黄陵断穹核部鳞片石墨矿成矿作用及成矿模式  

MINERALIZATION AND METALLOGENIC MODEL OF CRYSTALLINE FLAKY GRAPHITE DEPOSITS IN THE CORE OF HUANGLING FAULTED DOME

作　　者：秦元奎 徐江嬿 边敏 程林 张瑜 刘林 姚敬劬 Qin Yuankui;Xu Jiangyan;Bian Min;Cheng Lin;Zhang Yu;Liu Lin;Yao Jingqu(Hubei/Central South Institute of Metallurgical Geology,Yichang,Hubei 443003,China;Hubei Geological Exploration Fund Management Center,Wuhan,Hubei 430071,China)

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]湖北省地勘基金管理中心,湖北武汉430071

出　　处：《矿物岩石》2020年第3期67-79,共13页Mineralogy and Petrology

基　　金：湖北省国土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)(项目编号ETZ2017A07);湖北省自然科学基金重点项目《荆当盆地浅成中低温热液型铜多金属矿成矿规律研究及资源潜力评价》(项目编号2015CFA143)。

摘　　要：黄陵断穹核部是我国鳞片(晶质)石墨矿主要产区,并以品位高(固定碳含量9.44%~13.6%)、片径大(d=0.1~1.5mm)著称,对该区石墨研究具有重要理论和实际意义。前人研究多侧重于变质成矿作用,而对碳质来源、碳质富集等至关重要的沉积成矿作用涉及很少。本次研究开展了以探索沉积成矿作用为主、建立完整的沉积变质成矿模型的研究。详细调研7个主要矿床,采集标本155块,分析各类样品115个,系统恢复变质岩原岩,重建沉积相剖面。研究黄凉河期(Pt1h)的古地理格局,划分沉积相,确定碳质富集有利部位,研究结果认为:该区石墨矿碳质来源于微古植物(小球藻类),藻类在早元古代原始海洋滨海潮坪和潟湖环境繁衍、富集,遗体堆积形成碳质腐泥,为石墨矿提供了物质基础;吕梁期动力热变质作用改变了碳质的赋存状态,使有机碳裂解、单质化、有序化,变成晶质石墨。随着变质程度提高,自绿片岩相、角闪岩相至麻粒岩相,石墨结晶程度变好,片径变大。混合岩化进一步使石墨鳞片聚集,再生加大,形成大片径石墨。对这一类型石墨的地质找矿,应从沉积成矿作用切入,在岩相古地理方面进入深入研究,确立碳质岩系的岩相空间展布特征,选择找矿靶区。The core of Huangling fault dome is the main producing area of flake(crystalline)graphite ore in China,and is famous for its high grade(fixed carbon content 9.44%-13.6%)and large flake diameter(d=0.1-1.5mm),which has important theoretical and practical significance for the study of graphite in this area.Previous studies mostly focused on metamorphic mineralization,but the sedimentary mineralization of carbon source and enrichment was rarely involved.On the basis of establishment of a sedimentarymetamorphic metallogenic model,7major ore deposits were investigated in detail,155specimens were collected,and 115samples of various types were analyzed in order to explore the sedimentation-metallogenesis of the mineralization.The division of paleogeographic pattern and sedimentary facies,determination of positions of carbon enrichment in the Huanglianghe Period(Pt1h)show that the graphite ore micro carbon comes from the ancient algae(small ball algae).Algae thrived and enriched in the early Proterozoic primitive coastal tidal flat and lagoon environment,and the remains accumulated to form carbonaceous sapropel,which provided the material basis for graphite ore.The dynamic thermal metamorphism during the Luliang Period changed the occurrence of carbon,making the organic carbon split,homogenized and ordered into crystalline graphite.With the increment of metamorphism,the degree of graphite crystallization improved and the flake diameter increased from greenschist facies,amphibolite facies to granulite facies.The migmatization further led to the accumulation and enlargement of flaky graphite.It is proposed that the geological prospecting of this type of graphite should start from the sedimentary mineralization,combined with the study in the aspect of lithofacies and paleogeography.The establishment of the lithofacies spatial distribution characteristics of carbonaceous rock series is necessary for selecting target area.

关 键 词：黄陵断穹核部 鳞片石墨 成矿作用 成矿模式 

分 类 号：P611.31[天文地球—矿床学]