Rates, timing, & nature of sub-orbital sea-level change during MIS 5e

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Projections for the magnitude and rate of sea-level change in the future are highly dependent on ice sheet models that simulate the response of the polar ice sheets to sustained warming. Unfortunately, the physics associated with ice sheet collapse is not fully understood, requiring a different approach to estimate future ice sheet response. This project seeks to quantify rates of sea-level change during a past warm period known as the last interglacial, ~125,000 years ago. This information can then be used to constrain our projections of the rate of future sea-level rise. In particular, the principal investigator will investigate the rate of sea-level changes during this past warm period associated with meter-scale sea-level oscillations. The oscillations have been inferred from the features observed in sedimentary records from around the globe that suggest a dynamic instability in polar ice sheets during the warm period. The project includes student training and education (Ph.D. and masters students, and undergraduate students). A marine science class from the University of Florida will go to a sampling site in southern Florida to gain valuable field experience. There is strong international collaboration between the principal investigator, U.S. students, and researchers from Mexico and Australia. Joint support for U.S. students to collaborate with researchers from Australia was provided by the Office of International Science and Engineering.This project will address existing debates regarding the timing and nature of sea-level oscillations during Marine Isotope Stage (MIS) 5e. The approach is to study several key fossil reef sequences around the globe using a multidisciplinary approach that combines detailed analysis of taphonomy, diagenesis, reef assemblages, paleowater depth indicators, carbonate sedimentology and petrography, stratigraphy, glacial isostatic adjustment, surveying, and geochemical and geochronological data. Conventional bulk U-Th analyses will be complemented with laser ablation U-Th ages to investigate micro-scale carbonate phases and to evaluate spatial scales of preservation within the samples.