The shape of the wedge is determined by how readily the wedge will fail along its basal decollement and in its interior; this is highly sensitive to pore fluid pressure.
12.
This is particularly the case where a good basal decollement exists, usually in a weaker layer like a shale, evaporite, or a zone of high pore fluid pressure.
13.
Typically, you will see repeated sections of the same rock over and over as thrust faults, coming up from the decollement, stack the same layer on top of itself.
14.
In present-day central Switzerland however, the molasse formed a thick, competent mass that was thrust northward in one piece over a decollement horizon at the base of the Mesozoic, in Triassic evaporites.
15.
The slope of the surface of the southern flank of the Mediterranean Ridge ( its accretionary prism ) is low, about 1? which indicates very low shear stress on the decollement at the base of the wedge.
16.
Upper Triassic ( Keuper ) shale and evaporite deposits locally contain interbedded dolostones, tuffs, and diabase ( ophites ); these deposits behave plastically and commonly form a tectonic m�lange with contacts being expressed as decollement surfaces.
17.
The sedimentary cover in the SE Zagros is deforming above a layer of rock salt ( acting as a ductile decollement with a low basal friction ) whereas in the NW Zagros the salt layer is missing or is very thin.
18.
B . Clark Burchfiel, Brian Wernicke, James H . Willemin, Garry J . Axen & C . Scott Cameron, " A new type of decollement thrusting ", Nature 300, 513-515 ( 9 December 1982 ) Abstract
