RECONSTRUCTING A FIRE HISTORY FOR THE FISH LAKE PLATEAU, UT

The Fish Lake Plateau (2700-3500m) is located in south-central Utah within the transition zone between the Basin and Range and Colorado Plateau provinces. The Fish Lake Plateau is characterized by a horst and graben system. This area also experienced Pleistocene glaciation. Picea, Pseudotsuga, and minor Abies forest currently dominate the vegetation regime above ~3000 m with Populus and Artemisia at lower elevations. In the summer of 2006, a vibracore was used to extract a 2.29 meter sediment core from Frying Pan flat (38^o37'N, 111^o40'W, ~2700m). The flat contains an extensive marsh with creek and open waters at the northeast end, located to the northwest of Fish Lake and situated between the Hightop Plateau and Frying Pan hill. The sediments were analyzed for macroscopic charcoal and loss-on-ignition for the late-Holocene period. Preliminary data extending to ca. 3750 years, suggest that fire occurrence was infrequent with large fires occurring at ca. 1000 year intervals. Although this is a long interval between fires, it is consistent with the dominant vegetation and the location of the site on a wet meadow. The loss-on-ignition data indicate variations in the production of organics which may reflect a climatic signal and/or periodic erosion inputs on to the meadow surface. Pollen analysis of the core is underway which will provide additional information about the past environment on Frying Pan Flat.