【摘要】 当前古气候研究的热点是获取最近2000a来连续的高分辨率自然记录。为了解决湖泊沉积代用指标中古温度指标的难题,通过对青海湖沉积物单一种属介形虫壳体胖真星介(Eucyprisinflata)Li/Ca比值的测定,结合已有的210Pb和137Cs测定的沉积物沉积速率[1],成功恢复了青海湖底层水的古温度变化序列。将Li/Ca比值曲线与气象记录以及邻近地区都兰和祁连山树轮宽度指数恢复的温度变化序列对比,发现介形虫壳体Li/Ca比值与温度呈明显的负相关变化,Li/Ca比值高,温度低,Li/Ca比值低,温度高,表明介形虫Li/Ca比值是一种有效的古温度指示剂。更多还原

【Abstract】 Acquiring continuous and high resolution natural records in recent 2000years is the hotspot in palaeoclimate research.In order to resolve the problem of temperature proxy as an indicator for lake sedimentation,based on the Li/Ca ratios of shells of a single ostracod species Eucypris inflate retrieved from the Lake Qinghai sediments,together with the existing sedimentation rate data derived from 210 Pb and 137Cs from Xu et al.(2006),we have successfully reconstructed the variation in temperature during the past 800-years for the Lake Qinghai.By Comparison of ostracod Li/Ca ratios with temperatures inferred from meteorologic records and tree ring widths in Dulan and Qilianshan,we found that Li/Ca ratios of ostracod shells negatively correlate with temperatures.Higher temperatures correspond to lower Li/Ca ratios,and vice versa,suggesting that ostracod Li/Ca ratio probably is an effective proxy for bottom water temperature.更多还原