Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica
Abstract The central sector of Mühlig‐Hofmannfjellet (3°E/71°S) in western Dronning Maud Land (East Antarctic shield) is dominated by large intrusive bodies of predominantly orthopyroxene‐bearing quartz syenites (charnockites). Metasedimentary rocks are rare; however, two distinct areas with banded...
Published in: | Journal of Metamorphic Geology |
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crwiley:10.1111/j.1525-1314.1993.tb00181.x 2024-09-15T17:44:13+00:00 Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica BUCHER‐NURMINEN, K. OHTA, Y. 1993 http://dx.doi.org/10.1111/j.1525-1314.1993.tb00181.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1525-1314.1993.tb00181.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1525-1314.1993.tb00181.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Metamorphic Geology volume 11, issue 5, page 691-703 ISSN 0263-4929 1525-1314 journal-article 1993 crwiley https://doi.org/10.1111/j.1525-1314.1993.tb00181.x 2024-07-25T04:24:10Z Abstract The central sector of Mühlig‐Hofmannfjellet (3°E/71°S) in western Dronning Maud Land (East Antarctic shield) is dominated by large intrusive bodies of predominantly orthopyroxene‐bearing quartz syenites (charnockites). Metasedimentary rocks are rare; however, two distinct areas with banded gneiss–marble–quartzite sequences of sedimentary origin were found during the Norwegian Antarctic Research Expedition NARE 1989/90. Cordierite‐bearing metapelitic gneisses from two different localities contain the characteristic mineral assemblage: cordierite + garnet + biotite + K‐feldspar + plagioclase + quartz ± sillimanite ± spinel. Thermobarometry indicates equilibration conditions of about 650°C and 4 kbar. Associated orthopyroxene–garnet granulites, on the other hand, revealed pressures of about 8 kbar and temperatures of 750°C. The earlier granulite facies metamorphism is not well preserved in the cordierite gneisses as a result of excess K‐feldspar combined with interaction with an H 2 O‐rich fluid phase, probably released by the cooling intrusives. These two features allowed the original high‐grade K‐feldspar + garnet assemblages to recrystallize as cordierite–biotite–sillimanite gneisses, completely re‐equilibrating them. Phase relationships indicate that the younger metamorphic event occurred in the presence of a fluid phase that varied in composition between the lithologies. Article in Journal/Newspaper Antarc* Antarctic Antarctica Dronning Maud Land Wiley Online Library Journal of Metamorphic Geology 11 5 691 703 |
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Wiley Online Library |
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English |
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Abstract The central sector of Mühlig‐Hofmannfjellet (3°E/71°S) in western Dronning Maud Land (East Antarctic shield) is dominated by large intrusive bodies of predominantly orthopyroxene‐bearing quartz syenites (charnockites). Metasedimentary rocks are rare; however, two distinct areas with banded gneiss–marble–quartzite sequences of sedimentary origin were found during the Norwegian Antarctic Research Expedition NARE 1989/90. Cordierite‐bearing metapelitic gneisses from two different localities contain the characteristic mineral assemblage: cordierite + garnet + biotite + K‐feldspar + plagioclase + quartz ± sillimanite ± spinel. Thermobarometry indicates equilibration conditions of about 650°C and 4 kbar. Associated orthopyroxene–garnet granulites, on the other hand, revealed pressures of about 8 kbar and temperatures of 750°C. The earlier granulite facies metamorphism is not well preserved in the cordierite gneisses as a result of excess K‐feldspar combined with interaction with an H 2 O‐rich fluid phase, probably released by the cooling intrusives. These two features allowed the original high‐grade K‐feldspar + garnet assemblages to recrystallize as cordierite–biotite–sillimanite gneisses, completely re‐equilibrating them. Phase relationships indicate that the younger metamorphic event occurred in the presence of a fluid phase that varied in composition between the lithologies. |
format |
Article in Journal/Newspaper |
author |
BUCHER‐NURMINEN, K. OHTA, Y. |
spellingShingle |
BUCHER‐NURMINEN, K. OHTA, Y. Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica |
author_facet |
BUCHER‐NURMINEN, K. OHTA, Y. |
author_sort |
BUCHER‐NURMINEN, K. |
title |
Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica |
title_short |
Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica |
title_full |
Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica |
title_fullStr |
Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica |
title_full_unstemmed |
Granulites and garnet–cordierite gneisses from Dronning Maud Land, Antarctica |
title_sort |
granulites and garnet–cordierite gneisses from dronning maud land, antarctica |
publisher |
Wiley |
publishDate |
1993 |
url |
http://dx.doi.org/10.1111/j.1525-1314.1993.tb00181.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1525-1314.1993.tb00181.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1525-1314.1993.tb00181.x |
genre |
Antarc* Antarctic Antarctica Dronning Maud Land |
genre_facet |
Antarc* Antarctic Antarctica Dronning Maud Land |
op_source |
Journal of Metamorphic Geology volume 11, issue 5, page 691-703 ISSN 0263-4929 1525-1314 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1525-1314.1993.tb00181.x |
container_title |
Journal of Metamorphic Geology |
container_volume |
11 |
container_issue |
5 |
container_start_page |
691 |
op_container_end_page |
703 |
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1810491623530823680 |