Alleghanian orogenic-float on the Martic thrust during dextal transpression, central Appalachian Piedmont

Syntectonic sediment loading and fold-thrust belt structural architecture: An example from the central Appalachians (USA)

“…In each model, the rear of the wedge is dominated by an antiformal stack of metamorphic and/or igneous basement rocks and is likely strong and riding above a weak mylonitic décollement; therefore, it may have had a higher taper angle. The thrust stack includes thrust sheets that have been transported along reactivated Late Ordovician Taconic-age faults (e.g., Valentino et al, 1994;Krol et al, 1999;Kunk and Burton, 1999;Valentino et al, 2004;Kunk et al, 2005;Southworth et al, 2006;Wintsch et al, 2010). These thrust sheets may have provided the elevation in the rear of the wedge to allow for the observed syntectonic sediment thicknesses.…”

“…2; Plate 2A) shows the imbricate stack of the Reading Prong-Lebanon Valley nappe system that developed early during the Alleghanian orogeny (Faill, 1998). Above this structure is the Martic thrust sheet, which has been shown to have had activity into the Pennsylvanian (Valentino et al, 2004). With forelandward progression of the massif, syntectonic erosion develops a thick sediment wedge as much as 16 km thick over the future Anthracite belt (Plate 2A, stages 1 and 2) and 5-7 km toward the foreland.…”