苏皖沿江平原全新世气候变化与洪水事件研究

Sediment Record of Climatic Changes and the Flooding Events Since the Holocene in the Su-Wan Plain Along the Yangtze River

通过地貌调查并根据林峰桥地层剖面的粒度、地球化学以及碳同位素等环境替代指标分析得出 :苏皖沿江平原在距今 140 0 0aBP左右气候湿润 ,沼泽发育 ,大量的泥沙沉积 ;此后气候变干 ,沼泽开始退缩 ,直至消失 ,沉积作用减弱 ;在经过了长时间的沉积间断后又经历一次洪水泛滥期 距今约 10 2 0 0～ 10 80 0aBP ,该区经过新仙女木期的寒冷期后进入了全新世的增温期 ,沉积作用增强 ;后又经历多次气候冷暖波动 ,在 (76 40± 12 0 )～ 3 80 0aBP全新世最适宜期增温事件后 ,气温又开始下降 在研究中还发现 ,古洪水多发生在气候转型期 .

The Su-Wan Plain is formed by the sand sediment from the Yangtze River and it's tributaries. Analysis performed on the grain size, geochemistry and environment proxies Like carbon isotope etc. together with field investigaiton, indicate that Su-Wan Plain is humid climatically, and area of swamp land expanded and a large amount of sand deposited in the plain. Thereafter, climate turned to an arid condition, the area of the swamp land began to decrease and until disppeared. The study region underwent a period of flooding inundation after a long interruption of sedimentation. During 10 200～10 800 aBP, after a cold period in the Younger Dryas, the study region became warm climatically, which is so-called temperature-increasing epoch in the Holocene, and the sedimentation process became frequent. The decrease of temperature in the study region, after the temperature-increasing event in the (7 640±120)～3 800 aBP of the Holocene, came after many times of warm and cold climatic fluctuations. The study results suggest that the paleo-flooding events usually occurred during the climatic transition period. The study regin saw three paleo-flooding events so thah, many Cultural faults occured in a lot of the relics.