鄱阳湖地区晚更新世古环境变迁

晚更新世期间鄱阳湖北部地区,九江、湖口、彭泽一带发育风沙-黄土-湖沼相交互地层序列。本文通过对该序列5个露头剖面多环境代用指标分析,研究了该地区晚更新世环境变迁和季风变化过程。研究表明:约147-129.6kaBP,以较强的冬季风控制的气候为主,季风降水很少,气候偏冷干;129.6-76kaBP,早期,夏季风逐渐增强,至120kaBP后,夏季风进入强盛阶段,103kaBP后,夏季风较弱,97kaBP后,夏季风又一次增强,这一时段内古气候阶段性非常清楚,早中期暖湿程度较高,后期较弱,在暖湿的背景上存在110-106、103-92kaBP等冷事件;76-55kaBP,为强盛的冬季风时期,气候冷干;55-25kaBP,夏季风又一次增强,气候温暖湿润,中间有冷波动;25-16kaBP,气候变冷干,后期冬季风有所减弱;16kaBP后,夏季风明显增强,气候变温湿,13.0kaBP后,气候有变干的趋势. 

ENVIRONMENTAL CHANGE IN THE POYANG LAKE AREA DURING LATE-PLEISTOCENE

During Late-Pleistocene, a stratigraphic sequence of alternating wind-drift sand, loess and limnetic facies developed in the northern Poyang Lake area. In this paper, environmental change and course of monsoon chage during Late-Pleistocene have been studied based on the analysis of the environmental proxies collected from five exposure pro files in Jiujiang, Hukou and Pengze. As a result, we have found that there was a cold and dry climate controlled by stronger winter monsoon during 147-129.06 kaBP. Therer was an obvious periodicity of climate during 129.6-76 kaBP:it was warm and wet in the early and middle stage and became attenuated in the late stage with some intervening cold events. Moreover this period began with a n increasingly strong summer monsoon until 120 kaBP. when it beg an to decline, and became strong again after a weak period of 103-92ka BP. In the stage of 76-55ka BP, it was cold and dry, as a result of severe winter monsoon. The summer monsoon became strong again during 55-25 ka BP, leading to a warm and wet climate with cold fluctuations. The climate tended to become dry after 13ka BP.