Department of Earth Sciences and Astronomy, Fukuoka University of Education
Department of Earth Sciences and Astronomy, Fukuoka University of Education
Department of Mining and Mineral Engineering, Faculty of Engineering, Tohoku University
Geological Survey of Japan
Department of Earth Science, Faculty of Education, Kobe University
National Institute of Polar Research
Vanadium-bearing green garnets have been found in the Menipa mountain mass, central part of the Sør 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.
東南極，セールロンダーネ山地からバナジウム占有ザクロ石の発見
.png)
KJ00000139952
(381.14KB)
概要
