Research Interests

During the last glacial termination, meltwater routing of the Laurentide Ice Sheet (LIS) may have played a significant role in abrupt climate change and North Atlantic Deep Water (NADW) production. It is theorized that LIS meltwater from proglacial Lake Agassiz flooded the North Atlantic and subsequently weakened NADW production, forcing the North Atlantic region back to glacial conditions. Several meltwater events from the LIS were routed south, via the Mississippi River (MR) to the Gulf of Mexico (GOM). Previous studies show the presence of meltwater in the GOM before the onset of the Younger Dryas (12.8-11.5 ky B.P.) until approximately 13,000 ky B.P., when meltwater routing switched to an unknown spillway. Constraints on the exact timing and magnitude of these meltwater outbursts are currently unknown due to the lack of high-resolution sampling in the GOM. Sampled at an average temporal resolution of 25 years, core MD02-2550 from the anoxic Orca Basin in the GOM provides the necessary resolution to test meltwater routing history. Paired Mg/Ca (proxy for SST) and d18O values, coupled with radiocarbon dating of planktonic foraminifera species Globigerinoides ruber (pink and white varieties) will provide the timing of meltwater input to the GOM. Further analyses will compare GOM temperature variability and meltwater input to high-latitude temperature changes from Greenland and Antarctic ice cores, and the relative strengths of NADW and Antarctic Bottom Water (AABW). Preliminary results show evidence that the cessation of meltwater input to the GOM coincides with the onset of the Younger Dryas, indicating meltwater routing switched, possibly to an eastern route, immediately preceding the Younger Dryas. Additional results will further constrain the timing of meltwater in the GOM and compared to proxy records of changes in NADW strength will serve as an indirect test of the meltwater routing hypothesis. This research will aid in understanding LIS melting dynamics and proglacial Lake Agassiz meltwater routing history and its effects on NADW formation during the last glacial termination.