鄂尔多斯盆地奥陶系马五_(5)亚段沉积微相与古地理演化  

Microfacies and Paleogeographic Evolution of Ma_(5)^(5) Member in the Ordovician,Ordos Basin

作　　者：苏中堂 佘伟[2] 罗静兰 马国伟[3] 张帅 SU ZhongTang;SHE Wei;LUO JingLan;MA GuoWei;ZHANG Shuai(State Key Laboratory of Continental Dynamics,Northwest University,Xi’an 710069,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Oil&Gas Technology Research Institute,Changqing Oilfield Company,Xi’an 710018,China)

机构地区：[1]西北大学大陆动力学国家重点实验室,西安710069 [2]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059 [3]长庆油田油气工艺研究院,西安710018

出　　处：《沉积学报》2021年第6期1344-1356,共13页Acta Sedimentologica Sinica

基　　金：中石油科技重大专项(2016E-0514)。

摘　　要：碳酸盐岩微相分析有利于认识沉积相展布特征和古地理演化规律,对油气勘探具有指导意义。通过大量薄片、岩心资料在鄂尔多斯盆地奥陶系马五_(5)亚段划分出MFT1—MFT7七种沉积微相类型及MA1—MA4四种沉积微相序列,沉积微相与生物遗迹化石指示马五_(5)亚段为潮坪环境。结合沉积前古地形及古海平面变化信息,以单因素图件为基础,采用优势相法编制马五_(5)^(2)层(Ⅰ)、马五_(5)^(1)层(Ⅱ)岩相古地理图,沉积环境受沉积前古地形控制而分异:潮上带、潮间上带、潮间下带及潮下带自西向东依次分布,盆地东部高地形处发育潮间带沉积;随古海平面下降,马五15期沉积相带向东迁移,东部潮间带连片分布。Analysis of carbonate microfacies is helpful for understanding the distribution of sedimentary facies and the evolution of paleogeography,which is of guiding significance in oil and gas exploration.Based on a large number of thin-section data and core information,seven types of microfacies(MFT1MFT7)and four types of sedimentary array(MA1MA4)were defined in the Ordovician Ma^(5)^(5) member of the Ordos Basin.Microfacies and trace fossils show that the environment of the Ma_(5)^(5) member was a tidal flat.Paleogeographic maps of layers I and II were compiled,indicating that the environments were controlled by the paleotopography:a supratidal zone,an intertidal zone and a subtidal zone occur in sequence from west to east;the intertidal zone was also found in high terrain in the eastern basin.As the sea-level fluctuated,the facies migrated to the east,and the intertidal zone in the east was contiguous.

关 键 词：微相 沉积序列 沉积模式 古地形 构造—沉积分异作用 

分 类 号：P618.13[天文地球—矿床学]