Nappe

In geology, a nappe, or thrust sheet, is a large sheet like body of rock that has been moved more than two to five kilometers over a thrust fault from its original position. Nappes form in compressional tectonic settings, such as zones of continental collision or the overriding plate of an active subduction zone, when a mass of rock is forced over another rock mass along a low angle fault plane. The resulting structures can include large scale recumbent folds, shearing along the fault plane, stacks of imbricate thrust sheets, and features called fensters and klippes.