基于光释光测年研究青海湖三种沼泽湿地的发育及沉积速率  

The Study of Formation and Sedimentation Rate of Three Typical Wetlands in Qinghai Lake Watershed Using Luminescence Technique

作　　者：刘德梅[1,2] 陈桂琛[1] 赖忠平[3,4] 刘向军[4] 周国英[1] 宋文珠[1] 彭敏[1] 

机构地区：[1]中国科学院西北高原生物研究所,青海西宁810008 [2]中国科学院研究生院,北京100039 [3]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000 [4]中国科学院青海盐湖研究所,青海西宁810008

出　　处：《盐湖研究》2012年第3期9-14,共6页Journal of Salt Lake Research

基　　金：国家"十一五"项目(2007BAC30)

摘　　要：近百年来由于受气候暖干化、青海湖湖体水位下降和周围草地退化及沙化趋势加剧等生态环境变化,加速了湿地环境变迁的生态过程。本研究在青海湖北岸地区选取三种典型沼泽湿地(藏嵩草kobresia ti-betica、华扁穗草Blysmus sinocompressus、盐地凤毛菊Saussurea salsa),建立地层的年代序列,计算得到每一测年段内的沉积速率,结合前人研究的历史气候变化,分析湿地形成的历史背景,初步揭示三种沼泽湿地的发育和沉积规律与全球变化的耦合性。结果表明光释光测得的三种沼泽湿地其发育时期各不相同,华扁穗草沼泽湿地发育于8.436±0.6 ka,藏嵩草沼泽湿地发育于2.058±0.11 ka,盐地凤毛菊沼泽湿地发育于1.143±0.20 ka;从整个剖面的平均沉积速率来看盐地凤毛菊湿地沉积最快(0.63 mm/a),藏嵩草湿地次之(0.39 mm/a),华扁穗湿地最慢(0.09 mm/a)。三种沼泽湿地主要在气候由暖干向湿润期转变时形成,自形成以来由于受到全球变化和人类因素的影响,沉积并非随时间呈线性关系发展。In recent years, due to the warm and dry climate, Lake water-level decline and grassland deg- radation, desertifieation, it speeds up ecology process of wetland environment, which seriously impact on the sustainable development of Qinghai Lake watershed. In this study, sediment cores were sampled and dated using optically stimulated luminescence （OSL） dating method at three typical wetlands in north shore of Qinghai lake. Dating of sediment cores was used to establish the wetland sedimentary chrono-se- quenee, calculate sediment accumulation rates. Analysed wetland formation＇ s history background from paleoclimate change of previous research in local. Preliminarily reveals three wetlands formation and sedi- mentary regularity, and relate to the global climate change. The results showed that all OSL samples have strong signals and De value approximate Gaussian Distribution, the estimated OSL ages of all samples match the stratigraphic sequence, which suggests that OSL dating is a reliable method for determining a chronology of Holocene marsh deposits at Qinghai Lake watershed, kobresia tibetica, Blysmus sinocompres- sus ,Saussurea salsa have existed since approximately 8. 436 ± 0.6 ka, 1. 143 ± 0.20 ka, 2. 058 ± 0. 11 ka respectively. Different wetland have different sedimentation rate. The most of sediment rate is Saus- surea salsa marsh（0.65 ram/a）, then kobresia tibetica marsh（0.39 mm/a）, the last is Blysmus sinocom- pressus（O. 09 mm/a）. Compared with the past study last 8 000 year in this region, we found that every kind of marsh developing during wet period, and the changes of the sedimentary rate suggested that there arere a Linear Relationship between deposit and time in wetland, global climate change and anthropogen- ic impacts seriously affect on wetland evolution.

关 键 词：青海湖湿地 湿地发育 光释光测年 沉积速率 

分 类 号：P531[天文地球—古生物学与地层学]