Date of Award

6-2013

Degree Name

Doctor of Philosophy

Department

Geosciences

First Advisor

Dr. Michelle A. Kominz

Second Advisor

Dr. Alan E. Kehew

Third Advisor

Dr. Stephen F. Pekar

Fourth Advisor

Dr. William A. Sauck

Keywords

Antarctica, global paleo-climatology, Wilkes Land, Last Glacial Maximum, paleo-plate motion reconstructions

Abstract

I have applied the principles of basin analysis and geodynamics to several cores recovered from on or near the Antarctic continent to answer 2 independent questions about the tectonic evolution of Antarctica; as well as estimate the thickness of the Antarctic Ice Sheet at the Last Glacial Maximum.

I developed, and applied a modification of the backstripping modeling technique to compensate for the loading and erosion of glacial ice at the AND-1B site by combining a backstripping driven inverse model, with a driven ice-load model. This modification allowed me to identify and constrain the timing of major pulses of subsidence in the AND-1B core, which correspond to the development of several volcanic edifices that are adjacent to the AND-1B core site. These volcanoes have a complex history of emplacement that has been significantly obscured by the glacial dynamics of the McMurdo Sound region.

I applied models of ice loading, sediment compaction, and isostasy to generate two independent ice thickness estimates for the Antarctic Ice Sheet in McMurdo Sound, Antarctica. These two estimates are in good agreement, and predict ice thicknesses of approximately 1,700 meters at the AND-1B drill site at the Last Glacial Maximum. While this analysis is only explicitly valid during the Last Glacial Maximum, the specific details of sedimentology and chronology of the AND-1B core also implies that no ice sheets during the Pleistocene were significantly thicker than approximate 1,700 meters.

Lastly, I applied the principles of backstripping analysis to Integrated Ocean Drilling Program Core U1356 to determine the subsidence history of the Wilkes Land margin of Antarctica. The resulting subsidence history is incompatible with the accepted continental breakup age of this margin at 83 Ma. Instead it requires that the final breakup of the Wilkes Land margin of Antarctica from Australia occurred between 48 Ma and 36 Ma, most likely at approximately 43 Ma. This has implications for global paleo-climatology, paleo-oceanography, and paleo-plate motion reconstructions.

Comments

Fifth Advisor: Dr. Terry J. Wilson

Access Setting

Dissertation-Open Access

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