Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust
Metapelitic migmatites at Brattstrand Bluffs, East Antarctica, preserve granulite assemblages and a complex deformational history. Crystallized granitic melt accounts for ∼25% of exposed rocks, and was produced by biotite dehydration-melting reactions in the host metapelite. Variable degrees of melt...
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fthighwire:oai:open-archive.highwire.org:petrology:37/2/395 2023-05-15T13:59:50+02:00 Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust FITZSIMONS, I. C. W. 1996-04-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/37/2/395 https://doi.org/10.1093/petrology/37.2.395 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/37/2/395 http://dx.doi.org/10.1093/petrology/37.2.395 Copyright (C) 1996, Oxford University Press Articles TEXT 1996 fthighwire https://doi.org/10.1093/petrology/37.2.395 2013-05-27T02:59:59Z Metapelitic migmatites at Brattstrand Bluffs, East Antarctica, preserve granulite assemblages and a complex deformational history. Crystallized granitic melt accounts for ∼25% of exposed rocks, and was produced by biotite dehydration-melting reactions in the host metapelite. Variable degrees of melt production and extraction resulted in a range of bulk compositions in the residual metapelite, from quartz-rich migmatites to restitic quartz-absent pelite. Decompressional reaction textures indicate ∼11 km of exhumation after peak metamorphism at P—T conditions of ∼6 kbar and ∼860�C Decompression occurred during a single cycle of partial melting and melt crystallization at ∼500 Ma, and was synchronous with tectonic unroofing of the Brattstrand Bluffs migmatites along ductile shear zones. Exhumation has been proposed as a cause of dehydration melting in the Himalaya and elsewhere, but melting at Brattstrand Bluffs was ultimately driven by the tectonic perturbation and subsequent thermal relaxation responsible for high metamorphic temperatures. Exhumation did not drive melting reactions, but it is likely that the presence of melt focused deformation in the migmatites and thus promoted exhumation. Text Antarc* Antarctica East Antarctica HighWire Press (Stanford University) East Antarctica Brattstrand Bluffs ENVELOPE(77.020,77.020,-69.208,-69.208) Journal of Petrology 37 2 395 414 |
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HighWire Press (Stanford University) |
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English |
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Articles |
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Articles FITZSIMONS, I. C. W. Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust |
topic_facet |
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description |
Metapelitic migmatites at Brattstrand Bluffs, East Antarctica, preserve granulite assemblages and a complex deformational history. Crystallized granitic melt accounts for ∼25% of exposed rocks, and was produced by biotite dehydration-melting reactions in the host metapelite. Variable degrees of melt production and extraction resulted in a range of bulk compositions in the residual metapelite, from quartz-rich migmatites to restitic quartz-absent pelite. Decompressional reaction textures indicate ∼11 km of exhumation after peak metamorphism at P—T conditions of ∼6 kbar and ∼860�C Decompression occurred during a single cycle of partial melting and melt crystallization at ∼500 Ma, and was synchronous with tectonic unroofing of the Brattstrand Bluffs migmatites along ductile shear zones. Exhumation has been proposed as a cause of dehydration melting in the Himalaya and elsewhere, but melting at Brattstrand Bluffs was ultimately driven by the tectonic perturbation and subsequent thermal relaxation responsible for high metamorphic temperatures. Exhumation did not drive melting reactions, but it is likely that the presence of melt focused deformation in the migmatites and thus promoted exhumation. |
format |
Text |
author |
FITZSIMONS, I. C. W. |
author_facet |
FITZSIMONS, I. C. W. |
author_sort |
FITZSIMONS, I. C. W. |
title |
Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust |
title_short |
Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust |
title_full |
Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust |
title_fullStr |
Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust |
title_full_unstemmed |
Metapelitic Migmatites from Brattstrand Bluffs, East Antarctica--Metamorphism, Melting and Exhumation of the Mid Crust |
title_sort |
metapelitic migmatites from brattstrand bluffs, east antarctica--metamorphism, melting and exhumation of the mid crust |
publisher |
Oxford University Press |
publishDate |
1996 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/37/2/395 https://doi.org/10.1093/petrology/37.2.395 |
long_lat |
ENVELOPE(77.020,77.020,-69.208,-69.208) |
geographic |
East Antarctica Brattstrand Bluffs |
geographic_facet |
East Antarctica Brattstrand Bluffs |
genre |
Antarc* Antarctica East Antarctica |
genre_facet |
Antarc* Antarctica East Antarctica |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/37/2/395 http://dx.doi.org/10.1093/petrology/37.2.395 |
op_rights |
Copyright (C) 1996, Oxford University Press |
op_doi |
https://doi.org/10.1093/petrology/37.2.395 |
container_title |
Journal of Petrology |
container_volume |
37 |
container_issue |
2 |
container_start_page |
395 |
op_container_end_page |
414 |
_version_ |
1766268745906388992 |