Division and comparison of Pleistocene in Jianghan-Dongting area and Huangguang-Jiujiang area

In order to further clarify the division and comparison of Pleistocene of Jianghan-Dongting and Huangguang-Jiujiang areas in the middle reaches of Yangtze River, based on the regional geological survey, the unconformity relationship between the Early Pleistocene gravel layer and the overlying latticed laterite was identified in this paper. And the Quaternary System of this area has been studied, with supplementary of chronology study. Besides, reginal sequence division and comparative framework were established. The results show that gravel layers, such as Baishajing, Yangluo, Yichang and Jiujiang, were the pluvial facies sediments of Yangtze River, and epoch was late Early Pleistocene (Qp₁). The overlying reticulate red clay was formed in Middle Pleistocene (Qp₂), and the contact relationship between these two layers was unconformity. The stratigraphic framework of Pleistocene Series in this area was established based on the research results above. The major adjustment of hydrodynamic conditions and sedimentary environment represented by gravel layers, such as Baishajing, Yangluo, Yichang and Jiujiang, and the overlying reticulate red clay were the environmental response of the continuous connection of Three Gorges of Yangtze River. It also suggested that the continuous connection of Three Gorges of Yangtze River occurred in the Early to Middle Pleistocene.