Date of Award

5-2023

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Sandra Passchier

Committee Member

Ying Cui

Committee Member

Matthew Gorring

Abstract

Studying ice sheet behavior during the Pliocene Epoch is of great importance. The Early Pliocene was characterized by warm climatic conditions, similar carbon dioxide levels and high sea levels compared to the present. This time frame provides essential information on the foreseeable future of Earth’s cryosphere, particularly if climate change continues to persist. The sedimentary record of the Antarctic Peninsula Ice Sheet (APIS) is the focus of this study. At Ocean Drilling Program (ODP) Site 1097, cores were drilled into Pliocene strata at a shallow depth on the Antarctic Peninsula continental shelf. Sedimentary facies were interpreted, and twenty samples were selected and examined using laser particle size analysis and major and trace element geochemistry. The results provide evidence of glacial advance and retreat during the Early Pliocene. Sedimentary facies, particle size data, and bulk geochemistry support a persistent but dynamic APIS during this time. The data do not support the previous notion, based on ice- sheet modeling, that the Antarctic Peninsula could have been ice-free under warm Pliocene conditions. The lower part of the Pliocene section at Site 1097 shows evidence of ice distal sedimentary facies, whereas overlying Pliocene strata suggests that the APIS may have been a fully grounded ice sheet on the outer continental shelf, with facies attributed to subglacial environments. The low chemical index of alteration (CIA) values of the sediments point to a cool, dry climate and sediment with a strong glacial imprint. No significant changes in the source material are shown by trace and Rare Earth Element (REE) ratios.

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