地质论评2009，Vol.55Issue(6)：761-774,14.
鄂尔多斯盆地侏罗纪西界分析
On the Jurassic West Boundary of the Ordos Basin
摘要
Abstract
Because different geological structures with different properties formed in different periods were superposed together, western boundary of the Ordos Basin, especially the one in the Early-Middle Jurassic, is obscure and not easy to be discerned. So far, there has been no consensus in academy whether it located on west of the Helan Mountain or on east of the Yinchuan Basin (a Cenozoic basin situated to east of the Helan Mountain), affecting mineral resource appraisal and exploration. Based on the former research and our work, different ancient structures formed in different periods in Mesozoic are analyzed and sieved, and then the Early-Middle Jurassic western boundary of the basin is recovered. Writers consider that the huge north-south compressive structure formed in the Late Jurassic while east-west compressive structure formed in the Late Triassic. These two structures were superposed together, resulting in multiple deformations, complex superimposed structures and the irregular west basin boundary. The structure later is much clearer, appearing as a north-south thrust zone and a north-south "the Ancient Land Rise" across the basin. Since formation of the north-south compressive structure, west boundary of the basin was retreated eastward to east of the Zhuozhi Mountain thrust, the Hengshanbao-Ciyaobao fault and fold zone, the Maerzhuang thrust fault as well as the Kongdong Mountain thrust fault. However, the early compressive structure is obscure, appearing discontinuously and indistinct because of superimposing and reforming by the later. The early east-west compressive structure formed in Indosinian movement under the ancient Asian tectonic domain, while the later north-south compressive structure formed in the Yanshanian movement under the Pacific tectonic domain. During the transitional period of the Early-Middle Jurassic from the Ancient Asian to Pacific tectonic domains, the west Ordos Basin had developed nearly east-west tensional structure, forming nearly east-west uplifts and depresses, resulting in irregular instead of linear west boundary at north-south trend. Under this situation, "the ancient Yinchuan uplifts" and "the large Ordos Basin" coexisted, not controversial. The west boundary in the Early-Middle Jurassic was probably located in the Alxa Massif. The Mesozoic structures above were reformed again in Cenozoic, making the former structures more complicated and even complete destroy. Paying attention to structural analysis and sieving would be very important in the discussion on the Mesozoic structures and ancient boundaries of the basin.关键词
鄂尔多斯盆地西界/侏罗纪/三叠纪/叠加构造/构造筛分Key words
west boundary of the Ordos Basin/ Triassic/ Jurassic/ superimposed structures/ structural sieving分类
天文与地球科学引用本文复制引用
张珂,邹和平,刘忠厚,马占武..鄂尔多斯盆地侏罗纪西界分析[J].地质论评,2009,55(6):761-774,14.基金项目
本文为中国核工业地质局鄂尔多斯盆地西部铀成矿规律研究项目(编号HDKY0506-1)和国家自然科学基金资助项目(编号40672124)的成果. （编号HDKY0506-1）
