Studies on the Molybdenum Deposits of the Daito District, Shimane Prefecture, Japan

Abstract

The molybdenum deposits of the Daito district are located about 20Km southwest of Matsue city, Shimane prefecture, Chugoku province. The deposits under consideration are veins of mesothermal type, and now the most productive deposits of molybdenum in Japan. They are believed to have been formed in close relation to the granites distributed widely in this mining district. Molybdenite and quartz are principal vein minerals, but small amounts of biotite, plagioclase, adularia, epidote, galena, sphalerite, pyrite, calcite, and ankerite are also identified as accessory minerals. Wall-rock alteration is generally remarkable. It is characterized by the presence of an orderly arrangement of silicified zone, sericitized zone, and chloritized zone, from the inner side to the outer side of the ore veins.