Orogeny process whereby new mountains and other land-forms were thrust up, or else there would eventually be no land; he suggested that marine fossils in mountainsides must once have been at the sea-floor. Orogeny was used by Amanz Gressly (1840) and Jules Thurmann (1854) as "orogenic" in terms of the creation of mountain elevations, as the term "mountain building" was still used to describe the processes. Elie de Beaumont (1852) used the evocative "Jaws of a Vise" theory to explain orogeny, but was more concerned with the height rather than the implicit structures created by and contained in orogenic belts. His
Cadomian Orogeny Malo and Mancellian regions formed the orogeny. Crustal thickening took place afterwards. Secondly P. J. Treloar considers that the North Armorican Massif was put together from a series of terranes , their joins are the shear zones. The terranes are known as St Brieuc, St Malo and Mancellian terranes. Deformation in this model is caused by oblique subduction and is strike-slip, but not crustal thickening. The migmatite belts would then be explained by high heat flow in marginal basins. Cadomian Orogeny The Cadomian Orogeny was a tectonic event or series of events in the late Neoproterozoic, about 650–550 Ma, which