南秦岭大型钡成矿带有机地球化学特征与生物标示物研究  

RESEARCH ON THE ORGANIC GEOCHEMISTRY AND BIOMARKERS OF THE LARGE-SCALE BARIUM METALLOGENIC BELT IN THE SOUTHERN QINLING MOUNTAINS,CHINA

作　　者：刘家军[1] 柳振江[1] 杨艳[1] 杨丹[2] 冯彩霞[3] 谢徽[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室 [2]中国地质科学院矿产资源研究所流体包裹体与成矿模拟实验室,北京100037 [3]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550002

出　　处：《矿物岩石》2007年第3期39-48,共10页Mineralogy and Petrology

基　　金：国家自然科学基金(40573032);高等学校学科创新引智计划(B07011);中国地质大学地质过程与矿产资源国家重点实验室项目(GPMR0527)

摘　　要：在南秦岭一带的下寒武统硅岩建造中,既存在一大批重晶石矿床,又发育大量毒重石矿床,构成世界上极为罕见的大型钡成矿带。通过对矿床中岩矿石的热解、有机碳分析、氯仿沥青"A"抽提及生物标志化合物等研究,认为含矿地层中有机质的先质母体为菌藻类生物,某些生物标志物指标指示了沉积环境为封闭的缺氧环境。有机质演化受热和生物降解双重作用影响,接近和达到了成熟阶段。在含矿岩石与矿石中,Ba与有机碳含量具有不协调的负相关趋势,有机质成熟度越高,越利于Ba的富集。钡的超常富集,不仅是一个消耗大量有机碳的过程,而且是有机质成熟度不断加深的过程。More than 70 witherite and barite deposits occurred in the southern Qinling Mountains, and constituted a unique large-scale Ba metallogenic belt in the world. The ore bodies were hosted in the Lujiaping Formation of lower Cambrian. The study of organic geochemistry and bio-makers from some samples showed that the main organism in the ore-hosted strata contained the low and aquatic algae, and some bio-makers indicated that the sedimentary environment might be close to anoxic condition. The organic matters were close to maturation or reaching to maturation, which was thought to be influenced by both heating and biodegradation. In the orehosted rocks and ores, barium and organic carbon showed a tendency of negative correlation, this suggested that, to some extent, barium accumulation was consistent with the evolution of organic matter maturity. In the process of unconventional Ba enrichment, a lot of organic carbons were depleted and the maturity of organic matter became higher.

关 键 词：重晶石矿床 毒重石矿床 钡成矿带 有机地球化学 生物标志物 沉积环境 南秦岭 

分 类 号：P619.251[天文地球—矿床学]