陕西马元铅锌矿床中有机质的存在及其对成矿的作用  

The Existence and Effect of Organic Matter in the Mineralization Process of Mayuan Pb-Zn Deposit,North of the Yangtze Plate,China

作　　者：宋志娇[1] 陈翠华[1] 尹力[2] 张燕[1] SONG Zhijiao;CHEN Cuihua;YIN Li;ZHANG Yan(School of Earth Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Land and Resources Bureau of Pujiang,Chenndu,Sichuan 611630,China)

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]蒲江县国土资源局,四川成都611630

出　　处：《现代地质》2018年第6期1272-1282,共11页Geoscience

基　　金：国家自然科学基金面上项目(41372093);四川省科技计划项目(2018JY0477);资源勘查工程专业教育部卓越工程师教育培养计划项目(11100-18Z0524)

摘　　要：马元铅锌矿床位于扬子地台北缘,米仓山隆起带东段,是扬子地台周缘地区重要的铅锌矿床之一。矿体赋存于震旦系灯影组角砾状白云岩中,矿石中见大量沥青与闪锌矿、方铅矿紧密共伴生。为探讨马元铅锌矿床中有机质对铅锌成矿的作用,对矿床中的沥青、矿石及围岩进行了系统的矿相学、岩相学、显微测温、激光拉曼成分分析及碳同位素研究。结果表明:矿床中有机包裹体发育,且有机包裹体中含有甲烷、乙烷、硫化氢、二氧化碳等组分;包裹体均一温度、沥青的镜质体反射率所计算的演化最大古地温与碳同位素特征显示,矿床中的有机质可能是由震旦系灯影组地层中的古油藏发生热裂解形成,古油藏的热裂解为成矿作用提供了还原环境,并为成矿流体中的金属离子沉淀提供了还原硫。Mayuan lead-zinc deposit is located in the east of Micangshan tectonic belt,the northern margin of the Yangtze plate,which is one of the most important lead-zinc deposits in this area.The ore body is hosted in the Sinian Dengying Formation breccia dolomite,and there is a large amount of bitumen associated with sphalerite and galena in ores.In order to explore the effect of organic matter on lead-zinc mineralization in Mayuan lead-zinc deposit,detailed study of mineralogy,petrography,microthermometry and systematic analysis of laser Raman spectra and carbon isotopic compositions were carried out on bitumen,ores and surrounding rocks.The results show that there are a large number of organic inclusions in the deposit,and the organic inclusions are composed of CH4,C2H6,H2S,CO2 and other components.The result of homogenization temperature of inclu-sions,the maximum palaeotemperature calculated by vitrinite reflectance of bitumen and carbon isotopic compositions show that the organic matter in the deposit may be formed by thermal cracking of the paleo-oil reservoir once existed in the Sinian Dengying Formation.The thermal cracking of the paleo-oil reservoir provided a reduction environment and a reduction sulfur for lead-zinc mineralization.

关 键 词：有机质 流体包裹体 碳同位素 铅锌矿床 陕西马元 

分 类 号：P611.22[天文地球—矿床学] P618.42[天文地球—地质学]