WIDE-FIELD LIDAR IMAGING AND ONLINE INTERACTIVE MEASUREMENT OF A DINOSAUR TRACKWAY SITE FROM SOUTHWEST ARKANSAS, USA

In June 2011, a 4,200 square meter dinosaur trackway site was exposed within Lower Cretaceous strata (De Queen Limestone) revealing sauropod tracks and trackways and the first documented occurrence of theropod tracks and trackways in southwest Arkansas. The sauropod tracks were most similar to the ichnogenus Brontopodus. The theropod tracks were tentatively referred to the ichnogenus Eubrontes and attributed to the Lower Cretaceous carnosaur, Acrocanthosaurus atokensis, based on interpretations of similar tracks in Texas. Wide-field, ground-based LIDAR instruments (Z+F 5006i and Leica C10 laser scanners) were deployed to scan the entire site (0.006 m resolution). Scanners were mounted on a hydraulic boom lift providing downward-looking, circular 25-m radius scans of the trackway surface. Overlapping circular scans were processed and merged using LIDAR point-cloud processing software to yield a hill-shaded relief map of the entire trackway site. Digital tools were developed to permit interactive measurement and analysis of individual tracks and trackways, enablining broad dissemination of research-grade, high-resolution LIDAR data of this site to the vertebrate ichnology and paleontology communities through an online interface. A Beta-test version of the web site displaying the hill-shaded trackway site with interactive measurement tools will be presented. Refinement of wide-field LIDAR acquisition procedures and additional development of measurement and analysis tools would advance the study of dinosaur trackways by enabling more precise and detailed measures than could be obtained using standard field methods. Compilation of LIDAR scans from trackway sites worldwide would also aid comparative trackway studies since research-grade, high-resolution data from multiple sites could be viewed, measured, and analyzed simultaneously using online, interactive GIS platforms.