东秦岭沙沟银铅锌矿床成矿流体来源的锶同位素约束  

Sr-isotope constraint on the source of the fluids forming the Shagou Ag-Pb-Zn deposit, eastern Qinling orogen

作　　者：韩金生[1] 姚军明[1] 邓小华[2] 

机构地区：[1]中国科学院广州地球化学研究所矿物与成矿重点实验室,广州510640 [2]北京大学造山带与地壳演化重点实验室,北京100871

出　　处：《岩石学报》2013年第1期18-26,共9页Acta Petrologica Sinica

基　　金：国家973项目(2006CB403500);国家自然科学基金项目(40872067;41072061;41202050)联合资助

摘　　要：沙沟银铅锌矿床位于华北克拉通南缘的熊耳地体,属于受断裂带控制的中温脉状矿床。本文对沙沟含矿石英脉流体包裹体进行了锶同位素分析,并利用前人获得的成矿年龄(145Ma)进行了返算,获得其ISr-145变化于0.72019～0.73096之间,平均为0.72726。通过与熊耳地体及邻区相关地质体锶同位素组成对比,认为沙沟银铅锌矿的成矿流体不可能单独来自太华群,也不可能来自太华群与熊耳群或燕山期岩浆岩的混合,而可能是官道口群+栾川群经变质脱水产生的成矿流体与太华群水岩相互作用的结果。Abstract The Shagou Ag-Pb-Zn deposit is a quartz-vein system hosted in amphibolites and gneisses of the Taihua Group in the Xiong＇ er Terrane, on the southern margin of the North China Craton. In this paper, we present the Sr isotopic data of fluid inclusions in quartz separates from the Shagou deposit, and calculate the initial 86^Sr/86^Sr ratios at 145Ma （i. e. ISr-145 ） when the deposit was formed. The ISr-145 values of eight quartz samples range from 0. 72019 to 0. 73096, with an average of 0. 72726. Comparing with the associated lithologies in the Xiong＇ er Terrane and adjacent areas, it is concluded that the ore-forming fluids can not be only sourced from the Taihua Group. The possibility that Taihua Group mixed with Xiong＇ er Group or Yanshannian granitoids was excluded. Instead, the scenario shows that a crustal slab containing the Guandaokou and Luanchuan groups subducted northward along the Machaoying fault belts and provided the ore fluids which upwardly moved and interacted with the wallrocks to develop the Shagou Ag-Pb-Zn deposit.

关 键 词：锶同位素 沙沟银铅锌矿床 熊耳地体 A型俯冲 

分 类 号：P595[天文地球—地球化学]