青藏高原腹地湖泊沉积粒度特征及其古环境意义

Grain Size Characteristics and Their Environmental Significance of the Lacustrine Deposits in the Hinterland of Qinghai-Tibetan Plateau

选择青藏高原腹地可可西里为研究区,通过对该区湖泊沉积物粒度参数的分析,并且与其他环境代用指标进行比较,探讨了中更新世以来可可西里地区的环境演变。结果表明:粒度参数的变化特征可以很好地指示湖泊水位的变化,能反映湖区气候的变化情况,粒度参数所指示的湖泊水位波动及环境变化得到了其他环境代用指标很好的支持,说明对沉积物粒度研究是恢复区域气候环境变化的一种有效途径。同时该区湖泊沉积物粒度参数的变化规律和深海氧同位素曲线在冰期—间冰期旋回尺度上有较好的一致性,但也出现不同的变化特征,表明这一区域既有与全球一致的气候特征,也受区域气候变化影响,其原因可能与青藏高原的抬升有一定关系。

In Hoh Xil area,the hinterland of Qinghai-Tibetan Plateau,by the analyses of the grain-size parameters and the comparison with other proxies of the BDQ06 core sediments,the authors researched the environmental evolution of this area since the Middle Pleistocene.The variation in grain-size parameters,as a good indicator for the variation in lake level,could further reflect the climate change of lake region.These environmental changes reflected by the grain-size of BDQ06 core sediments were well supported by other proxies and proved by other research results.The sediment gain size provides a new effective way to recover the climate changes.Furthermore,the climate change in this area was compared with the LR04 marineδ18 O record;the results indicated that there were very strong similarity on the scale of glacial-interglacial cycle,and there were also obvious regional differences.That means this area responded to global climate change with regional characteristics which might be related with the tectonic uplifting of Qinghai-Tibetan Plateau.