.; Gibson, I.L. 1992 Granites of Edward VII Peninsula, Marie Byrd Land: anorogenic magmatism related to Antarctic-New Zealand rifting. Transactions of the Royal Society of Edinburgh: Earth Sciences, 83 (1-2). 281-290. https://doi.org/10.1017/S0263593300007963 <https://doi.org/10.1017/S0263593300007963> |
op_doi |
https://doi.org/10.1017/S0263593300007963 |
container_title |
Earth and Environmental Science Transactions of the Royal Society of Edinburgh |
container_volume |
83 |
container_issue |
1-2 |
container_start_page |
281 |
op_container_end_page |
290 |
_version_ |
1766251742677172224 |