Constraints on Marine Isotope Stage 3 and 5 Sea Level From the Flooding History of the Karimata Strait in Indonesia

Global mean sea level (GMSL) during intermediate interglacial Marine Isotope Stage 3 (MIS 3) (60–26 ka) has proven difficult to constrain. Paleo-sea estimates based on ice margin, modeling, and paleo-shoreline reconstructions indicate that MIS GMSL was substantially higher than reconstructed from deep-ocean benthic foraminifera oxygen isotope (δ18O) coral records, implying much smaller sheets 3. Here, we use the δ18O Mg/Ca chemistry of surface thermocline dwelling in Sulu Sea western Pacific margin estimate relative changes influx South China flow through over last 140 ka. We show this throughflow is controlled part by modulating depth 36 m deep Karimata Strait at southern end Sea. constrain maximum allowable beginning −22 ± 6 −29 5 m, respectively, minimum stages 5c 5a (117–72 range −3 8 −8 −11 7 −12 respectively. Our results GMSL, but do not rule out paleo-shoreline-based or lower seawater δ18O-based estimates. favor highest confirm Sunda Shelf served as a land-bridge for human megafauna migration when humans first arrived Borneo.