中仑昆山北坡黄土特征及其环境

PRITLIMINARY STUDY ON LOESS AND ITS SEDIME NTARY CONDITIONS ON NORTHERN SLOPE OF MIDKUNLUN MTS.

根据野外调查和实验分析资料,阐述和分析中昆仑山北坡黄土的形成时代、物质成分和结构及沉积条件,认为黄土属晚第四纪风积物质,现代黄土堆积持续进行,物质主要来源于塔克拉玛沙漠。在干旱气候背景上,7000—5000a.B.P.为明显相对湿润时期。

Through field investigations and various laboratory dating and analysing it is assumed that the loess mostly originated from the huge Taklimakam deserts and accumulated mainly during the latest Quaternary period from the last glaciation maximum through Holocene. The loess is of good uniformity in its material composition and regarded as 'sand loess' because of its coaser-grained matter.The unstable heavy minerals, carbonate and CaO and the pH-value in the loess are higher in this district compared with the north central china, meaning that that the loess was deposited under drier arid climate environment. The sporo-pollen assemdlage is dominated by small scrubs and herbaceous plants, representing arid steppe environment . Quite different from the continental Europe. The formation of the moden morphological pattern and the climate condition is the environmental base for the loess accumulation, which causes large continuation of the loess deposition on the northern slope of Mid-kunlun Mts..The dry and cold climate might be more favourable for the loess formation to be processed in large scale in the last glaciation maximum. On arid background there was existed some humid oscillations associated with the loess . From 7,000 to 5,000 a.B.P.the climate was considerably improved when relatively thick soil developed and lots of snail, Succinea pfeiferi,lived.