江苏宜兴骆驼墩遗址地层全新世沉积环境研究

HOLOCENE SEDIMENTARY ENVIRONMENTS OF LUOTUODUN SITE,YIXING,JIANGSU PROVINCE

主要通过对骆驼墩遗址地层样品的粒度和重砂矿物的鉴定、样品中锆石形态的对比研究,铷锶值的测定与分析,了解该区域全新世以来的沉积环境及其气候变化,探索气候变化与人类文明和文化发展的关系。对骆驼墩遗址文化层下的自然淤积层的粒度分析和锆石形态研究发现该区域在人类出现之前可能经历过浅水泻湖环境;结合重矿物及铷锶研究发现,该区域在全新世早期降水量较大,气候较为湿热,之后气候逐渐变得温暖湿润,为人类文明的出现和文化的发展提供了一个优越的气候条件;通过对地层中文化层样品的重矿物鉴定及百分含量分析、ZTR稳定系数及Rb/Sr分析发现,全新世的气候是不断变化的。尤其在马家浜文化时期、良渚文化时期和广富林文化时期气候经历过温湿与干凉的交替变化过程。同时良渚文化时期的中晚期稳定系数出现了该地层的最高值,说明当时气候较为湿热,降水量偏多,这与良渚文化的消失与洪水有关的结论相一致。

This paper is designed to discuss the Holocene sedimentary environment of the Taihu Lake area and the relationship between cultural evolution and climate change on the basis of a dynasty framework established by ^14C dating and through study of deposited layers at Luotuodun Site using experimental methods such as susceptibility analysis of heavy minerals,identification of zircon,content test of Rb and Sr, and grain size analysis. Luotuodun Site is located in the Taihu Lake area, Yixing,Jiangsu Province. The shape correlation of zircons from different layers of the site shows that a lagoon environment might exist in the Early Holocene. Heavy mineral data and Rb/Sr ratios from the same layers suggest that relatively hot and humid conditions in the Early Holocene were followed by relatively warm and moist conditions. The warm and moist conditions extended to the Middle Holocene. Such climate conditions were very suitable for the development of human civilization. Finally, heavy mineral data,ZTR stability coefficients,and Rb/Sr ratios from individual cultural layers including layers of the West Zhou Dynasty to the Spring-Autumn period show that there was an alternation of the moist and cool climate to the warm and humid climate in each of all of the Majiabang culture period, the Liangzhu culture period, and the Guangfulin culture period. The peak of ZTR stability coefficients occurred in the middle and late of the Liangzhu cultural period, reflecting a humid and hot climate with too much rainfall. This result is in line with the previous conclusion that the disappearance of the Liangzhu culture is related to flood.