关键词: 查格剖面, 微量化学元素, 元素旋回, 古气候变化

Abstract:

Chagelebulu section locates in the south-east of Badain Jaran Desert, where is the tail part of the modern summer monsoon of East-Asia, and it is regarded as a high-resolution geology-palaeoclimate record section in the non-monsoon areas in our country. There are 25 sedimentary cycles that are made up of aeolian palaeo-dune sands, loess, palaeosol, lacustrine facies and alluvial-hillslope sandy soils and gravels in this section. The paper makes some analyses on the 16 trace chemical elements, including relatively active elements (V, Sr, Ni, Cu, Zn, As) and relatively stable elements (P, Mn, Zr, Cr, Pb, Rb, Nb, Y). The results are as follows: the content and variation of the 16 trace elements show remarkably regular changes in the pace with the 25 coarse-fine sedimentary cycles and they manifest 25 changeable cycles between peak and valley values, which compose a multi-fluctuating process line of relatively gather and migrate. The low distribution of these two types trace elements in the aeolian palaeo-dune sands and the alluvial-hillslope sandy soils and gravels represent erosion and accumulation under wind force during the cold-arid climate, whereas their assemble in the loess, fluvio-lacustrine facies and palaeosols are related to its specially low-lying landform position under the warm and humid climate background. The above trace elements change of relatively migrate and gather is the result of 25 cycles of cold-dry and warm-humid, which is probably caused by the repeatedly mutual alternate in the Badain Jaran Desert between the winter monsoon and the summer monsoon influenced by the climate vicissitudes during glacial and interglacial periods since the late Pleistocene.

Key words: Chagelebulu section, trace chemical element, element cycle, palaeo-climate