CoachA nappe is a large sheet of rock, often a few kilometres thick and tens of kilometres long, carried along a low-angle thrust or in the overturned limb of a large recumbent fold far from its place of origin; the rocks of a nappe are allochthonous, those that stayed in place autochthonous. A nappe stack is a pile of nappes in which the structurally higher nappes usually come from farther inside the orogen.
| unit (top to bottom) | origin and rocks |
|---|---|
| Austroalpine nappes | margin of Apulia north of the Periadriatic Line: basement and cover slices detached from their lower crust |
| Margna–Sesia nappes (Sesia zone, Dent Blanche) | fragments rifted off the outermost Apulian margin when the ocean opened |
| Upper Penninic nappes | Piemont–Liguria ocean: ophiolites, exhumed mantle, calcareous schists |
| Middle Penninic nappes | the Briançonnais ribbon continent |
| Lower Penninic nappes | Valais ocean: ophiolites and calcareous schists |
| Subpenninic nappes | European basement detached from its lower crust |
| Helvetic nappes | limestone-rich cover of the near European margin, detached from its basement |
| Southern Alps | Apulia south of the Periadriatic Line: a south-verging fold–thrust belt, mostly Miocene, 10 to thick |