摘要
本研究通过对山东省东平湖现生沉水植物、湖水、沉积岩芯样品的14C年代的测定,并将结果与210Pb测年结果进行对比研究,同时结合东平湖形成的历史过程与黄河洪水事件的分析,探讨了东平湖沉积物的碳库效应,初步确定了东平湖形成年代。研究表明:东平湖大致形成于公元516年前后,是黄河泛滥的产物;东平湖碳库效应随沉积层序有显著变化,其中湖泊多年平均硬水效应为484 a,沉积物碳库效应年龄一般为1000~2000 a,最高可达3700 a。这种沉积物碳库效应随沉积层序发生变化的原因与历史时期黄河泛滥、古济水、流域老碳以及人类活动等多种因素的复杂影响有关。由于东平湖沉积物碳库效应年龄随时间并非恒定,因此必须在仔细分析不同层序的沉积物的基础上,运用多种可能的方法测定沉积物年龄,并相互比较验证,以建立准确的年代框架,为该区古环境变迁信息解读提供可靠的年代基础。
We present here determine 14C ages of submerged aquatic plant (Potamogeton malaianus), lake water and sediments from Lake Dongping in Shandong province, China, comparing the result with the 210Pb dating and combining with the analysis of the formation of Lake Dongping and flood event of the Yellow River, to evaluate the reservoir age. It shows that the Lake Dongping formed in around 516 AD for the flood of the Yellow River, and reservoir effect of sediments does exist with the depth. The average annual hardwater effect age is 484 a. The reservoir ages of the lake sediments are changes between 1000 a and 2000 a, up to 3700 a. The reason for the reservoirs ages changing with the depth is related to the “old carbon” sediments carrying from the historical flood of the Yellow River, peleo-Jishui river, catchment and human activities. Due to the reservoir age of lacustrine sediments in Lake Dongping is temporally variable, it is necessary to carefully analyse the different lithologic characteristics of the sediment layers and use various possible methods to determine the age of sediments, in order to establish a precise chronological framework for a reliable age basis to interpret the paleoenvironmental changes in this area.
基金
国家自然科学基金项目(41072258,40772209)。
