2001 Appalachian Tectonic Studies Field Trip Summary

Fold-thrust structures in northeastern Alabama and northwestern Georgia

Rick Groshong and Dennis Harry, University of Alabama

The year 2001 ATSG field trip was held May 11-13 to see and discuss the fold-thrust structures in the northeastern corner of Alabama and the northwestern corner of Georgia. There was a kinematic-model and seismic-interpretation workshop on Friday May 11. The trip addressed two structural questions, the kinematics of the long, straight plateau-style Wills Valley anticline - Lookout syncline, and the geometry and kinematics of the complex fold-thrust structures immediately to the southeast of it in Alabama and Georgia.

Click on an image to enlarge it.

We now know from a good seismic line that the broad, asymmetric center of the Wills Valley anticline is developed over a listric thrust but that the anticline changes at both ends to be tighter and more symmetric before dying out. Kinematic models for this structure were discussed. Just southeast of the Lookout syncline, the Georgia fold-thrust structures form a knot of diverse trends that need to be explained, including their relationship to the overlying Rome thrust. In addition to good field exposures at key locations, we have three excellent regional seismic lines that dramatically improve our understanding of what is going on in the area in terms of both basement and cover structure and the relationship between them.

Highlights of the 2001 ATSG trip included the excellent weather, the opportunity to compare a seismic interpretation with the rocks, and the discovery of the Rome thrust in outcrop. The exposed fault is steeply dipping and contains the Cambrian Conasauga Formation in the hangingwall and Ordovician Sequatchie and Silurian Red Mt. Formations in the footwall. Everyone was very pleased that Tim Chowns of the State University of West Georgia was along as the third co-leader to provide definitive stratigraphic identifications.  Photos were provided by Bill Dunne and Nathan Kuhle. The overview and DeSoto Falls photos are from locations close to Mentone on Lookout Mountain. We thank the following participants for their enthusiastic participation in the workshop and field trip:

Severine Caritg, U. Neuchatel Pablo Cervantes ,Texas A&M Tim Chowns, State U. West GA Jae Won Chung, Texas A&M Pelin Cubuk, Texas A&M Nancye Dawers, Tulane Bill Dunne, U. Tennessee

Rodger Faill, PA Geological Survey Marty Finn, Texas A&M Matthew Giffels, U. West Virginia Milan Heath, U. Tennessee Nathan Kuhle, Texas A&M Marcella McIntyre, U. of Alabama Matt Mittenthal, U. of Alabama

Vernon Moore, Texas A&M Dick Nickelsen, Bucknell, emeritus Jake Ramsey, Texas A&M Jennifer Whisner, U. Tennessee Paul Winberry, U. of Alabama Nick Woodward, DOE Hongwei Yin, U. of Alabama Li Zhang, Texas A&M

Rick Groshong and Dennis Harry
University of Alabama