作　　者： ; ; ; ; ; ; ; ; ; ; (齐士峥）; (龚琪岚）; (周凤琴）;

机构地区： 南京大学地理与海洋科学学院

出　　处： 《地理科学》 2012年第7期878-884,共7页

摘　　要： 选择位于江汉平原的JZ-2010湖相沉积剖面为研究对象,利用AMS14C测年建立江汉平原12.76 cal.ka B.P.以来环境演变的时间序列。对湖相沉积物中元素Rb和Sr的差异分布、Rb/Sr值、Ti元素含量以及磁化率等多项环境代用指标的综合分析表明:江汉平原12.76 cal.ka B.P.以来环境干湿变化经历了晚冰期由偏干转向偏湿波动、全新世开始湿度增强、全新世中期偏湿到湿润再至干湿波动,全新世晚期至现代偏湿到偏干的过程。磁化率波动与江汉平原新石器时代各文化类型出现或转型相关。江汉平原环境干湿变化体现东亚季风环流影响,驱动机制主要是北半球夏季太阳辐射变化;还受到东北、北、西三面环山而东南面向夏季风倾斜开放的地势影响。 Six AMS radiocarbon ages combined with the concentration and distribution of element Rb, Sr and Ti, Rb/Sr ratio and magnetic susceptibility are utilized to reconstruct the moisture evolution in the Jianghan Plain during the last 12.76 ka. The multi-proxy integrated indicators of the regional moisture conditions turned from dry to wet after the Late Glacial and progressively became better and reached its optimum period until the mid-Holocene, however, punctuated by several humidity decrease phases. Begin with the severe dry event around 4.42-4.00 cal.kaBP, the environment was dry again in the Jianghan Plain as a whole. It can be inferred that the evolution of moisture condition in the study area was dominated by the East Asian monsoon system which likely be driven by the solar insolation changes on the Northern Hemisphere. As the first time to apply the Rb/Sr ratio and Ti concentration in tracing moisture evolution in a region with typical subtropical humid cli- mate, this study highlights the different effects and consequences of the proxies throughout the paleoenviron- ment process. Also the regional characteristics of continuously subsided since the Cretaceous period as well as the topography opening down to southeast. What＇ s more the variations of magnetic susceptibility are well coincided with the transition of Neolithic culture of the Jianghan Plain.

关 键 词： 江汉平原 元素含量 磁化率 干湿变化

领　　域： [环境科学与工程]