江苏仑山金矿床金的赋存状态和富集机理研究  

Research on Occurrence and Enrichment Mechanism of Gold in the Lunshan Gold Deposit,Jiangsu Province

作　　者：陆邦成 余金杰[2] 陈春生[3] 王铁柱[2] 车林睿[1] 陆振裕[3] 尹灵强 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]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 [3]江苏省地质矿产局第三地质大队,江苏镇江212001

出　　处：《现代地质》2016年第2期316-327,共12页Geoscience

基　　金：江苏省地质矿产局科研项目(2014-KY-5);国家自然科学基金项目(41372091)

摘　　要：江苏仑山金矿床为新发现的小型金矿床,金矿体赋存于白垩系杨冲组地层中,容矿岩石为碳质泥岩和泥质粉砂岩。金矿石中金属矿物以黄铁矿为主,少量黄铜矿、方铅矿和闪锌矿,非金属矿物为石英、方解石、萤石和绢云母等。成矿阶段分为沉积成岩阶段和热液阶段,后者又细分为Ⅰ和Ⅱ两个亚阶段,沉积成岩阶段和热液Ⅰ亚阶段为主要的成矿阶段。通过典型矿石的扫描电镜-能谱分析以及矿石矿物黄铁矿的电子探针分析,对仑山金矿床金的赋存形式和富集机理进行了初步探讨。结果表明,仑山金矿床中金以显微不可见金和显微自然金二种形式存在,显微不可见金以纳米级自然金(Au0)和固溶体金(Au+)的形式赋存于黄铁矿中,自然金以粒间金和裂隙金的形式赋存于碎屑石英颗粒之间和碎屑石英裂隙中。沉积成岩阶段草莓状黄铁矿、细粒黄铁矿和针状黄铁矿的Co/Ni比值均大于1,暗示其可能受到后期热液作用影响。沉积成岩阶段容矿地层发生了金的预富集,后期热液成矿阶段流体叠加作用最终导致了仑山金矿床的形成。The Lunshan gold deposit is a newly discovered small gold deposit in Jiangsu Province.The gold bodies are hosted in the Cretaceous Yangchong Formation,including carbonaceous mudstone and argillaceous siltstone.The metal minerals are mainly composed of pyrite with minor chalcopyrite,galena and sphalerite. Whereas quartz,calcite,fluorite and sericite are the main non-metallic minerals.Metallogenic stages include sedimentary diagenetic stage,hydrothermal stage Ⅰ and hydrothermal stage Ⅱ.The sedimentary diagenetic stage and hydrothermal stageⅠare the main metallogenic stages.An integration of optical microscopy,scan-ning electron microscopy equipped with energy dispersive system and electron microprobe was used to study the occurence,distribution and enrichment mechanism of gold in the Lunshan gold deposit.The results indicate that gold occur as microscopic invisible and native species.The microscopic invisible gold is present as nanopa-rticles of native gold (Au0 )and solid solution gold (Au +)in pyrite.The visible native gold occurs either as intergranular gold between detrital quartz grains or as fissure gold in the detrital quartzs.The Co /Ni ratios of framboidal,fine-grained and acicular pyrites are greater than one,indicating that they were affected by the late hydrothermal fluids.The preliminary gold enrichment in the sedimentary diagenetic stage superimposed by later ore-forming fluids lead to the formation of the Lunshan gold deposit.

关 键 词：仑山金矿床 成矿阶段 赋存形式 富集机理 江苏 

分 类 号：P618.51[天文地球—矿床学]