鄂尔多斯地区中新元古代构造沉积演化研究

Tectonic and depositional evolution of Meso-NeoProterozoic in Ordos Area

综合利用地质、测井和地震等资料,探究鄂尔多斯地区中新元古代的构造沉积演化过程,以便恢复研究区中新元古界的原始构造沉积格局和开展深层油气勘探。研究结果表明,研究区中新元古代长城纪、蓟县纪、青白口纪和震旦纪经历了4个构造-沉积演化阶段:裂谷阶段、被动大陆边缘阶段、边缘沉降阶段和边缘坳陷阶段。研究后认为,长城系主要为一套陆相-滨海相石英砂岩沉积建造,发育辫状河、三角洲、滨浅海、浅海和深海等沉积相。蓟县系主要为浅水陆表海沉积,发育砂坪、云坪、燧石云坪、开阔台地和浅海等沉积相。青白口系主要为滞留海盆和大陆斜坡等沉积环境。震旦系主要为冰川沉积,发育大陆冰川、滨岸、陆棚等沉积相。

The tectonic and sedimentary evolution of Meso-Neo Proterozoic in Ordos Area is ascertained in order to restore the original tectonic and sedimentary pattern and to explore oil and gas.In this paper,based on geological,seismic and logging data,the tectonic and depositional evolution of Meso-Neo Proterozoic have been studied in Ordos Area.The research shows that the Ordos Area underwent four tectonic and sedimentary evolutionary stages in Changchengian,Jixianian,Qingbaikou and Sinian Period of Meso-Neo Proterozoic.They are rift,passive continental margin,marginal subsidence and marginal depression,respectively.The Changchengian System was mainly composed of a set of terrestrial-littoral facies quartz sandstone,and developed braided river,delta,littoral shallow sea,shallow sea and deep sea sedimentary facies.The Jixianian System was mainly epeiric sea sedimentary facies with shallow water,including sand flat,dolomitic flat,flint dolomitic flat,open platform and shallow sea facies.Within Qingbaikou Period,the sedimentary environment of Ordos Area was retention marine basin and continental slope.There was glacial deposits in the Sinian System developed continental glacier,littoral sediment and shelf sedimentary facies.