Southwest monsoon changes indicated by oxygen isotope of ostracode shells from sediments in Qinghai Lake since the late Glacial
Southwest monsoon changes indicated by oxygen isotope of ostracode shells from sediments in Qinghai Lake since the late Glacial
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DOI：
10.1007/s11434-007-0086-3
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发表时间：
2007-02-01
影响因子：
--
通讯作者：
Liu WeiGuo
中科院分区：
文献类型：
--
作者：
Liu XingQi;Shen Ji;Liu WeiGuo
青海湖QH-2000孔沉积物中介形虫壳体的δ O-18记录可以较好地反映季风变化。正三角洲O-18值平均为千分之2.37，表明17.5和11 cal. ka BP之间的季风降水量较低。在5180年，季风降水从11 cal. kaBP的正值迅速转变为10 cal. kaBP的负值，表明季风降水急剧增加。在10 - 6 cal. kaBP之间观察到一个普遍较高的季风降水间隔，δ O-18值平均为-2.15 ‰。δ O-18值为正值，表明6 ~ 2.5cal.kaBP之间季风降水减少。δ O-18在2.5 ~ 0 cal. kaBP之间保持正值，平均值为3.0 ppm，表明季风降水量低而高。青海湖QH-2000孔沉积物中介形虫壳δ O-18记录所反映的气候变化以及更广泛的区域对比表明，晚冰期以来青海湖的气候可能受西南季风而非东南季风的控制。
The delta O-18 records of ostracode shells in sediments of core QH-2000 from Qinghai Lake can be used as a better proxy to reflect monsoon changes. Low monsoon precipitation between 17.5 and 11 cal. ka BP is indicated by positive delta O-18 values averaging 2.37 parts per thousand. A fast shift in 5180 from positive at 11 cal. ka BP to negative at 10 cal. ka BP indicates sharp increase of monsoon precipitation. An interval of generally high monsoon precipitation is observed between 10 and 6 cal. ka BP with delta O-18 values averaging -2.15 parts per thousand. Decrease of monsoon precipitation between 6 and 2.5 cal. ka BP is indicated by positive delta O-18 values. delta O-18 keeps positive values averaging 3.0 parts per thousand between 2.5 and 0 cal. ka BP suggesting low high monsoon precipitation. The climatic changes indicated by delta O-18 records of ostracode shells in sediments of core QH-2000 from Qinghai Lake and our broader regional comparison show that the climate in Qinghai Lake since the late Glacial is probably controlled by southwest monsoon other than southeast monsoon.