松辽盆地西南部钱家店铀矿床富矿砂岩中烃类地球化学特征  

Geochemical characteristics of hydrocarbons in ore-rich sandstones in the Qianjiadian uranium deposit,southwestern Songliao Basin

作　　者：赵龙 陈浩[1] 蔡春芳[2] 金若时 魏佳林 ZHAO Long;CHEN Hao;CAI Chunfang;JIN Ruoshi;WEI Jialin(College of Resources and Environmental Engineering,Mianyang Teachers’College,Mianyang 621000,Sichuan,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Tianjin Center,China Geological Survey,Tianjin 300170,China)

机构地区：[1]绵阳师范学院资源环境工程学院,四川绵阳621000 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国地质调查局天津地质调查中心,天津300170

出　　处：《地质通报》2022年第2期498-508,共11页Geological Bulletin of China

基　　金：绵阳师范学院科研启动项目《松辽盆地西南部砂岩型铀矿床中微生物和油气参与铀成矿作用研究》(编号:QD2019A06);科技部重点研发项目深地资源勘查专项《北方砂岩型铀能源矿产基地深部探测技术示范》(编号:2018YFC0604200);国际地球科学计划项目《砂岩型铀矿表生流体成矿作用》(编号:IGCP657)。

摘　　要：松辽盆地西南部钱家店铀矿床的形成与油气充注和微生物还原作用有关,但该铀矿床中油气的来源及其烃源岩类型、沉积环境、成熟度、潜在的充注多期次性等问题并没有深入研究。对该矿床富矿砂岩中吸附烃和包裹体烃进行离线破碎法抽提,通过色谱-质谱分析探讨烃类的地球化学特征。结果显示,吸附烃和包裹体烃具有相似的组成,均显示淡蓝色的荧光特征;含矿层中至少有2期石油充注混合,早期充注的石油发生了严重的生物降解作用,C_(15+)范围内存在很多未分离的复杂混合物(UCM),含C_(26)~C_(30)17α,21β25-降藿烷系列化合物;晚期充注的石油未发生或发生了轻微的生物降解,生物标志化合物指示其来源于下白垩统九佛堂组烃源岩,该烃源岩形成于半深湖—深湖局部水体分层的还原环境,有机质类型为腐殖-腐泥型,热演化程度已经达到成熟。作为研究油气和微生物参与砂岩型铀矿成矿作用系统性研究的一部分,对完善该研究体系具有重要意义,也可为油铀兼探、煤铀兼探等多矿种综合勘查提供帮助。The formation of the Qianjiadian uranium deposit in the southwest of Songliao Basin is related to hydrocarbon charging and microbial reduction.However,the origin of oil and gas in the uranium deposit and the types of source rocks,sedimentary environment,maturity and potential multi-stage charging have not been thoroughly studied.The geochemical characteristics of hydorcarbons from adsorbed organic matter and inclusions in ore-rich sandstones were analyzed by means of off-line crushing extracting method and gas chromatography-mass spectrometry.The result shows that two types of hydrocarbons have light blue fluorescence emission color,suggesting similar compositions,and at least two stages of petroleum charge the uranium reservoir.The earlier charged petroleum was heavily biodegraded,showing large unresolved complex mixture(UCM)humps and a suite of C_(26)~C_(30)17α,21β25-norhopanes.The later charged petroleum was not or just slightly biodegraded,and biomarkers indicate that it was derived from the Lower Cretaceous Jiufotang Formation which was mature humic-sapropelic source rock deposited in a reduced and stratified semi-deep/deep lacustrine.As part of the systematic work of studying biogenic and petroleum-related uranium mineralization in sandstone-hosted uranium deposit,this result is of great significance to improve the research system,and is also helpful to multi-mineral comprehensive exploration such as oil-uranium co-exploration and coal-uranium co-exploration.

关 键 词：砂岩型铀矿 吸附烃 烃类包裹体 生物标志化合物 钱家店铀矿 油铀兼探 矿产勘查工程 

分 类 号：P619.14[天文地球—矿床学] P618.13[天文地球—地质学]