Reconstructing a Postglacial Mineral Dust Record in the Eastern Uinta Mountains, Utah, Poster 26

Atmospheric mineral dust is recognized as an important part of ecosystem function in alpine environments, as it supports biogeochemical cycling and is a source of primary nutrients. Past research on dust delivery to the Uinta... [ view full abstract ]

Atmospheric mineral dust is recognized as an important part of ecosystem function in alpine environments, as it supports biogeochemical cycling and is a source of primary nutrients. Past research on dust delivery to the Uinta Mountains of northeastern Utah has shown dust to be essential in pedogenesis, soil fertility, and surface water buffering against acidification. Modern dust deposition has been tracked through active and passive dust collectors in the field, confirming the accumulation of dust in the alpine zone and providing geochemical dust composition data. History of dust deposition is less easily accessible, and must be reconstructed from collected material. Past dust deposition is recorded in alpine lakes, which provide an archive of undisturbed sediment accumulation over a long period. Geochemical properties of local sediment are constrained by watershed surficial material, while data from nearby dust collectors constrain geochemical properties of the modern dust. These are representative of two end member sources of sediment into the Taylor Lake basin. Geochemical analysis of a radiocarbon-dated core from Taylor Lake enables comparison of exotic and local material contributions to the lake over time. Geochemical analysis indicates high concentrations of calcium in the dust, while watershed material contains high levels of aluminum. A high Ca/Al ratio in the lake core in combination with radiocarbon ages suggests time intervals since the last glaciation of increased relative dust contribution compared to watershed material.