鄂尔多斯盆地西部冲断推覆构造带研究新进展  

New Progress in Research of the Thrust-Nappe Tectonics in Western Ordos Basin

作　　者：章贵松[1] 张军[1] 欧阳征健[1] 任军峰[1] 

机构地区：[1]中国石油长庆油田分公司勘探开发研究院

出　　处：《低渗透油气田》2008年第1期7-14,共8页

摘　　要：鄂尔多斯盆地西部冲断推覆构造带由拗拉槽和被动陆缘演化而来，演化过程大体分为古生代统一伸展闭合、中生代南挤北坳最终；中断推覆的两种不同动力学体制和5个发展阶段。提出鄂尔多斯盆地西部冲断推覆构造带可划分为桌子山－贺兰山；中断体系、六盘山弧形冲断体系，它们是相对独立的冲断推覆构造。其中六盘山弧形冲断体系是由祁连、华北陆缘地体组成的复合冲断推覆构造，具有独特的双层地体叠置结构。青铜峡－固原断裂的实质是北祁连地体向华北陆缘地体仰，中的运动面和地体叠置的分界线。主张将华北地台西界由青铜峡－固原断裂移至中卫－海原－宝鸡一线．六盘山盆地划属华北地台。指出祁连、华北陆缘地体于海西期开始拼贴，在拼贴过程中可能形成晚古生代“原前陆盆地”，现覆于六盘山地区北祁连地体之下。晚三叠纪以来递进的冲断推覆，在祁连地体之上又形成六盘山等山间盆地，并引起祁连地体冲断前锋大小罗山与鄂尔多斯盆地西缘（华北陆缘地体）构造响应一起褶皱隆升．成为分隔六盘山盆地与鄂尔多斯盆地中生代沉积的“古陆梁”。“原前陆盆地”、六盘山盆地、“古陆粱”是北祁连地体在冲断推覆过程中不同阶段的产物，伴随着北祁连地体冲断形成和演化。新生代以来，受喜山运动的影响，鄂尔多斯盆地西部冲断推覆构造带仍处于改造之中。The authors put forward in the paper that the thrust-nappe tectonic bolt in western Ordos basin can be divided into Zhuozishan-Helan Mountain Thrust system and the arc Liupan Mountain Thrust system. They are relatively independent thrust-nappe tectonic. Thereinto the arc Liupan Mountain thrust system is a composite thrustnappe tectonic belt that is made up of the Qilian and continental margin of North China geo-bodies. It has a unique two-tier structure of the superimposed geo-bodies. The Qingtongxia- Guyuan fault, in essence, is the boundary between the movement surface of north Qilian geo-body up-thrusting to the continental margin of North China geo- bodies and the superposition geo-bodies. It is advocated in the paper that the western boundary of the North China Platform should moved from Qingtongxia - Guyuan fault to Zhongwei - Haiyuan - Baoji line. And the Liupanshan basin is zoned into North China Platform. It is pointed out that the Qilian, the continental margin of North China started to collage in the Hercynian. During the process of collaging, the ＂original foreland basin＂ was likely to be formed in Late Paleozoic, and now underlies the north Qilian geo-body in the Liupan Mountain area. Since the Late Triassic the progressive thrust-nappes formed inter-mountain basins of Liupan Mountains etc. on the Qilian geo- body. And It caused the western nmrgin of Ordos basin （the continental margin of North China） folded and uplifted. This became a ＂paleo-continental uplift （beam）＂ that separated the Liupanshan Basin from the Mesozoic sedimenta- tion of Ordos Basin. The ＂original foreland basin＂, Liupanshan Basin and the ＂paleo-continental uplift （beam）＂ are products of the different stages during the thrust-nappe process of the North Qilian geo-body. They were thrnstedly formed and evolved along with North Qilian geo-body. Since the Cenozoic, influenced by the Himalayan movement, the western thrust-nappe tectonic belts in Ordos Basin are still in the transformation.

关 键 词：沉积演化 冲断体系 祁连地体 华北陆缘地体 叠置结构 冲断推覆构造 鄂尔多斯盆地西部 

分 类 号：P54[天文地球—构造地质学]