Millennial-scale East Asian summer monsoon hydroclimate variability during 47–39 kyr B.P. inferred from a stalagmite IRMsoft-flux record in Southeastern China
Journal
Global and Planetary Change
Journal Volume
253
Start Page
104954
ISSN
0921-8181
Date Issued
2025-10
Author(s)
Abstract
The East Asian Summer Monsoon (EASM) exhibited millennial-scale oscillations during the Last Glacial Period, characterized by alternating cold stadials and warm interstadials that were broadly synchronous with climate changes in the North Atlantic. However, the mechanism linking regional hydroclimate variability to high- and low-latitude forcing remains debated. Here, we present precisely dated speleothem multi-proxy records, including δ18O, δ13C, and an environmental magnetic proxy (IRMsoft-flux), spanning 46.92–39.18 kyr B.P. from Xianyun Cave, southeastern China. The IRMsoft-flux, serves as an indicator of precipitation intensity, revealing increases during Dansgaard-Oeschger (DO) events 12 and 11, consistent with enhanced water vapor influx into southern China. Maximum moisture availability occurred between 43.96 and 42.98 kyr B.P., encompassing the DO 11 event and a weak monsoon interval, as corroborated by concurrent δ13C depletion, enhanced growth rate, and high initial 234U/238U ratio. This period of increased hydrological activity coincides with the peak of the half-precession cycle, which influences the vertical temperature gradient in the equatorial western Pacific, as well as the minima of west-east sea surface temperature gradient (ΔSST) in the equatorial Pacific. During this El Niño-like state, a weakened East Asia Hadley circulation (EAHC) and a southward shift of the Western Pacific Subtropical High (WPSH) amplified moisture convergence over southern China. Our findings demonstrate that the thermocline variability in the tropical Pacific, propagated hydroclimatic signals to subtropical East Asia via ocean-atmosphere circulation coupling, particularly affecting regions near the water vapor source from tropical Pacific.
Subjects
East Asian summer monsoon
El Niño-like
Environmental magnetism
Half-precession
Stalagmite
Publisher
Elsevier BV
Type
journal article