Sequatchie Valley structure and stratigraphy
The linear Sequatchie anticline interrupts the continuity of the Appalachian Cumberland Plateau from east-Central Tennessee southward into Alabama to near the latitude of Birmingham. The anticline was breached by erosion during the late Tertiary, thereby producing Sequatchie Valley and revealing the details of its geologic structure—the anticline is thrust faulted on its northwest flank, and that thrust is now known to be part of a tectonic ramp that extends upward from the Lower Cambrian Rome Formation to flatten to the northwest into a higher detachment within the weak shale and coal beds in the Pennsylvanian deltaic sedimentary rocks. The same thrust emerges to the northwest as the Cumberland Plateau overthrust, and appears to be a mirror-image analog of the Pine Mountain fault located in the Plateau to the northeast.
The purpose of this one-day field trip is to (1) provide an introduction to the Sequatchie Valley structure and the Mississippian-Pennsylvanian strata that form the crest and limbs of the anticline, and (2) gain some insight into the evolution of the topography in the southern Cumberland Plateau as the valley was exhumed during the late Tertiary. The first field trip stop is along Tennessee State Route (SR) 8 northwest of Dunlap to examine well-exposed rocks and structures along the upper detachment where it propagates along coal and shale beds in the Pennsylvanian section. The second field trip stop is up the southeast flank of the anticline along Tennessee SR-111 east of Dunlap to review the nearly continuous exposure of the Paleozoic section from the Devonian-Mississippian Chattanooga Shale to the top of the Mississippian.
Figures & Tables
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.
- Chattanooga Shale
- Cumberland Plateau
- field trips
- Lower Cambrian
- North America
- road log
- Rome Formation
- Sequatchie Valley
- United States