Global ice volume during MIS 3 inferred from a sea-level analysis of sedimentary core records in the Yellow River Delta

Estimates of global ice volume during the glacial phase of the most recent ice age cycle are characterized by significant uncertainty, reflecting the relative paucity of geological constraints on sea level relevant to this time interval. For example, during the middle stages of Marine Isotope Stage 3, published estimates of peak global mean sea level (GMSL) relative to the present range from −25 m to −87 m. The large uncertainty in GMSL at MIS 3 has significant implications for estimates of the rate of ice growth in the period leading to the Last Glacial Maximum (∼26 ka). We refine estimates of global ice volume during MIS 3 by employing sediment cores in the Bohai and Yellow Sea that record a migration of the paleoshoreline at ∼50-37 ka through a transition from marine to brackish conditions. In particular, we correct relative sea level at these sites for contamination due to glacial isostatic adjustment using a sea-level calculation that includes a gravitationally self-consistent treatment of sediment redistribution and compaction, and estimate a peak global mean sea level of −38 ± 7 m during the interval 50-37 ka. With suitable sedimentary core records, the approach described herein can be extended to refine existing constraints on global ice volume across the entire glacial period.