Pleistocene "Super-interglacials" and Hydroclimates of the Tropical Indo-Pacific Warm Pool

Glacial-interglacial cycles are driven by changes in the Earth's orbital configuration, ice sheet dynamics, and atmospheric CO2 concentrations. The combination of these forcings modulated both the magnitude and pacing of glacial cycles during the Pleistocene. Anthropogenic climate change threatens to tip the present climate to a warmer extreme, a global climate potentially more analogous to warmer "super-interglacials" of the past. These include the penultimate interglacial, Marine Isotope Stage (MIS) 5e, and MIS11c, which is characterized by extreme, if not total melting of Northern Hemisphere ice sheets. Although these super-interglacials are known from terrestrial polar records, in the tropics, the relative strength of these interglacials, and whether these intervals exhibit unique hydroclimatic states, is less clear. Moreover, the super-interglacials occur under different orbital configurations, including high (MIS 5e) and low (MIS 11c) eccentricity, which allows for evaluation of the impact of super-interglacials in the tropics under different boundary conditions. Using geochemical proxies in lake sediments from Lake Towuti (Sulawesi, Indonesia), this project analyzes δD and δ13C of leaf wax n-alkanes, and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to present a snapshot of hydroclimate, vegetation-related carbon cycling, and temperatures during interglacials MIS5e and 11c, and another low-eccentricity interglacial, MIS19c. Comparing each interglacial will allow for an examination of the relative strength of insolation and North Hemisphere glaciation tropical climate dynamics, providing critical insight into tropical paleoclimate in the IPWP and constraining possible responses to anthropogenic climate change.