本文選題：鋯石U-Pb年齡 + 流體包裹體��； 參考：《巖石礦物學(xué)雜志》2017年05期

【摘要】：安徽東溪金礦床位于桐柏-大別造山帶北淮陽構(gòu)造帶的中生代曉天火山盆地中,是桐柏-大別成礦帶具有代表性的淺成低溫?zé)嵋航鸬V床。金礦體以含金方解石脈和方解石-石英脈形式產(chǎn)出,受NW向斷裂控制,賦礦圍巖為毛坦廠組安山質(zhì)火山巖。該礦床熱液成礦過程由早到晚可分為粗晶方解石階段和方解石-石英階段。早、晚階段方解石中流體包裹體十分發(fā)育,主要類型有純液相、純氣相和富液二相流體包裹體。早階段流體包裹體均一溫度范圍為128~172℃,冰點(diǎn)溫度介于-0.7~+23.4℃之間,鹽度為0.35%~0.92%;晚階段流體包裹體均一溫度范圍為105~160℃,冰點(diǎn)溫度介于-0.5~+9.1℃之間,鹽度為0.18%~0.52%。成礦流體從早階段演化到晚階段,溫度和鹽度具有小幅度的降低趨勢。巖漿熱液和加熱循環(huán)的大氣降水的混合可能是引起金屬元素富集、沉淀的主要機(jī)制,該礦床是地表淺部熱液對流系統(tǒng)的產(chǎn)物。LA-ICP-MS鋯石U-Pb同位素研究表明,賦礦安山巖的鋯石~(206)Pb/~(238)U加權(quán)平均年齡為126.7±1.4Ma(1σ,MSWD=0.95),代表了其火山作用時(shí)限。結(jié)合礦床地質(zhì)特征認(rèn)為,東溪金礦床成礦時(shí)間可能與安山巖噴發(fā)時(shí)限基本一致。該礦床形成于早白堊世陸殼強(qiáng)烈伸展和巖石圈地幔上涌的動(dòng)力學(xué)背景。
[Abstract]:Dongxi gold deposit, located in the Mesozoic Xiaotian volcanic basin of the northern Huaiyang tectonic belt of the Tongbai Dabie orogenic belt, is a typical epithermal hydrothermal gold deposit in the Tongbai Dabie metallogenic belt. The gold orebody is formed in the form of gold-bearing calcite vein and calcite quartz vein, controlled by NW fault, and the host rock is Anshan volcanic rock of Maotanchang formation. The hydrothermal metallogenic process of the deposit can be divided into coarse calcite stage and calcite quartz stage from early to late. The fluid inclusions in the early and late stages of calcite are well developed. The main types of fluid inclusions are pure liquid phase, pure gas phase and liquid rich two-phase fluid inclusions. The homogenization temperature range of fluid inclusions in early stage is 128 ~ 172 鈩，

本文編號：1814682