FOURTEEN YEARS OF RESEARCH AT FOSSIL BUTTE NATIONAL MONUMENT:
DETAILED LOOKS INTO AN EOCENE LAKE
H. Paul Buchheim
Loma Linda University
Loma Linda, CA 92350
The investigator has spent fourteen years studying the sedimentology, stratigraphy, and paleontology of Eocene Fossil Lake in the Fossil Basin within which Fossil Butte National Monument is located. The research has largely depended on high resolution paleogeographic analysis of correlated sedimentary units. Over one hundred stratigraphic sections have been measured and sampled. About six of these sections have been sampled on a decimeter to centimeter resolution. The collected samples have been subjected to X-ray diffraction, isotope, total organic carbon, petrographic, and paleontologic analysis.
The results have been rewarding. The paleoenvironments of Eocene Fossil Lake are now better understood. Facies maps showing the distribution of facies as well as the size and shape of Fossil Lake have been constructed. The location of river inlets, volcanic vents, and the shores of the lake have been delineated.
The fossil fishes, which are central to the purpose of the park, have received taphonomic and paleoecologic study. As a result, we now know details about their distribution and preservation. The origin of the finely laminated sediments are now better understood. This aspect is receiving more intense study at this time. Other studies have focused on the unusual ichno facies, lake-margin and fluvial interactions, and paleobotany.
The above studies have discovered new scientific problems that will provide many productive future studies for years to come. Studies proposed for the near future include the origin of possible turbidite beds, soft sediment deformation structures, and laminae cycles.