太湖西部地区8.2ka BP以来的高分辨率孢粉记录

HIGH-RESOLUTION PALYNOLOGICAL RECORD IN THE WESTERN REGION OF TAIHU LAKE SINCE8.2 ka BP

通过AMS14 C测年技术建立年代标尺,对太湖西部地区LTD-12号钻孔301cm以上的岩芯进行高分辨率孢粉分析,重建太湖西部地区8.2ka BP以来的气候和植被,并探讨了太湖地区新石器文化对气候变化的响应。结果表明:1)太湖西部地区8.2ka BP以来的植被类型演替过程大体为:以松属—常绿栎—落叶栎—枫香为主的含针叶成分的常绿落叶阔叶林→以落叶栎-常绿栎-枫香树属为主的常绿落叶阔叶林→以松属-枫香为主的针阔叶混交林→以松属为主的次生性质的针叶林。2)太湖西部地区高分辨率孢粉记录的气候变化可划分为2个大的阶段:(a)8.2~4.4ka BP为中全新世温暖湿润期,最适宜期出现在6.9~5.5ka BP;(b)4.4ka BP^0ka BP为晚全新世降温期,气候从暖稍湿向暖干过渡。3)太湖地区的新石器文化总体上响应于气候的变化。环太湖平原地区至今未发现10~7ka BP的新石器遗址可能与当时过于潮湿和不稳定的气候环境有关;6.9~5.5ka BP温暖湿润的气候适合人类的生存,促使了马家浜文化的出现、繁荣和发展;5.0ka BP左右的干燥降温事件可能导致了崧泽文化的衰落;良渚文化的消亡可能与4.4ka BP前后该地区的气候突变事件有关。

In this paper,by using AMS^14C method to establish the time scale and making high-resolution pollen analysis of the Drilling LTD-12 above 301 centimeters deep, we reconstructed the vegetation and cli- mate of the western region of Taihu Lake since 8.2 ka BP, and discussed the response of Neolithic Culture to climate change. The results showed that at the period of 8.2 ka BP to 4.4 ka BP, the climate was warm and humid on the whole, and the vegetation was evergreen and deciduous broad-leaved mixed forest containing a little conifers, mainly donated by Pinus, Quercus and Liquidambar, and the most optimum period appeared in the period of 6.9 ka BP to 5.5 ka BP. After 4.4 ka BP, the climate was changing into cool and dry, comparing to the former period, and the vegetation was coniferous forest donated by Pinus, with a secondary property. The development of Neolithic Cultures in the region of Taihu Lake showed a good correlation with the climate change. For example, the Majiabang Culture and the Songze Culture appeared and prospered in the most warm and humid period of 6.9 ka BP to 5.5 ka BP, which was suitable for human being,s survival. However, the Songze Culture declined and finally disappeared when the climate changed into cool and dry. The pollen record also revealed that the disappearance of Liangzhu Culture may related to the 4.2 ka event. Why there were not any found Neolithic site from early Holocene to 7 ka BP, it may be a result of extremely humid climate, which was not suite for survival.