CORRELATION OF DRAINAGE PATTERNS AND LINEAMENTS FROM LIDAR DIGITAL ELEVATION MODELS, SOUTHEAST GEORGIA COASTAL PLAIN

The Coastal Plain of Georgia is a segment of the Atlantic Coastal Plain composed primarily of Tertiary-age sedimentary deposits. Although these sediments have not been deeply buried, regional compression has created systematic fracture sets throughout this area. Stream patterns and the arrangement of channels in southeastern Georgia are largely influenced by slope, lithology, and structure. This study was conducted to investigate the correlation between drainage patterns and automatically extracted lineaments from LiDAR-derived digital elevation models, and their relationship to fracture set orientations documented by previous workers. Lineaments are linear features in a landscape that express an underlying geological structure such as a fault or fracture zones that can characterize the drainage patterns of a region. Rectilinear stream patterns in the study area, Bulloch and Screven counties, suggest control by structural features such as fracture sets. High resolution LiDAR digital elevation models were used to capture the subtle lineations found in the low relief study area. These lineaments were extracted from shaded relief images of the LiDAR-derived DEM and compared with rose diagrams of existing fracture measurements to investigate their correlation. A stream network for the study area was derived using a LiDAR DEM. Streams that suggested a rectilinear pattern (i.e. 80-90˚ bends) were identified and their flow azimuths plotted on a rose diagram. A comparison of the two rose diagrams shows the extracted lineaments and field mapped fractures correlate well, and there is a strong similarity between the orientation of lineaments/fractures and rectilinear drainage patterns. These results confirm the hypothesis that the rectilinear drainage patterns seen in the southeastern Georgia Coastal Plain are controlled by structural lineaments. This method may be useful for estimating fracture orientations in low relief areas with minimal rock outcrops, as well as, furthering the understanding of the structural forces that control drainage patterns in Georgia’s Coastal Plain.