A drought event in central eastern China during MIS 6 revealed by elemental ratio and δ¹³C records from Hulu Cave

Speleothem oxygen isotope (δ¹⁸O) records from Hulu Cave in central eastern China have revealed detailed information on millennial-scale oscillations that punctuated the transition from the penultimate glacial period to the last interglacial period (i.e., MIS 6 to MIS5). It remains uncertain, however, what is the most pronounced drying episode among these millennial-scale monsoon oscillations. Here, we present new δ¹³C and trace element (Mg/Ca, Sr/Ca) data from the same cave, spanning 155 to 133 thousand years ago (ka), to investigate local hydroclimatic and ecological changes during the penultimate glacial period. While Mg/Ca and Sr/Ca exhibit orbital-scale trends consistent with their parallel δ¹⁸O record, the δ¹³C record displays subdued oscillations around distinct baselines, indicating a different response of overlying vegetation and soil conditions to insolation forcing. We identify a drought eventbetween 140.5 and 134.9 ka, which was likely triggered by a North Atlantic ice-rafted debris (IRD) episode and sustained by the expansion of the Eurasian ice sheet and cooling in the Indo-Pacific Warm Pool (IPWP). Within this event, we detect a pronounced megadrought from ∼139.5 to 137 ka, lasting ∼2.5 kyr, marked by peak trace element ratios, uranium enrichment, and extremely low growth rate, also displayed in the δ¹⁸O record. Our findings suggest that millennial-scale drying in East Asia was controlled by both northern high- and low-latitude climatic changes.