The Wet-dry Variations of The Horqin Sandy Field Recorded by Loess Deposit of The Late Quaternare

Horqin sandy land,located at the transitional region between the Northeastern plain and the Mongolia Plateau,is sensitive to climate changes.In this paper,Optical stimulated luminescence dating(OSL) has been used to obtain ages of the typical profile.Combining with the sedimentary facieses,magnetic susceptibility,organic content and grain size,which can be employed as proxy indicators of the paleoclimate and paleoenvironment changes,it is suggested that climate of the sandy land has been changed with dry and wet at 10~3~10~4time scale,especially at approximately 146.96 ka BP,141.98 ka BP and 107.06 ka BP,the paleoclimate and paleoenvironment have significantly shifted.Accordingly,the vegetation in this area has undergone a succession of dry-cold grassland,desert grassland and warm-moist or milder-humid forest grassland,sparse grassland.The changes of the climate in Horqin sandy land are consistent with variations of the East Asian monsoon during late Quaternary.