青藏高原中部色林错SL-1孔粒度参数指示的5.33 ka BP以来的水位变化

Lake Level Changes Indicated by Grain-size of Core SL-1 Sediments Since 5.33 ka BP in Selin Co, Central Qinghai-Tibetan Plateau

对取自青藏高原中部色林错深水区的SL-1孔开展年代学和粒度参数研究,以此重建了该湖5.33 ka BP以来的水位变化。结果表明,5.33～4.25 ka BP是一期较为稳定的高湖面期,湖面波动较小,始终维持在高湖面,后期（4.30～4.25 ka BP）湖面开始下降;4.25～2.20 ka BP,风力加强,湖面较上一期有所降低,属湖面降低期,风力作用的影响增加;2.20～1.90 ka BP,稳定的低湖面期;1.90 ka BP至今,高湖面期。但有几期短暂而快速的湖面降低,湖面降低的持续时间一般为20-50 a,具有约0.10 ka和0.20 ka的周期性,约0.20 ka的准周期基本贯穿了色林错自5.33 ka BP以来的湖面变化。这种周期在青藏高原冰芯氧同位素恢复的温度序列中也存在,说明在百年尺度上,温度对色林错的湖面变化有一定影响。

This paper studies the chronology and the grain-size of core sediments retrieved from deep area of Selin Co, central Qinghai-Tibetan Plateau （QTP）, to reconstruct the lake level changes since 5.33 ka BP. Lake level changes of Selin Co are in several distinct stages： 5.33-4.25 ka BP sees a continuous high lake level with tiny fluctuations; the lake level goes down during the period of 4.25-2.20 ka BP, and the wind contributes much to the sedimentary of Selin Co; 2.20-1.90 ka BP is a stable low lake level period; 1.90 ka BP-present sees a high lake level since 5.33 ka BP with several short and fast fluctuations. 0.1 ka and 0.2 ka cycles are recovered during this period. The low lake level usually lasts for only 20-50 a. The 0.20 ka cycle, which can also be seen in the temperature sequence recorded in the ice core from the QTP, goes through the whole period since 5.33 ka BP, indicating that on the centennial scale, the air temperature is important for the lake level variations of Selin Co.