鄂尔多斯盆地西北部桌子山地区中—新生代隆升事件的确定及其构造意义

发布时间：2018-05-21 09:34

本文选题：桌子山地区 + 中-新生代　；参考：《西北大学》2015年硕士论文

【摘要】：桌子山地区位于鄂尔多斯盆地西北部,该地区为鄂尔多斯盆地构造隆升研究较为薄弱的地方。桌子山地区中-新生代出露地层较全,岩性以砂岩为主。该区自中-新生代以来不同时期受不同构造运动的影响较为强烈。区内断层、褶皱构造发育,且构造线呈近南北向展布。逆冲构造为该区最大的构造特点,且逆冲构造多为断层所破坏。根据区内地层接触关系、地震剖面结构、构造变形特征等可以看出区内部分地层之间出现平行不整合甚至角度不整合,地层不同程度的遭受到剥蚀。从桌子山地区的裂变径迹数据可以得出,该区自三叠纪以来主要经历了以下三个时期的快速隆升阶段：晚侏罗世-早白垩世(155Ma-110Ma)、晚白垩世晚期-古近纪早期(85Ma-45Ma)和新近纪以来(20Ma-OMa)。桌子山东麓断裂东西两侧的样品新近纪以来的隆升速率有一定差异,表明桌子山东麓地区可能存在差异隆升过程。磷灰石裂变径迹热演化史模拟可知桌子山地区中-新生代的隆升剥蚀量可达3000余米。该区地层的隆升剥蚀对应于一定的构造事件。桌子山地区自晚三叠世以来便受构造活动的强烈影响。晚三叠世受印支运动的影响,桌子山地区逐步结束了内陆坳陷环境,局部地区开始遭受剥蚀。早-中侏罗世桌子山地区处于弱拉张环境,接受一定范围的沉积。晚侏罗世,桌子山地区开始强烈隆升,并且主要断裂基本形成。侏罗纪隆升剥蚀量可达700m左右。早白垩世隆升速率减小,到了晚白垩世直至古近纪早期,该区强烈隆升,且构造变形作用进一步加强,褶皱、断裂构造基本形成,面貌已接近现今,白垩纪隆升剥蚀量达到1100m左右。新生代以来桌子山地区受喜马拉雅运动的影响而进一步抬升,特别是自上新世以来该区发生了快速隆升,剥蚀量可达1300m左右。桌子山地区中-新生代以来受周围多个块体的联合影响,这些块体的综合作用铸就了该区复杂的应力环境,这是该区构造现象复杂的根源。桌子山地区不同时期的隆升与区域构造活动密切相关,受控于一定的深部地球动力学环境。
[Abstract]:The Tabaoshan area is located in the northwest of Ordos Basin, where the study of structural uplift in Ordos Basin is weak. Mesozoic-Cenozoic outcrop strata are relatively complete and sandstone is the main lithology in Guoshan area. Since the Mesozoic-Cenozoic, the area has been strongly influenced by different tectonic movements in different periods. In this area, the fault, fold structure is developed, and the tectonic line is distributed in the north-south direction. Thrust structure is the largest structural feature in this area, and the thrust structure is mostly destroyed by fault. According to the stratigraphic contact relationship, seismic profile structure and structural deformation characteristics, it can be seen that there are parallel unconformities or even angular unconformities among some strata in the region, and the strata are eroded to varying degrees. From the fission track data of the Taijiaoshan area, it can be concluded that the area has experienced three stages of rapid uplift since Triassic: late Jurassic-early Cretaceous (155Ma-110 Ma), late Cretaceous to early Paleogene (85 Ma-45 Ma) and Neogene (20 Ma-O Ma.). There are some differences in the uplift rates between the samples from the east and west sides of the table Shandong foot fault since the Neogene, which indicates that there may be a differential uplift process in the table-Shandong foothill area. The thermal evolution simulation of apatite fission track shows that the uplift and denudation amount of Mesozoic to Cenozoic can reach more than 3000 meters. The uplift and denudation of the strata in this area correspond to a certain tectonic event. The Taijiaoshan area has been strongly influenced by tectonic activity since the late Triassic. Due to the Indosinian movement in the late Triassic, the Taijiaoshan area gradually ended the inland depression environment, and the local area began to be eroded. The early-Middle Jurassic table mountain area is in a weak extensional environment and accepts a certain range of deposits. In the late Jurassic, the Taijiaoshan area began to uplift strongly, and the main faults were basically formed. The denudation amount of Jurassic uplift can reach about 700m. From the late Cretaceous to the early Paleogene, the uplift of the area was strong, the tectonic deformation was further strengthened, the fold and the fault structure were basically formed, and the appearance of the uplift was close to that of the present, and the uplift rate decreased in the early Cretaceous period until the early Paleogene. The Cretaceous uplift and denudation amount is about 1100m. Since the Cenozoic, the Taijiaoshan area has been further uplifted by the Himalayan movement, especially the rapid uplift occurred since the Pliocene, and the denudation amount can reach about 1300m. Since the Mesozoic to Cenozoic, the Taijiaoshan area has been influenced by several blocks around the area. The complex stress environment has been cast by the combined action of these blocks, which is the root of the complex tectonic phenomena in this area. Uplift in different periods is closely related to regional tectonic activity and is controlled by a certain deep geodynamic environment.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P542

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