Collaborative Research: Continued Study of Physical Properties of the WAIS Divide Deep Core

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1043528/AlleyThis award supports a project to complete the physical-properties studies of the WAIS Divide deep ice core, now being collected in West Antarctica. Ongoing work funded by NSF, under a grant that is ending, has produced visible stratigraphy dating, inspection of the core for any melt layers, volcanic horizons, flow disturbances or other features, analysis of bubble number-densities allowing reconstruction of a two-millennial cooling trend in the latter Holocene at the site, characterization of other bubble characteristics (size, etc.), density studies, characterization of snow-surface changes at the site, preliminary c-axis studies, and more. The current proposal seeks to complete this work, once the rest of the core is recovered. The intellectual merit of the proposed activity starts with quality assurance for the core, by visual detection of any evidence of flow disturbances that would disrupt the integrity of the climate record. Inspection will also reveal any melt layers, volcanic horizons, etc. Annual-layer dating will be conducted; thus far, the visible strata have not been as useful as some other indicators, but the possibility (based on experience in Greenland) that visible examination will allow detection of thinner annual layers than other techniques motivates the effort. Bubble number-density will be used to reconstruct temperature changes through the rest of the bubbly part of the core, providing important paleoclimatic data for earlier parts of the Holocene. Coordinated interpretation of c-axis fabrics, grain sizes and shapes, and bubble characteristics will be used to learn about the history of ice flow, the processes of ice flow, and the softness of the ice for additional deformation. Analysis of surface data already collected will improve interpretation of the layering of the core. It is possible that the annual-layer dating will not be sufficiently successful, and that the core will be undisturbed with no melt layers; if so, then these efforts will not yield major publications. However, success of the other efforts should produce improved understanding of the history and stability of the ice sheet, and key processes controlling these, and the quality assurance provided by the visual examination is important for the project as a whole. The broader impacts of the proposed activity include education of a PhD student and multiple undergraduates, and research opportunities for a junior faculty member at an undergraduate institution. The proposed activity will help support an especially vigorous education and outreach effort providing undergraduate instruction for over 1000 students per year, reaching thousands more citizens and many policymakers, and preparing educational materials used at many levels.