柴达木盆地东北缘石炭系生物礁发育特征及其地质意义  

Carboniferous Organic Reef Development Characteristics and Geological Significance in Northeast Margin of Qaidam Basin

作　　者：王志金 陈世悦[1] 马帅 汪峰 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266555

出　　处：《沉积学报》2017年第6期1177-1185,共9页Acta Sedimentologica Sinica

基　　金：中国地质调查局地质调查项目(12120115003301)~~

摘　　要：对柴达木盆地东北缘石炭系地层中生物礁的发育特征及区域展布进行了系统阐述。基于野外实地考察与室内镜下分析,采用地球化学与岩石学方法相结合,总结归纳柴达木盆地东北缘石炭系生物礁的岩石学特征、生物特征以及地层特征,分析生物礁主要产出层位及规模大小,探讨其古环境与油气地质意义。研究结果表明:柴达木盆地东北缘石炭系造礁生物主要为四射珊瑚,其次为横板珊瑚,发育锥状、盘状的单体珊瑚和管状、丛状、蜂窝状的群体珊瑚,附礁生物为腕足、等;珊瑚礁在岩层中以点状产出,呈不连续带状分布,依据其在地层中的发育规律与展布特征,分为簇状竖直丛生管状珊瑚、簇状水平延伸管状珊瑚以及簇状顶端向下倾斜管状珊瑚;根据岩石中的生物颗粒含量,生物礁灰岩储层岩石类型分为珊瑚骨架灰岩、珊瑚颗粒石灰岩、生物颗粒质石灰岩、含生物颗粒石灰岩以及泥晶灰岩。柴达木盆地东北缘早石炭世以碳酸盐台地环境为主,晚石炭世以海陆交互的潮坪环境为主。研究区石炭系生物礁主要位于下石炭统怀头他拉组三、四段,在石灰沟、旺尕秀等剖面可见厚层油砂,指示柴达木盆地东北缘石炭系具有良好的生烃潜力。The organic reef in the Carboniferous System along the northeast margin of Qaidam Basin was reported in this paper,and the organic reef development characteristics and regional distribution were descripted. Based on field research and indoor microscopic analysis,combining core observation and description,using geochemistry and petrology method,summarizing the biological,stratum and petrology feature of organic reef in Carboniferous,northeast margin of Qaidam Basin. The article analyzed the main output layer and scale of the organic reef,discussed the palaeoenvironment and petroleum geological significance in northeast margin of Qaidam Basin. The results showed that research area＇s Reef-building organism is mainly composed by Tetracoralla and also include some Tabulata,the morphology of coral reef is very abundant,such as pyramidal-shape or plate-shape solitary coral,tubular,fasciculate and cellular colonial coral. Reef-inserted organisms were mainly Brachiopod and crinoid. Coral reef is punctiform or discontinuous banded in stratums,three kinds of types are identified by coral reef developing laws and distributional characteristics：clusters of vertical tubular coral,clusters of horizontal extension tubular coral and clusters of the top downward sloping tubular coral. According to biological content in rock,organic reef can be classified to coral skeletons limestone,coral grain limestone,biological granular limestone,containing biological granular limestone and micrite. In Early Carboniferous epoch in northeast margin of Qaidam Basin,the sedimentary environment is mainly carbonate platform while Late Carboniferous epoch it became tidal flat environments which was a transitional zone between marine and continent. Organic reef in the study area is mainly located in the third or fourth section in Huaitoutala Formation of Lower Carboniferous. It developed good source rock and thick layer of oil sands,showing strong ability of hydrocarbon generation and oil migration process.

关 键 词：柴达木盆地东北缘 石炭系 生物礁 珊瑚 造礁生物 

分 类 号：P618.1[天文地球—矿床学]