神居古潭結晶片岩中の特殊鉱物について

Abstract

The Kamuikotan metamorphic complex develops as irregular long zone between the Mesozoic and Cenozoic formations along the western side of the Hidaka mountain ridge in Central Hokkaido. It runs about 200 km in a direction of nearly north to south, from areas of boundary of Teshio and Kitami Provinces to Hidaka Province.In general the normal Kamuikotan complex is made up the products due to slight regional metamorphism, in which the chief petrological members are black siliceous schists and next comes an abundance of green schists, small amonnts of quartzite, phyllite, mylonite and crysrtalline limestone are intercalated in the complex. From the geological and petrographical points of view, it may reasonably be assumed that the Kamuikotan complex can be readily correlated with the Franciscan formation in California.Comparatively large lenses or belts of the ultra-basic rocks run parallel with the trend of the Kamuikotan complex, being restricted mainly to the tectonic lines is the zone of the complex. It is noticeable that various interesting crystalline schists locally develop between the normal schistose rocks of the Kamuikotan complex and the ultra-basic intrusives, which have attracted special attention because of the presence of some special minerals, especially soda-bearing silicates. These special rocks may be a product brought about by contact metamorphic action due to ultra-basic intrusion and occurrence of the special minerals in them originated from pyrometasomatism, primarily owing to the action of some especially soda-rich hydrothermal solution drived from the ultra-basic intrusions.The subject matter of this paper is an outline of these some special minerals in the pyro-metasomatized rocks, with special reference to the general properties of the following members ; (A) glaucophane and crossite, (B) riebeckite and crocidolite, (C) aegirine-augite, (D) stilpnomelane, (E) piedmontite, (F) garnet, (G) lawsonite, and (H) pumpellyite.