【作者】 白勇；

【导师】 周立发；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2012， 博士

【摘要】 鄂尔多斯西南缘跨越了西缘冲断带、天环坳陷、北祁连-北秦岭逆冲推覆构造系、渭北隆起、汾渭地堑、小秦岭构造带等多个构造单元。不同构造体系在不同构造阶段的复合叠加及不同构造体系在同一构造阶段的联合叠加,使得该区现今地质构造及其演化特征极为复杂。燕山期既是奠定研究区现今基本构造格局的关键阶段,也是油气运移和聚集的主要时期,喜山运动则对该构造格局进行了改造,这使得对鄂尔多斯西南缘中、新生代构造特征的研究具有重大意义。本文以板块构造学、构造地质学和盆山耦合理论为指导,以野外地质调查和地球物理资料的处理和综合解释为手段,以历史的演化的观点研究鄂尔多斯西南缘现今基底结构、盖层的构造模式、不同构造层次、不同构造区段构造变形特点,建立现今研究区三维结构模型。通过对重、磁资料进行处理、解释、对部分已有的地震剖面、CEMP剖面重新解释,并以横穿鄂尔多斯西缘和南缘的5条主干地质—地球物理综合解释剖面、相关的辅助剖面及重点构造区段解剖作为研究重点,进行精细的构造研究。研究结果表明：北祁连—北秦岭逆冲推覆构造带的结晶基底与华北地块结晶基底有较大差异,研究区华北地块的结晶基底由2个北东向基底隆起和2个北东向基底断陷组成；研究区存在深层构造与浅层构造的不谐调即立交桥式构造；海原—洛南断裂从铁炉子沿王曲—哑柏断裂向西延伸,向西与八渡—虢镇断裂相连；圣人桥—三门峡—淮南断裂是鄂尔多斯南缘东西向构造带的北界,从富平向西延伸至千阳附近隐入盆地,推测该断裂在研究区内可能向东延伸至三门峡；渭北隆起北缘断裂是鄂尔多斯稳定地块与南缘燕山期构造带的界线；燕山期鄂尔多斯南缘为大型的复背斜,其核部在渭河盆地,渭北隆起为其北翼,小秦岭构造带及洛南地区为与之配套的向斜,渭河盆地很可能不存在上古生界与中生界；在鄂尔多斯西缘冲断构造带,陡立的奥陶系、寒武系、蓟县系主要分布在青龙山—平凉断裂上盘靠近断裂的部位及甜水堡—四十里铺低凸起带上,其主要构造样式为高角度逆冲构造,不存在逆掩推覆构造。更多还原

【Abstract】 The southwest of Ordos spans Ordos’s west thrust belt,Tianhuan depression, north Qilian and north Qinling thrust—nappe structures,northern uplift to Wei river,Fenwei graben and Xiaoqinling structure belt. Different tectonic systems at different stages were added together and the same tectonic system at different stages was added’together,which makes today’s structure and its evolutionary features extremely complex.Yanshan period is not only the key stage at which the foudermental tectonic pattern today was formed in the research region,but is the key period of petroleum and gas accumulation as well.The Hymalayan movement then reformed the pattern.All these things show that the research on the features of Mesozoic and Cenozoic structures in the southwest of Ordos is particularly important,Basaed on plate tectonics,structural geology and basin—range coupling theory, the author makes a research on the basement structure, structure pattern of caprock,structural deformation features at different tectonic areas and different tectonic depths in the view of history and evolution and establishes the three dimentional structure model today of the research region by means of field geolongical survey and geophysical data processing and comprehensive interpretation. By processing and interpreting of gravitational and aeromagnetic data,reinterpreting some of the seismic profiles and CEMP profiles and taking5backbone geological—geophysical comprehensive interpretation profiles which cross west and south of Ordos,relevant supporting profiles and key structural sectors as the focus of research,the author makes a sophisticated research.The results of the research show that north Qilian and north Qinling thrust—nappe structures’crystalline basement is quite different from that of north China block and the crystalline basement of north China block in the research area consists of2NE basemental uplifts and2basemental rifts;there is discordance beteen deep structures and superficial structures in the research region; Haiyuan—Luonan fault extends from Tieluzi to the west along Wangqu—Yabai fault which extends to the west and is connected with Badu—Guozhen fault; Shengrenqiao—Sanmenxia—Huainan fault is the border of Ordos’s west thrust belt which extends west from Fuping to near Qianyang and is buried under the basin,and it is speculated that the fault extends east to Sanmenxia within the research region; the northern edge fault of northern uplift to Wei river is the border beteewn Ordos stable block and the Yanshan period structure belt of south Ordos; During Yanshan period south Ordos is a huge anticlinorium whose core is located at Wei river basin and whose northern wing is northern uplift to Wei river and Xiaoqinling structure belt and Luonan region are the syncline which matches the anticlinorium,and there probably aren’t upper Paleozoic and Mesozoic in Wei river basin;in Ordos’s west thrust belt, the steep dipping Ordovician,Cambrian system and Jixian system are located at the parts of Qinglongshan—Pingliang fault’s hanging wall which are near the fault and Tianshuibu—Sishilipu low uplift belt,where the main structure pattern is high—angle thrust structure and no overthrust nappe exists.更多还原