Late Quaternary hydroclimatic variations in the hyper-arid Dunhuang Basin, northwestern China

Abstract

The changes in paleoclimate and their driving mechanisms in northwestern (NW) China since the Late Quaternary remain unclear and controversial. This is due to the scarcity of relatively continuous sedimentary records with high-resolution chronological controls in this hyper-arid region. To address this gap, a new sedimentary record was drilled from Yitang Lake in the Dunhuang Basin of NW China, and used to reconstruct the long history of regional hydroclimatic changes since the Late Pleistocene. A comprehensive high-resolution geochronology of the upper part of the drilling core indicates a significant sedimentary hiatus between approximately 100 ka and 23 ka, likely due to the dry and harsh environmental conditions during the Last Glacial period (MIS 4 to MIS 2). Since then, the study area has experienced a relatively dry Late Glacial period (∼23–11 ka), gradually wetter early Holocene (∼11–8 ka), and moist mid-Holocene (∼8–5 ka), followed by a drying trend after approximately 5 ka. Hydrological variations in this area since the Late Quaternary were mainly controlled by changes in precipitation and glacier meltwater from the northeastern Tibetan Plateau. These alterations were ultimately regulated by shifts in atmospheric circulation patterns, as well as the dynamic interplay between the westerlies and the East Asian summer monsoon at both orbital and suborbital scales.