PALAEOENVIRONMENTAL IMPLICATIONS OF LI/CA RATIOS OF OSTRACOD SHELLS FROM LAKE QINGHAI DURING THE PAST 800 YEARS

Acquiring continuous and high resolution natural records in recent 2000 years 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 ²¹⁰Pb 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.