Climate and ecology changes during the last deglaciation revealed by stalagmite from Shima Cave, central China

We reconstructed high-resolution paleoclimate records with 24 ²³⁰Th/U dates, 706 sets of stable isotope values (δ¹⁸O and δ¹³C) from a stalagmite from Shima Cave, Hunan Province, central China. The stalagmite grew during the last deglaciation from 19.7 to 13.3 ka, with a 1500-year hiatus during Heinrich Stadial 1. We interpret stalagmite δ¹⁸O as the East Asian summer monsoon (EASM) intensity, while δ¹³C as terrestrial CO₂ related with biomass production and local hydrogeochemical processes. Long-term trend and millennial-scale changes in δ¹⁸O record are absent in the δ¹³C record, possibly due to the low biomass production and small vegetation changes in central China across the studied period, which is contrast to an obvious recovery of the biomass in northern China during the Bølling-Allerød period. Besides, high frequency of δ¹³C record displays quasi periods of 30–50 years, which are consistent with typical periodicities of the Pacific Decadal Oscillation (PDO). Furthermore, comparison of our δ¹⁸O record with measures of solar variability shows clear evidence for solar forcing on the EASM on the centennial timescale, which could possibly be mediated by the Atlantic Meridional Overturning Circulation and El Niño/Southern Oscillation/PDO. Therefore, we suggest that monsoonal climate and ecological changes during the last deglaciation could have been modulated by solar activity and sea surface temperature variability in both the Atlantic and the Pacific Ocean.