DEVELOPING TERRESTRIAL-LIDAR MODELS OF PERIGLACIAL BOULDER-FIELD FABRIC

Boulder colluvium mantles with areas of unvegetated boulder fields can be found throughout the Late-Pleistocene periglacial fringe of the Mid-Atlantic, USA. The genesis of these boulder fields has been attributed to different processes that include fluvial, glaciofluvial, and freeze-thaw coupled with down-slope gelifluction. The latter has gained preference as the most appropriate model for boulder field genesis in recent years; however, the exact process by which these areas form remains unclear. Data to support the movement of boulders by gelifluction has typically relied on intense field surveys that require direct measurements of boulder aspect and slope. In this study, we develop laboratory terrain models consisting of small blocks of known geometry and orientation, and create DEMs of these physical models from terrestrial LIDAR. Analyses of the DEMs successfully characterize the known biases and trends in slope and orientation of the blocks. Our results suggest that a DEM created from terrestrial LIDAR provides an effective method for characterizing boulder field fabric without direct boulder measurement. The continuation of this project will involve analyses of a Pennsylvania boulder field using the same methods.