A high-resolution multiproxy speleothem record of Eastern China hydroclimate variation during last glacial maximum

Abstract

The Last Glacial Maximum (LGM, 23-19 ka BP), marked by the greatest global ice volume expansion and lowest sea level during the last glacial period, is a critical epoch for comprehending historical climate variability. It has been extensively utilized as a reference point for assessing abrupt glacial climate shifts and the underlying external influences in climate model simulations. Although numerous proxies have advanced our comprehension of the LGM global climate, the evolution of LGM hydroclimate in densely populated monsoonal eastern China remains ambiguous, mainly due to complicated rainfall patterns and limited hydroclimate records. To address this shortcoming, here we present a high-resolution multiproxy speleothem record depicting the evolution of hydroclimate in central China spanning from 30 to 18 ka BP. Our hydroclimate proxies (δ¹³C and Mg/Ca), combined with other terrestrial records in eastern China, reveal a wet central southern China during the LGM while a dry northern China. The iTraCE simulation further revealed positive summer (JJA) and winter (DJF) net precipitation contributions in central southern China during the LGM, linked with orbital forcing and enhanced exposure of the low-latitude continental shelves. Our record also identifies a ∼400-year hydroclimate cycle during the late LGM, which is similar to the Atlantic Meridional Overturning Circulation (AMOC) variations, indicating a strong coupling between East Asian hydroclimate and high-latitude climate via atmospheric and oceanic teleconnections on a centennial scale.