四川省中坝晶质石墨矿床地球化学特征及成因分析  

Geochemical Features and Genesis Analysis of the Zhongba Scaly Graphite Deposit in Sichuan Province

作　　者：夏锦胜 孙莉[1,4] 肖克炎[1,4] 汪君珠[2] 陈贤 崔宁[1,4] XIA Jinsheng;SUN Li;XIAO Keyan;WANG Junzhu;CHEN Xian;CUI Ning(MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;Natural Resources Bureau of Liupanshui,GuiZhou 553000,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Center of Metallogenic Regularity and Prediction,China Geological Survey,Beijing 100083,China)

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]六盘水市自然资源局,贵州六盘水553000 [3]中国地质大学(北京)地球科学与资源学院,北京100083 [4]中国地质调查局矿产资源成矿规律与成矿预测研究中心,北京100037

出　　处：《现代地质》2019年第6期1286-1294,共9页Geoscience

基　　金：国家重点研发计划项目(2016YFC0600504);国家自然科学基金项目(41802250);中国地质调查局地质调查项目“全国矿产资源潜力动态评价”(DD20160100)。

摘　　要：四川省中坝晶质石墨矿床位于康滇地轴中段西缘,是我国重要的晶质石墨矿床之一。通过野外地质特征调查和矿物特征梳理,结合含石墨变质岩系的地球化学特征分析可知,中坝石墨矿床主要赋存在前震旦纪会理群大田组变质岩层中。矿体呈层状、似层状和透镜状产出,主要含矿岩石为白云母石英片岩。矿石平均固定碳含量12. 19%;石墨矿物多呈鳞片状,其中大鳞片石墨(> 0. 15 mm,或> 100目)占67%,中小鳞片石墨(<0. 15 mm,或<100目)占33%;含石墨变质岩系中的Si O2含量很高,Ca O和烧失量含量一般,微量元素分析表明中高场强元素变化范围较小,Ni/Co值为15. 92~41. 04,显示出极度贫氧-厌氧环境。∑REE含量偏高,REE的分异程度高,轻稀土较重稀土富集,Eu和Ce负异常明显。石墨的δ13C值分布范围为-27. 64%^-28. 44%之间,平均为-28. 14%,表明石墨为有机碳成因。综合推测中坝晶质石墨矿床为有机成因的区域变质型晶质石墨矿床。The Zhongba scaly graphite deposit,one of the important graphite deposits in China,with a proved reserve of 15.55 million tons,located on the western margin of central Xikang-Yunnan axis.The study on the geological and geochemical features could be used to help define the genesis of the deposit.Through the field and microscopic observation combining with major and trace elements analysis,the graphite ore bodies are hosted in white mica quartz schist of Datian Formation,Huili Group in Pre-Sinian system in the form of layers and lens.The average grade is 12.19%.Big flake graphite(>0.15 mm)occupies 67%of the total graphite while the small to mediate ones occupies 33%.The graphite-bearing metamorphic rock is rich in SiO2 with poor CaO and LOI.The high field strength elements vary little in the ore.Ni/Co value varies from 15.92 to 41.04 indicating oxygen poor or anaerobic environment.The total REE content is relatively high with high differentiation degree.Light REE content is higher than that of HREE with negative Eu and Ce value.The test results of graphiteδ13 C is from-27.64%to-28.44%,and the average is-28.14%,indicating the causes of graphite is the organic carbon.So,the Zhongba deposit is a regional metamorphic scaly graphite deposit of organic carbon origin.

关 键 词：四川中坝 晶质石墨矿 地球化学特征 矿床成因 

分 类 号：P619[天文地球—矿床学]