鄂尔多斯地区中新元古代构造沉积演化与岩相古地理研究

Meso-Neoproterozoic of Ordos area is a potentially important exploration area of concern. For a long time, the fundamental geological research on Ordos area especially the tectonic and sedimentary evolution of Ordos basin does not give enough attention, and research status of meso-Neoproterozoic in Ordos area can not meet the demand of oil and gas exploration. Therefore, this subject on the basis of previous work, comprehensive geological section, drilling, logging, seismic, gravity and magnetic data，Archean and Proterozoic basement structure and "aulacogen" of the Ordos area will be redefined and the meso-Neoproterozoic stratigraphic division and correlation scheme will be established. The relationship of the spatial distribution of the meso-Neoproterozoic strata and the tectonic and sedimentary evolution will be found out in order to investigating the tectonic attribute and lithofacies paleogeographic pattern of prototype basins in different tectonic period. Based on the findings above，regional geodynamics of sedimentary basins formed in different periods of the meso-Neoproterozoic will be studied. The results of these studies will provide the basic data for geological research and guidance for oil and gas exploration of Meso-Neoproterozoic in Ordos area.This will have important theoretical meaning and realistic economic value.

鄂尔多斯地区中新元古界是一个值得关注的重要潜在勘探领域。长期以来，其基础地质研究尤其是盆地的构造沉积演化未给予足够重视，研究现状尚不能满足油气勘探的需求。因此，本项目在前人研究的基础上，综合野外地质剖面、钻井、测井、地震、重磁等资料，对鄂尔多斯地区太古代-元古代基底构造与“坳拉槽”重新厘定；建立该地区中新元古代地层划分对比方案，查明中新元古界空间展布规律和中新元古代构造沉积演化过程，探索中新元古代不同构造时期原型盆地的构造属性及岩相古地理格局; 在此基础上，探讨中新元古界不同时期沉积盆地形成的区域地球动力学背景。以期为鄂尔多斯地区中新元古界地质研究提供基础资料，并为中新元古界油气勘探提供指导，这将具有重要的理论意义和现实的经济价值。

为了查明鄂尔多斯地区中新元古界构造沉积演化过程，本项目在前人研究的基础上，综合野外地质剖面、钻井、测井、地震、重磁等资料，对鄂尔多斯地区中新元古界结晶基底、地层系统、原盆属性、岩相古地理、演化过程和地球动力学背景进行了研究，其结果为鄂尔多斯地区中新元古界地质研究提供了基础资料，并为中新元古界油气勘探提供了指导，具有重要的理论意义和现实的经济价值。研究结果揭示鄂尔多斯地区基底结构具备横向分块的不均一性镶嵌的特点，具有坳、隆相间的格局。西磑口“霍山砂岩”应归位于长城系，高山河群归属于中元古界长城系上部，渣尔泰山群对应于长城系。长城纪原盆属性为陆内裂谷，沉积了大面积的滨海及浅海相石英砂岩，主要发育近岸扇、扇三角洲、低隆、滨海、局限浅海、浅海和深海等沉积相；蓟县纪原盆属性为大陆边缘坳陷，主要发育砂坪、砂云坪、燧石云坪、开阔海台地和浅海等沉积相，沉积厚层燧石结核/条带白云岩；震旦纪原盆属性为边缘坳陷，仅在周缘残留冰期冰碛砾岩与间冰期泥页岩。鄂尔多斯地区中新元古代经历了基底拼合阶段、长城纪大陆裂谷发育阶段、蓟县纪陆表海阶段和震旦系边缘坳陷阶段等几个演化阶段。