Environmental Evolution Of Western Taihu Plain During The Holocene Achived By Luotuodun Core

Since the Holocene, human beings have created a splendid civilization in Taihu plain. While actively adapting to and remoulding the natural world, the man-nature relationship undergone dramatic changes accompanied with cultural development. Today Taihu Plain is an important economic center, where the prehistoric civilization is brilliant. However, the researches in environment evolution and archaeology in western Taihu plain were few. This study focused on analysis of AMS-14C dating, grain-size, magnetic susceptibility, chemical elements and organic carbon isotope proxies from the Luotuodun Core beside the Luotuodun Site to reconstruct the paleo-climate and paleo-environment in western Taihu plain. Combined with some archaeological materials, regional environmental changes were analyzed to provide a theoretic basis for coordination development man and nature.1) Based on the analysis of the proxies, the regional environmental change can be divided into the following four stages. Stage Ⅰ:13.0-9.1 ka BP, hydrodynamic is weak and magnetic susceptibility value is changeless, indicating the stable provenance. The cool and dry climate makes the S13C value increase. Stage Ⅱ:9.1-6.7 ka BP, results of grain-size, magnetic susceptibility and chemical elements showed a significant rise of hydrodynamic. The 513C values decreased, while Quercus D and Quercus E increased to a high level, showed warm-humid climate. Stage Ⅲ:6.7-3.0 ka BP, hydrodynamic reduced with an increase in 813C value. Contents of pollon indicating warm-humid climate decreased, meaning that the climate is cool and dry. Stage Ⅳ:3.0 ka-, contents of clay increased while sedimentary dynamic weakened further, showing the swamp facies. Quercus D, Quercus E and aquatic herb reduced and the climate is still cool and dry. The increase in fern spores and cruciferous concentration probably resulted from human activities.2) Climate change controlled by the insolation heating and the EA summer monsoon in the western Taihu plain is consistent with it in the eastern Taihu plain since the Holocene, perhaps as a consequence of the paleo-climate in this region closely contacted with the East Asian monsoon.In the early Holocene, the climate was cool and dry, and then turned to warm and wet gradually in the mid-Holocene. After the Holocene Megathermal, the climate was back to cold and dry.3) Both the formation of peat and the warm and wet climate were conducive to the development of rice agriculture in Luotuodun site. Ancestors settled here and developped a unique culture called Luotuodun-Wujiabu Type which is given priority to flat-bottomed pottery. During the late period of Majiabang Culture, cultural pattern of western and eastern respective was broken by the cultural shock of Beiyinyangying Culture. Then the uniform Songze Culture period developed, and Luotuodun site gradually lose the position of cultural center. During the Liangzhu culture, marshes and wetlands around the Taihu Lake plain dried up as sea-level declined gradually, thereby providing more area for cultural and agricultural development. The cultural center in Taihu basin migrated from north to south east gradually.