| 英文摘要： |
The paleolake that once existed in the Hetao Basin, China, represents an important stage of the Yellow River drainage system evolution in the region, but it has not been studied in detail to date. In particular, the formation and driving forces of the paleolake evolution since the late Pleistocene is still poorly understood. In this study, optically stimulated luminescence and radiocarbon dating were combined with multiproxy analysis of lacustrine sediments in the central Hetao Basin to reconstruct the paleolake evolution. Proxies included carbonate O-18 and C-13 isotopes, grain size, magnetic susceptibility, and color. In combination with stratigraphic records, the proxies indicated the existence of a lake environment in the Hetao Basin between similar to 150 and similar to 18 ka BP. The paleolake between 150 and 130 ka BP was an open system. Between 130 and 54 ka BP, the paleolake basin closed, with high lake levels at the beginning of the period and then a gradual decrease. After 54 ka BP, the paleolake began to outflow and gradually shrank in size, and after 18 ka BP an alluvial fan covered the region, and the paleolake disappeared. We propose a combination of tectonic uplift and climate changes as the main drivers of paleolake formation and evolution since the late Pleistocene. (C) 2017 Elsevier Ltd and INQUA. All rights reserved. |
