Onset of Antarctic Glaciation at the Eocene-Oligocene Transition in the Weddell Sea and its Impact on Ocean Circulation

Author

Victoria Hojnacki, Montclair State University

Date of Award

8-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Sandra Passchier

Committee Member

Clement Alo

Committee Member

Ying Cui

Committee Member

Suzanne O'Connell

Abstract

The Eocene – Oligocene Transition (EOT) (34 Ma) represents a greenhouse to icehouse climate transition that is marked by the appearance of permanent ice sheets in Antarctica. Studying this period of climate change allows us to understand how different Earth systems reacted under changing atmospheric CO₂ conditions. Though the timing of the development of the East Antarctic Ice Sheet is well supported, the development of the West Antarctic Ice Sheet is still up for debate. Ocean Drilling Program Site 696 is the only paleoarchive of the EOT in the Weddell Sea region and offers an opportunity to better constrain the West Antarctic Ice Sheet. The Weddell Sea region is the primary area of Antarctic Bottom Water formation, which is a vital aspect of global thermohaline circulation. In addition to the Weddell Sea site, International Ocean Discovery Program Site U1558 will be used to track global ocean circulation during the EOT. The main purpose of this study is to (1) understand the evolution of ice sheet development in the Weddell Sea region at the Eocene-Oligocene boundary and (2) assess paleoceanographic response to ice sheet development at the Eocene-Oligocene boundary. Through the use of multiple points of analyses and proxies, this study demonstrates the existence of a marine based ice sheet in the Weddell Sea at the EOT, as well as, changing oceanographic conditions associated with this climate event, including the export of Antarctic Bottom Waters. Though the EOT is a cooling climate transition and our modern climate trend is warming, studying events such as this allows us to better understand the way the climate, cryosphere, and ocean systems interact with each other.

File Format

PDF

Recommended Citation

Hojnacki, Victoria, "Onset of Antarctic Glaciation at the Eocene-Oligocene Transition in the Weddell Sea and its Impact on Ocean Circulation" (2024). Theses, Dissertations and Culminating Projects. 1452.
https://digitalcommons.montclair.edu/etd/1452