第四纪悸动：来自柴达木盆地构造增强的证据及其对多圈层的响应

QUATERNARY SHAKING：EVIDENCES OF TECTONIC INTENSIFICATION FROM THE QAIDAM BASIN AND ITS INFLUENCE ON MULTI-SPHERICAL INTERACTION

本研究通过详细的野外工作、钻井资料分析、内流盆地填充基本特征分析，广泛综合前人的研究成果，对柴达木盆地第四纪构造活动及其地质意义进行分析和总结。柴达木盆地中下更新统普遍卷入构造，盆地边缘沉积速率的显著分异，以及盆地总体平均沉积速率的显著增加和在第四系中广泛出现的巨厚砾石层，都显示柴达木盆地第四纪以来构造活动显著增强，是奠定柴达木盆地现今构造样式和地貌形态最为重要也是决定性的事件。第四纪以来由冰川活动所引起周缘山地的大规模物质剥蚀卸载过程和柴达木盆地巨量沉积加载过程，可能是引起该地区第四纪以来构造增强的重要诱因。

With an average elevation of ca. 2700 m, the modern Qaidam Basin is the largest topographic depression inside the northern Tibetan Plateau. The Qaidam Basin is bounded by three huge fault zones： The Eastern Kunlun Fault Zone to the south, the Altyn Tagh Fault Zone to the northwest and the Qilian Shan-Nan Shan Thrust Zone to the northeast. The central part of the Qaidam Basin accepted 2 - 3 km of the Quaternary sediments. Through detailed field work, analyses of drilling data, theoretical derivation of endorheic basins and combination of former studies, this study explores and summarizes the Quaternary tectonic activity and its geological implications in the Qaidam Basin. The widespread deformed Lower to Middle Pleistocene strata distribute at the margin of the Qaidam Basin. Meanwhile, the differentiation of sedimentary rates in the margins of the Qaidam Basin obviously increased during the Quaternary. A large number of drilling wells at the front of the Altyn Tagh Mountains and the northern Qaidam Basin experienced subsidence of the Cenozoic sedimentary floor since the Early Cenozoic and uplift of the Cenozoic sedimentary floor during the Quaternary. On the other hand, most of the drilling wells near the central part of the Qaidam Basin, the southeastern Qaidam Basin and the Gasikule Lake experienced an obvious subsidence of the Cenozoic sedimentary floor during the Quaternary. Besides, according to well data, the average sedimentary rate of the total Qaidam Basin significantly increased during the Quaternary. Moreover, the widespread occurrence of thick gravel layers has been observed in the Quaternary strata. All these evidences indicate that the tectonic activity obviously enhanced during the Quaternary and it is the most important and decisive event establishing the modern basic tectonic pattern and geomorphic landscape of the Qaidam Basin. During the Quaternary, the mass unloading caused by glacial exhumation in the erosion region of the surrounding mountains and the sedimentary loading in the Qaidam Basin may induce the Quaternary tectonic intensification in the Qaidam Basin.