Trace-Elements Characteristics of Tumen Section in Southern Tengger Desert and its Paleoclimatic Implications for#br# the Last Deglacial

The Tumen sequence(52L~41FD) on the southern edge of the Tengger Desert is composed of three layers of dune sands, two layers of lacustrine facies, two layers of paleosoil and five layers of sand loess. The results of trace elements analysis show that the concentrations of 10 trace elements in the last Deglacial of Tumen profile vary as Mn, P, Sr, Rb, Cr, V, Zn, Ni, Cu, Nb. The content of each element shows crest in the layers of lacustrine facies, paleosoil and sand loess, but shows trough in the layers of dune sands. As the sedimentary facies are alternated in the vertical direction of the profile, the elemental content also forms an elemental fluctuation process line. Based on the analysis of trace elements in combination with the particular terrain, it is considered that the elements represented by Zn(ppm) and P(ppm) are used as the climatic substitutes to indicate the fluctuation of Asian monsoon climate. Eight cold and warm incidents could be distinguished in terms of the elements. The cold incidents are C1(11870~11640 a BP), C2(12650~12050 a BP), C3(13340~13010 a BP), C4(13810~13620 a BP) and the warm incidents are W1(12050~11870 a BP), W2(13010~12650 a BP), W3(13620~13340 a BP), W4(14850~13810 a BP). The last deglaciation climate fluctuation which was recorded by the last deglaciation segment of Tumen section is highly similar to the data collected from Greenland GRIP ice core and Nanjing hulu cave stalagmite. It shows that the last deglaciation Asian monsoon climate changes of this region may be closely related to the climate mechanism in Northern Hemisphere.