Cambrian to Lower Miocene), (4) Upper mobile group (Miocene salt, decollement level), and (5) In competent group (Lower Miocene to Plio--Pleistocene, mostly clastic sediments) .
The main basal decollement horizon is located in Lower Paleozoic Hormuz salt or Cambrian Shale beds, over the entire study area.
Detachments faults have been mapped on Cape Breton Island north of the study area by Lynch (2001); his Ainslie detachment fault is younger and probably related to decollement
along evaporite horizons, but his Margaree detachment could be coeval with the older detachment that we describe.
This means that where the decollment is shallow and many splay faults reach the surface, the folds will be narrow and closely spaced; deep decollements
result in wide folds at greater distances from one another.