Variations of Geochemical Elements in Xining Loess Deposit and the Paleoclimatic Implications

In the northeastern Qinghai-Tibetan Plateau,more palaeo climatic proxy are needed to compare with each other and to retrieve climatic variance.Some geochemical elements are of the most sensitive proxy indicators of the paleoclimate changes.On the basis of the geochemical element measurement,we found the climate had become drier and colder gradually in xining area during the past 13.6Ka,.The plateau winter monsoon appeared to be a high-frequency changes.but summer monsoon varied gradually.The varlations of the plateau winter monsoon and the plateau summer monsoon in the Panzishan area were to some extant different from that in the Loess Plateau.There wasn't a reversed-phase relation between the stronger plateau summer monsoon and the weaker winter monsoon.Analogously,the plateau summer monsoon wasn't under the weakest when the plateau winter monsoon was the strongest.