Using Lake Sediment Records to Reconstruct Post-Glacial Dust Delivery to High-Elevation Lakes in the Uinta Mountains, Utah

Dust is increasingly recognized as an important component of biogeochemical cycling and ecosystem function in mountain environments. Previous work has shown that delivery of dust to the Uinta Mountains of northeastern Utah has... [ view full abstract ]

Dust is increasingly recognized as an important component of biogeochemical cycling and ecosystem function in mountain environments. Previous work has shown that delivery of dust to the Uinta Mountains of northeastern Utah has influenced pedogenesis, soil nutrient status, and surface water chemistry. An array of passive and active samplers in the alpine zone of the Uintas provides detailed information about contemporary dust fluxes, along with physical and geochemical properties of modern dust. Reconstruction of changes in the dust system over time, however, requires continuous sedimentary archives sensitive to dust inputs. Radiocarbon-dated cores collected from the subalpine Marshall and Bald Lakes may provide these records. Dust collectors in the vicinity of each lake constrain the geochemical properties of modern dust, whereas samples of regolith constrain properties of the local surficial material within the watershed. Together, these represent two end member sources of clastic sediment to each lake basin: allochthonous dust and autochthonous regolith. Geochemical analysis of the sediment cores allows the relative contribution of exotic and local material to the lake to be considered as a time series covering the post-glacial interval. Early findings suggest dust records from high-elevation lakes track regional aridity.