EVIDENCE FOR CENOZOIC TOPOGRAPHIC REJUVENATION ASSOCIATED WITH THE LAUREL CREEK LINEAMENT IN THE SPRUCE PINE 7.5-MINUTE QUADRANGLE, WESTERN NORTH CAROLINA, USA

Multiple linear fracture systems (lineaments) across western North Carolina, USA are associated with Cenozoic topographic rejuvenation of the Blue Ridge Mountains. These systems are composed of joints and faults that strike obliquely to the rock units across the region. This, along with previous constraints on the direction of fault motion, knickpoints along stream channels, and paleostress analysis suggests these fracture systems are not associated with the Paleozoic assembly of Pangea but are younger. One of these lineaments, the Laurel Creek Lineament, extending from Hot Springs east toward Spruce Pine, North Carolina, has not been previously mapped. A 2005 earthquake on fractures within this lineament suggests it is an active system. Geologic field mapping of rock units and fractures in the Spruce Pine 7.5-minute quadrangle was conducted to document fractures, fault offsets, and the direction of fault motion. Near-vertical joints and faults are exposed throughout the quadrangle and dominantly strike toward 080°/260°. Fault offsets documented were centimeter to meter in magnitude. Fault slicken lines and offset rock units suggest that the north block moved up relative to the south block, supported by knickpoints along stream channels on the north block and not the south. Previous studies on the Boone Lineament, north of Spruce Pine, showed that fracture system moved with the south side up. These data indicate that the block of crust between the Boone Lineament and the Laurel Creek Lineament has been uplifted by these fracture systems.