摘要
内蒙古河套盆地为受断裂控制形成的新生代断陷盆地,盆地中积水成湖,称河套古湖。晚更新世时期,河套古湖为继承性闭塞型断陷湖。上更新统主要为湖泊沉积体系,地层划分建组为上部东河村组、中部万水泉组、下部达拉特组。达拉特组在湖盆连续沉降条件及半深湖-深湖中硫酸盐型、碳酸盐型湖水交替环境下沉积形成。万水泉组在湖盆沉降速率与沉积速率大体平衡条件及浅湖-半深湖中半咸水湖环境下沉积形成。东河村组在湖盆沉降速率小于沉积速率条件下以及半咸水湖、局部时期为碳酸盐湖环境下的滨浅湖中沉积形成。晚更新世末期,河套古湖处于大湖水期,晋陕内蒙古交界处河流袭夺、河套盆地北侧山前断裂强烈活动和超强地震导致河套古湖湖水快速外泄,银川盆地、河套盆地、晋陕峡谷贯通而形成今日黄河河道。
The Hetao Basin in Inner Mongolia is a Cenozoic faulting basin.It is also called Paleo-Hetao Lake as an inherited and closed sag pond in the Late Pleistocene.The lake sedimentary system was mainly formed in the Late Pleistocene,encompassing the Donghecun,Wanshuiquan and Dalate Formations in its upper,middle and lower sections,respectively.As the lake basin continued to subside,the Dalate Formation was formed under semi-deep and deep lake sedimentary conditions in an alternating sulphate and carbonate water environment.In contrast,equilibrium between lake basin subsidence and sedimentation led to the formation of the Wanshuiquan Formation in shallow to semi-deep brackish waters.As the rate of sedimentation surpassed rate of subsidence,the Donghecun Formation was formed in brackish-water and at times in carbonate beach and shallow lake environment.At the end of Late Pleistocene,the Paleo-Hetao Lake experienced a high water period.River capture at the boundary between Inner Mongolia,Shanxi and Shaanxi,and strong fault activity and extremely powerful earthquake in the northern Hetao Basin,caused the outflow of the Paleo-Hetal Lake linking the Yingchuan and Hetao Basins and the gorge between Shanxi and Shaanxi to form the modern day Yellow River.
作者
聂宗笙
NIE Zongsheng(The Institute of Crustal Dynamics,China Earthquake Administration,Beijing 100085,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2019年第4期259-272,共14页
Earth Science Frontiers
关键词
河套盆地
河套古湖
上更新统
环境演变
河流袭夺
超强地震
黄河的贯通
Hetao Basin
Paleo-Hetal Lake
Upper Pleistocene
environmental change
river capture
extremely strong earthquake
formation of Yellow River
