Seismic record of West Antarctic Ice Sheet dynamics during the late Oligocene to early Miocene in the Eastern Basin, Ross Sea Public Deposited

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Last Modified
  • March 21, 2019
Creator
  • Brazell, Seth
    • Affiliation: College of Arts and Sciences, Department of Geological Sciences
Abstract
  • The Antarctic cryosphere is an important driver of global climate change and ocean circulation. The Antarctic Ice Sheet is comprised of the stable, terrestrially-based East Antarctic Ice Sheet (EAIS) and the marine-based West Antarctic Ice Sheet (WAIS) that may be prone to a collapse that would contribute over 3 m to global sea level rise. The Antarctic Ice Sheets have unique evolutionary histories and understanding how they have influenced and been influenced by global changes through the Cenozoic will yield a more robust understanding of their response to future climate change. 98% of Antarctica is currently covered in ice, posing challenges for investigators. Much of our understanding of the evolution of the Antarctic cryosphere has been developed from far field oxygen isotope records of global temperature and ice volume change; however, more direct records of Antarctic Ice Sheet dynamics from the continent and margin conflict with interpretations derived from these records. The Ross Sea embayment in Antarctic drains ~25% of the continent, receives input from both the EAIS and WAIS and contains a thick section of Cenozoic deposits, making it an important location to investigate the evolution of the Antarctic cryosphere. The Eastern Basin, Ross Sea contains a thick section of Cenozoic strata that records the evolution of the WAIS. This study reexamines legacy and recent seismic reflection data and uses spectral attribute analysis to enhance the resolution of the datasets. I document spectral decomposition techniques that enhance the temporal resolution of multi-channel seismic profiles. Using the spectral decomposition technique, I develop a higher resolution, third-order sequence stratigraphic model of late Oligocene to early Miocene sequences within the Eastern Basin to test hypotheses about the evolution of the WAIS. I identify evidence of an expanding late Oligocene WAIS and waning ice volumes during the early Miocene. Using seismic-stratigraphic stacking patterns, I correlated relative sea level fluctuations recorded in the Eastern Basin to global eustatic and oxygen isotope events and refined chronostratigraphic correlations of regional horizons and unconformities. These findings have important implications for the initiation and evolution of the West Antarctic Ice Sheet during the late Paleogene and early Neogene.
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  • In Copyright
Advisor
  • Benninger, Larry
  • Sorlien, Christopher
  • Rial, Jose
  • Surge, Donna M.
  • Stewart, Kevin
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill
Graduation year
  • 2017
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