黄陵断穹核部鳞片石墨矿地球化学特征与成因研究  

Geochemical Characteristics and Genesis of Flake Graphite Ores in the Core of the Huangling Fault Dome,Hubei Province

作　　者：程林 杨勇 边敏 杨宏伟 刘林 刘海 黄德将 姚敬劬 CHENG Lin;YANG Yong;BIAN Min;YANG Hongwei;LIU Lin;LIU Hai;HUANG Dejiang;YAO Jingqu(Hubei/Central South Institute of Metallurgical Geology,Yichang,Hubei 443003;Hubei Geological Bureau,Wuhan,Hubei 430071)

机构地区：[1]湖北冶金地质研究所(中南冶金地质研究所),湖北宜昌443003 [2]湖北省地质局,湖北武汉430071

出　　处：《地质与勘探》2020年第4期745-758,共14页Geology and Exploration

基　　金：湖北省自然资源厅科技计划项目“黄陵背斜核部晶质石墨矿矿物岩石地球化学及成矿作用的研究”(编号:ETZ2017A07);湖北省自然科学基金重点项目(编号:2015CFA143)联合资助。

摘　　要：黄陵断穹核部石墨矿是我国鳞片(晶质)石墨矿的主要产区,对该区石墨矿的研究具有重要理论和实际意义。该区已有石墨矿研究成果多侧重于矿床地质方面,对矿床成因分析缺乏地球化学支撑。为此,本文从地球化学层面查明石墨矿原岩类型,碳质富集岩相、变质作用和晶质石墨的形成,为矿床成因和成矿作用提供地球化学依据。通过系统采集区内主要石墨矿样品,进行主量元素、微量元素、稀土元素和同位素分析,根据矿床地球化学原理和分析方法,阐明石墨矿的物质来源,成矿元素集散行为和矿床形成机制。根据主量元素含量和组合,推断石墨的原岩为碳质粉砂质泥岩。微量元素的双重性指示石墨矿的物质有两个来源:中太古代野马洞岩组和中太古代东冲河片麻杂岩。独特的稀土元素配分型式说明物源转化为原岩时存在着强烈的地球化学反应。石墨矿的碳同位素组成支持碳质来自有机物的观点。The core of the Huangling fault dome,Hubei Province is a major deposit of flake(crystalline)graphite ore in China.Previous studies of graphite ore in this area focus on geology of the deposit,while lacking geochemical support for the genetic analysis of the deposit thus limiting the further research.To fill this gap,this work investigated the types of primary rocks,carbonaceous enriched lithofacies,metamorphism and formation of crystalline graphite from the geochemical perspective,so as to provide geochemical basis for the genesis and mineralization of the deposit.Research methods include collecting the main graphite ore samples in the area and analyzing the main elements,trace elements,rare earth elements and isotopes.According to the geochemical principle and analysis,the material source of the graphite ore,the distribution pattern of ore-forming elements and the forming mechanism of the deposit were expounded.Results suggest that the primary rock of graphite is carbonaceous silty mudstone according to the content and combination of major elements.Contents and association of bulk elements permit to infer that the protolith of graphite ores is carbonaceous silky mudstone.The dual nature of the trace elements suggests that two kinds of material sources:Middle Archean Yemadong Formation and Dongchonghe gneissic complex.The particular REE distribution patterns indicate the existence of geochemical reactions in the process of conversion from material sources to protolith.The carbon isotope compositions support the argument that graphite carbon originated from organic matter.

关 键 词：鳞片石墨 地球化学 主量元素 微量元素 稀土元素 同位素 黄陵断穹核部 

分 类 号：P571[天文地球—矿物学]