Hydrographic variability in the northern South China Sea over the past 45,000 years: New insights based on temperature reconstructions by Uk'37 and TEXH86 proxies from a marine sediment core (MD972146)

Millennial-scale climate variability was persistent feature for Greenland ice core and North Atlantic marine records during the Marine Isotope Stage (MIS) 3. Studying high quality climatic archives outside of the Greenland and North Atlantic with precise constraint of absolute dating and high resolution sampling is a prerequisite to understand how the millennial-scale changes well expressed in North Hemisphere (NH) high latitudes had been propagated out to the other regions. Here, we generated the surface and subsurface hydrography (Uk'37 and TEXH86 temperatures) and terrestrial material input (n-alkanes) records with precise AMS 14C dated control for the 45 ka from a core (MD972146) retrieved from the northern South China Sea (SCS). Then, we compared our records to the oxygen isotope record from a Greenland NGRIP ice core, and the mean grain size record from a loess sequence at Gulang, China. We found that the millennial-scale oscillations of hydrolography and terrestrial material inputs records during the time since the last deglaciation and of ∼33-45 ka share similar patterns in timing and amplitude of the NH high latitude climate. However, we found that a non-NH pattern of millennial-scale oscillations for the late MIS 3, ∼20-33 ka of our hydrography and terrestrial material inputs records. Our studies imply that the changes of obliquity also may be important in determining the timing and amplitude of millennial-scale East Asian Monsoon (EAM) variability expressed in the northern SCS hydrography and terrestrial material inputs.