METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA
Lenses up to 5m in size of ultramafic rocks occur in quartzo-feld-spathic, locally migmatized, gneisses at four localities of the eastern Sør Rondane Mountains. A composite lens at one locality consists of harzburgite, orthopyroxenite and garnet amphibolite, and a second, consists entirely of harzbu...
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Geological Survey of Japan
1990
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ftnipr:oai:nipr.repo.nii.ac.jp:00002617 2023-05-15T13:48:59+02:00 METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA Hiroshi MAKIMOTO Masao ASAMI Edward S. GREW 1990-09 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2617 http://id.nii.ac.jp/1291/00002617/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2617&item_no=1&attribute_id=18&file_no=1 en eng Geological Survey of Japan Department of Geological Sciences, College of Liberal Arts, Okayama University Department of Geological Sciences, Univeristy of Maine National Institute of Polar Research https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2617 http://id.nii.ac.jp/1291/00002617/ AA1072335X Proceedings of the NIPR Symposium on Antarctic Geosciences, 4, 9-21(1990-09) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2617&item_no=1&attribute_id=18&file_no=1 Departmental Bulletin Paper P(論文) 1990 ftnipr 2022-11-19T19:41:20Z Lenses up to 5m in size of ultramafic rocks occur in quartzo-feld-spathic, locally migmatized, gneisses at four localities of the eastern Sør Rondane Mountains. A composite lens at one locality consists of harzburgite, orthopyroxenite and garnet amphibolite, and a second, consists entirely of harzburgite. Harzburgite contains chromite-poor spinel (Cr/(Cr+Al)~0.1), which indicates that it was equilibrated under conditions of the spinel lherzolite facies. Temperature estimates for the ultramafic lenses represent that they preserved at least two stages of metamorphic temperature conditions. The higher temperatures (~750℃) estimated by the maximum Al-content of orthopyroxene and the pyroxene geothermometers are consistent with those of the early granulite-facies metamorphic event reported in the eastern Sør Rondane Mountains. This indicates that the ultramafic lenses and the surrounding metamorphic rocks recrystallized under the same granulite-facies metamorphic temperature conditions. The lower temperatures (520-670℃) obtained from garnet rim-biotite pairs probably correspond to the later, discrete amphibolite-facies event in the Mountains. Report Antarc* Antarctica East Antarctica National Institute of Polar Research Repository, Japan East Antarctica Sør-Rondane ENVELOPE(25.000,25.000,-72.000,-72.000) Sør Rondane Mountains ENVELOPE(25.000,25.000,-72.000,-72.000) |
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Open Polar |
collection |
National Institute of Polar Research Repository, Japan |
op_collection_id |
ftnipr |
language |
English |
description |
Lenses up to 5m in size of ultramafic rocks occur in quartzo-feld-spathic, locally migmatized, gneisses at four localities of the eastern Sør Rondane Mountains. A composite lens at one locality consists of harzburgite, orthopyroxenite and garnet amphibolite, and a second, consists entirely of harzburgite. Harzburgite contains chromite-poor spinel (Cr/(Cr+Al)~0.1), which indicates that it was equilibrated under conditions of the spinel lherzolite facies. Temperature estimates for the ultramafic lenses represent that they preserved at least two stages of metamorphic temperature conditions. The higher temperatures (~750℃) estimated by the maximum Al-content of orthopyroxene and the pyroxene geothermometers are consistent with those of the early granulite-facies metamorphic event reported in the eastern Sør Rondane Mountains. This indicates that the ultramafic lenses and the surrounding metamorphic rocks recrystallized under the same granulite-facies metamorphic temperature conditions. The lower temperatures (520-670℃) obtained from garnet rim-biotite pairs probably correspond to the later, discrete amphibolite-facies event in the Mountains. |
format |
Report |
author |
Hiroshi MAKIMOTO Masao ASAMI Edward S. GREW |
spellingShingle |
Hiroshi MAKIMOTO Masao ASAMI Edward S. GREW METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA |
author_facet |
Hiroshi MAKIMOTO Masao ASAMI Edward S. GREW |
author_sort |
Hiroshi MAKIMOTO |
title |
METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA |
title_short |
METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA |
title_full |
METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA |
title_fullStr |
METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA |
title_full_unstemmed |
METAMORPHIC CONDITIONS OF ULTRAMAFIC LENSES FROM THE EASTERN SØR RONDANE MOUNTAINS, EAST ANTARCTICA |
title_sort |
metamorphic conditions of ultramafic lenses from the eastern sør rondane mountains, east antarctica |
publisher |
Geological Survey of Japan |
publishDate |
1990 |
url |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2617 http://id.nii.ac.jp/1291/00002617/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2617&item_no=1&attribute_id=18&file_no=1 |
long_lat |
ENVELOPE(25.000,25.000,-72.000,-72.000) ENVELOPE(25.000,25.000,-72.000,-72.000) |
geographic |
East Antarctica Sør-Rondane Sør Rondane Mountains |
geographic_facet |
East Antarctica Sør-Rondane Sør Rondane Mountains |
genre |
Antarc* Antarctica East Antarctica |
genre_facet |
Antarc* Antarctica East Antarctica |
op_relation |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2617 http://id.nii.ac.jp/1291/00002617/ AA1072335X Proceedings of the NIPR Symposium on Antarctic Geosciences, 4, 9-21(1990-09) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2617&item_no=1&attribute_id=18&file_no=1 |
_version_ |
1766250287991881728 |