Gravity-slide sheets are common in areas of sufficient topographic relief provided by extensional and compressional tectonism. They occur throughout the Basin and Range Province of Nevada and Utah but are perhaps best exposed in the thrust belt of southeast Idaho and northwest Wyoming. The Idaho-Wyoming slide sheets developed adjacent to extensional basin-bounding faults, which in turn were initiated at a ramp in the Absaroka thrust. Initial coherent sheets may have been up to 12 km 2 in aerial extent, but as a result of differential movement rates, these larger sheets were broken into smaller blocks by strike-parallel extension during emplacement. Folds on the down-slope edges of the sheets suggest movement analogous to a tank tread: Through interbed shear the limestone beds rolled forward and were dragged beneath the leading edge of each sheet. It is not known whether initial emplacement was catastrophic or by creep, but undisrupted cleavages within footwall Tertiary mudstones and coherent bedding within the sheets suggest creep for at least the later phases of movement.

Precambrian crystalline basement of the Appalachian Blue Ridge deforms inhomogeneously by developing relatively narrow ductile deformation zones (DDZs). The Paleozoic sedimentary cover develops open to tight folds and penetrative fabrics. A transition between these two styles occurs at the base of the sedimentary cover in the Early Cambrian Chilhowee quartzites of the central Appalachians and in the Late Proterozoic arkosic sandstones of the southern Appalachians. On a mesoscopic scale, the transition zone sediments show tight to isoclinal folds with highly deformed overturned limbs analogous to mesoscopic (1 cm to 10 m wide) DDZs in crystalline basement. Deformation zones in the basement cut across the basement/cover contact and feed into the overturned limbs of tight folds. On a microscopic scale, both arkoses and granitic basement rocks show thin (5 mm) DDZs characterized by grain-size reduction and alteration of feldspars to quartz and mica. The actual style and symmetry of deformation varies with metamorphic grade, proximity to major thrust faults, and amount of tectonic shortening. In the Grandfather Mountain area of the southern Blue Ridge Province, sets of low-dipping DDZs close to major thrust faults approximate a simple shear deformation field. In the central Appalachians of northern Virginia, similar simple shear deformation features are observed close to major thrust faults, but sets of DDZs define a flattening plane perpendicular to tectonic transport direction higher up within the thrust sheets.