Rates of erosion and landscape change along the Blue Ridge escarpment, southern Appalachian Mountains, estimated from in situ cosmogenic 10Be

Linari, C. L., Bierman, P. R., Portenga, E. W., Pavich, M. J., Finkel, R. C. and Freeman, S. P.H.T. (2017) Rates of erosion and landscape change along the Blue Ridge escarpment, southern Appalachian Mountains, estimated from in situ cosmogenic 10Be. Earth Surface Processes and Landforms, 42(6), pp. 928-940. (doi: 10.1002/esp.4051)

Abstract

The Blue Ridge escarpment, located within the southern Appalachian Mountains of Virginia and North Carolina, forms a distinct, steep boundary between the lower-elevation Piedmont and higher-elevation Blue Ridge physiographic provinces. To understand better the rate at which this landform and the adjacent landscape are changing, we measured cosmogenic 10Be in quartz separated from sediment samples (n = 50) collected in thirty-two streams and from three exposed bedrock outcrops along four transects normal to the escarpment, allowing us to calculate erosion rates integrated over 104–105 years. These basin-averaged erosion rates (5.4–49 m My-1) are consistent with those measured elsewhere in the southern Appalachians and show a positive relationship between erosion rate and average basin slope. Erosion rates show no relationship with basin size or relative position of the Brevard fault zone, a fundamental structural element of the region. The cosmogenic isotopic data, when considered along with the distribution of average basin slopes in each physiographic province, suggest that the escarpment is eroding on average more rapidly than the Blue Ridge uplands, which are eroding more rapidly than the Piedmont lowlands. This difference in erosion rates by geomorphic setting suggests that the elevation difference between the uplands and lowlands adjacent to the escarpment is being reduced but at extremely slow rates.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Portenga, Mr Eric and Freeman, Professor Stewart
• Authors: Linari, C. L., Bierman, P. R., Portenga, E. W., Pavich, M. J., Finkel, R. C., and Freeman, S. P.H.T.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences; College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Earth Surface Processes and Landforms
• Publisher: Wiley
• ISSN: 0197-9337
• ISSN (Online): 1096-9837
• Published Online: 10 September 2016
• Copyright Holders: Copyright © 2016 Wiley
• First Published: First published in Earth Surface Processes and Landforms 42(6):928-940
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher