西南地区稀散元素伴生成矿的主要类型及伴生富集规律  

Types of dispersed elements bearing ore-deposits and their enrichment regularity in Southwest China

作　　者：陶琰[1] 胡瑞忠[1] 唐永永[1] 叶霖[1] 戚华文[1] 樊海峰[1] TAO Yan;HU Ruizhong;TANG Yongyong;YE Lin;QI Huawen;FAN Haifeng(The State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,550081)

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室

出　　处：《地质学报》2019年第6期1210-1230,共21页Acta Geologica Sinica

基　　金：中国地质调查局地质大调查项目“大宗急缺矿产和战略性新兴产业矿产调查”工程“我国三稀资源战略调查”(编号12120113078200)、“稀有稀土稀散矿产调查”(编号1212011220804);国家重点研发计划重点专项(编号2017YFC0602503);国家自然科学青年基金项目(编号41703047)资助成果

摘　　要：西南地区稀散元素资源丰富,主要以伴生元素矿床产出,寄主矿床类型主要为沉积岩容矿型铅锌矿(伴生Cd、Ge、Ga、Tl)、锡石硫化物矿床(伴生In、Cd)和沉积型铝土矿(伴生Ga)及含锗煤等。这些矿床往往集中产出,主要分布在三江铅锌铜银多金属矿成矿域、川滇黔铅锌多金属成矿域、滇东南锡多金属矿成矿域、黔西北铝土矿含矿带及滇西第三系含煤盆地。本文以滇东南锡石硫化物矿床(个旧、都龙、白牛场)及沉积岩容矿型铅锌矿(包括兰坪金顶铅锌矿和川滇黔铅锌银多金属成矿域中的会泽、大梁子、天宝山和富乐铅锌矿等)等为主要对象,开展了不同金属硫化物中稀散元素含量及电子探针面扫描分析,查定了稀散元素伴生富集的赋存状态,并在矿床地球化学研究基础上,综合分析了这些稀散元素的伴生富集规律。研究结果进一步表明,稀散元素(In、Cd、Ge、Ga、Tl)伴生富集都具有明确的载体矿物专属性:热液矿床中In、Cd、Ge、Ga主要富集在闪锌矿中,Tl主要富集在黄铁矿中;沉积铝土矿中Ga的载体矿物主要是一水铝石,含锗煤中Ge主要以有机质结合态赋存在腐殖体中。在伴生富集规律上,In主要伴生富集在锡石硫化物矿床中,滇东南三大锡石硫化物矿床(个旧、都龙、白牛场)具有相似的地质地球化学特征,成因上与燕山晚期花岗岩侵入密切相关。沉积岩容矿型铅锌矿普遍含有Cd、Ge、Ga、Tl,但不同矿床在不同稀散金属富集程度上存在明显差异,其中,金顶矿床中的闪锌矿高度富Cd,平均含量达1.23%,其成因可能与生物有机作用有关。临沧盆地西缘含锗煤产出在以花岗岩为基底的帮卖陆相含煤碎屑岩盆地中,具有工业意义的Ge只集中在第一含煤段的煤层中,其含煤段有硅质岩和薄层含碳硅质灰岩,在上部缺乏硅质岩的两个含煤段的煤中无Ge矿化。Ga在铝土矿中的伴生富集具有全球Dispersed elements resources is rich in SW China and the most occur in trace and minor amounts in various ore deposits, few in their own independent deposits.The host ore deposits include sediment-hosted Pb-Zn deposits(associated Cd, Ge, Ga, Tl), Cassiterite sulfide deposits(associated In, Cd) of magmatic hydrothermal origin, Bauxite(associated Ga) and Ge-rich coal, etc.These deposits are distributed in the metallogenic area such as Sanjiang Pb-Zn metallogenic region, Sichuan-Yunnan-Guizhou Pb-Zn metallogenic region, Sn metallogenic region in SE Yunnan, bauxite zone in NW Guizhou province and Tertiary coal-bearing basin in Western Yunnan.In this paper, taking the typical dispersed elements bearing ore-deposits as example, the analysis of dispersed elements contents in various metal sulfides and surface scanning by electron probe were carried out to determine the enrichment and occurrence state of dispersed elements in host minerals in the ores.Combined with metallogeny analyses of the host ore-deposits, the regularity of the dispersed element enrichment are discussed.The study shows that the enrichment of the dispersed elements such as In, Cd, Ge, Ga, Tl has their carrier mineral specificity: In, Cd, Ge and Ga are enriched in sphalerite while Tl is enriched in pyrite in hydrothermal ore-deposits;otherwise, Ga is enriched in aluminium oxyhydroxide in bauxite, and Ge is enriched in huminite in Ge-rich coal seam.Indium is associated withcassiterite sulfide deposits.The three cassiterite sulfide deposits in SE Yunnan(Gejiu, Dulong and Bainiuchang) have similar geological and geochemical characteristics, and their geneses are related to the granite intrusion of late Yanshanian period.Sediment-hosted Pb-Zn deposits generally contain Cd, Ge, Ga and Tl, but it is quite different in enrichment levels of these dispersed elements among them.Sphalerite in Pb-Zn deposits of Sichuan-Yunnan-Guizhou Pb-Zn metallogenic region are rich in Ge, Ga;while sphalerite in Jinding deposit have the highest Cd content in average of 1.23%, w

关 键 词：西南地区 稀散元素 伴生富集 成矿规律 

分 类 号：P618.2[天文地球—矿床学]