抄録
The sulphur deposit of the Narugo mine is mainly muddy sediment on the bottom of a lake on the top of a volcano, which is accompanied by several minor deposits of sublimation and impregnation types. Muddy deposit occurs partly in minute laminae and partly in lenticular or irregular bodies. It is so fine-grained and muddy that some special treatments are necessary for its mining and extraction, for which the knowledge of its mineral paragenesis is desirable. The present study is made for this purpose with the following results.
Infered from the results of microscopic, electron-microscopic, chemical, differential thermal and X-ray studies, the ore consists of sulphur and pyrite, associated with, enumerated in decreasing order, kaolinite, halloysite, glassy fragments, pumice, quartz, silicified rock, opal, cristobalite, montmori-llonite, diatom crust, sericite, alunite, plagioclase, limonitic material, a titanium mineral and hypersthene.
The most part of the ore has been formed by free chemical precipitation but some minor portion by impregnation. This is infered from the evidence of replacement of some other minerals and rock fragments by sulphur and pyrite.
Some relations of the ore paragenesis to its mining, dressing and smelting are also mentioned.
