| East-west-, southeast-northwest-, and north-south-trending lineaments separate zones of differential uplift and rejuvenated topography in the western North Carolina Blue Ridge Province. Sometime in the Miocene, over 200 m.y. after the birth of the Atlantic Ocean, the Blue Ridge of western North Carolina was uplifted, likely not as a broad uniform section of the crust, but rather as blocks bounded by conjugate fracture zones that today form the Swannanoa, Laurel Creek, Tuckasegee, Franklin, and other unnamed lineaments. The Swannanoa and Laurel Creek are two east-west lineaments visible in satellite imagery for 250 and 120 km. These previously recognized but poorly documented structures contain lineament-parallel outcrop-scale joints and dextral-normal faults formed from a near-vertical principal stress consistent with the focal mechanism from a 2005 earthquake. Streams draining into the lineaments have recorded uplift-related local base level change as knickpoints upstream of active topography and downstream of relict landscapes. |
