西宁地区黄土地球化学元素所揭示的古气候变化

Variations of Geochemical Elements in Xining Loess Deposit and the Paleoclimatic Implications

在青藏高原东北部,黄土地球化学综合参数是一种对古气候反映较为敏感的指标;地球化学元素变化曲线说明西宁盘子山地区自13.6万年以来在长时间尺度上(万年到十万年)气候逐渐向干冷的方向变化;高原冬季风气候变动属于高频波动,存在短时间尺度的快速变化;夏季风气候具有渐变性,每一次气候变动过程持续时间都较长;盘子山地区与黄土高原地区冬、夏季风的变化特征有不同之处,表现在夏季风最强与冬季风最弱不存在反相位关系,同样冬季风最强的时期夏季风也并不表现为最弱,体现了高原季风系统与东亚季风系统不同的变化特征。

In the northeastern Qinghai - Tibetan Plateau, more palaeo climatic proxy are needed to compare with each other and to retrieve climatic variance. Some geochemical elements are of the most sensitive proxy indicators of the paleoclimate changes. On the basis of the geochemical element measurement, we found the climate had become drier and colder gradually in xining area during the past 13.6Ka,. The plateau winter monsoon appeared to be a high-frequency changes, but summer monsoon varied gradually. The variations of the plateau winter monsoon and the plateau summer monsoon in the Panzishan area were to some extant different from that in the Loess Plateau. There wasn＇t a reversed-phase relation between the stronger plateau summer monsoon and the weaker winter monsoon. Analogously, the plateau summer monsoon wasn＇t under the weakest when the plateau winter monsoon was the strongest.