Department of Geography and Spatial Information Techniques, Ningbo University, Ningbo 315211, China.
Institute of East China Sea, Ningbo University, Ningbo 315211, China.
Int J Environ Res Public Health. 2020 Sep 28;17(19):7099. doi: 10.3390/ijerph17197099.
A 2.5 m long sediment core (XH-2) obtained from Xianghu area, near the Kuahuqiao site, were analyzed for grain size, diatom index, and geochemistry of organic carbon. The results of the total organic carbon (TOC) and stable organic carbon isotope (δC) in sediment samples from core XH-2 in the Xianghu area in Zhejiang Province have revealed the evolution history of sedimentary environmental and climatic changes during the breeding-prosperity-decline period of the Kuahuqiao culture. During 9300-8200 cal a BP, TOC contents were relatively high and stable, whereas δC values tended to be negative. This condition indicated that the climate was humid, and the sedimentary environment in the Xianghu area was stable. During 8200-7500 cal a BP, TOC contents presented a fluctuating declining trend, and δC values were significantly high, implying that the climate was arid, and the Xianghu area was gradually reduced to land. Thus, conducive conditions were provided for the development of the Kuohuqiao culture (7700-7400 cal a BP). From 7500 cal a BP, TOC contents obviously declined, and δC values were partially low, suggesting strengthened hydrodynamic force and wet conditions in the Xianghu area. This condition was related to the rise in sea level at approximately 7400 cal a BP, and the Kuahuqiao site became obsolete due to the transgression event. The TOC contents in core XH-2 were remarkably influenced by grain size, whereas no significant correlation existed between the δC variability and grain size. Sedimentary environment changes in the Xianghu area from 9300 to 6600 cal a BP, which was reflected by the TOC and δC records in core XH-2, accorded with the diatom results in this core and those in the Baima Lake area.
从距跨湖桥遗址不远的湘湖地区采集了一段 2.5 米长的沉积物岩芯（XH-2），对其粒度、硅藻指数和有机碳地球化学进行了分析。对浙江省湘湖地区 XH-2 岩芯沉积物样品中总有机碳（TOC）和稳定有机碳同位素（δC）的研究结果揭示了跨湖桥文化的繁殖-繁荣-衰落时期，沉积环境和气候变化的演化历史。在 9300-8200 年前 cal a BP，TOC 含量相对较高且稳定，而 δC 值趋于负值。这种情况表明气候湿润，湘湖地区的沉积环境稳定。在 8200-7500 年前 cal a BP，TOC 含量呈波动下降趋势，δC 值明显升高，表明气候干旱，湘湖地区逐渐沦为陆地。因此，为跨湖桥文化的发展（7700-7400 年前 cal a BP）提供了有利条件。从 7500 年前 cal a BP 开始，TOC 含量明显下降，δC 值部分较低，表明湘湖地区水动力增强，湿度增加。这种情况与大约 7400 年前 cal a BP 的海平面上升有关，跨湖桥遗址由于海侵事件而废弃。XH-2 岩芯中的 TOC 含量明显受到粒度的影响，而 δC 变化与粒度之间没有显著的相关性。从 9300 到 6600 年前 cal a BP，湘湖地区的沉积环境变化，反映在 XH-2 岩芯中的 TOC 和 δC 记录中，与该岩芯和白马湖地区的硅藻结果一致。
