岡山縣久米郡坪井鉱山付近の地質及び鉱床 : とくに岩石及び鉱床の形態について

On the Geology and Ore-deposit of the Tsuboi Mining District, with Special Reference to the Crystalline Schists and the Morphology of Ore-deposit.

MITSUNO Chiharu

廣島大學地學研究報告

Geological report of the Hiroshima University

Crystalline schists in this district consist of pelite-schists, sanpstone-schists, siliceousschists, limestone-schist, basic-tuff-schists, diabase-schists, serpentine-schists, acidic-tuff-schists and quartz-porphyry-schists, which belong to the Sangun metamorphic zone. The original rock species of crystalline schists have been determined after the field occurrence and microscopic observation.
The stratigraphical succession of the formation of crystalline schists in the district is tabulated in the descending order as follows:
[Original table is skipped. For more details, please refer to the full text.]
The Tsuboi mine is a type of "kieslager" lying in basic-tuff-schist in the lowest zone.
The arrangement of ore bodies shows an échelon type and each ore body consists of small ore body groups, and the relation between these small ore body groups is also an échelon type.
The crystalline schists in the district have distinct S-surface (S2) which crosses the schistosity plane (S1) at high angles (about NW 70°).
The S2-surface cut the S1-plane, chloritized rocks (Hinouchi) and ore veinlets, and ore bodies (mainly pyrites) have been crashed by the movement, represented by the S2-surface, and filled up by chalcopyrites and pyrrhotites.
In the adits, the author has observed several faults, along which ore bodies and chloritized rocks have been found.

jpn

廣島大學理學部地學教室

[ISSN] 0073-2303

[NCID] AN00213676