| The Holocene is not only the Climatic Optimum, but also the important period marking the origin and development of the civilization. The reciprocal influence between human civilization and environment evolution is one of the most important research parts since Holocene epoch.Taihu Lake area in Jiangsu province is situated at the subtropical monsoon region, and it also locates in the transition zone from the continental crust to the oceanic crust. Due to the special geographical location, a range of things in this area, such as vegetation characters, geological structure, social production and life-style, have the transitional characteristics. In addition, being close to Yangtze River and the Pacific Ocean, the social production and life of the local ancient people in Taihu Lake area have been significantly influenced by the climate and sea-level change. Therefore, the environmental research about the stratums of the archaeological sites in different places of Taihu Lake area can not only uncover the latest scientific evidence for the civilization evolution, but can also provide more essential information about the climate and environmental change. All these data then can help to better understand the correlation and influence mechanisms between the human civilization evolution and environmental change.Supported by the National Nature Sciences Foundation of china (Environmental archaeology on the influence of climate-sea-level change on the civilizing process of Jiangsu in the Neolithic Age) and the International Cooperation Foundation, the author succeeded in carrying out the case study of the two archaeological sites (Luotuodun Site and Dongshancun Site) and the natural section (Pingwang natural stratigraphic section) briefly depicted above. Within the framework of archaeological time division, a series of natural science laboratory methods such as AMS14C dating, foraminifera, charophytes, spore-pollen, granularity, the content test of Rb/Sr/Ti/Zr, geochemistry, heavy mineral, and zircon are applied. Via this process, the author reestablished the sedimentary environmental change sequence in early Holocene in Taihu Lake area and explored the causes why Neolithic sites between10kaBP to7kaBP have not be found in the Taihu Lake area of Jiangsu province.Luotuodun Site, which lies across the transitional zone from mountains to plains, is a typical site of Majiabang Culture in the west area of Taihu Lake. Dongshancun Site, near the Yangtze River delta, is a typical site of Songze Culture in the northeast of Taihu Lake. They both have10ka-7kaBP natural sedimentary layers. The natural stratigraphic section in Pingwang lies on the southeast of Taihu Lake. This natural section and the above two sites each has its uniqueness and representativeness in Geographical location, Characteristics of site, Sedimentary stratum, Cultural relics and artifacts. So by analyzing the sedimentary environment of the three places, we can expect to generate more information on environmental evolution in Taihu Lake area about the early Holocene and understand the relationship between the climate changes, sea-level development of human civilization more comprehensively. Also it can facilitate our understanding of how the ancient people manage to acclimatize themselves to the nature and how the natural environment exerts its influence upon the civilization evolution.The analysis reveals that peat horizon exists in all the three sites (Luotuodun Site, Dongshancun Site and Pingwang natural section) while charophytes and lots of phytodetritus can only be found in Dongshancun Site. In addition, change of grain size and the salinity in layers, surface morphology of the zircon are also identified. By comparing with relevant research by other scholars, we conclude that the sedimentary environment of Taihu lake area in9.8ka-7.2kaBP is freshwater lacustrine-swamp facies with low hydrodynamic conditions.Further analysis of the change of Rb/Sr, formation and retreat process of the peat horizon in layers, hydrodynamic conditions of the grain size, the changes of the oxides content, and material such as spore-pollen indicates that the climate was warm and humid as a whole across10ka-7kaBP in Taihu area. However, within11.6ka-11.2kaBP, the temperature was lower compared with the previous period, and the rainfall had a decreasing trend after a sharp climate anomalies. Throughout9.8ka-9.1kaBP, the weathering had obvious change between strong and weak, and the rainfall underwent increase-decrease fluctuation. The period of9.1ka-8.2kaBP saw a warm and humid climate and an increase-decrease fluctuation of rainfall, especially a cold-dry fluctuation in8.2kaBP. It demonstrated a relatively stable and warm-wet climate in8.2-7.0kaBP, but the sediment dynamics was very unstable, featuring higher frequent fluctuations, and the rainfall was significantly increased in7.2kaBP.The analysis on the characteristics of the stratigraphic sections and the climate factor implies that there are at least five abnormal jump of climate in Taihu Lake area in Early Holocene: cold-dry in11.3ka-11.2kaBP, cold-dry in9.1kaBP and8.2kaBP, warm-wet in7.2kaBP and cold-dry in5.9kaBP.The hypsography of Taihu Lake area is low and flat and the underground water level is higher, which facilitate the influence of water fluctuation upon the distribution of the Neolithic sites. The benthic foraminifera in layers of Luotuodun site shows that the Taihu Lake area had once experienced a serious water fluctuation in a certain time period of9.0ka-7.2kaBP.Analysis of the environment of Taihu lake area together with the pertinent research heritages confirm that the climate was warm and humid and the weathering had drastically changed between strong and weak in early Holocene. In such unstable sedimentary environment few sites can be sustained. At the same time, it is possible that the archaeological sites were buried by the thick deposits between10kaBP and7kaBP which presents difficulties to discover them. Further, the missing of Neolithic sites between10kaBP to7kaBP in the Taihu Lake area of Jiangsu province can be explained as consequence upon the comprehensive dynamics involving all these factors discussed in the foregoing. |
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