Deformation history of a foreland thrust belt in a recess : an example from the Roanoke recess, Appalachians, USA

The purposes of this thesis are to investigate the kinematic evolution of the Appalachian foreland thrust belt around the Roanoke recess; to compare the kinematic evolution of a recess to an adjacent salient to see if they deformed in a manner that mirrors their geometry; and to investigate the role of blind thrust through the deformation of the recess. The key results are: (1) deformation around the recess was continuous as opposed to 'two-step', initiated to the southwest and migrated northeastward while shortening directions rotated counterclockwise from N-S to almost E-W; (2) the recess did not deform as a simple inverse to the Pennsylvania salient; and (3) shortening magnitudes within the recess are sufficient to necessitate blind thrusting through the deformation history.The study area is located on the Appalachian Plateau in the inner arc of the Roanoke recess where map-scale structures of the central and southernAppalachian foreland thrust belt meet. The stratigraphic unit for the study is theMississippian Greenbrier Group that is well exposed and contains both abundantstylolitic cleavage and other strain markers for analysis. The primary methods for achieving the purposes of the thesis are: (1) construction of a cross section across the Plateau in the inner arc of the recess to integrate shortening components from map to microscale; (2) chronicling of the abundance and geometry of outcrop-scale folds and faults; (3) analysis of stylolitic cleavage foreshortening directions, magnitudes and sequences; (4) analysis of the finite strain in cleavage microlithons using framework grains in grainstones as strain markers; and (5) analysis of calcite-twin strains to resolve deformation sequences and the contribution of volume-constant deformation to the kinematic behavior.