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Speaker: Julia Wellner, Associate Professor, Department of Earth and Atmospheric Science, University of Houston

Host: Ginny Catania

Title: Sedimentary Record of Ice-Ocean Interactions at Thwaites Glacier, Antarctica: Why all the Fuss about Tipping Points & Doomsday Glaciers?

Abstract: Today, Antarctica is covered by an ice sheet that, if it were to melt, has the capacity to contribute on the order of nearly 60 m to global sea-level rise. Most of that ice is stable, and is expected to be so long into the future, but parts of the West Antarctic Ice Sheet, particularly Thwaites and Pine Island glaciers, are susceptible to sudden retreat. In the geologic past, the ice was significantly expanded, reaching the continental shelf break around most of the margin. As the ice sheet retreated to its modern extent, the shrinking ice left behind a sedimentary signature of deglacial history. Over repeated cycles of glacial advance and retreat, sedimentary deposits of alternating glacial and interglacial periods have built up on the continental shelf. Because the stability of the Antarctic Ice Sheet is strongly influenced by the ocean, the sedimentary deposits from the ice-ocean margin are the ideal place to study the controls on stability or instability of the ice.

This talk will focus on using the sedimentary record from the West Antarctic margin to estimate the controls on glacial stability, examining records of retreat since the last glacial maximum. A focus will be on the sedimentary records from where Thwaites Glacier has retreated over just recent decades, allowing an examination of the factors influencing the ice today and how they differ from past periods.