鄂尔多斯盆地三叠系延长组沉积充填演化及其对印支构造运动的响应

通过对鄂尔多斯盆地三叠系延长组地层发育特征、湖盆充填演化、盆地边缘沉积特征以及事件沉积发育规律的分析，探讨了早印支运动与鄂尔多斯盆地的沉积响应过程。研究表明，长10-长9沉积期，印支运动较弱，鄂尔多斯盆地基本继承了晚海西期以来的构造平稳的格局，湖盆开始发育；从长8沉积末期开始，鄂尔多斯盆地南部构造活动开始增强，秦岭造山带在该时期迅速隆升使北秦岭地区沿商丹断裂带发育一系列山间盆地的砾岩堆积，同时导致盆地南部海相碳酸盐岩基底遭受剥蚀，碳酸盐岩岩屑在砂岩中开始出现；长7沉积期，伴随着湖盆的强烈扩张、西南部磨拉石建造的快速堆积以及事件沉积频发，印支运动活动强烈，鄂尔多斯盆地进入板块碰撞拼接、幕式构造运动最活跃的时期；长6-长4+5沉积期，鄂尔多斯盆地西南部地层中仍有震积岩出现，但凝灰岩含量急剧减少，表明构造活动的强度和频率降低，湖盆开始重新进入稳定沉降期。延长期湖盆演化随着印支运动发展经历了初始拗陷、强烈拗陷、回返抬升和萎缩消亡的完整过程，具有快速沉降、缓慢充填、沉积中心不断向西南迁移的特征。

Evolution of Sedimentary Fillings in Triassic Yanchang Formation and Its Response to Indosinian Movement in Ordos Basin

Based on stratigraphy,lake basin fillings,basin margin sediments,and regularity of event deposits in the Triassic Yanchang Formation,we discussed the early Indosinian event and sedimentary response in Ordos basin.The results indicated that the Indosinian movement was weak within 9 and 10 intervals of Yanchang Formation,the basin inherited the structurally smooth pattern since late Hercynian,and the lake basin began to develop.At 8 interval of Yanchang Formation,the Qinling orogenic uplift made the basin tec...