Archive - The Great Smoky Thrust Fault at White Oak Sink

November 13, 2021


Every weekend we present a notable item from our archives.

This EPOD was originally published May 22, 2014.

Photographer: Charles Carrigan
Summary Authors: Charles Carrigan; Jacqueline Phillips

The Great Smoky Thrust Fault separates the Blue Ridge Mountains from the Valley and Ridge Province of east Tennessee. It brought up Precambrian metamorphic rocks and placed them on top of Ordovician limestone. This fault records over 248 mi (400 km) of displacement, the sum total of all the other thrust faults present in the Valley and Ridge.

This photograph, taken within Great Smoky Mountain National Park at White Oak Sink, shows the Great Smoky Thrust as a horizontal line near the bottom of the photograph. The metamorphic rocks above it are strongly foliated, shown here dipping to the right. This fault was active during the Alleghanian Orogeny, a mountain-building event in the Late Carboniferous and early Permian periods. The resulting collision between North America and Africa brought together all of the world’s continents forming the supercontinent Pangaea. Here at White Oak Sink a small creek flows over the fault and enters a cave in the limestone below. Photo taken on March 9, 2014.

Photo Details: Camera: Canon EOS REBEL T4i; Lens: EF-S18-135mm f/3.5-5.6 IS STM; Focal Length: 24mm; Aperture: f/8.0; Exposure Time: 0.500 s (1/2); ISO equiv: 100;  Camera RAW file was developed for color and contrast using Adobe Photoshop Elements 11.0 Windows. 

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