Date of Award

5-2017

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

Stefanie Brachfeld

Committee Member

Matthew L. Gorring

Committee Member

Sandra Passchier

Subject(s)

Drift- Antarctica- Weddell Sea, Ice streams-- Antarctica -- Weddell Sea, Ice sheets--Antarctica--Weddell Sea--Dynamics, Ronne Ice Shelf (Antarctica)

Abstract

This project seeks to advance our understanding of Antarctic Ice Sheet dynamics and to gain insight into the bedrock composition beneath the Antarctic Ice Sheet by “fingerprinting” ice streams that drain into the Ronne-Filchner Ice Shelf. The Ronne- Filchner Ice Shelf is the second largest ice shelf in Antarctica and receives ice drained from both the West and East Antarctic Ice Sheets through a series of ice streams. In response to global warming, this sector has the potential to contribute dramatically to sea level rise, especially from the Recovery Catchment. Till samples were collected from lateral moraines adjacent to the Foundation, Academy, and Recovery ice streams, all located within the Weddell Sea sector, during a December 2014 field season. Extensive analyses of sieved fine fraction (< 63 pm) show that all three ice streams have major element profiles that are consistent with the upper continental crust, though with Na and Ca depletion. Al/Ti and Fe/Ti ratios are also consistent with upper continental crust for all three ice streams. Recovery Ice Stream is the only one of the three ice streams to contain Mn- bearing minerals, including psilomelane and hausmannite. Foundation Ice Stream is the only stream containing V- bearing titanomagnetite. The Foundation Ice Stream also contains the most ilmenite. Academy Glacier till exhibits the most alteration textures in Fe-oxides (63%), and Recovery exhibits the most homogeneous Fe-oxide grains (24%). Through developing these geochemical and mineral signatures, this project will allow researchers to develop proxy records for ice stream activity in marine sedimentary records and better understand which ice streams may be the most vulnerable to ice loss as a response to global warming.

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