Late Quaternary hydroclimate change inferred from lake sedimentary record in arid central Asia

Abstract

Arid central Asia is a key region in the study of global climate change; however, the characteristics and mechanisms of regional hydroclimate changes during the late Quaternary remain poorly known. Here we present a new hydroclimate record from Lake Ebinur in arid northwestern China based on a comprehensive multiproxy analysis. The results show that Lake Ebinur formed at ~33.5 ka under relatively warm and humid conditions that continued to 26.7 ka. The following Last Glacial Maximum was cold and dry from 26.7 to 18.5 ka, most notably during the interval between 21.3 and 18.5 ka, suggesting a two-step hydroclimate change. The moisture conditions started to improve at 15 ka and reached their highest level during the Middle Holocene (8.7–4.4 ka). A comparison of our record with other records in the Northern Hemisphere indicated that the moisture changes in central Asia followed similar variability trends to those of the east Asia monsoon region during the last glacial period, suggesting common driving forces, such as the boreal solar insolation and its associated Northern Hemisphere ice-sheet volume. The Holocene moisture optimum in central Asia was delayed by 2000–3000 years relative to that in east Asia, which demonstrated a large influence of the remnant Northern Hemisphere ice-sheet forcings on the mid-latitude Asia atmospheric circulation (e.g. mid-latitude westerlies and Siberian High) in the Early Holocene.