干旱区湖泊沉积物代用指标意义——猪野泽表层沉积物样品为例

Meanings of proxies of lake sediments in arid region:surface sediments in Zhuye Lake

于猪野泽古湖盆南北向中心线及湖盆边缘东北部两个区域内采集表层沉积物样品共45个,既包含来源于地表径流的沉积物,也有在湖泊内部形成的沉积物.分别对其粒度、TOC、w(C)/w(N)及δ13C等分析后发现猪野泽表层沉积物颗粒随地势自高向低逐渐变细,且沉积物中的TOC和w(C)/w(N)逐渐升高,δ13C则相反.据此可知,猪野泽古湖泊表层沉积物的粒度及地球化学指标特征符合干旱区内陆河终端湖泊沉积物千年尺度上的一般规律,故可使用这些指标推测猪野泽古湖泊的水动力条件和湖面水位等.

45 surface sediment samples from not only surface runoffs but also the lake itself were taken from the middle and northeastern parts of Zhuye Lake. After analyzing the grain size, TOC content, w（C）/w（N） andδ13C of those samples, it was clear that the surface sediments of Zhuye Lake have been getting thinner along with the descent of elevation, while the TOC content and w（C）/w（N） have been increasing but δ13C content decreasing. Accordingly, the characteristics of the grain size and geochemical proxies from the surface sediments of Zhuye Lake meet the regular lacustrine patterns well on millennial-scale. Therefore, it is possible to use these proxies to explicate the hydrodynamic strength and lake levels of Zhuye Lake.