Mineralogical Study of Skarn-Type Cu-W Deposit at the Kuga Mine, Yamaguchi Prefecture, Japan

概要

論文の詳細を見る
The skarn-type Cu-W orebodies at the Kuga mine are classified in this paper into two groups; orebodies not containing relict limestone and orebodies containing limestone in their inner parts. Mineralogical features are compared between the limestone-absent Umenoki 5 orebody, and limestone-bearing Suho 3-A and 3-D orebodies. Sulfide minerals and hydrous silicate minerals are present in larger amounts in the Umenoki 5, whereas anhydrous skarn minerals such as clinopyroxene and garnet are present more abundantly in the Suho 3-A and 3-D. Wolframite occurs only in the Umenoki 5. Siderite and ankerite are ubiquitous in the Umenoki 5, whereas these two carbonate minerals are very rare in the Suho 3-A and 3-D. Garnet from the Umenoki 5 contains larger amounts of almandine and spessartine components than that from Suho 3-A and 3-D. FeS contents of sphalerites range from 18.3 to 19.9 mol% in the Umenoki 5 and from 21.3 to 23.9 mol% in the Suho 3-A and 3-D. These markedly different mineralogy between two groups of orebodies may be mainly attributed to the difference in activities of metal ions such as Ca, Fe and Mn, and to variations in pH and fo2 during the mineralization, which is essentially related to the presence or absence of free CaCO3.
資源地質学会の論文