干旱区生态环境知识资源中心

Massive and foliated talc ore with disseminated and massive Cu-Zn sulfides at Derhib area are confined to a shear zone located at the boundary between ophiolitic serpentinites and metapelites. Regional zoning and small-scale heterogeneity of the talc ore are characteristic. Chalcopyrite, sphalerite and pyrite are the major sulfide minerals. Metamorphic features are characteristic. Three silver-minerals are documented from the deposit; hessite (Ag2Te), electrum (Ag,Au) and volynskyite (AgBiTe2). These minerals occur in intimate association with altaite (PbTe) and hedleyite (Bi14Te6). A bimodal distribution of FeS in sphalerite encapsulated in pyrite is observed. Sphalerite geobarometry indicates peak metamorphic conditions of 2.3 to 4 kbars. Field, textural and petrographical features indicate a genetic relationship between talc and the massive sulfides.