Palaeohydmlogical investigations were carried out in the Guchuan Basin in the upper reaches of the Weihe River valley, China. A set of palaeoflood slackwater deposits （SWDs） was found interbedded in the Holocene Ioe...Palaeohydmlogical investigations were carried out in the Guchuan Basin in the upper reaches of the Weihe River valley, China. A set of palaeoflood slackwater deposits （SWDs） was found interbedded in the Holocene Ioess-paleosol sequence at the Guchuanzhen site （GCZ）. These palaeoflood SWDs were studied by field observations and laboratory analyses including concentrations of chemical elements and optically stimulated luminescence （OSL） dating. The results showed that the palaeoflood SWDs were the result of the secondary separations of the surface soil and weathered soil layers during the process of water transport and deposition, and without obvious weathering during soil development. These extraordinary flood events were dated back to 3,200-3,000 a B.P. with the OSL method and checked by archaeological dating of the human remains retrieved from the profile. These extraordinary flood events were therefore considered as regional expression of known climatic events and demonstrated the climatic instability in the Holocene. This result is important for understanding the effects of global climate change on the dynamics of river systems.展开更多
The upper reaches of the Weihe River and adjacent areas of the Xihanshui River is a part of the Loess Plateau west to Longshan Mountain and the northern Qinling Mountain,which is made up of the Valley Plain,the Loess ...The upper reaches of the Weihe River and adjacent areas of the Xihanshui River is a part of the Loess Plateau west to Longshan Mountain and the northern Qinling Mountain,which is made up of the Valley Plain,the Loess hills and earth-rock mountains.In primitive society,Cultural methods changes from ash-pit-dibbling cultivation to fire-farming cultivation,then to bush-fallow cultivation.With cultivating methods evolution,the agricultural land-use pattern changes from scattered point to point-shaft,to point-shaft and shape-like strip.This process is essentially a land-use space by the river valley expanding to the loess hills,then to earth-rock mountain,the use of agricultural land in primitive society lays a future land-use pattern.展开更多
基金funded by the National Natural Science Foundation of China(41030637)the Science and Technology Project of Baoji City(14SFGG-2)+1 种基金the Fundamental Research Funds for Key Subject Physical Geography of Baoji University of Arts and ScienceShaanxi Province and the Key Library Program of Education Department of Shaanxi Province(15JS008)
文摘Palaeohydmlogical investigations were carried out in the Guchuan Basin in the upper reaches of the Weihe River valley, China. A set of palaeoflood slackwater deposits （SWDs） was found interbedded in the Holocene Ioess-paleosol sequence at the Guchuanzhen site （GCZ）. These palaeoflood SWDs were studied by field observations and laboratory analyses including concentrations of chemical elements and optically stimulated luminescence （OSL） dating. The results showed that the palaeoflood SWDs were the result of the secondary separations of the surface soil and weathered soil layers during the process of water transport and deposition, and without obvious weathering during soil development. These extraordinary flood events were dated back to 3,200-3,000 a B.P. with the OSL method and checked by archaeological dating of the human remains retrieved from the profile. These extraordinary flood events were therefore considered as regional expression of known climatic events and demonstrated the climatic instability in the Holocene. This result is important for understanding the effects of global climate change on the dynamics of river systems.
文摘The upper reaches of the Weihe River and adjacent areas of the Xihanshui River is a part of the Loess Plateau west to Longshan Mountain and the northern Qinling Mountain,which is made up of the Valley Plain,the Loess hills and earth-rock mountains.In primitive society,Cultural methods changes from ash-pit-dibbling cultivation to fire-farming cultivation,then to bush-fallow cultivation.With cultivating methods evolution,the agricultural land-use pattern changes from scattered point to point-shaft,to point-shaft and shape-like strip.This process is essentially a land-use space by the river valley expanding to the loess hills,then to earth-rock mountain,the use of agricultural land in primitive society lays a future land-use pattern.
