A test of holographic radar for detection of hidden vertebrate tracks and trackways

Previous testing has indicated that holographic radar can image surficial and shallowly-buried dinosaur tracks if the track surface presents a dielectric contrast. This paper reports on blind scanning of stratigraphic surfaces just above known, exposed trackways. Testing at Valley Quarries Fairfield operation near Gettysburg, PA yielded mixed results that could not be ground-truthed. Additional testing was conducted on the famous rock surface at Dinosaur State Park in Rocky Hill, CT, where large Eubrontes and Grallator tracks are exposed, along with filled/buried tracks whose locations are visually identifiable. The scans produced at Dinosaur State Park showed that RASCAN holographic radar was capable of clearly imaging surficial tracks based on their relief — an admittedly trivial result. For the important task of imaging subsurface/hidden tracks, the holographic radar's performance varied significantly across several tracks/conditions. The authors believe that difficulty in recognition of unexposed tracks may be related to a lack of radar detection in the absence of a clay film that both prevents easy separation of the mold from its cast (which precludes visual identification), and fails to provide a good dielectric contrast on the track surface (which hinders subsurface radar imaging). However, if radar reflectors of roughly correct dimensions are identified in rocks of suitable age and paleoenvironment, these reflectors may indicate the presence of exposable tracks.