Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica
P(論文) Chemical compositions of biotites and hornblendes in metamorphic rocks around Lutzow-Holmbukta show that these minerals have the characteristics of granulite facies ones. Some low-Ti biotites and hornblendes may be due to low TiO_2 content of host rocks. Chemical natures of biotites and hornbl...
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ftnipr:oai:nipr.repo.nii.ac.jp:00001029 2024-09-09T19:08:34+00:00 Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica Kanisawa, Satoshi Onuki, Hitoshi Yanai, Keizo 1979-10 application/pdf https://nipr.repo.nii.ac.jp/record/1029/files/KJ00000011573.pdf eng eng Memoirs of National Institute of Polar Research. Special issue 14 153 163 AA00733561 https://nipr.repo.nii.ac.jp/record/1029/files/KJ00000011573.pdf 1979 ftnipr 2024-06-17T04:00:22Z P(論文) Chemical compositions of biotites and hornblendes in metamorphic rocks around Lutzow-Holmbukta show that these minerals have the characteristics of granulite facies ones. Some low-Ti biotites and hornblendes may be due to low TiO_2 content of host rocks. Chemical natures of biotites and hornblendes reflect those of their host rocks, that is, biotites from metabasites are phlogopite and Na_2O-rich ones, while those from paragneisses are Fe-rich and Na_2O-poor ones. The replacement of R^<2+> by R^<3+> ions in octahedral sites in biotites increases from metabasites through charnockites to paragneisses. Hornblendes from metabasites are richer in Na_2O than K_2O, but the proportion is reversed in hornblendes from charnockites and hornblende gneisses. The values of log (ƒ_<H_2O>/ƒ_<HF>) of fluid phase coexisting with biotites during crystallization are 4.3 in metabasites and 3.8 in paragneisses, respectively. From the available data of the F content of hydrous minerals in various metamorphic terrains, it can be presumed that the ratio of ƒ_<H_2O>/ƒ_<HF> decreases during progressive metamorphism. departmental bulletin paper Other/Unknown Material Antarc* Antarctica East Antarctica Memoirs of National Institute of Polar Research Polar Research National Institute of Polar Research Repository, Japan East Antarctica |
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National Institute of Polar Research Repository, Japan |
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English |
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P(論文) Chemical compositions of biotites and hornblendes in metamorphic rocks around Lutzow-Holmbukta show that these minerals have the characteristics of granulite facies ones. Some low-Ti biotites and hornblendes may be due to low TiO_2 content of host rocks. Chemical natures of biotites and hornblendes reflect those of their host rocks, that is, biotites from metabasites are phlogopite and Na_2O-rich ones, while those from paragneisses are Fe-rich and Na_2O-poor ones. The replacement of R^<2+> by R^<3+> ions in octahedral sites in biotites increases from metabasites through charnockites to paragneisses. Hornblendes from metabasites are richer in Na_2O than K_2O, but the proportion is reversed in hornblendes from charnockites and hornblende gneisses. The values of log (ƒ_<H_2O>/ƒ_<HF>) of fluid phase coexisting with biotites during crystallization are 4.3 in metabasites and 3.8 in paragneisses, respectively. From the available data of the F content of hydrous minerals in various metamorphic terrains, it can be presumed that the ratio of ƒ_<H_2O>/ƒ_<HF> decreases during progressive metamorphism. departmental bulletin paper |
author |
Kanisawa, Satoshi Onuki, Hitoshi Yanai, Keizo |
spellingShingle |
Kanisawa, Satoshi Onuki, Hitoshi Yanai, Keizo Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica |
author_facet |
Kanisawa, Satoshi Onuki, Hitoshi Yanai, Keizo |
author_sort |
Kanisawa, Satoshi |
title |
Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica |
title_short |
Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica |
title_full |
Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica |
title_fullStr |
Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica |
title_full_unstemmed |
Chemical Characteristics of Biotites and Hornblendes from Metamorphic Rocks around Lutzow-Holmbukta, East Antarctica |
title_sort |
chemical characteristics of biotites and hornblendes from metamorphic rocks around lutzow-holmbukta, east antarctica |
publishDate |
1979 |
url |
https://nipr.repo.nii.ac.jp/record/1029/files/KJ00000011573.pdf |
geographic |
East Antarctica |
geographic_facet |
East Antarctica |
genre |
Antarc* Antarctica East Antarctica Memoirs of National Institute of Polar Research Polar Research |
genre_facet |
Antarc* Antarctica East Antarctica Memoirs of National Institute of Polar Research Polar Research |
op_relation |
Memoirs of National Institute of Polar Research. Special issue 14 153 163 AA00733561 https://nipr.repo.nii.ac.jp/record/1029/files/KJ00000011573.pdf |
_version_ |
1809822791700054016 |