安徽桐城板桥地区晶质石墨矿物学特征及成矿变质作用分析  

Analysis of Mineralogical Characteristics and Mineralization Metamorphism of Crystalline Graphite in Banqiao area,Tongcheng,Anhui Province

作　　者：李小东[1] 雷丁尔 LI Xiao-dong;LEI Ding-er(Geological Survey of Anhui Province(Anhui Institute of Geological Science),Hefei 230001,China)

机构地区：[1]安徽省地质调查院(安徽省地质科学研究所),安徽合肥230001

出　　处：《中国非金属矿工业导刊》2025年第1期26-30,36,共6页China Non-Metallic Minerals industry

基　　金：安徽省公益性地质工作项目“宣城地区晶质石墨矿调查评价”(编号:2022-g-1-6)。

摘　　要：桐城板桥地区位于大别造山带东侧,北淮阳浅变质带与大别杂岩带的接触带附近,是安徽省区域变质型晶质石墨矿的重要找—成矿区之一。本文运用多种矿物学研究方法,对安徽桐城地区的晶质石墨矿物学特征开展研究,并对石墨成矿变质作用进行分析。研究显示,石墨矿石样品中的晶质石墨呈鳞片状,石墨鳞片厚度60.52~71.93nm,C原子含量在92.03%~97.41%;石墨化度值在0.69~0.709,(002)层面间距为0.3354~0.3355nm,3R多型含量17.95%~18.66%;δ^(13)C值为-31.203‰~-29.4‰,表明碳质的主要来源为地层中的生物有机碳质,更接近泥炭及现代有机质水平;成矿变质作用分析显示,拉曼估算变质温度约为490℃,结合粉晶衍射特征参数判断,研究区石墨变质相为低变质绿片岩相,不高于普通角闪岩相,为区域变质成因。The Banqiao area of Tongcheng is located on the eastern side of the Dabie orogenic belt,near the contact zone between the North Huaiyang epimetamorphic belt and the Dabie complex belt,which is one of the important prospecting-metallogenic areas of metamorphic crystalline graphite deposits in Anhui Province.In this paper,a variety of mineralogical research methods are used to study the mineralogical characteristics of crystalline graphite in Tongcheng area of Anhui Province,and the mineralization and metamorphism of graphite are analyzed.The results show that the crystalline graphite in the graphite ore sample is scaly,the thickness of graphite flake is 60.52~71.93nm,and the content of C atom is 92.03%~97.41%;The graphitization degree is between 0.69 and 0.709,the(002)plane spacing is 0.3354~0.3355nm,and the 3R polymorphism content is 17.95%~18.66%;The carbon isotope analysis shows that the δ^(13)C value is-31.203‰~-29.4‰,indicating that the main source of carbon is the biological organic carbon in the stratum,which is closer to the level of peat and modern organic matter;The analysis of metallogenic metamorphism shows that the metamorphic temperature estimated by Raman is about 490℃.Combined with the characteristic parameters of powder diffraction,the graphite metamorphic phase in the study area is low metamorphic greenschist facies,which is not higher than ordinary amphibolite facies,and is the cause of regional metamorphism.This study can provide a theoretical reference for the study of the metallogenic process of crystalline graphite in Tongcheng area.

关 键 词：安徽桐城 晶质石墨 矿物学特征 变质作用 区域变质 

分 类 号：P619.252[天文地球—矿床学]