皖南第四纪风尘堆积序列粒度特征及其意义

THE GRAIN SIZE FEATURES OF QUATERNARY AEOLIAN DUST DEPOSITION SEQUENCE IN SOUTH ANHUI AND THEIR SIGNIFICANCE

通过系统采样与粒度测试，在同北方黄土充分对比的基础上分析和讨论了皖南第四纪风尘堆积序列（向阳剖面）的粒度特征；并根据堆积物的粒度与古气候—环境之间的内在联系，对该地区气候环境的演变及风尘堆积物的物源变迁等问题进行了初步探讨和分析。

On the basis of systematic sampling and testing,the grain size features of Quaternary aeolian dust deposition sequence(Xiangyang section),which is located in the south of Anhui Province,are analyzed and discussed in this paper. The acolian dust deposition in south Anhui mainly consists of fine particles(<50μm),and is similar to the loess in northen China,but comparatively finer.The grain size probability curves of Xiangyang section could be divided into two types and is more complicated than that of northern loess.The features of grain size parameters show some difference from northern loess,indicating the forming environment of Xiangyang section was much warmer and wetter than that of northern loess. The vertical changes of grain size in Xiangyang section have important paleoenvironmental significance.The cyclic variation of content of <1μm particles sensitively recorded 8 paleoclimatic fluctuations of cool—warm and dry—wet.It is shown by the trend of Kd value variation that the trend of paleoclimate was from warm—wet to cool—dry.The vertical changes of coarse grain contents recorded the apparent change of material source in the forming process of Xiangyang section.