淮北平原中更新世以来古气候和沉积环境演变:来自涡河流域沉积物粒度和地球化学的证据

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

通过对毗邻中国南北地理分界线的第四系标准孔岩芯进行粒度和地球化学研究,探讨了淮北平原中更新世以来的古气候变化和沉积环境变迁。研究表明淮北平原中更新世气候在暖湿与干冷(温凉)频繁交替中总体经历了从暖湿趋于干冷,与中国东部季风区北部的温带季风气候变化趋势属同相位演变,而与受控于亚热带季风气候的长江中下游及淮河源区古气候演变模式总体呈反相位。晚更新世,气候总体经历了干冷(即温干—严寒—干冷)、温湿、转向干冷,却表现出与以长江中下游及淮河源区气候演化格局更相似,而与中国北方气候总体上由暖湿向干旱化转变步调不一致。进入全新世,淮北平原与中国南北方气候均回暖,降水相应增多。涡河流域GBK1标准孔区域沉积环境总体上经历了中更新世早中期从半深湖演化到浅湖、滨湖,到晚期湖泊快速收缩直至消失,演化为泛滥平原或河流;晚更新世以来主要为河流和泛滥平原。淮北平原区域气候变化总体上对全球变化有着积极的响应,或许因其地处中国南北地理分界线边缘,致使其气候又具区域独特性。

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.