The Evolution of Appalachian Fluviokarst: Competition between Stream Erosion, Cave Development, Surface Denudation, and Tectonic Uplift

Content Provider	Semantic Scholar
Author	White, William Blaine
Copyright Year	2009
Abstract	The long and complex depositional and tectonic history of the Appalachians has produced a substrate of folded and faulted sandstones, shales, and carbonate rocks (leaving aside the metamorphic and igneous core). The Appalachian fluviokarst is an evolving landscape developed on the carbonate rocks. The erosion of surface streams competes with dissolutional processes in the carbonate rocks, and both compete with tectonic uplift of the eastern margin of the North American plate. The Appalachians have undergone erosion since the Jurassic and 5 to 15 km of sediment have been removed. Many karst landscapes have come and gone during this time period. The earliest cosmogenic- isotope dates place the oldest Appalachian caves in the early Pliocene. Various interpretations and back-calculations extend the recognizable topography to the mid to late Miocene. Much of the present-day karst landscape was created during the Pleistocene. There have been many measurements and estimates of the rate of denudation of karst surfaces by dissolution of the carbonate bedrock and many estimates of the rate of downcutting of surface streams. Curiously, both of these estimates give similar values (in the range of 30 mm ka 21 ), in spite of the differences in the erosional processes. These rates are somewhat higher than present-day rates of tectonic uplift, leaving the contemporary landscape the result of a balance between competing processes. Introduction of tectonic forces into the interpretation of karst landscapes requires consideration of the long-term uplift rates. In the Davisian point of view, uplift was episodic, with short periods of rapid uplift followed by long static periods that allowed the development of peneplains. In the Hackian point of view, uplift has occurred at a more or less constant rate, so that present topography is mainly the result of differential erosion rates. Attempts to back-calculate the development of karst landscapes requires a conceptual model somewhere between these rather extreme points of view.
File Format	PDF HTM / HTML
Alternate Webpage(s)	https://mypages.valdosta.edu/dmthieme/Crit/White_2009.pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article