The Yellow River Ancient River Migration Evolution And Its Formation Mechanism In Hetao Area On The Holocene

The migration of the ancient river track records the history of the river system's own development,while reflecting the evolution of paleogeographic environment and landforms.The ancient channel of the Yellow River is an important part of the Quaternary hydrological network in the Hetao Plain,and is an important evidence for the evolution of the Holocene Hetao plain.The migration of the Holocene Yellow River is related to the evolution of the river basin,climate change and new Tectonic movement has important research significance.This study analysis of 1:50000 field geological and geomorphic survey,drilling data through the ETM image,combined with the measured profile,geophysical techniques,accurate delineation of the the Yellow River surface and location of buried channel;Using the OSL and14 C dating more accurately identified the ancient age of the Yellow River,the Holocene ancient Yellow River channel staging,in order to obtain the ancient channel of the ancient paleogeographic information,and finally to the Yellow River ancient river migration causes evolution mechanism is discussed in detail.The Yellow River is believed that since the Holocene ancient river can be divided into five stages: Phase ? ancient river,North and south two branch,South branch located in the north of the Western Renaissance,the depth of 2~6m,the north branch located in the south of Hulesitai brazilwood,depth of 8.2~9m,the age is9.93~7.4kaB.P.;Phase?ancient river,the main river located in the Seerteng mountain,in the North West-South East to the ugab River,buried in the ancient river at lower4~11m,In the same period of Taer lake are the ancient river,with the depth of 7~9m,EW,age 7.4~4.1kaB.P.;stage III call DeGeneres too ancient river,central,and Southern Renaissance Taer lake south have been developed,but the main channel for tal Lake ancient river,the depth of 2~9m,age 4.1~1.2kaB.P..Phase IV of the ancient river,buried depth is 2.5~4m,the main distribution area in the town of Renaissance,from the southwest to the northeast and turned to the southeast,a "few" font distribution,the age is 1.2~0.4kaB.P.Phase V,ancient river(present-day the Yellow River),Ordos along the northern margin fault from west to East,the wandering river formed about 4~5km wide East-West river area,recently built by the human being,the river tends to be stable,since the age of 0.2kaB.P.In recent years,the Yellow River in the Hetao area changed frequently,the overall migration path,presented by the Piedmont gradually migrated southward,finally to present the trend of river swing.The specific process of migration for the early Holocene of the two north-south ancient river south weak trend of migration,and spread into South and North Branch of the river;from the late Holocene early in Tale Lake as the center of the large scale grid river river,to the late mid-holocene ancient river and reduced to two north-south the North Branch,and gradually from the mainstream level for the northern tributaries,North Branch of the river dried up last night since the late Holocene,the formation of the South Branch of the mainstream form of modern the Yellow River.The migration of river evolution of the main control factors for active faults and seismic activity of the ancient surface is not stable,and the Holocene climatic and hydrological changes caused by changing the late human activities important influence factors of migration is the Yellow River ancient river.