CONSTRAINING THE OXYGEN VALUES OF THE LATE CRETACEOUS WESTERN INTERIOR SEAWAY USING MARINE BIVALVES

Author

Camille H. Dwyer, University of New Mexico - Main CampusFollow

Publication Date

Summer 7-15-2019

Abstract

The Western Interior Seaway (WIS) remains an oceanographic enigma, including its circulation, similarity to the open ocean, and the fidelity of geochemical proxies to reconstruct paleoenvironments. Across the late Campanian and early Maastrichtian I test whether: 1) the WIS had unique δ¹⁸O_VPDB compared to other marine settings, 2) increasing oceanographic restriction changed the stable isotope composition, and 3) biases, e.g., taxonomy or diagenesis, influenced stable isotope compositions. Results indicate distinct δ¹⁸O_VPDB in the WIS compared to other marine settings. δ¹⁸O_VPDB values were stable through time, suggesting insignificant oceanographic restriction and a maintained open-ocean connection despite marine regression. The spread of δ¹⁸O_VPDB values suggests that mixing of multiple isotopically distinct water bodies in combination with changing evaporation regimes may strongly influence ocean chemistry. Therefore, interpretation of δ¹⁸O_VPDB in WIS carbonates as a paleotemperature proxy should be done cautiously and the isotopic composition of mixing water bodies must be considered.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Dr. Corinne Myers

Second Committee Member

Dr. Viorel Atudorei

Third Committee Member

Dr. Jason Moore

Language

English

Keywords

Campanian, Maastrichtian, Oxygen Isotopes, Diagenesis, Multiple Linear Regression, Vital Effects, Oceanographic Setting, Restricted Epicontinental Seaway, Carbon Isotopes, Mollusks

Document Type

Thesis

Recommended Citation

Dwyer, Camille H.. "CONSTRAINING THE OXYGEN VALUES OF THE LATE CRETACEOUS WESTERN INTERIOR SEAWAY USING MARINE BIVALVES." (2019). https://digitalrepository.unm.edu/eps_etds/262