Earth and Planetary Sciences ETDs

Publication Date

Summer 7-12-2024

Abstract

This project incorporates several lines of evidence to better understand the climate at Lake Chalco. Chapter 1 utilizes oxygen isotopes from carbonates and show that the Inter Tropical Convergence Zone varies on primarily glacial and millennial timescales; precession is not observed. These data indicate glacials periods were shallower and interglacials were wetter periods at Lake Chalco. Chapter 2 studies carbon, nitrogen, C/N, and TOC proxies and finds that the lake conditions during the glacials and interglacials are primarily a mixed algal-macrophyte-terrestrial organic matter. Deviations show that the lake during the interglacials had more algal organic matter- reflecting influxes of nutrients during deeper lake periods. Glacials have more C3 terrestrial organic matter, while C4 organic matter peaks near glacial-interglacial boundaries, reflecting drying trends during glacial/interglacial transitions. Chapter 3 uses an atmospheric model to calculate the isotope ratios of carbonates at differing precipitation, humidity, temperature, and lake throughflow combinations in the past.

Degree Name

Earth and Planetary Sciences

Level of Degree

Doctoral

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Peter Fawcett

Second Committee Member

Zachary Sharp

Third Committee Member

Tyler Mackey

Fourth Committee Member

Rebecca Bixby

Fifth Committee Member

Josef Werne

Language

English

Keywords

Paleoclimate, Isotope-Geochemistry, Pleistocene, Northern Tropics, Mexico

Document Type

Dissertation

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