黑龙江三矿沟矽卡岩型Cu-Fe-Mo矿床矿石硫化物硫、铅同位素特征及锆石U-Pb定年

三矿沟Cu-Fe-Mo矿床是大兴安岭地区三矿沟—多宝山构造-成矿带中一个比较典型的矽卡岩型矿床,矿体形成与三矿沟复式英云闪长岩体侵入关系密切。在分析该矿床成矿地质条件的基础上,对矿石硫、铅同位素组成特征和锆石U-Pb测年数据进行了研究,探讨了成矿物质来源和成矿成岩年代。研究表明,硫同位素组成变化范围较大,显示塔式分布效应,估算得到成矿热液系统的总硫同位素值约为-1.5‰,反映成矿过程中硫主要来源于深源岩浆,极少量可能来自于地层;矿石铅同位素具有壳幔混合铅的特征,反映了该矿床成矿物质主要为壳幔混合来源,与岩浆作用密切相关;锆石206Pb/238U加权平均年龄范围为（168.18±0.96）^200±1Ma,代表了英云闪长岩的侵位时间,表明三矿沟矽卡岩型Cu-Fe-Mo矿床的成岩成矿年代为早侏罗世。

S-Pb isotopic characteristics of ore sulfides and U-Pb dating of zircon from the Sankuanggou skarn-type Cu-Fe-Mo deposit in Heilongjiang Province

The Sankuanggou skarn-type Cu-Fe-Mo deposit occurs in the Sankuanggou-Duobaoshan tectonicmetallogenic belt of the Da Hinggan Mountains,and there exists close relationship between the formation of ore bodies and the intrusion of Sankuanggou multiple tonalite.Based on an analysis of the ore-forming geological conditions,the authors studied sulfur and lead isotopic compositions and zircon U-Pb dating data of ores from this ore deposit and,on such a basis,discussed the sources of ore-forming materials and the rock-forming and ore-forming epochs.Studies have shown that the composition of sulfur isotope varies greatly and has a distributional effect of tower type,the δ 34 S ∑ S of the ore-forming hydrothermal system is about-1.5‰,suggesting that sulfur was mainly derived from deep magmatic source,with a very small amount probably derived from the strata.The lead isotopic composition of ore sulfides indicates the derivation of lead from the mixed crust-mantle materials,suggesting that the ore-forming materials came mainly from crust-mantle mixing sources and were closely related to magmatism.The 206 Pb/ 238 U weighted mean ages of zircons range from(200±1)Ma to(168.18 ±0.96)Ma,which represent the intrusive time of tonalite and suggest that the rock-forming and ore forming epoch of the Sankuanggou Skarn-type Cu-Fe-Mo polymetallic deposit is Early Jurassic.