Spatial pattern of modern sedimentation rate of Qinghai Lake and a preliminary estimate of the sediment flux  

作　　者：XU Hai LIU XiaoYan AN ZhiSheng HOU ZhaoHua DONG JiBao LIU Bin 

机构地区：[1]State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Shaanxi 710075, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Science Bulletin》2010年第7期621-627,共7页

基　　金：supported by the National Key Technology R&D Program (Grant No.2007 BAC30B01);West Light Foundation of the Chinese Academy of Sciences(Grant No.2007ZD01)

摘　　要：We investigated the spatiotemporal distribution of1 37Cs radioactivity in surface sediment of Qinghai Lake,and developed the spatial pattern of sedimentation rate.The1 37Cs inventory is higher near the estuary/bank area,but lower at the central lake.On the other hand,the average1 37Cs activity is lower near the estuary/bank area,but higher at the central lake.The mass accumulation rate(MAR) and the fluxes and contents of the terrestrial detritus(e.g.SiO2,Fe2O3,and Ti) are higher near the estuary/bank area,but lower at the central lake.The chemical/biogenic deposits(e.g.the autogenic carbonates) take up higher fractions at the central lake.These suggest that the spatial pattern of recent sedimentation rate is dominated by the deposition of terrestrial detritus.The average MAR(0.0337 g cm-2a-1) was estimated based on those of different cores of Qinghai Lake and was verified by a Ca mass-balance method.The fluxes of total lake sediments,terrestrial detritus,and direct atmospheric deposits were also estimated.We investigated the spatiotemporal distribution of 137Cs radioactivity in surface sediment of Qinghai Lake, and developed the spatial pattern of sedimentation rate. The 137Cs inventory is higher near the estuary/bank area, but lower at the central lake. On the other hand, the average 137Cs activity is lower near the estuary/bank area, but higher at the central lake. The mass accumulation rate （MAR） and the fluxes and contents of the terrestrial detritus （e.g. SiO2, Fe2O3, and Ti） are higher near the estuary/bank area, but lower at the central lake. The chemical/biogenic deposits （e.g. the autogenic carbonates） take up higher fractions at the central lake. These suggest that the spatial pattern of recent sedimentation rate is dominated by the deposition of terrestrial detritus. The average MAR （0.0337 g· cm^-2 al） was estimated based on those of different cores of Qinghai Lake and was verified by a Ca mass-balance method. The fluxes of total lake sediments, terrestrial detritus, and direct atmospheric deposits were also estimated.

关 键 词：现代沉积速率 沉积物通量 空间格局 青海湖 陆源碎屑沉积 137Cs 估算 高等教育 

分 类 号：P736.21[天文地球—海洋地质] P426.616[天文地球—海洋科学]