SYNDEPOSITIONAL FRACTURE SETS AND DEFLECTIONS OF RIVERS AND SHORELINES: TOOLS FOR ANALYSIS OF CENOZOIC DEFORMATION IN THE ATLANTIC COASTAL PLAIN, GEORGIA AND SOUTH CAROLINA

Cenozoic deformation within Atlantic Coastal Plain strata in Georgia and South Carolina is typically initiated with syndepositional fracture sets of orthogonal joints and/or orthogonal sets of conjugate normal faults which are indicative of horizontal extension at or near the paleo-ground-surface. Documented examples of such extension at or near the paleo-surface appear to be caused by uplifts above then-active vertical or steeply dipping reverse faults with extension occurring in arched areas above the faults. Broad areas of later Quaternary surface uplift may be identified by utilizing river deflections in combination with deflections of shoreline features. Analysis of fracture sets within areas of such modern or paleo-uplifts places constraints on possible orientations of the underlying steeply dipping faults which caused such uplifts.