Finding of vanadium-bearing garnet from the Sor Rondane Mountains, East Antarctica
Vanadium-bearing green garnets have been found in the Menipa mountain mass, central part of the Sor Rondane Mountains, East Antarctica. These garnets are the main constituent minerals of granulite-facies metamorphosed graphite-bearing calcareous metapelite. They show three types of mode of occurrenc...
| Main Authors: | , , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English Japanese |
| Published: |
National Institute of Polar Research
1990
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| Subjects: | |
| Online Access: | https://doi.org/10.15094/00008687 https://doaj.org/article/736752d677f243b0a7fd4b7a21af9ab3 |
| Summary: | Vanadium-bearing green garnets have been found in the Menipa mountain mass, central part of the Sor Rondane Mountains, East Antarctica. These garnets are the main constituent minerals of granulite-facies metamorphosed graphite-bearing calcareous metapelite. They show three types of mode of occurrence as follows; i) large porphyroblast (type-1), ii) fine crystal (type-2) in kelyphite rim around type-1 garnet, and iii) fine-grained porphyroblast (type-3) in matrix. These three types of vanadium-bearing garnets exhibit distinct characters in chemical compositions. The V^<3+>, Cr^<3+> and Fe^<3+> contents in these garnets increase from type-1 to type-3 through type-2 with increasing consistency of green color, while the Cr_2O_3/V_2O_3 and Fe_2O_3/V_2O_3 ratios are constant. Therefore, the form of cation substitution in vanadium-bearing garnets is shown as 4V^<3+>, (Cr^<3+>, Fe^<3+>)⇋5Al^<3+>. Modes of occurrence and chemical characteristics of vanadium-bearing green garnets are described here, and physical properties of these garnets are also examined. |
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