长江三角洲西部地区13200 cal aB.P.以来环境演变及对长江两岸文化交流与传播影响研究

ENVIRONMENTAL EVOLUTION IN THE WESTERN REGION OF THE YANGTZE RIVER DELTA SINCE 13200 CAL A B.P. AND ITS EFFECTS ON CULTURAL EXCHANGE BETWEEN BOTH SIDES OF THE YANGTZE RIVER

长江三角洲西部地区对气候变化反应敏感,但由于缺乏高分辨率的研究材料使学者们对该区域的气候演变过程有着不同的解释,另外,新石器时代环境演变对长江两岸文化交流与传播的影响也还没有引起学者们的关注,为了解决上述科学问题我们在长江三角洲西部高淳地区获得了一个13200 cal a B.P.以来的406 cm厚湖泊沉积剖面,依据孢粉、腐殖化度、烧失量、元素地球化学等古气候记录重建了13200 cal a B.P.以来的气候演变过程并在此基础上探讨了长江两岸新石器时代文化交流与传播路线,研究表明:13200~4400 cal a B.P.期间气候以暖湿为主要特征,但在早期有波动,属于从冷干向暖湿转化的过渡期,4400 cal a B.P.以来以温凉湿润为主要特征,另外,长江三角洲西部地区13200 cal a B.P.以来的气候演变过程并不稳定,高淳剖面古气候代用指标记录了三次气候突变事件,分别为"新仙女木"事件、"8.2 ka"事件和"4.2 ka"事件,6000~4000 cal a B.P.期间的气候变化过程有利于长江三角洲西部长江两岸新石器时代文化之间的交流与传播,沿古中江两岸分布的考古遗址发掘出土的器物表明古中江是长江两岸文化交流与传播的重要通道。

The western region of the Yangtze River Delta is sensitive to climatic changes; however, scholars have different interpretations of the climatic evolution process in this region due to the lack of high-resolution data. In addition, the effects of environmental evolution in the Neolithic Age on cultural exchange have not at-tracted the attention of scholars. In order to provide insights into these scientific questions, we obtained a 406 cm-thick lake sediment profile since 13200 cal a B.P. in the western Gaochun area of the Yangtze River Delta and reconstructed the climatic evolutionary history since 13200 cal a B.P. based on paleoclimatologic data such as sporopollenin, humification degree, loss on ignition, elemental geochemistry, etc. On this basis, we investi- gated the routes of cultural exchange between both sides of the Yangtze River during the Neolithic Age. Our study found that during the 13200-4400 cal a B.P. period, the climate was mainly warm and wet but there were fluctuations during the early period, which represents a transition period from cold and dry to warm and wet conditions. Since 4400 cal a B.P., the climate was mainly warm, cool, and humid. In addition, the climate evo-lution of the western region of the Yangtze River Delta was not stable since 13200 cal a B.P. The Gaochun pa-leoclimatic profile records 3 abrupt climate change events, including the ＂Younger Drays,＂ ＂8.2 ka,＂ and ＂4.2 ka＂ events. During the 6000-4000 cal a B.P. period, the climate conditions were beneficial to cultural exchange between Neolithic cultures on both sides of the western area of the Yangtze River Delta. Artifacts unearthed frlom archaeological sites that were distributed at both banks of the Yangtze River near the ancient Zhongjiang city show that Zhongjiang was an important venue for cultural exchange between both banks of the river.