Thermoluminescence Dating Studies of Lake Cores from Alaska

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This award is in support of one element of paleoclimatology from Arctic Lakes and Estuaries (PALE). Arctic lakes are recognized as valuable repositories of paleoenvironmental proxy information (e.g. fossil pollen, sediment chemistry) that is important for paleoclimatological studies. However, beyond the usual 30-40 ka limit of radiocarbon dating, dating control needed form the interpretation of such fossil pollen records is presently unavailable. Preliminary, single-analysis thermoluminescence (TL dating results have been obtained for one Arctic lake core (Squirrel Lake) to test the capability of TL dating for such Arctic sediments, but some results are ambiguous. This award outlines TL dating and other tests(e.g. measurement of TL emission spectra) designed to assess the cause of these ambiguous, preliminary results for some samples for the Squirrel Lake core. The proposed dating experiments will refine the limitations and usefulness of TL sediment dating procedures for Arctic lake sediments, provide the first "radiometrically" dated record beyond 30-40 ka for Arctic lakes, and provide a firmer basis for future application of TL dating to long-core (0-200 ka) sediment records for circumpolar Arctic lakes.