A combined fluid inclusion and S-H-O-He-Ar isotope study of the Devonian Ashele VMS-type copper-zinc deposit in the Altay orogenic belt, northwest China

摘要

The Altay orogenic belt of Kazakhstan and China incorporates one of the world-class volcanogenic massive sulfide (VMS) polymetallic metallogenic belt. More than 12 large and superlarge VMS deposits have been found in this belt. The Ashele Basin is located at the western end of the Chinese Altay bordering Kazakhstan and hosts the large Ashele copper-zinc deposit, which is a typical VMS deposit and the largest one in this basin. The principal orebodies are stratabound and located between basalt and tuff units in the Ashele Formation. The mineralization has a two-layered structure that consists of an upper stratiform, concordant, massive Cu-Zn (or barite) orebody, and a lower veinlet-disseminated and stockwork Cu (or Cu-Pb-Zn-Ag) orebody associated with silicic alteration. Several exhalative rocks, such as barite, hematitic jasper, pyrite and silicified units also occur.