25 New Research in the Appalachian-Ouachita Orogen: Integrated studies from the Foreland to the Hinterland (Posters)

This session welcomes research from the Ouachita-Appalachian foreland, Blue Ridge, and Piedmont, focusing on old paradigms and new problems. Contributions across scales that utilize mapping, petrology, paleontology, geochemistry, geophysics, and/or geochronology are welcome.

Tuesday, 10 March 2026
9:00 AM - 5:00 PM
RCC, Lower Level Hall

Three New Geologic Cross Sections in the Black Warrior Basin (Appalachian Plateaus Province) and Valley and Ridge Province of the Southern Appalachian Basin, West-Central to Northeastern Alabama

Paper number: 25-4
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

The U.S. Geological Survey (USGS) has created three new geologic cross sections each running from northwest to southeast 1) from Sumter County to Greene County in west-central Alabama, 2) from Fayette County through Tuscaloosa County to Bibb County in central Alabama, and 3) from Cullman County through Blount and Etowah Counties to St. Clair County in northeast Alabama. These sections are the seventh, eighth, and ninth in a series of USGS Appalachian Basin geologic cross sections. These new geologic cross sections are 35, 57, and 45 miles (56, 92, and 72 kilometers) long, oriented perpendicular to the structural trend of the Appalachian Mountains. Stratigraphic correlations between 18 wells used to build the sections were based on gamma ray well logs, core and mud log records, and seismic profiles.  Previously published geologic cross sections; geologic maps; stratigraphic correlation charts; and oil, gas, and coal exploration reports were also used to interpret the structural and stratigraphic relationships of the study areas. 

               The new cross sections display several important structural features including: (1) normal faulting of crystalline basement rocks in the Birmingham graben and adjacent horst blocks; (2) decollement thrust faults that verge to the northwest and intersect the surface; (3) ductile duplex “mushwad” structures, composed of thick sequences of highly contorted weak shales that overlie a regional decollement and underlie competent carbonate roof rocks of an overlying thrust ramp; (4) the Greene-Hale-Perry-Bibb Synclinorium, where Devonian to Silurian black shales have been explored for oil and gas; (5) probable thrust faulting in the Wiley Dome area of the otherwise normal faulted Black Warrior Basin; and (6) thick sequences of coal-bearing Pennsylvanian rocks in the Warrior and Cahaba coal basins in Fayette, Tuscaloosa, and Bibb Counties. The cross sections provide information about the region’s structural and stratigraphic framework that can be used for petroleum systems exploration  (e.g., coal-bed methane in Alabama coal basins, Devonian shale gas in the Chattanooga and Floyd Shales, and Cambrian shale gas in the Conasauga Formation); the identification of potential CO2 storage reservoirs in sandstone, and carbonate formations; and regional investigations of fluid flow dynamics in the southern Appalachian Basin.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411540

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