The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.

Date of Award

Fall 2025

Document Type

Masters Thesis

Department or Program Affiliation

Geology

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Ponton, Camilo

Second Advisor

Foreman, Brady

Third Advisor

Saenger, Casey Pearce

Abstract

The Paleocene–Eocene Thermal Maximum (PETM, ~56 mya) was a period of rapid global warming that profoundly disrupted climate and hydrologic systems. While marine records for the PETM are well studied, changes within continental interiors, specifically the hydrologic response to rapid warming, remain less understood. This thesis reconstructs precipitation changes in the North American continental interior using compound-specific hydrogen isotope analyses of plant wax biomarkers (n-alkanes and n-alkanoic acids) from the Piceance Creek Basin, Colorado. A positive excursion in δDprecip of ~29‰ is observed at the onset of the potential Paleocene-Eocene boundary, followed by a return to baseline values by its termination. The magnitude of this shift cannot be fully explained by changes in temperature, vegetation, or source-water effects alone, and is best interpreted as a transition to more arid baseline conditions with episodes of extreme seasonal rainfall. These findings are consistent with independent sedimentological and paleosol proxies, and with a cross-basin comparison of the Bighorn Basin further north in the Rocky Mountain region. Furthermore, the observed excursion lends evidence to a change in moisture source of local precipitation, potentially showing the effect of hyperthermals on the hydrological cycle on larger scales. This work expands the geographic distribution of early Paleogene paleoclimate proxies, demonstrates the utility of novel bulk-sampling approaches for biomarker analysis in low-organic deposits, and underscores the complex, non-linear hydrologic responses to rapid warming. By refining our understanding of Paleocene-Eocene hydrology in continental interiors, these results also provide insights into potential hydrologic consequences of ongoing anthropogenic climate change.

Type

Text

Keywords

Paleoclimate, PETM, lipids, biomarkers, hydrogen, isotopes, waxes

Publisher

Western Washington University

OCLC Number

1558602469

Subject – LCSH

Paleoclimatology--Colorado--Piceance Creek Basin--Paleocene; Paleoclimatology--Colorado--Piceance Creek Basin--Eocene; Paleohydrology--Colorado--Piceance Creek Basin; Precipitation (Meteorology)--Effect of global warming on--Colorado--Piceance Creek Basin; Climatic changes--Colorado--Piceance Creek Basin; Lipids--Analysis; Biochemical markers--Colorado--Piceance Creek Basin--Analysis

Geographic Coverage

Piceance Creek Basin (Colo.)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

Download

Included in

Geology Commons

Share

COinS