石碌钴-铜矿床流体包裹体和稳定同位素特征及成因  

Fluid inclusions, stable isotopes and origin of Shilu Co-Cu deposit,Hainan Province

作　　者：余金杰[1] 任军平[2] 陈福雄[3] 王永辉[3] 梁将 车林睿[4] 

机构地区：[1]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [2]天津地质调查中心,天津300170 [3]海南矿业联合有限公司,海南昌江572700 [4]中国地质大学,北京100083

出　　处：《矿床地质》2013年第5期884-898,共15页Mineral Deposits

基　　金：国土资源部公益性行业科研专项经费项目“我国典型金属矿科学基地研究(编号:200911007-24)”;国家重点基础研究发展规划项目(编号:2012CB416803)联合资助

摘　　要：海南石碌钴-铜矿体赋存于石碌群第六层的下段,即介于铁矿体与石碌群第五层片岩之间的含钴-铜层位中,容矿岩石主要为白云岩、透辉石透闪石化白云岩。钴-铜矿床的形成经历了海底喷溢沉积期、石英-硫化物期(热液期)和表生期。海底喷溢沉积期石英包裹体均一温度变化于112~205℃,多集中在130~205℃;盐度w(NaCleq)为1.74%~6.59%;密度变化于0.88~0.95 g/cm3。温度范围与很多古代沉积喷流矿床及正在活动的海底热液成矿作用的温度相似,盐度低于曾报道的多数沉积喷流矿床的流体包裹体盐度值,但与那些同为低密度成矿流体的喷流沉积矿床极为相近。海底喷溢沉积期形成的硬石膏δ34S值为+21.4‰^+21.8‰,平均值为+21.6‰,强烈富集重硫,硬石膏δ34S值代表着新元古代石碌群沉积时海水的δ34S值。石英-硫化物期石英、白云石和方解石均一温度多集中在170~270℃;盐度w(NaCleq)为1%~7%;密度变化于0.88~0.95 g/cm3。成矿流体属于中温低盐度流体。石英-硫化物期成矿流体δD值为-63‰^-83‰,成矿流体δ18O水值变化于1.3‰~6.8‰之间,指示成矿流体来源于岩浆,成矿后期有大气降水的加入。石英-硫化物期硫化物δ34S值为+8.1‰^+21.2‰,硫源来源于石碌群中蒸发岩的溶解作用。石碌钴-铜矿床属中温热液充填交代矿床,与矿床周围花岗质岩浆活动有关。The Shilu Co-Cu ore bodies hosted in lower 6th member of the Neoproterozoic Shilu Group occur between schist of 5th member of the Neoproterozoic Shilu Group and the iron ore bodies.These ore bodies are hosted by dolomite and diopsidic and tremolitic dolomite.The Shilu Co-Cu ore-forming process has experienced exhalative sedimentation,epigenetic silicification and sulfidation,and supergene enrichment stages.The homogenization temperatures of fluid inclusions in exhalative sedimentary quartz vary from 112℃to 205℃,mostly between 130℃and 205℃,similar to those of the ancient and modern seafloor exhalative sedimentary deposits.The salinitiesw（NaCleq）of sedimentary fluid inclusions vary from 1.74%to 6.59%,lower than those of many exhalative sedimentary deposits and equal to those of the lower dense exhalative sedimentary deposits.The densities of sedimentary fluid inclusions vary from 0.88 to 0.95 g/cm3.Theδ34S values of exhalative sedimentary anhydrites present a narrower range,from＋21.4‰to＋21.8‰,indicating that sulfur was derived directly from sea water.The homogenization temperatures of fluid inclusions in quartz,dolostone and calcite of the quartz-sulfide period are mostly concentrated on 170-270℃,with a salinityw（NaCleq）range of 1%to 7%and a dense range of 0.88 to 0.95 g/cm3,indicating that the ore-forming fluids of the quartz-sulfide period were mesothermal and had low salinities.Theδ34S values of sulfides in Co-Cu ores of the quartz-sulfide period vary from＋8.1‰to＋21.2‰,indicating that the sulfur was derived either directly from a anhydrite source or from a dissolution of evaporite rocks rather than being of magmatic origin.TheδD values of quartz of the quartz-sulfide period vary from-63‰to-83‰and theδ18OH2Ovalues of quartz are between＋1.3‰and＋6.8‰, suggesting that the ore-forming fluid was mainly from magma with the later addition of some meteoric water. The authors hold that the Shilu Co-Cu deposit is a mesothermal metasomatic and infilling deposit associated wi

关 键 词：地球化学 流体包裹体 稳定同位素 钴-铜矿床成因 石碌 

分 类 号：P618.62[天文地球—矿床学] P618.41[天文地球—地质学]