Despite its critical role in regulating the global climate and carbon cycle, the evolution of Pacific abyssal circulation has not been fully deciphered during the last glacial cycle. Here, we present redox-sensitive elemental and benthic δ¹³C records of the Pacific Deep Water (PDW) since ~ 90 ka using a sediment core from the deep South China Sea, which reflects the state of Pacific abyssal circulation. Our results indicate the enhanced abyssal Pacific overturning and improved PDW ventilation during warm MIS 1, 3 and 5. During these times, enhanced abyssal Pacific overturning was accompanied by a reduced volume of North Pacific Intermediate Water. The associated weakening of vertical stratification in the North Pacific may facilitate contemporary atmospheric CO₂ increases.
 

abyssal Pacific overturning; oxygenation history; benthic carbon isotope; redox element; South China Sea; last glacial cycle