坦桑尼亚林迪地区纳钦圭阿石墨矿床地质特征及找矿模型  

Geological characteristics and prospecting model of Nachingwea graphite deposit in Lindi Region,Tanzania

作　　者：杜菊民[1] 陈春生 黄夕川 陈诚 陈焦 刘平 周傲 Du Jumin;Chen Chunshen;Huang Xichuan;Chen Cheng;Chen Jiao;Liu Ping;Zhou Ao(Jiangsu Geology&Engineering Co.Ltd.,Nanjing 210018,Jiangsu,China;Jiangsu Institute of Geology and Mineral Resources Survey,Nanjing 210049,Jiangsu,China)

机构地区：[1]江苏省地质工程有限公司,江苏南京210018 [2]江苏省地质矿产调查研究所,江苏南京210049

出　　处：《地质学刊》2021年第4期341-348,共8页Journal of Geology

基　　金：江苏省地质勘查专项资金项目“坦桑尼亚林迪地区纳钦圭阿石墨矿预查”(苏财建[2018]96号);江苏省省外、国外矿产资源风险勘查专项资金项目“坦桑尼亚林迪地区纳钦圭阿石墨矿普查”(苏矿地发[2019]139号)。

摘　　要：坦桑尼亚林迪地区是世界上重要的石墨成矿带,纳钦圭阿石墨矿是成矿带新发现的典型矿床之一。矿区分南北2个矿段,共圈定工业矿体17条,推断石墨矿物资源量>100万t,固定碳平均品位为4.05%。矿体赋存于石墨片岩-片麻岩中,呈层状、透镜状产出,走向北东—北北东,产状与围岩一致,矿体与围岩呈渐变过渡关系。矿石类型为石墨片岩-片麻岩型,矿石矿物为鳞片状石墨,脉石矿物主要为石英、长石、云母及少量金属矿物。矿石中片度≥147μm(+100目)的石墨占94.43%,工业类型为大鳞片晶质石墨矿石。以视极化率6%为异常下限,共圈定4处激电异常,高极化率异常与低电阻率异常对应良好,探矿工程确定为矿体出露位置。该石墨矿的找矿模型:新元古代莫桑比克活动带中一套中高级副变质岩系为区域找矿标志,石墨片岩、石墨片麻岩露头为矿区找矿的直接标志,延伸方向与地层走向一致的条带状低阻、高极化异常带为地球物理找矿标志。该石墨矿的地质特征及找矿模型可作为在坦桑尼亚寻找同类矿床的参考。The Lindi area is an important graphite metallogenic belt in Tanzania,and the Nachingwea graphite deposit is one of the most recently discovered typical deposits in this metallogenic belt.The mine is divided into a northern section and a southern section,and a total of 17 industrial ore bodies are delineated.The inferred graphite mineral resources amount to more than one million tons,and the average fixed carbon grade is 4.05%.Orebodies occur in graphite schist-gneisses and are produced in a layered and lenticular shape,trending northeast-north-northeast,the occurrence is consistent with the surrounding rock,and the orebody and surrouding rock are in a gradual transition.The ore type is graphite schist-gneiss type,the ore mineral is flake graphite,and the gangue minerals are mainly quartz,feldspar,mica,and a small amount of metal minerals.The ore graphite with a flake length larger than 147μm(+100 mesh)accounts for 94.43%,and the industrial type is large scale flake crystalline graphite ore.Taking the apparent induced polarization rate of 6%as the abnormal lower limit,a total of 4 IP anomalies have been delineated.The high polarization anomalies correspond well with low resistivity anomalies.The ore body is exposed just as verified by the prospecting project.The prospecting model of the graphite deposit is summarized as follows.A set of intermediate and high-level para-metamorphic rock series in the Neoproterozoic Mozambique active zone are regional prospecting signs.Graphite schist and graphite gneiss outcrops are direct signs of prospecting in the mining area.The geophysical prospecting mark is a strip-like low-resistance and high-polarization anomaly zone whose extension direction is consistent with the stratigraphic strike.The geological characteristics and prospecting model of this graphite deposit can provide reference for prospecting for similar deposits in Tanzania.

关 键 词：晶质石墨矿床 地质特征 地球物理特征 找矿模型 坦桑尼亚纳钦圭阿 

分 类 号：P619.252[天文地球—矿床学]