Exploring the origins of modern topographic relief in the southern Appalachians: An excursion through the transient landscape of the Cullasaja River basin, North Carolina
Published:January 01, 2015
Sean F. Gallen, Karl W. Wegmann, 2015. "Exploring the origins of modern topographic relief in the southern Appalachians: An excursion through the transient landscape of the Cullasaja River basin, North Carolina", Diverse Excursions in the Southeast: Paleozoic to Present, Ann E. Holmes
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This one-day field trip highlights research into the late Cenozoic evolution of topography in the Appalachian Mountains through geomorphic observations in the Cullasaja River basin, located in Macon County, North Carolina. Herein we present observations, data, and modeling results that challenge the paradigm of the Appalachians as a dead and slowly decaying orogen. Previous studies on the Cenozoic evolution of topography in the Appalachians are reviewed, showing that the post-orogenic history of eastern North America is best described by spatial and temporal changes in topographic relief, erosion rate, and sediment flux. When these data sets are placed in the context of other geologic and geophysical studies, they indicate that the Appalachians are a dynamic mountain range. We review previous studies in the Cullasaja basin that document and characterize the magnitude of base-level fall, relief production, and ensuing landscape response to such changes. These studies show that topographic relief within the basin was relatively subdued in the Miocene and subsequently has been rejuvenated ~160%, transforming the landscape into the rugged mountains we recognize today. We highlight hillslope and fluvial geomorphic observations that show landscape disequilibrium associated with ongoing adjustment to ~500 m of late Cenozoic base-level fall. Potential mechanisms for topographic rejuvenation of the Appalachians, such as climate change and epeirogenic uplift, are discussed using available field observations.
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Diverse Excursions in the Southeast: Paleozoic to Present
This volume includes nine field trip guides that explore geological history and visit four regional geologic provinces—Blue Ridge, Valley and Ridge, Cumberland Plateau, and the Nashville dome. Two guides focus on the Cumberland Plateau structure and hydrology. Two explore aspects of the Nashville dome, including Mississippian Waulsortian mounds and meso-scale structural deformation. Various aspects of the Valley and Ridge are visited on three trips, including the 1925 Scopes trial in Dayton, Tennessee, structural aspects of the Sequatchie Valley, and regional Silurian Red Mountain/Rockwood stratigraphy. Two field trips explore features of the Blue Ridge province—one investigates southernmost Appalachian exposures of metamorphosed lower Paleozoic rock, and another focuses on the Appalachian geomorphological response to uplift during the late Cenozoic.