2018-19 Grant-in-Aid of Research
Paleoecological Interpretations of Microfossils from the Black Mountain Turtle Layer, Bridger Formation
Jeremy A. McLarty
A model has been proposed by Buchheim et al. (2000) for the deposition of specific fossil-rich horizons within the Bridger Formation, Wyoming. This model was developed to explain the unusually high density of turtle fossils found in certain stratigraphic intervals of these horizons. In this model, a lake system filled with volcanic ash causing a mass death of turtles in the lake, eventually changing the area from a lake system into a floodplain environment.
Schafer (2008) investigated microfossils from different geographic locations within one of the horizons studied by Bucheim et al. (2000), the Black Mountain Turtle Layer. Schafer (2008) performed a taxonomic analysis of the microfossils and found that although aquatic taxa were present, the dominant taxa were terrestrial. This finding disagreed with the lake system model developed by Buchheim et al. (2000).
The taxonomic analysis done by Schafer (2008) was very general in its classifications. A more refined taxonomic analysis, to genus if possible, would give us a deeper understanding of the paleoenvironment of the Black Mountain Turtle Layer. It would provide us with a better understanding of the taxonomic makeup of the Black Mountain Turtle Layer, which could have implications in understanding how ecosystems change over time. A better understanding of how the taxonomic makeup changed could also help reconcile the differences between Schafer (2008) and Buchheim et al. (2000).