Age of the Cutler Dam Alloformation (Late Pleistocene), Bonneville basin, Utah

Luminescence geochronology, especially infrared stimulated luminescence ana lyses on marsh mud, shows that a relatively deep lake reached its peak (sim ilar to 1340 m above sea level) in the Bonneville basin 59,000 +/- 5000 yr ago. The age is consistent with nonfinite C-14 ages and with amino acid geo chronology on ostracodes. The Cutler Dam Alloformation was deposited during this lake cycle, which, like the subsequent Bonneville lake cycle, appears to have reached its maximum highstand following the peak of a global glaci al stage (marine oxygen-isotope stage 4) but at a time when other records f rom North America show evidence for cold climate and expanded glacier ice. (C) 2001 University of Washington.