Geochemical Characteristics And Its Implicatios Of The Red Earth Formation In Jiujiang City Of Jiangxi Procince China

Red earth formation in South China contains large amount information of the Quaternary paleoenvironment and paleoclimate in Tropical-subtropical area, which is of great significance to restore the environment evolution process. However, selecting proper indicator in red earth is difficult. The geochemical method plays an important role in both reflecting paleoclimate and deciding material source. In this study, the constant element of red earth formation in Jiujiang area was tested and analyzed in order to reveal the paleoclimate evolution process and judge the causes of the red earth formation in the middle and lower reaches of the Yangtze. Initial results achieved are as following:The average constant element of the red earth formation in Jiujiang is compared with Luochuan loess and UCC. The distribution patterns of the red earth formation in Jiujiang is similar to Luochuan loess as well as the UCC, indicating the red earth formation originates from the earth’s crust and is a typical aeolian deposits.The Si、Al、Ti elements are good for weathering resistance, keeping the information of the sources. The red earth in Jiujiang shows higher value of TiO2/Al2O3、SiO2/Al2O3 and lower value SiO/TiO2 than the loess and paleosol from Luochuan, indicating that the red earth is not from the north desert. The reticulate red clay and Xiashu loess have a slightly different projection region, suggesting their same material source and different weathering alteration process.The weathering index indicates that the red earth in Jiujiang went through a warmer and wetter environment than the loess in Luochuan and has reached the strong weathering stage. The weaker weathering intensity in the Xiashu loess compared with the reticulate red clay indicates the instable hot and moist climate in Jiujiang and the climate becomes cold and dry.