The full-glacial environment of the northern Seward Peninsula, Alaska, reconstructed from the 21,500-year-old kitluk paleosol

Paleoenvironmental conditions are reconstructed from soils buried under vol canic ash ca. 21,500 years ago on the Seward Peninsula. Soil development wa s minimal, reflecting the continuous regional deposition of loess, which or iginated from river floodplains and the exposed Chukchi shelf. Cryoturbated soil horizons, ice wedges, and ice-lens formation indicate a permafrost en vironment and mean annual temperatures below -6 degrees to -8 degrees C. Sh allow active layers (average 45 cm), minimal evidence for chemical leaching of soils, and the presence of earthen hummocks indicate a cold and seasona lly dry climate. Neither steppe nor polar desert soils are appropriate anal ogues for these zonal soils of loess-covered central Beringia, No exact ana logues are known; however, soils underlying dry tundra near the arctic coas t of northern Yakutia, Russia, and under moist, nonacidic tundra of the Ala skan North Slope have properties in common with the buried soils. (C) 2000 University of Washington.