Pedogenesis in Alpine Ecosystems of the Eastern Uinta Mountains, Utah, U.S.A.

Abstract

We characterized 12 pedons from alpine and upper subalpine areas (>3300 m) along the south slope of the eastern Uinta Mountains in northeast Utah. Although the soils are derived mostly from quartzitic residuum and till, half of them have received calcareous eolian sediment, probably from the Uinta Basin. This eolian sediment is trapped effectively by Geum/sedge communities and has changed the soil chemistry to where more than half of the soils have a base saturation in excess of 50%. One of the pedons (U90-5) above treeline has a distinct argillic horizon, suggesting that clay movement is either a contemporary process in alpine soils of the central Rocky Mountains or that the argillans are relict features from a previous milder soil climate. Although some soils above 3400 m have a mean annual temperature of −2°C or lower, they do not contain permafrost in the upper 2 m. Alpine soils of the Uintas described in this study are Aquic Cryorthents; Pergelic, Dystric, and Typic Cryochrepts; Typic, Lithic, and Pergelic Cryumbrepts; Pergelic Cryoborolls; and Pergelic and Typic Cryoboralfs.