SPATIAL ANALYSIS AND VISUALIZATION OF LOWER CRETACEOUS TRACKWAYS IN DINOSAUR VALLEY STATE PARK, CENTRAL TEXAS

Dinosaur Valley State Park is a 1524-acre recreational area situated on the Paluxy River near Glen Rose, Texas. The Paluxy River has exposed numerous trackways in limestones of the Lower Cretaceous (113 my) Glen Rose Formation. These trackways are some of the best examples of tridactyl (Acrocanthosaurus and Iguanodon) and sauropod traces found in Texas and are famous worldwide. Previous mapping has resulted in a series of plan maps without uniform scale, detail, or intended purpose. These maps are not spatially referenced to a geodetic datum, thus, exact spatial positions are not preserved and can not be linked to other projects. Our mapping techniques utilize improved technology to create comprehensive, geospatially referenced maps that are easily interpreted and visualized. Dinosaur trackways are uncovered, sketched in plan view, labeled and then photographed. Multiple points on each track are then surveyed to millimeter-scale accuracy using a laser theadolite. Survey data from the trackways are converted into a shapefile, projected, and overlayed with digital orthophotographs within ArcGIS. USGS digital raster graphics (1:24,000) of the park were merged together and digitized to create a 3-D model of the park in ArcScene. Photographs are hyperlinked to the track features within the GIS. Direction of travel and stride-lengths are determined by the GIS as an example of the analytical viability of the mapping project. The GIS mapping has accurately linked numerous dinosaur trackways and have preserved their geospatial position. The GIS is also instrumental to further paleontological analysis of the trackways and aids in the visualization of the tracks. Our techniques represent a modern approach that facilitates both the academic and recreational value of the dinosaur trackways.