An analysis of mineralogical characteristics and mineralization temperature of the Daxiao Pb-Zn deposit in Dongchuan, Yunnan Province

The Daxiao Pb-Zn deposit is located on the secondary level uplift along the middle east part of the Kang-Dian axis, in Dongchuan, Yunnan Province.Its orebodies show veined and stratoid forms, and occur in interstratified crack and plume-like frac-ture of Wangchang Formation in Kunyang Group which lies in the south of Baihechang anticline.The ore minerals are composed of galena, native silver and a small quantity of sphalerite and pyrite, and the gangue minerals include quartz and calcite.Their textures mainly consist of euhedral-subhedral-anhedral granular texture, metasomatic relict texture and crystalloblastic texture, while main structures are disseminated structure, massive structure, banded structure and vein structure.Mineralization of this deposit could be di-vided into hydrothermal metallogenesis and supergenetic oxidation period, the former was made of three mineralization stages and the most important stage for Pb-Zn was the second stage, its metallogenic temperature ranged from 140℃ to 220℃, while metallogenic epoch was late Indosinian.Industrial ore was formed by the driving force of Indosinian movement that prompted activation-mix-ing-migration-accumulation of ore-forming elements to form the deposit.The genetic type of the ore deposit belongs to sedimenta-ry reformation hydrothermal ore deposit.