Doctoral Dissertations

Keywords and Phrases

Central America; Elemental abundances; Lake Izabal; Precipitation; Sea surface temperatures; Varves

Abstract

"Holocene hydroclimate reconstructions have contributed to our understanding of the mechanisms controlling precipitation in Central America. Recent hydroclimate proxy records from the region, however, have revealed considerable spatiotemporal complexity in precipitation variability. This complexity is hypothesized to result from the interaction between multiple oceanic-atmospheric processes that converge in the region. This project analyzed three sediment cores from Lake Izabal, eastern lowland Guatemala, with the goal of understanding changes in precipitation, lake productivity, and lake water chemistry during the Holocene. Our proxy results indicate that precipitation in the region increased from the early to the middle Holocene, when Lake Izabal became a meromictic lake following a marine incursion. Anoxic bottom waters lasted ~3,500 years, preserving 2,186 mm-scale dark and light laminae couplets that are distinctly different in color, composition, and texture. At ~4,800 calibrated years before present (cal yr BP), Lake Izabal became a polymictic lake, and precipitation in the region stabilized, remaining high until ~1,200 cal yr BP, with an abrupt decrease in precipitation thereafter. Our findings indicate that Lake Izabal is highly sensitive to changes in Caribbean sea level and Caribbean sea-surface temperatures, the former controlling lake water chemistry and the latter controlling precipitation. Our results also add to new hydroclimate proxy data from the region, highlighting the complexity in precipitation variability in the area. Additional paleoclimate proxy records from Central America are needed to improve our understanding of how global warming will affect environmental conditions and regional hydroclimate variability"--Abstract, page iv.

Advisor(s)

Obrist-Farner, Jonathan

Committee Member(s)

Oboh-Ikuenobe, Francisca
Yang, Wan
Hogan, John Patrick
Eckert, Andreas

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics

Comments

This research was partially supported by NSF/GSA (National Science Foundation/Geological Society of America) Graduate Student Research Grants No. 12101-18 and No. 12638-19, funded by NSF Award No. 1949901. This research was also partially supported by the American Association of Petroleum Geologists (AAPG) Grants-in-Aid, and the Visiting Graduate Student Travel Grant Program from the National Lacustrine Core (LacCore) Facility and the Continental Scientific Drilling Coordination Office.

The author wishes to thank the Geosciences and Geological and Petroleum Engineering Department at Missouri S&T for support.

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2022

Journal article titles appearing in thesis/dissertation

  • A progressively wetter early through middle Holocene climate in the eastern lowlands of Guatemala
  • Sedimentological and geochemical characterization of a varved sediment record from the northern neotropics

Pagination

xi, 146 pages

Note about bibliography

Includes bibliographic references.

Geographic Coverage

Guatemala

Rights

© 2022 Edward Fernando Duarte, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12156

Electronic OCLC #

1344518663

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Included in

Geology Commons

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