巴林左旗双尖子山银(铅、锌)矿床位于大兴安岭南段,为超大型热液脉型矿床,在时空分布上与中生代构造—岩浆岩关系密切。双尖子山银多金属矿化多呈席状、细脉浸染状、网脉—脉状在下二叠统大石寨组火山—沉积岩产出,并且构成似层状、(长)扁豆状、透镜状和囊状矿体。初步研究表明:与银多金属共生的绢云母和辉钼矿同位素年龄分别为146.9±1.9 Ma和162.6±2.6 Ma,与区域侏罗纪火山岩同位素年龄160~147 Ma基本一致。根据矿区外围白音诺尔花岗岩体锆石年龄142~115 Ma,可以推测双尖子山银多金属主成矿作用与侏罗纪构造—岩浆活动相关,而与后期大规模中酸性岩浆侵位并无直接的成因联系。根据矿床产出环境、矿化和热液蚀变特征的初步研究结果表明,双尖子山可能经历了多次矿化的叠加,其可能与古太平洋板块远程俯冲和中生代动力机制转换作用有关。
Located in the southern segment of the Great Hinggan Mts. ( Da Hinggan Range, or Great Xing' an Mts. ) in Hinggan--Mongolia Orogenic Belt (XMOB), the Shuangjianzishan Ag--polymetallic deposit in Balinzuo Qi(Balin Zuoqi; Baarin Left Banner) is a newly discovered superlarge scale epithermal deposit, which is closely related to the Mesozoic tectono-magmatic activities in space, age and genesis. The polymetallic mineralization (Ag, Zn, Pb, and Cu) hosted by the volcano--sedimentary rocks is composed of the layered, lenticular, wedge shaped and cystic orebodies occurring as disseminated, vein, sheet, and veinlets. Preliminary study showed that the sericite yielded an Ar-Ar plateau age of 146.9 ± 1.9 Ma, and the molybdenite from the silver polymetallic ore yielded a model age of 162.6 ± 2.6 Ma. These two ages are identical with the age of regional Jurassic volcanic rocks (160 - 147 Ma). Therefore, the formation of the Shuangjianzishan silver polymetallic deposit is related to the Jurassic tectono--magmatic activities caused mainly by the remote effect of the subduction of the Mesozoic Paleo- Pacific plate during the tectonic transformation.