AVIAN TAPHONOMY OF FOSSIL LAKE, OREGON

The historic and scientifically significant vertebrate fossil locality at Fossil Lake, Oregon, contains an extensive avifauna that was last studied in the mid-20th century. The South Dakota School of Mines and Technology Museum of Geology has amassed a new and extensive collection from Fossil Lake in which virtually all specimens are tied to a set of lithologically distinct units. The large number of specimens and the degree of stratigraphic and spatial control imposed by the collecting methodology provide an unparalleled opportunity for new studies of the locality. Class-level taxonomy and gross taphonomic condition were tabulated for a sample of 9365 avian specimens collected over six years. Five hundred sixty isolated fossil bird bones and one skeleton collected during 1990 were identified and examined for taphonomic condition. Four fossils and four sediment samples were analyzed by SEM-based methods. Patterns of accumulation, preservation, breakage, and weathering within the deposit are incorporated into a taphonomic and paleoenvironmental model. A volcanic maar is suggested as the primary mechanism that controlled and influenced accumulation and preservation of the fossils at Fossil Lake.