辽河盆地西部凹陷沙河街组砂岩碳酸盐胶结物特征  

Characteristics of Carbonate Cements in Sandstone of Shahejie Formation in Western Depression,Liaohe Basin

作　　者：朱芳冰[1,2] 周红[1,2] Zhu Fangbing;Zhou Hong(School of Earth Resources,China University of Geosciences,Wuhan 430074,China;Key Laboratory of Tectonics and Petroleum Resources,Ministry of Education,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学资源学院,湖北武汉430074 [2]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074

出　　处：《地球科学》2022年第12期4724-4730,共7页Earth Science

基　　金：国家自然科学基金重大项目(No.41690130).

摘　　要：碳酸盐胶结物中氧碳同位素组成研究是分析成岩过程中流体-岩石相互作用的重要技术方法.综合运用岩石学、矿物学和地球化学方法,对辽河盆地西部凹陷沙河街组砂岩中碳酸盐胶结物的化学组成和碳酸盐胶结物及成岩流体同位素组成特征进行系统分析.研究表明,研究区碳酸盐岩主要为方解石和白云石,胶结物主要类型为嵌晶式胶结、孔隙式胶结、斑块状胶结和星点状胶结.碳、氧稳定同位素组成能有效地反映成岩-成矿流体及其他物质的来源,碳酸盐胶结物与现今浅层地下水氧同位素组成差异巨大而与变质水同位素组成具有相似性,反映了盆地演化过程中活动热流体对成岩作用的影响.包裹体的氢、氧同位素组成可表征成矿溶液的演化特征,砂岩碳酸盐胶结物包裹体更富集氢的轻同位素和氧的重同位素,表明发生了明显的“氧-18漂移”.碳酸盐胶结的成矿溶液表现出“受热雨水”的同位素组成特征,反映了深源活动热流体对成岩作用的影响.The study of oxygen and carbon isotopic compositions of carbonate cements is an important technical method to analyze fluid-rock interaction during diagenesis.By means of petrology,mineralogy and geochemistry,the chemical composition and isotopic composition of carbonate cements and diagenetic fluids in sandstones of Shahejie Formation in western depression of Liaohe basin are systematically analyzed.The results show that the carbonate rocks in the study area are mainly calcite and dolomite,and the main types of cementation are inlaid cementation,pore cementation,patchy cementation and star-point cementation.The stable isotopic composition of carbon and oxygen can effectively reflect the origin of diagenetic and ore-forming fluids and other materials.The oxygen isotopic composition of carbonate cements is very different from that of shallow groundwater but similar to that of metamorphic water,which reflects the influence of active thermal fluid on diagenesis during basin evolution.The hydrogen and oxygen isotopic compositions of the inclusions can represent the evolution characteristics of the ore-forming solutions.The inclusions of the sandstone carbonate cements are enriched with light isotopes of hydrogen and heavy isotopes of oxygen,indicating the obvious"oxygen-18 drift".The carbonate cemented ore-forming solution shows the isotopic composition of"heated rain",which reflects the influence of deep active thermal fluid on diagenesis.

关 键 词：辽河盆地 沙河街组 碳酸盐胶结物 同位素地球化学 石油地质 

分 类 号：P618[天文地球—矿床学]