SHORT-TERM SEDIMENT ACCUMULATION RATES DETERMINED FROM EOCENE ALLUVIAL PALEOSOLS

A new method uses alluvial paleosols to calculate sediment accumulatio n rates for thin (25 m) stratigraphic intervals and allows the reliabl e interpolation of ages for stratigraphic levels within a thick strati graphic interval bounded by established dates. Sediment accumulation r ates calculated for a 650 m composite section in the Eocene Willwood F ormation of Wyoming span time intervals ranging from only 0.05 to 0.25 my. Important sedimentologic changes coincide with changes in accumul ation rate and indicate close and direct relations between the history of basin subsidence and depositional patterns.