Ph.D. Student Michael Comas Receives GSA Research Grant

Grant Supports Work with Marine Sediment Cores from West Antarctica

Third-year University of Houston Ph.D. student Michael Comas was awarded a 2022 Geological Society of America Student Research Grant for his work with marine sediment cores in West Antarctica.

Michael Comas and Asmara Lehrman (University of Alabama) studying a freshly-collected sediment core aboard the RV/IB Nathaniel B. Palmer, Amundsen Sea, Antarctica.

Comas is working as a member of the Thwaites Glacier Offshore Research Project to help understand the modern retreat history of Pine Island Glacier. He is advised by Dr. Julia Wellner, an associate professor of stratigraphy, sedimentology, and glacial processes, in the Department of Earth and Atmospheric Sciences.

Currently, Pine Island Glacier is the single-largest contributor to global mean sea-level rise in all of Antarctica. Satellite data show that Pine Island Glacier (along with neighboring Thwaites Glacier) is losing mass at a rate which could potentially destabilize the entire West Antarctic Ice Sheet. Comas is analyzing sediment cores collected near Pine Island Glacier to help understand when this mass loss was initiated in the 20th century. His analyses include downcore petrophysical measurements, grain size distribution, and radioisotopic dating using 210Pb and 14C.

The research funding from the GSA will be used to obtain 14C dates within recently collected sediment cores. These dates will be derived from calcareous foraminifera samples found within Amundsen Sea sediments.

While Comas conducts geochronological dating of 210Pb isotopes at UH, there are limitations to this method. For several cores collected near Pine Island Glacier, the record of glacial dynamics continues further downcore than excess 210Pb can be detected; however, the dating of 14C from foraminiferal tests will provide dates for deeper sediments. The age models derived from these 14C dates will be crucial for providing an accurate timeline for the pace of retreat of Pine Island Glacier in the pre-satellite 20th century.

Understanding when Pine Island Glacier began to lose ice mass may also help to identify oceanic and atmospheric forcing mechanisms that may have driven this retreat.