Abstract:

Field investigations were carried along the upper reaches of the Hanjiang River.Typical Holocence eolian loesssoil profile with interbedded palaeoflood slackwater deposits (SWD) was found at the Liaowadian site at the Hanjiang riverbank in Yunxian county,Hubei province.A set of samples for sedimentary analysis and for OSL dating was taken from the profile.OSL age of the samples was obtained by using the single aliquot regenerativedose（SAR）protocol.In combination with the stratigraphic correlation and archaeological dating,the extraordinary palaeoflood events recorded by SWD were dated to 1800-1700 years during the Eastern Han dynasty and Weijin period (A.D. 200-300).The climatic records from the upper Hanjiang River basin and various regions within China and over the world indicated that the flooding episode corresponded to the global climatic decline that lasted for several centuries.The extraordinary floods occurred because of the climatic instability,that resulted in high variability of precipitation and resulted in great floods and droughts.This is of great significance in understanding the regional hydrological response to global climatic change