| 刘文恒,刘继顺,罗江华,潘家永,牛宇奔,杨婉芩.东川南缘雪岭矿区隐伏铜矿地质地球化学特征及成矿机制[J].地质找矿论丛,2018,33(4):495-506 |
| 东川南缘雪岭矿区隐伏铜矿地质地球化学特征及成矿机制 |
| Geological and Geochemical Features and Metallogenic mechanism of concealed copper deposit in Xueling mining area at the southern margin of Dongchuan, Yunnan, China |
| 投稿时间：2017-12-25 |
| DOI：10.6053/j.issn.1001-1412.2018.04.001 |
| 中文关键词: 雪岭矿区 隐伏铜矿床 地质地球化学特征 同位素特征 成矿机制 云南省 |
| 英文关键词:Xueling mining area concealed copper deposit Geological and geochemical characteristics Isotopic signature metallogenic regularity Yunnan province |
| 基金项目:东华理工大学核资源与环境重点实验室开放基金项目（编号：NRE1613）、地质资源经济与管理研究中心开放基金项目（编号：17JC02）、江西省数字国土重点实验室开放基金项目（编号：DLLJ201708）、东华理工大学博士科研基金项目（编号：DHBK201409）联合资助。 |
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| 中文摘要: |
| 雪岭矿区位于康滇地轴云南段东川矿区南缘，区内主要出露震旦系和寒武系沉积地层，其浅部可见铜多金属脉状矿化沿断裂带和辉绿岩脉产出，深部勘探发现了全隐伏在陡山沱组中的层状铜矿。铜矿化以黄铜矿、斑铜矿为主，呈浸染状、网脉状、薄层状和星点状赋存于深灰色破碎状白云岩、黑色炭泥质岩和石英脉中，矿体具明显沉积及热液叠加改造特征。常量元素分析显示岩矿石SiO2、Fe2O3、FeO、K2O等含量较高，而Na2O、CaO和MgO含量偏低；微量元素分析显示围岩Cu、Pb、Zn、Ag元素含量较高，富集U、Y等元素，亏损Nb、Zr、Ti、Yb等高场强元素和Sr，矿石样品则富集U、Nd等高场强元素，亏损Ba、K、Sr等大离子亲石元素和Nb；球粒陨石标准化的稀土元素配分模式为轻稀土富集、重稀土亏损的右倾形态，且呈现出铕的强烈亏损。陡山沱组改造型脉状矿体方解石和黄铁矿样品δDV-SMOW值分别为-137.3×10-3和-110.2×10-3，δ18O水值分别为-11.3×10-3和-1.29×10-3，显示成矿流体来源于大气降水形成的层间封存水；矿石富集重硫，硫主要来源于海相硫酸盐的还原作用，部分受到深部昆阳群古铜矿床硫和生物硫的影响；铅来源于放射性成因铅较高的源区，具壳幔混合铅的特征，且矿石、围岩、昆阳群古铜矿的铅同位素组成具一定亲缘性，显示成矿物质主要来源于下伏昆阳群古铜矿，部分来源于围岩。综合研究认为，该铜矿与滥泥坪矿区所含陡山沱组铜矿相似，均为昆阳群古铜矿残余风化壳在海解作用下铜质析出，在成岩及构造作用下活化迁移并沿炭泥质还原性岩石、石英脉及构造有利位置沉淀富集所致。本区找矿重点应为深部陡山沱组铜矿以及下伏昆阳群古铜矿床。 |
| 英文摘要: |
| The Xueling mining area is located at the southern margin of Dongchuan mining area belonging to Kangdian axis in the Yunnan Province. Here are mainly exposed Sinian and Cambrian sedimentary strata. Cu-polymetallic vein mineralization occur in shallow strata along fault zone and diabase dyke. The concealed stratiform copper deposit was encountered in Doushantuo Formation at depth. The copper minerals are mainly chalcopyrite and bornite, occurring as dissemination, network, lamellar, star spots in dark gray broken dolomite, black carbon muddy rock and quartz vein. The ore bodies have obvious features of sedimentation and hydrothermal superposition and reconstruction. The major elements analysis indicates that the content of SiO2, Fe2O3, FeO, K2O is higher in the rock and ore, while the content of Na2O, CaO, MgO is lower. The trace element analysis of surrounding rocks are characterized by the enrichment of Cu, Pb, Zn, Ag, U, Y and depletion of Sr and high field strength element such as Nb, Zr, Ti, Yb. In addition, ores are rich in high field strength element such as U, Nd and depleted in Nb also the lithophile element such as Ba, K, Sr. The chondrite-normalized REE patterns indicate that they are rich in LREE and deficient in HREE with obvious Eu depletion. δDV-SMOW values of calcite and pyrite of reworked vein orebody in Doushantuo Formation is respectively -137.3‰ and -110.2‰, and δ18O水 values is respectively -11.3‰ and -1.29‰. It shows that the metallogenic fluid was mainly derived from interlayer sealing water formed by meteoric water, the ores enriched in 34S, the sulfur mainly from marine sulfate reduction and mixed with some ancient copper deposit sulfur of deep Kunyang Group and biogenic sulfur, lead from high radioactive genetic Pb source area characterized by crust-mantle mixed lead. There is some consanguinity among lead isotopic compositions for ore, surrounding rock and Kunyang Group's ancient copper deposit thus the metallogenic material mainly came from ancient copper deposit of deep Kunyang Group, partly from the surrounding rock. By synthetic analysis, the copper deposit in Xueling is similar to the copper deposit of Doushantuo Formation in Lanniping mining area. Cu is from halmyrolsis of the weathered crust and activated and migrated by diagenesis and structural activity then enriched along carbonaceous muddy rock, quartz vein and favorable structural place to form mineralization. The prospecting target of Xueling mining area should be focused on the deep copper deposit in Doushantuo Formation and the underlying ancient copper deposit in Kunyang Group. |
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