EAGER: Exploration of the Denali Basal Ice Core Archive

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This award uses funds, under the auspices of the EArly Concept Grant For Exploratory Research (EAGER) program, to explore the use of the basal ice from the Mt. Hunter (Denali National Park) ice core for reconstructing hydroclimate variability in Central Alaska through the Holocene. The approach employed in this EAGER project will test the viability of dating constraints in the bottom ten meters of the core and explore new approaches for paleoclimate proxy measurement. The researchers aim to address the following questions:1) Are there conformable strata within the basal ice of Mt. Hunter?The researchers will explore the feasibility of using novel high resolution (laser ablation ICP-MS, micro-stable isotope analyses) and 14-Carbon measurements to test the stratigraphic continuity hypothesis. If the measurement techniques provide chronological information with appropriate errors and the Denali ice core archive proves to have a continuous stratigraphic record, then a large portion of the Holocene may be accessible in the archive.2) What is the history of summer temperature in Central Alaska through the Holocene?The researchers will test a new approach to analyze compressed melt features using Scanning Electron Microscopy (SEM) that has the potential to significantly expand our knowledge of past summer temperature variability.3) How long has ice been present on the Mt. Hunter plateau?Access to bed material contained in the lowest portion of the Mt. Hunter ice cores provides an opportunity for investigation of this question in Central Alaska. The researchers will test the validity of cosmogenic isotope analysis (10-Berillium) on small pebbles and sediment contained in the basal core sections. Such analyses are unique on lithogenic material recovered in an alpine ice core.If successful, cosmogenic isotope analysis of samples from basal ice will open new research avenues for combining glaciological, paleoclimate, glacial geology, and subglacial environment disciplines. Exploration of new measurements in the Denali ice core archive will potentially provide scientific breakthroughs on several important paleoclimate fronts such as: 1) improvement and extension of existing ice core accumulation time series, and evaluation of hydroclimate variability over the Holocene; 2) evaluation of the impact of various modes of climate variability, particularly El Nino-Southern Oscillation (ENSO), on regional climate in the North Pacific over the Holocene; 3) understanding regional differences in the hydrological cycle particularly given the potential societal impacts of ENSO-related variability on North Pacific hydrology; 4) evaluation of regional hydroclimate variability and glacier response during a documented warm period (Holocene climate optimum); and 5) reconnaissance effort with cosmogenic isotope analyses may yield valuable initial information on ice stability in Central Alaska over much longer time periods. This as an important step towards designing and implementing a comprehensive research strategy addressing long-term (e.g., Plio-Pleistocene) ice dynamics in Alaska. Such results would have a broad impact across the geosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.