Abstract:The Dachang antimony ore field is one of the important antimony resource area of China and the Dachang deposit is located in the middle of this ore field. The rocks containing ore bodies are called "Dachang bed" which refers to the top of Lower Permian limestone of Maokou Formation and the bottom of the Upper Permian Emeishan basaltic lava intercalated with volcaniclastic sedimentary rocks；this ore-bearing bed is characterized by alteration-heavy silicification and argillization——and is habitually assigned to Upper Permian Field lithological characteristics divide the Dachang bed into three members, they are in upward succession intensely silicified rocks, basaltic conglomerate or intensely silicified conglomeratic clay rocks, and clay rocks. Basaltic conglomerate, believed to be the ore source bed of this area. Was formed as a result of deposition of the first cycle basalt transported into the shallow sea after it was quenched and broken up in the water body. During the argillization of basaltic conglomerate, substantial amounts of siliceous material was released and then served as an important source for silicification of the Dachang bed; the eruption of basaltic magma and the halmyrolysis of tuffaceous material also gave off some siliceous material. Assuming the stratoid form, the stibnite ore accumulations occur concordantly in the Dachang bed; they are made up of quite a lot of minor ore bodies which are mainly banded and lenticular in form and in less occasions take the shape of vein or mass aggregates. Lithological characters have had much to do with the configuration of ore bodies the distribution of ore bodies are closely related to the paleokarst erosion surface of Maokou limestone and are evidently governed to some extent by fractures. Mineral association in the deposit seems quite simple with stibnite as the major ore mineral and quartz and kaolinite as the major gangue minerals. Dickite-bearing quartz-stibnite and pyrite-bearing clay minerals-quartz- stibnite make up the major industrial ore types. Wall rock alterations are also not complicated; they are predominantly intense silicification and argillization accompanied by pyritization, fluoritization and baritization. Silcification played a significant role in mineralization. An analysis of inclusions in white comb quartz associated intimately with stibnite reveals that ore-forming fluids were hot brine with some added meteoric water being -123.2‰ and concentration 18.8‰). Stibnite has sulfur isotope value of -0.58‰-2.7‰ and S32/S34 of 22.233-22.244. The Dachang stibnite deposit is a typical stratabound deposit. Plenty of ore-related elements such as F, Cl, S, Fe, Cu, Pb, As, Au, Sb were brought by the Hercynian basaltic lava flow into and then retained in a water body. Under suitable physico-chemical conditions, a source bed was formed. Later, intensive Yenshanian orogeny and geothermal gradient activated antimony as well as other elements and produced a sulfate type hot brine with added meteoric water at about 300℃. Loaded with antimony and other elements, this hot brine moved along the paleokarst surface of Maokou limestone and filled in exfoliation space, joints, cracks and fractures to form the stibnite deposit approximately at the temperature of 140℃.
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陈豫，刘秀成，张启厚.1984.贵州晴隆大厂锑矿床成因探讨[J].矿床地质,3(3):1~12.1984.A Tentative Discussion On The Genesis Of The Dachang Antimony Deposit,Qinrglong County, Guizhou Province[J].Mineral Deposits3(3):1~12
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