滇西镇康县放羊山铜铅锌矿床成矿流体及矿质来源探讨  

Sources of Ore-Forming Fluids and Mineral Materials of the Fangyangshan Cu-Pb-Zn Polymetallic Deposit in Zhenkang County,Western Yunnan

作　　者：沙建泽 邓明国[3] 吴清华 杨淑胜 魏汐竹 金梦迪 燕利军 SHA Jianze;DENG Mingguo;WU Qinghua;YANG Shusheng;WEI Xizhu;JIN Mengdi;YAN Lijun(Yunnan Institute of Geological Survey,Kunming,Yunnan 650216;MNR Key Laboratory of Sanjiang Metallogeny and Resources Exploration Utilization,Kunming,Yunnan 650051;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650093;School of Earth Science,Yunnan University,Kunming,Yunnan 650500)

机构地区：[1]云南省地质调查院,云南昆明650216 [2]自然资源部三江成矿作用及资源利用重点实验室,云南昆明650051 [3]昆明理工大学国土资源工程学院,云南昆明650093 [4]云南大学地球科学学院,云南昆明650500

出　　处：《地质与勘探》2021年第4期865-878,共14页Geology and Exploration

基　　金：国家自然科学基金项目(编号:41363001);中国地质调查局地质调查项目“云南省镇康芦子园-云县高井槽地区铁铅锌铜多金属矿整装勘查区矿产调查与找矿预测(编号:121201004000150017-88)”联合资助。

摘　　要：云南镇康县放羊山矿床位于西南“三江”多金属成矿带保山地块的南部,昌宁-孟连缝合带与怒江断裂带之间,是芦子园矿集区内重要矿床之一。该矿床上寒武统沙河厂组地层中产出似层状、透镜状的矿体,呈近东西向产出,主要矿石矿物为黄铜矿、闪锌矿和方铅矿。通过在矿区系列工作,总结矿床地质特征,结合矿床S、Pb同位素组成,探讨矿床的成矿物质来源。矿床金属硫化物的δ34 S值均为正值,介于8.24‰~14.91‰,平均11.59‰(n=13),与周边的水头山矿床、芦子园矿床δ34 S值接近,S同位素组成分布与花岗岩极为相似。各成矿阶段矿物δ34 S值有部分重叠,表明S同位素组成较为稳定,来源单一。矿床中Pb同位素组成较稳定(206 Pb/204 Pb=18.2984~19.0580,平均18.4991,207 Pb/204 Pb=15.7731~15.8510,平均15.7904,208 Pb/204 Pb=38.6550~39.4110,平均38.8410,n=13),投点主要分布在上地壳演化线上方,△γ-△β图解中分布在地幔与上地壳混合的俯冲型铅和上地壳源铅范围内,表明Pb主要来自以岩浆作用为主的上地壳物质。认为其深部壳源含矿岩浆热液为放羊山矿床的成矿流体和矿质的来源,矿床的形成与深部隐伏中酸性岩体有关。The Fangyangshan Cu-Pb-Zn polymetallic deposit is located in southern Baoshan block,Sanjiang metallogenic belt,between the Changning-Menglian suture zone and Nujiang fault zone,western Yunnan,which is one of the important deposits in the Luziyuan ore-concentration area.Stratiform-like and lens-like orebodies are hosted in marbleized-limestone of Shahechang Formation of Upper Cambrian,occurring in nearly east-west direction.Main ore minerals include chalcopyrite,sphalerite,galenite,pyrrhotite,and pyrite.Gangue minerals include dolomite,chlorite,calcite,quartz and sericite.Based on plenty of field work and analysis of S-Pb isotope samples,this work summarizes the geological characteristics and explores ore mineral sources of the Fangyangshan deposit.Results show thatδ34 S values are about 8.24‰to 14.91‰,with an average value of 11.59‰(13 samples),which is quite similar to nearby deposits such as Shuitoushan and Luziyuan.Some of theδ34 S values of different samples are quite even,implying that they formed in different stages of mineralization.It indicates that S isotopes are quite stable and may share the same source-granite.Pb isotope values vary in a very small interval(206 Pb/204 Pb=18.2984~19.0580,avg=18.4991;207 Pb/204 Pb=15.7731~15.8510,avg=15.7904;208 Pb/204 Pb=38.6550~39.4110,avg=38.8410,sample number is 10).These projection points are distributed above the upper-crustal-evolution line in the“lead isotopic compositions of the sulfides diagram”,and distributed in the magmatism zone and upper crust zone in the“lead isotopic△γ-△βdiagram”.All data suggest that Pb element of the Fangyangshan deposit came from upper crust minerals under the magmatism process in western Yunnan.In sum,this work concludes that upper-crust magma fluids are the original sources of ore-forming fluids of the Fangyangshan deposit,and the formation of orebodies in the Fangyangshan deposit are closely related with concealed intermediate-acid rock bodies at depth in this area.

关 键 词：S-Pb同位素 成矿物质来源 找矿潜力 保山地块 放羊山铜铅锌矿床 

分 类 号：P618.65[天文地球—矿床学] P597[天文地球—地质学]