Imaging Mantle Viscosity and Why it Matters for Ice Age Climate

I will present work that aims to constrain Earth’s viscosity based on sea level records and the glacial isostatic adjustment (GIA) process. I will show a local inference for the western US followed by laying out a framework that allows imaging global 3D varying viscosity in Earth’s interior. This framework draws on approaches from seismic tomography and I will present first tests with synthetic data that shows the potential for this technique. In the second part of the talk I will explore how GIA feeds back into affecting the Laurentide ice sheet. We include proglacial lakes (lakes that form at the ice sheet margin) in our GIA model and show that they can speed glacial collapse. Since GIA causes proglacial lakes to be bigger during the deglaciation than the glaciation, this process contributes to the sawtooth shape of ice age climate.

Speaker: Jacky Austermann, Columbia University

Room 350/372