The Last Glacial Paleoclimate Indication Recorded In Aeolian Deposits In Northern Jiangxi

Yellow brown soil is distributed widely in C hina Southern, which has the thick sequence with accumulation attribute s. Its parent material may have aeolian origin. Yellow brown soil layer has been studied in the middle and lower reaches of Yangtze River of the N ingzhen mountains area. It has an important significance to research on information contained in these strata, especially for the recover Paleoclimate of the South China and Yangtze River Basin since late Pleistocene. In this paper Taipingguang section is a research object,which is currently found the most thick in the yellow brown soil and material preliminary judgment for the aeolian attribute. On the basis of the luminescence dating(OSL),the paper is integrated use of the earth element chemistry, particle size, color and other index, It is very important to elaborate paleoclimate information evolution characteristics of the paleoenvironment during the last glacial period in northern Jiangxi regional, basic attributes in the source of dust further proof of parent materials on Taipingguan section, study shows:The OSL dating results was about 85-90 ka at the starting time and the termination to date from 10-12 ka from top to bottom: loess-paleosol-plinthitic loess dust deposition, lasted for about 80 thousand years.Based on granularity, chroma, weathering degree and plinthitic features, Taipingguan profile can is identified at least four loess-paleosol sedimentary sequence. The plinthitic yel ow soil at the bottom, in fact, is a kind of paleosol.Tai Pingguan section yellow brown soil, the size of wind of "basic particle" powder sand(5-50 m) content reached the 50% above, clay times, sand content is the minimum, less than 10%, sandy particles were less than 120 um. Here shows that the yellow brown soil texture is sandy clayey silt. The grain size parameters, grain size composition and Wushan loess, loess in Xuanche ng, N ing Zhen loess parent material is dust in the Southern Loess are basically the same, and and sediment of Yangtze River significant difference.Tai Pingguan section of yellow brown layer of constant elements reveal, the profile of the chemical weathering than Nanjing Yanziji Xiashu loess, Luochuan Loess is higher, than the Yangtze River floodplain slightly higher. In the upper part of the loess paleosol layers in C A removal, Na stage significantly, at the bottom of the vermiculated red soil bed with re moval of K, Si and Al rich phase, the chemical weathering intensity in order to increase.The size, color and soil chemical weathering intensity reveals that there is a significant "sedimentary soil cycle" Tai Pingguan profile, sand and coarse silt and clay and silty sand ratio, than the corresponding numerical loess soil, the loess is mainly in winter monsoon period to explain deposition; chemical weathering strength during the deposition of ancient soils with Rb/Sr and CIA index, the corresponding value is greater than the paleosol loess layer, indicating that the chemical weathering intensity in the paleosol layer is bigger, the climate is warm and wet, enhanced strength of summer monsoon. The sedimentary cycles with soil cyclic change characteristics of 20 thousand years showed that climatic fluctuations in Yangtze River Basin. Led by the winter and summer monsoon, with remarkable characteristics of the cycle of the precession cycle.