Leveraging Glacial Isostatic Adjustment Models to Improve Sea-Level Reconstructions Derived from Continental Shelf Stratigraphy

• Main Author: King, Meghan E.
• Other Authors: Creveling, Jessica R., Stoner, Joseph S., Clark, Peter U., Brook, Edward J., Minc, Leah D., College of Earth, Ocean, and Atmospheric Sciences
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: New Zealand; Ice Sheet
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/r207tx687

Stratigraphic records derived from continental shelf environments are integral to the reconstruction of glacial-interglacial sea-level change. In this dissertation I leverage glacial isostatic adjustment models to quantify the physical processes that may distort the extraction of accurate information about the amplitude and source of glacioeustasy. In Chapter 2, we explore the influence of glacial isostatic adjustment (GIA) on continental shelf stratigraphic correlation by developing a numerical model that creates synthetic stratigraphic records from local sea-level and sedimentation histories. These results establish that GIA not only obscures accurate correlation, but distorts the underlying signals of sea-level change preserved in the records. In Chapter 3, we constructed a series of ‘viscoelastic’ fingerprints of individual ice sheet collapse to examine if locations where Mid-Pliocene Warm Period (MPWP) stratigraphic records exist can faithfully capture the amplitude of these sea-level signals. Our results suggest that no one location can be used to estimate MPWP glacial-interglacial sea-level change because of inherent biases related to GIA. In Chapter 4, we utilized these ‘viscoelastic’ fingerprints additively to test current hypotheses about the source and asynchronous or concurrent phasing of MPWP ice sheet melt with respect to the Whanganui Basin, New Zealand. We found that a single local sea level record at this location cannot distinguish between different phases of ice melt, nor the geographic source – prompting a re-evaluation of current assumptions within the community. In Chapter 5, we integrate the numerical models from Chapters 2-4 in order to measure the variability in stratigraphic records produced by differing physical processes. Our results suggest that the greatest variability, and thus uncertainty in extracting accurate glacioeustatic signals, within stratigraphic records can be attributed to subsidence and sedimentation. Therefore, this improved understanding of how tectonics and ...