99 Recent Advances in Paleoceanography and Paleoclimatology (Posters)

Monday, 19 October 2009
9:00 AM - 6:00 PM
Hall A

DEVELOPING A PROXY RECORD FOR MOISTURE VARIABILITY THROUGH THE HOLOCENE FOR THE KENAI LOWLANDS, ALASKA, KENAI NATIONAL WILDLIFE REFUGE

Paper number: 99-20
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

Reconstructing fluctuations in regional groundwater tables during the Holocene from closed basin lakes of Alaska’s Kenai Peninsula is being investigated by a team of geoscientists and ecologists from the College of Wooster, Middlebury College, and University of Cincinnati in collaboration with the Kenai National Wildlife Refuge. Twenty-three overlapping lake sediment cores were taken from a complex series of kettle basins within Jigsaw Lake in the Kenai Lowlands of the Kenai National Wildlife Refuge. Detailed three dimensional sediment packages mapped using sediment cores and geophysical seismic surveys are being analyzed to separate the landscape evolution signal (kettle-development) from the climate signal (regional lake levels) in this region where an interior dry-cold Alaskan climate dominates.

Jigsaw Lake was studied previously and our work builds upon these studies that include physical proxies, radiocarbon dating, testate amoebae and peat analyses. Sediment coring locations were determined based upon detailed geophysical and bathymetric maps, which allowed for precision coring. Ongoing sediment core analyses include the description of stratigraphy, magnetic susceptibility, bulk density, loss on ignition, macrofossil sampling for radiocarbon ages (pending), dating and identification of tephras and colorimetric peat analysis. Pending radiocarbon analyses and ongoing examination of the tephras will determine over what interval the rising lake levels occurred. Dating from previous studies suggests an early to mid-Holocene age increase in lake level. The intensive sampling, use of geophysics, locally consistent stratigraphies and recognition of tephras should produce a well-constrained record of past climate and past changes in landscape as relative lake levels are reconstructed and criteria to recognize local kettle development and regional lake level variations are assessed.