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通过对青海湖沉积物中成体特异湖浪介(Limnocythere inopinata)的体长测定,运用青藏高原特异湖浪介的体长与盐度关系的经验公式,定量重建了青海湖近0.9 ka来的古盐度变化序列.同时利用胖真星介(Eucypris inflata)壳体的Sr/Ca比值,结合湖水以及现生介形虫壳体的Sr/Ca比值,定量恢复了相同时段的古盐度序列.对两种不同方法恢复的古盐度作了比较评价,与历史气候序列进行对比,结果表明利用介形虫体长恢复盐度具有较高的可信度,而利用介形虫壳体微量元素恢复盐度的方法在青海湖不适宜应用.从恢复的盐度变化序列来看,1160-1290年的湖水低盐度表明中世纪暖期时该地区气候较为湿润,而小冰期的3个冷期所对应的1410-1540,1610-1670和1770-1850年的3个湖水高盐度期表明该地区在小冰期的冷期,气候较为干燥,而最近几十年的高盐度和近几十年的气候暖干化是一致的.所恢复的青海湖古湖水盐度的变化曲线与该地区树轮所恢复的降水曲线较好的一致性,可以说明本文所重建的盐度变化是比较可靠的,具有一定的区域代表性.
Based on the body length measurement of the Limnocythere inopinata in the sediments of Qinghai Lake and using the empirical formula of the relationship between body length and salinity of the special lake waves on the Qinghai-Tibet Plateau, the paleo- Salinity changes, and the ancient salinity sequences of the same period were quantitatively recovered by using the Sr / Ca ratio of Eucypris inflata shell and the Sr / Ca ratio of lake and live ostracod shells. The paleosalinity restored by the two different methods were compared and compared with the historical climate sequence. The results showed that the use of ostracods length recovery salinity has high credibility, and the use of ostracode shell trace elements The method of restoring salinity is not suitable for application in Qinghai Lake.From the sequence of salinity recovery, the low salinity of the lake in 1160-1290 indicates that the climate in the region was humid during the Middle Ages, while the three cold periods in the Little Ice Age The corresponding high salinity periods of the three lakes of 1410-1540, 1610-1670 and 1770-1850 show that the cold climate in the area was relatively cold during the Little Ice Age, while the high salinity in recent decades and recent decades The year’s climate is warm and dry is the same. The recovery of Qinghai The consistency of the change curve of the lake water salinity of Lake Hu and the precipitation curve restored by tree rings in this area shows that the salinity change reconstructed in this paper is more reliable and has some regional representativeness.