Date of Award
Master of Science
Robert D. Hatcher, Jr
William M. Dunne, Steven G. Driese
The southern Appalachian Valley and Ridge is composed of a wedge of Cambrian through Pennsylvanian siliciclastic and carbonate rocks, deformed during latest Paleozoic by the collision of Laurentia and Gondwana. This collision caused the southern Appalachian foreland fold-thrust belt to deform as a critically tapered wedge. This study utilized structural and stratigraphic data to examine the mechanical behavior and timing of emplacement of the southwest end of the Tellico-Sevier syncline within this wedge. The study area is located in southeast Tennessee at the southwest end of the Tellico-Sevier syncline, which is in the first Valley and Ridge thrust sheet west of the Blue Ridge. The Tellico-Sevier syncline is a northeast-plunging syncline that extends from Etowah, Tennessee, northeast to southwestern Virginia. The northwest limb is bounded by the Chestuee fault, which is thought to be the decollement upon which the syncline was transported. The southeast limb of the syncline is truncated by the Conasauga Creek fault, which emplaced an overturned anticline of Knox and Conasauga Group rocks. Four balanced and retrodeformed cross sections were constructed through the study area, three perpendicular to the trend of the syncline and one parallel. In addition, there was one other section (D-D’) that was not retrodeformed and balanced. Cross sections B-B’ and D-D’ have apparent normal dip-slip fault displacement; however, all map-scale faults in the cross sections and study area are thrust faults. Examination of the cross sections and map-view fault relationships indicates that the northwest limb of iv the syncline formed first and the southeast limb formed later when the Chestuee thrust sheet underthrust itself. After the southeast limb was formed, the decollement that was transporting the Chestuee thrust sheet was pinned and an overturned anticline formed as a displacement gradient fold. This order of thrusting and folding is interpreted to mean that the syncline and overturned anticline formed by out-of-sequence thrusting, thus indicating that emplacement of the Valley and Ridge foreland fold-thrust belt as a critically tapered wedge was partially accommodated by out-of-sequence thrusting.
Heath, Milan A. II, "Structural and Stratigraphic Investigations at the Southwest End of the Tellico-Sevier Syncline, Southeast Tennessee. " Master's Thesis, University of Tennessee, 2003.