GPR imaging of prehistoric animal remains in volcanic ashAuthors:
Well-preserved ash deposits are located at Ashfall Fossil Beds State Historical Park near Royal, Nebraska. The ash beds preserve a record of the once thriving Great Plains in the US Midwest approximately twelve million years ago. Initial studies confirmed the suitability of ground penetrating radar for high-resolution subsurface imaging of paleontological features at Ashfall. Grids of 500 MHz and 1000 MHz frequency GPR profiles were acquired over the remaining unexcavated areas of the site. Prominent ash layers and the top of the underlying sandstone were mapped at depths ranging from approximately 0.60 m to 1.4 m. Four characteristic GPR reflectors associated with animal remains were identified throughout the ash bed site. These four criteria were mapped to locate the presence of skeletal remains, scattered bones, ichnofossils and or altered ash deposition. Interpretation of the GPR grids identified numerous locations of potential buried animal remains.