【摘要】 侏罗纪是东亚大地构造发展的重要转折时期,在鄂尔多斯盆地及其周缘可划分为两个性质不同的构造变形阶段。早中侏罗世,盆地处于弱引张应力环境,引张方向近N-S至NNE-SSW向,伸展变形主要发生在盆地周边地带,其发生与晚三叠世华南-华北地块沿秦岭造山带碰撞后的陆内应力场调整作用有关。中晚侏罗世,盆地遭受多向挤压应力作用,挤压方向近W-E、NW-SE和NE-SW,在盆地周缘形成展布方向不一、构造样式不同的边界挤压构造带,盆地轮廓基本定型。西缘近N-S向逆冲-推覆构造带的形成与阿拉善地块和陇西地块向东挤出作用有关;东缘及东南缘总体呈“S”形展布的挤压边界带表现为反向逆冲断裂及其相关褶皱,推测发生在山西台褶带深部滑脱系统的前锋上盘断坡。盆地北侧大青山地区近东西向大型推覆构造和早中侏罗世伸展断陷盆地构造挤压反转,表明阴山造山带在中晚侏罗世时期强烈的N-S向缩短变形和再生造山。鄂尔多斯盆地周缘边界构造带记录了中晚侏罗世强烈的陆内多向内挤压作用和大陆地壳增厚过程,其发生的动力学背景与周邻不同板块(古太平洋、西伯利亚、特提斯)同时向东亚大陆汇聚产生的远程效应有关。中晚侏罗世多向挤压变形加速了鄂尔多斯盆地生烃过程,对多种能源矿产富集和成藏定位产生重要影响。更多还原

【Abstract】 The Jurassic era was an important period for tectonic evolution of the East Asia continent. In the Ordos basin this tectonic evolution can be divided into two deformation stages. The Ordos basin was under weak extension during the early to Middle Jurassic, with the stretching direction being N-S to NNE-SSW, and with deformation mainly concentrated around the margins of the basin. This extension was possibly associated with intra-continental stress adjustment following the Late Triassic collision between the North and South China Blocks along the Qinling mountains. During the Middle to Late Jurassic, the Ordos basin was subjected to multi-directed compressions, with the maximum stress axes oriented along W-E, NW-SE and NE-SW. The resulting compressional belts with different trends and structural styles were formed around the Ordos basin and the basin was reshaped. A N-S trending thrust and nappe belt was developed along the western margin of the Ordos basin, resulting from eastward extrusion of the Alashan and Longxi blocks. The eastern boundary belt is characterized by W-dipping reverse faults (back-thrust) and associated folds, which are inferred to have occurred on the frontal hanging wall ramp of a westward propagating decollement system beneath the Shanxi Highlands. Large-scale thrust and nappe structures and inversion tectonics of the Early to Middle Jurassic grabens along the Daqingshan Mountains to north of the Ordos basin, indicate strong N-S crustal shortening and rejuvenation of the Yinshan range. The boundary structural belts around the basin are a good record of multi-directed compressions and continental crust thickening during the Middle to Late Jurassic. This was dynamically associated with far-field effects produced by synchronous convergences toward the east Asia continent of different plates (Siberia, Paleo-Pacific, Tethys). This multi-directed compressional deformation accelerated hydrocarbon generation and should have had a profound impact on accumulation and localization of the multi-energy mineral deposits in the Ordos basin.更多还原