Ice Sheets and Sea Level

The timescales and triggering mechanisms of ice sheet growth and retreat remain uncertain, making it difficult to predict how the cryosphere will respond to future climate warming. One approach that Earth scientists use to address this challenge is to examine how ice sheets evolved during periods in Earth history with climate conditions similar to present and future scenarios. However, the sparse geologic record limits these reconstructions. A major component of my research aims to fill this knowledge gap by studying the geochemistry of sediments and sedimentary rocks, which record changes in ice conditions through time.

Antarctic Ice Dynamics on Decade to Millennial Timescales

I have ongoing research projects investigating Antarctic subglacial precipitates–rocks formed in water at the base of the ice sheet. By integrating textural and geochemical analyses of these samples with aqueous geochemical and ice sheet thermodynamic models, we have shown that the Antarctic ice sheet thins at its margins in response to millennial-scale Southern Hemisphere warming events. This rapid ice sheet response is triggered by ocean forcing that melts buttressing ice shelves, leading to accelerated ice flow. Check out our publication in Nature Communications.

A second project involving Antarctic subglacial precipitates provides evidence that this ice dynamic response to ocean forcing can occur within decades of Southern Hemisphere climate change. Read about this work in our recent preprint!

This research challenges the widely held assumption of a static East Antarctic ice sheet on suborbital timescales, and links Antarctic ice sheet volume to ocean-atmosphere-cryosphere teleconnections.

An example of an Antarctic subglacial precipitate. Layers are consist of calcite (orange) and opal (white).

The Laurentide Ice Sheet

I am also investigating sedimentary records that describe subglacial and proglacial conditions in the now extinct Laurentide Ice Sheet.

Using U-series geochronology to date carbonates that formed beneath the Laurentide at Baffin Island, Canada, we identified evidence for three distinct episodes of ice sheet surging coinciding with Heinrich stadials one through three respectively. This dataset represents the first terrestrial archive of millenial cycles of enhanced LAurentide ice flow, providing evidence that ocean thermal forcing likely triggered Heinrich events. Read more about this work in our paper in Science Advances.