青海省门源县寺沟锑矿地质特征与矿床成因分析

门源寺沟锑矿位于走廊南山南坡Cu-Pb-Zn-Au(Ag)-Cr-Fe-煤成矿带。出露地层为志留系下统肮脏沟组(S_1a)的砂、板岩序列,岩浆活动相对较微弱,断裂构造十分发育,区域主要以北西向主干断裂为主,其次有北北西向和南北向断裂,矿体分布在构造蚀变带中,通过野外观察、薄片分析、地球化学分析等方法,对寺沟矿区地质特征及其矿床成因进行分析,认为锑矿成矿元素Sb主要来源于奥陶系大梁组和志留系肮脏沟组(赋矿层),大量有机质、孔隙水中硫酸盐形成以H_2S为主的还原剂,提供了硫源。矿体严格受构造破碎带控制,构造破碎带的存在为含矿热液的运移和沉淀提供了通道和容矿空间。矿床属构造热液蚀变岩型锑矿床,对寻找带内类似的新矿床具有重要的借鉴意义。

Geological characteristics and genesis of the Sigou Sb deposit in Menyuan County, Qinghai

Menyuansigou Sb deposit is located at the Cu-Pb-Zn-Au(Ag)- Cr-Fe-Coal metallogenic belt, the southern margin of the Zoulangnan Mountain, exposed to the Lower Silurian Angzanggou Fomation sandstone and slate sequence. In the studied area, magmatic action is relative weak but the faults are developed well, and the main faults are north and west, followed by the northwest and nearly south-north faults. The Sb ores are distributed in tectonic alteration zone. By the field observation, microscope image analysis and geochemical data, this work analyzed geological characteristics and genesis of the Sigou deposit. The Sb element is mainly derived from the Ordovician Daliang formation and the Silurian Angzanggou formation (Ore-bearing Horizon), and the reductant is mainly H₂S from the sulphate in organic matter and void water. The ore body is strictly controlled by the structural fracture zone, and tectonic fracture zone provides the channel for the migration and and capacity space for precipitation of the ore-containing hydrothermal fluid. The Sb deposit belongs to the tectonic hydrothermal alterated deposit, which is of great significance for seeking similar new deposits in the belt.