GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 63-7
Presentation Time: 3:10 PM

RELICT APPALACHIAN UPLANDS IN THE NORTHERN VIRGINIA BLUE RIDGE


EVANS, Mark A., Department of Geological Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06050 and BARTHOLOMEW, Mervin J., Earth Sciences, University of Memphis, Memphis, TN 38152

North of the James River, three large areas of relict Appalachian Uplands (referred to by relict streams/nearby peaks) occur along the crest of the Blue Ridge in northern Virginia. These areas are: 1) the Tye River –Elk Pond Mountain region at Montebello; 2) the Stony Creek-Devils Knob region at Wintergreen; and 3) the Big Meadows-Hawksbill Mountain region along the Skyline Drive. These areas contain elevated, low-gradient drainages above approximately 2600 ft (793 m) elevation with up to ~1500 ft (457 m) of local relief. Below approximately 2600 ft elevation, very steep slopes mark the irregular shape of the ~1000-ft (305 m) high, east-facing Blue Ridge escarpment. In contrast, the west-facing escarpment is generally less steep, several hundred feet lower, and reflects stronger structural/lithology control. Cenozoic mass-wasting and fluvial deposits occur along the base of both escarpments consistent with Cenozoic erosion and migration of the escarpments. Balanced cross sections across the Blue Ridge and fold-thrust belt, detailed geologic maps, LiDAR, geomorphic features, and topographic analysis provide ways of assessing if Neogene or Quaternary tilting and/or vertical displacement of the relict upland regions has occurred relative to incision.