北阿尔金地区大平沟金矿H-O-S-Pb同位素地球化学特征对金矿成因的启示  

H-O-S-Pb Isotopic Geochemistry of Dapinggou Gold Deposit in Northern Altun and Its Implications for Ore Genesis

作　　者：雷如雄[1] 赵同阳[2] 李平 董连慧[2] 李基宏[3] 吴昌志[4] Lei Ruxiong;Zhao Tongyang;Li Ping;Dong Lianhui;Li Jihong;Wu Changzhi(College of Earth Science and Resources,Chang’an University,Xi’an 710054,China;Xinjiang Bureau of Geology and Mineral Resources,Urumqi 830000,China;Nanjing Center,China Geological Survey,Nanjing 210016,China;School of Earth Sciences and Engineering,Nanjitig University,Nanjing 210093,China)

机构地区：[1]长安大学地球科学与资源学院,西安710054 [2]新疆维吾尔自治区地质矿产勘查开发局,乌鲁木齐830000 [3]中国地质调查局南京地质调查中心,南京210016 [4]南京大学地球科学与工程学院,南京210093

出　　处：《吉林大学学报（地球科学版）》2019年第6期1578-1590,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家重点研发计划项目(2017YFC0601203);中国地质调查局项目(1212011140056);中央高校基本科研业务费专项资金(300102278102)~~

摘　　要：大平沟金矿床是北阿尔金地区典型金矿床之一,矿化类型以钾长石石英脉型和蚀变岩型为主,矿体赋存于近东西向韧性剪切带中,围岩为太古宇米兰岩群钾长变粒岩。矿石矿物以黄铁矿为主,另有少量褐铁矿和自然金等。大平沟金矿床含金石英脉中石英的δ18 OVSMOW值为12.4‰~15.3‰,估算的流体δ18 OH2O值介于7.4‰~10.3‰之间,石英中流体包裹体的氢同位素为-97‰^-66‰,表明成矿流体以变质流体来源为主;含金石英脉中硫化物的δ34SVCDT值为6.9‰~8.3‰,主要为壳源硫,与典型造山型金矿的硫值一致;硫化物的206Pb/204Pb值为18.310 1~19.373 9,207 Pb/204 Pb值为15.587 2~15.654 1,而208 Pb/204Pb值为38.119 1~39.143 9,反映硫化物的铅来源具有造山带铅特征。综合分析认为,大平沟金矿床属于造山型金矿,其形成受近东西向次级断裂和韧性剪切带控制,成矿流体以变质流体为主,成矿物质来源于太古宙深变质岩。Dapinggou gold deposit is one of the typical gold deposits in Northern Altun. The depositis characterized by K-feldspar quartz vein-type and altered rock-type mineralization. The goldmineralization occurs within near the E-W ductile shear zone with the K-feldspar leptynite of ArchaeanMilan Group as the principal host rock. The ore minerals are mainly pyrite, with minor limonite andnatural gold. The measured δ18OVSMOW values for the gold-bearing quartz range from 12.4‰ to 15.3‰ ,the estimated δ18OH2O fluid values range from 7.4‰ to 10.3‰ , and the ^ DVSm w values of fluid inclusionsin quartz range from 97‰ to 66‰ , indicating that the ore-forming fluid is dominated bymetamorphic sources. The ^34 Svcdt values of sulfide minerals range from 6.9% to 8.3% in accordancewith those of the typical orogenic gold deposits. The 206Pb/204Pb ratios of sulfides range from 18.310 1 to 19.373 9,207 Pb/204 Pb ratios from 15.587 2 to 15.654 1,and the 208Pb/204Pb ratios from 38.119 1 to 39.143 9, indicating the lead source of sulfide the same as the orogenic type. It is proposed thatDapinggou gold deposit can be classified as the orogenic gold deposit, the gold formation is controlled bythe near EW secondary fault and the ductile shear zone, the metallogenic material is derived from theArchaean metamorphic rocks, and the ore-forming fluids are mainly metamorphic fluids.

关 键 词：同位素地球化学 造山型金矿 大平沟金矿床 北阿尔金 

分 类 号：P597[天文地球—地球化学] P618.51[天文地球—地质学]