川西地区梭罗沟金矿床成矿物质来源:来自黄铁矿Re-Os同位素的限定  

Source of ore-forming materials of Suoluogou gold deposit,West Sichuan:Constraints from pyrite Re-Os isotopes

作　　者：胡古月[1] 冯希尧 王兆成 魏永锋 张文林 李超[4] 宫江华[1] HU GuYue;FENG XiYao;WANG ZhaoCheng;WEI YongFeng;ZHANG WenLin;LI Chao;GONG JiangHua(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resource,Chinese Academy of Geological Sciences,Beijing 100037,China;Sichuan Gold Co.,LTD,Xichang 615800,China;Sichuan Gold Group Co.LTD,Chengdu 610213,China;National Research Center for Geoanalysis,Beijing 100037,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037 [2]四川黄金股份有限公司,西昌615800 [3]四川黄金集团有限公司,成都610213 [4]国家地质实验测试中心,北京100037

出　　处：《岩石学报》2025年第5期1571-1583,共13页Acta Petrologica Sinica

基　　金：川资投函〔2024〕206号、容大矿业科字〔2024〕05号和四川容大矿业集团有限公司投资项目联合资助详细信息。

摘　　要：梭罗沟金矿床产于松潘-甘孜造山带木里弧形逆冲-滑脱叠置岩片区,为赋存于扬子板块西缘基底上部火山-沉积建造中的构造蚀变岩型金矿床。本次研究对梭罗沟金矿床的矿石黄铁矿开展了Re-Os放射性同位素定年测试,获得等时线年龄263.5±2.7Ma(MSWD=55)。结合赋矿玄武岩结晶岩浆锆石(252.8±2.3Ma)和石英脉中最年轻的捕获锆石年龄(119±1.7Ma)数据,本文认为梭罗沟金矿的成矿物质来源可能与区域上的晚二叠世火山岩地层相关,且黄铁矿未经历高温岩浆流体改造和长距离的搬运作用。甘孜-理塘洋盆闭合后,弧-陆碰撞造山作用使得区域上发生不连续岩片逆冲叠置事件,喷发于扬子板块西缘的二叠-三叠纪海相火山岩以构造岩片的形式向东南方向推覆,并在岩块内部形成了大量的韧-脆性剪切带。119Ma之后(尤其是新生代时期),在区域高热流条件下,沿剪切带迁移的中-低温变质流体萃取了晚二叠世火山-沉积地层中的金元素,并近原地就位于"薄皮构造"的剪切带内,形成梭罗沟金矿床。考虑到区域上的诸多金矿床产于扬子板块西缘,本文推测其成矿物质的初始来源可能来自甘孜-理塘洋内的火山岩,但也不能排除晚二叠世峨眉山大火成岩省相关火成岩的贡献。The Suoluogou gold deposit is located in the Muli thrust-detachment tectonic slices unit of the Songpan-Ganzi Orogenic Belt.It is a structurally controlled alter-rock-type gold deposit hosted within a set of volcanic-sedimentary sequence on the western margin of the Yangtze Plate.This study conducted Re-Os isotopic dating on the ore pyrite from the Suoluogou gold deposit,from which yields a concordant age of 263.5±2.7Ma(MSWD=55).Combining with the crystallization age of the ore-bearing basalt magma zircon(252.8±2.3Ma)and the youngest detrital zircon age in the quartz veins(119±1.7Ma),we suggests that the source of the mineralizing materials for the Suoluogou gold deposit may be related to the regional Late Permian volcanic activities,and the pyrite has not undergone high-temperature magmatic fluid alteration or long-distance transport.After the closure of the Ganzi-Litang Ocean Basin,the arc-continent collision orogeny caused discontinuous thrust stacking events in this region.The Permian-Triassic marine volcanic rocks erupted on the western margin of the Yangtze Plate were thrust southeastward in the form of tectonic slices,forming numerous ductile-brittle shear zones within the rock blocks.After 119Ma(especially during the Cenozoic era),medium-to low-temperature metamorphic fluids migrated along the shear zones which extracted gold elements from the Late Permian volcanic-sedimentary strata and emplaced nearly in situ within the shear zones of the"thin-skinned tectonic"structure under regional high heat flow conditions,forming the Suoluogou gold deposit.Considering that regional gold deposits are all located on the western margin of the Yangtze Plate,this paper speculates that the initial source of the mineralizing materials may have come from the volcanic rocks within the Ganzi-Litang Ocean,but the contribution of igneous rocks related to the Late Permian Emeishan Large Igneous Province cannot be ruled out.

关 键 词：松潘-甘孜造山带 峨眉山大火成岩省 逆冲-滑脱叠置岩片 蚀变岩型金矿 黄铁矿Re-Os定年 

分 类 号：P578.292[天文地球—矿物学] P597.2[天文地球—地质学] P618.51