広島県能美島飛渡瀬の含方鉛鉱曹長石岩について

On Galena-bearing Albite Rock from Hitonose, Nômi Island, Hiroshima Prefecture

TOYODA Hideyoshi

SASAKI Hiroshi

廣島大學地學研究報告

Geological report of the Hiroshima University

A syenitic rock designated the galena-bearing albite-rock by the present author has been found occurring in the Hiroshima granite at Hitonose in the eastern part of Nômi Island, Hiroshima Prefecture.
The rock in question exposes as a sort of lenticular dike, about 15 m in width and about 30 m in extension, pointing to NW-SE in trend, and reveals either a gradual conversion to the country rock on the southern side or the contact with a fault on the northern side.
The very rock is microscopically predominant in albite asssociated with a few amount of acmitic pyroxene, epidote, allanite, apatite and so forth, and, on the basis of its relation to the Hiroshima granite as well as in comparison with the previous data, surely believed to have genetically been resulted from pneumatolytic replacement through sodic emanation ascending at the last stage in post-activity of the related granitic magma.
The content of galena in the rock concerned is estimated 20 per cent on an average, whereas, because of scarcity of Pb in content, there is still a room to be inspected for an industrial use.

jpn

廣島大學理學部地學教室

[ISSN] 0073-2303

[NCID] AN00213676