Evolution of paleoclimate and sedimentary environment in the Huaibei Plain since Middle Pleistocene: evidence from grain size and geochemistry of sediments from the Guo River basin

Based on the study of grain size and geochemistry of Quaternary standard boreholes adjacent to the geographical boundary between the north and south of China, changes in paleoclimate and sedimentary environment in the Huaibei Plain since the Middle Pleistocene are discussed. The results show that the climate of the Middle Pleistocene in the Huaibei Plain experienced a general change from warm wet to dry cold in the frequent alternation of warm and wet, and dry cold (warm and cool), which is in phase with the temperate monsoon climate change trend in the northern part of eastern China monsoonal region, but in inverse phase with the paleoclimate evolution model in the middle and lower reaches of the Yangtze River, and the source area of the Huai River that is controlled by the subtropical monsoon climate. In the Late Pleistocene, the climate experienced dry and cold (i.e., warm dry and cold dry cold), warm wet, and dry cold, but it was more similar to the climate evolution pattern in the middle and lower reaches of the Yangtze River and the source area of the Huai River, but was not consistent with the climate change pattern from warm wet to arid in northern China. In the Holocene, the climate in the Huaibei Plain and in the south and north of China was warmer with increased precipitation. Generally speaking, the sedimentary environment of GBK1 standard borehole in the Guo River basin evolved from semi deep lake to shallow lake and lakeside Lake, and then contracted and disappeared in the Middle Pleistocene, evolving into flood plain or river; since Late Pleistocene, it is mainly river and flood plain. The regional climate change of the Huaibei Plain has a positive response to global change on the whole. Perhaps because of its location at the edge of the geographical boundary between the north and south of China, the regional climate of the Huaibei Plain is unique. © 2022, Science Press. All right reserved.