Date of Award


Document Type


Degree Name

Master of Science (MS)


College of Science and Mathematics


Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Ying Cui

Committee Member

Sandra Passchier

Committee Member

Clement Alo


The Paleocene-Eocene Thermal Maximum (PETM; ca. 56Ma) is a time when global temperatures greatly increased due to rapid carbon emissions. The event is marked by a negative carbon isotope excursion (CIE) that is observed in both marine and terrestrial records. However, the amount, rate, and source of the emitted carbon remains highly debated. This study investigates the response of the eastern Tethys, an understudied subtropical shallow marine environment, and assesses the climatic impacts during the PETM. An Earth system model of intermediate complexity (cGENIE) ran six “double-inversion” experiments with δ11B and δ13Ccarb forced onto the surface ocean to assess the impacts of ocean acidification and determine the origin of the released carbon. Additionally, the eastern Tethys terrestrial paleoenvironment was reconstructed through black carbon (BC) isotopes, a paleo-fire archive, to determine how vegetation and precipitation responded during the PETM. The model shows that the eastern Tethys resists ocean acidification the longest by maintaining a comparatively higher pH than the global ocean. The diagnosed carbon flux reveals two distinct carbon emission pulses with different δ13C signatures, suggesting that the North Atlantic Igneous Province (NAIP) could be the trigger mechanism for the PETM that then creates feedbacks into a second, more depleted carbon emission pulse. The δ13CBC values agree with bulk carbonates and n-alkane isotopes collected from the eastern Tethys, suggesting changes in regional precipitation shifted the vegetation type. Overall, understanding the Earth system responses in the eastern Tethys can infer carbon cycle history and evaluate the global and regional responses to the PETM.

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