Rapid Paleoclimate Changes during MIS3a Reflected by Lacustrine Deposits of Dujiangyan in the Eastern Margin of Qinghai-Tibet Plateau

The later phase of marine isotope stage 3 (i.e.MIS3a) on Qinghai-Tibet plateau was characterized by its special warm-humid climate.The constructed AMS14C calendar age-depth model,the component of n-alkanes,together with the grain size and total organic carbon (TOC) of lacustrine sediments in Dujiangyan S1 Section are used to elucidate the paleoclimate changes.The results indicate that rapid fluctuation on millennial scale was the main characteristic in the eastern margin of Qinghai-Tibet plateau during 43.6-34.6 kaBP.The Dansgaard-Oeschger events 11-7 can be reflected by these proxies,especially TOC.Comparison between TOC curve and oxygen isotope record from Hulu Cave and Greenland GRIP indicates that paleoclimate records in Dujiangyan respond to ice volume change in the high-latitude area and Asia monsoon oscillation.But the difference was shown because the influence of insolation values precession was strong in this area.