Abstract Quaternary saline lake deposits are well formed and widely distributed in the Qaidam Basin, on the northeastern Tibetan Plateau, NW China. Studying these lacustrine salt mineral deposits in closed lakes would improve our understanding of tectonic deformation, Asian interior aridification and monsoon climate associated with global cooling and Tibetan Plateau uplift. Previous paleoclimate records in the Qaidam Basin are mostly documented by geochemical proxies, pollen spectra and sedimentary characteristics, however, supportive evidence from the rock magnetic index of sediments with salt deposits in the basin has not been well studied. Here, we present a continuous, high-resolution 1.0 Myr rock magnetic record from the well-dated drill core SG-3 with typical saline lake deposits in the western Qaidam Basin. The results show that deposits with low magnetic susceptibility (χ) are caused by low contents of magnetic minerals with single-domain (SD) grains, but those with high χ have relatively high contents of magnetic minerals with SD and pseudo-single-domain (PSD) grains. In full consideration of the sedimentary environments, weathering and erosion associated with the tectonic uplift of the northeastern Tibetan Plateau and the global climate since the middle Pleistocene, we propose that χ variations in the closed lake are influenced by the input of debris and regional precipitation. Combing the χ changes with pollen and grain size records, we demonstrate that the drying process in central Asia since 1 Ma, with obvious aridification increases at 0.6 Ma and 0.13 Ma, has been mainly induced by the uplift of the Tibetan Plateau under global cooling.

中文翻译：

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柴达木盆地西部1 Ma以来SG-3岩心岩石磁记录及其对青藏高原东北部古气候的影响

摘要 青藏高原东北部柴达木盆地第四系盐湖沉积发育良好，分布广泛。研究封闭湖泊中的这些湖相盐矿床将增进我们对与全球变冷和青藏高原隆升相关的构造变形、亚洲内部干旱化和季风气候的理解。柴达木盆地以往的古气候记录主要是通过地球化学代理、花粉光谱和沉积特征来记录的，但盆地内含盐沉积物的岩石磁性指数的支持性证据尚未得到很好的研究。在这里，我们展示了来自柴达木盆地西部具有典型盐湖沉积物的年代良好的钻芯 SG-3 的连续、高分辨率 1.0 Myr 岩石磁记录。结果表明，低磁化率（χ）矿床是由单畴（SD）晶粒磁性矿物含量低引起的，而χ高的矿床则具有相对较高的SD和伪单畴磁性矿物含量。 PSD) 谷物。综合考虑青藏高原东北部构造隆升的沉积环境、风化侵蚀和中更新世以来的全球气候，我们认为封闭湖的χ变化受碎屑输入和区域降水的影响。将 χ 变化与花粉和粒度记录相结合，我们证明自 1 Ma 以来中亚的干燥过程，在 0.6 Ma 和 0.13 Ma 时明显干旱化增加，主要是由全球冷却下青藏高原的隆升引起的。