新疆准噶尔盆地哈图金矿成矿流体的某些物理化学特征及与成矿关系

GEOCHEMISTRY OF ORE-FORMING FLUID AND METALLOGENESIS PROGNOSIS OF HATU GOLD DEPOSITS IN JUNGAR BASIN,XINJIANG,CHINA

哈图金矿是位于准噶尔盆地西缘的大型石英脉型金矿床。石英及黄铁矿矿物及矿物包裹体稀土元素、微量元素及爆裂温度等研究表明,哈图金矿的主要矿化类型—石英脉型矿体与蚀变岩型矿体是不同来源的流体叠加成矿,而不是同一种成矿流体在不同温度下矿质沉淀产物。石英脉型矿体主要与花岗岩浆热液关系密切,蚀变岩型矿体主要与深源流体有关,在矿体浅部它们强烈的挤压复合部位形成明金富矿体石英脉。石英脉型矿体石英的爆裂曲线出现α-β转变峰,这种转变峰的强度从上向下增强,反映了流体初始温度较高,应与侵入岩浆热液有关,向矿体浅部,由于大量的循环天水的加入及远离了岩浆源,使成矿流体温度降低,石英的爆裂曲线没有α-β转变峰。大量天水的加入,使流体温度降低的同时,金也大量析出、富集形成含明金富矿体。蚀变岩型矿体石英爆裂曲线不出现α-β转变峰,反映其形成温度低于石英转变峰的温度,应与侵入岩浆无明显密切关系。

Hatu large gold deposit is located on the western margin of Juggar basin, Xinjiang. Gold mineralization is characterized by auriferous quartz vein and Au-bearing altered fracturing zone. The studies on mineralogy, fluid inclusions, and decrepitation temperature indicate that the gold deposit was formed by mixing of two kinds of fluids from different origins, instead of by gradual evolution of a single fluid. The fluids came from magmatism and deep-derived origins. The bonanza in quartz vein was formed and localized at the overlapping position of two types of fluids under intensive compression. There are α-β change apex in the decrepitation curve from auriferous quartz vein and Au-bearing altered fracturing zone orebodies. The intension of α-β change apex is buildup from up to down. It means that the origin temperature of two different fluids is quite high and fluids are related with intrusive magma. In the shallow parts of orebodies, the fluids are affected by rainwater, and temperature decreases. Gold is separated out from the fluids and formed rich gold orebodies. Hatu gold deposit is related with deep magma, and there exist some polymetallic orebodies in deep and around Hutu gold deposit.