2005 Salt Lake City Annual Meeting (October 16–19, 2005)

Paper No. 9
Presentation Time: 10:25 AM


BOWES, Matthew J., Geology/ Geophysics, University of Alaska Fairbanks, 900 Yukon Drive, Fairbanks, AK 99775, HEISER, Patricia A., Geology, University of Alaska Anchorage, 3211 Providence Dr, Anchraoge, AK 99518, BEGET, James and WALLACE, Kristi, Alaska Volcano Observatory, USGS, Anchraoge, AK 99518, ftmjb@uaf.edu

Lake Clark National Park (LACL) covers over four million acres of southwest Alaska, contains critical sockeye salmon habitat, archeological sites from pre European contact, and hosts several ongoing multidisciplinary quaternary studies (climate change, ecology glaciology, etc.). LACL is located along the northeast portion of the Aleutian Arc and adjacent to historically active Cook Inlet Volcanoes. Tephra layers represent a single instance in time and can be used to assemble a chronological framework for other significant events and/or other studies requiring time specific information. Tephra studies are an integral part of understanding the dynamics, extent, cyclic occurrence, and hazards associated with volcanic events. Although numerous studies have cataloged tephra fall in other locations (Katmai, Anchorage, and Kenai Peninsula) the LACL region has gone relatively unstudied. Therefore, a regional study is warranted by the suitability of LACL's numerous lakes and their proximity to multiple active volcanic centers. Numerous (8) lakes, separated by up to 40 miles, within LACL have been cored to obtain the paleoenvironmental record. These cores contain a sequence of visually distinguishable ashes (approx.6 appear correlateable) which range from historic times to approximately 12,000 years and it is likely that several can be positively correlated across the region with additional analysis. Stratigraphic position, physical description, magnetic susceptibility, C14 age, petrography, and electron microprobe analysis will be used, when possible, to correlate ash layers across the LACL region. This study follows protocols that will allow these data to be used in future Alaska tephra studies. Correlations and chronological framework established in this study will aid ongoing geologic and biologic research in lacustrine systems and will serve as a guide for comparison to land-based geological, archeological, and paleoecological studies. Additionally, these data may prove useful in understanding the variability in subaerial and lacustrine records while improving the confidence of correlations between the two depositional environments.