Orogeny Orogeny An orogeny is an event that leads to both structural deformation and compositional differentiation of the Earth's lithosphere (crust and uppermost mantle) at convergent plate margins. An orogen or orogenic belt develops when a continental plate crumples and is pushed upwards to form one or more mountain ranges; this involves a series of geological processes collectively called orogenesis. Orogeny is the primary mechanism by which mountains are built on continents. The word "orogeny" comes from Ancient Greek (, , + , , ). Although it was used before him, the term was employed by the American geologist G.K. Gilbert
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