Temporally and Spatially Uniform Rates of Erosion in the Southern Appalachian Great Smoky Mountains
Matmon A, Bierman PR, Larsen J, Southworth S, Pavich M, Caffee M. 2003. Temporally and Spatially Uniform Rates of Erosion in the Southern Appalachian Great Smoky Mountains. Geology. 31(2):155-158
ABSTRACT: Cosmogenic nuclide, fission track, long term sediment budget, and sediment yield data indicate that the Great Smoky Mountains and the southern Appalachians are eroding and generating sediment at a similar rate, about 30 m My-1, over both time and space. In this study, we measured 10Be in fluvial sediment samples (n=25) from eight Great Smoky Mountain drainages (1 to 190 km2). Results suggest spatially homogeneous sediment generation (on the 104 to 105 year time scale and >100 km2 spatial scale) at 73±13 tons km-2 yr-1, equivalent to bedrock erosion at 27±5 m My-1. At these scales, the cosmogenic nuclide data support Hack's classic model of Appalachian dynamic equilibrium. 10Be modeled rates of erosion are similar to Mesozoic and Cenozoic erosion rates estimated by other methods (10 to 60 m My-1). In contrast, unroofing rates during the Paleozoic orogenic events that formed the Appalachian Mountains imply higher integrated erosion rates (≥102 m My-1) consistent with rates reported from other active mountain belts. These results suggest that mountain belts erode rapidly during and immediately after orogenesis. However, erosion rates decrease significantly after termination of tectonically driven uplift, enabling the survival of ancient mountain belts, such as the Appalachians, as topographic features in the contemporary landscape.
- Type
- Journal Article
- Authors
- Matmon, Ari; Bierman, Paul; Larsen, Jennifer; Southworth, Scott; Pavich, M; Caffee, M
- Units
- GRSM
- Keywords
- APHN, Appalachian Highlands Network, erosion, Flat Creek, geology, Great Smoky Mountains National Park, GRSM, GRSM-00954, hillslope, sediment, SER, Southeast Region