GROUND AND AERIAL SURVEY OF FOSSIL EOCENE BONE BED IN OGLALA NATIONAL GRASSLANDS, NEBRASKA

In the summer of 2016, a preliminary aerial and ground survey of an Eocene bone bed was conducted in the Oglala National Grasslands, Nebraska. Concentrated cranial and post-cranial elements are associated with channel sandstones and consist of a variety of mammalian taxa. A surveyed 91 m² grid was established and all surface specimens were mapped and recovered for each meter square. Individual elements from each square were identified and counted. Squares with greatest concentrations overlay the ancient stream channel, other high concentrations are from squares that overly natural drainages. Approximately 3009 fossil specimens were recovered and counted from the grid where 882 (29%) were those that were identifiable. Identifiable specimens within the grid consist of 73% small-sized, 15% medium-sized, 10% large-sized animals, and 1% plant material. We estimate that approximately 35 small-sized (cat-sized and smaller), 5 medium-sized (larger than a cat to deer-sized), and 2 large-sized (larger than a deer) animals are represented within the area of the grid. At least eight taxa are mammalian, but also include bird, crocodile, tortoise, amphibian, and fish. Plant varieties include petrified wood and two different seed types. A hand-drawn map of the grid and bone-bed was constructed to show areas of high bone density and orientation. This data will then be compared to aerial images containing spectral data (RGB, IR, and UV) from drones. Using MATLAB, the spectral signature of bone phosphate was isolated, and used to locate potential zones within the designated field area where samples may be exposed. If successful, drone technology could provide a more efficient technique for prospecting of fossil specimens within the White River Group.