Quaternary tectono-sedimentary evolution of Chishan Uplift in the Dongting Lake

Tectonic activities were reactivated since Pleistocene at the Chishan Uplift of the Dongting Lake where complicated geological phenomena are observed. As an important geological unit in the Dongting Lake, the study of the uplift and the evolutionary characteristics of the Quaternary structures and depositional systems is of great significance to the exploration of the Quaternary history of the lake. Thus, a thorough study from the perspectives of geological structure, stratigraphic framework, lithology and paleoclimate as well as cultural relics, is made by the authors in this paper. Results show that: In the late Early Pleistocene, the structural activity of Chishan uplift was first depressed and then stable, and in the early to middle Pleistocene, it was stable - depressed-stable-raised-stable. In the beginning of late Middle Pleistocene, the area with the elevation of 0 m and above of the bedrock surface of Chishan uplift had been uplifted and formed land, and human activities began to appear. At the same time, paleolithic sites were left on the top of the Quaternary strata at that time. From late Middle Pleistocene to early Holocene, the Chishan Uplift was denuded, and the aeolian deposits were deposited in the lower area of Chishan uplift.