Alleghanian orogeny the super-continent Pangaea, which contained all major continental land masses. The collision provoked the orogeny: it exerted massive stress on what is today the Eastern Seaboard of North America, forming a wide and high mountain chain. Evidence for the Alleghanian orogeny stretches for many hundreds of miles on the surface from Alabama to New Jersey and can be traced further subsurface to the southwest. In the north, the Alleghanian deformation extends northeast to Newfoundland. Subsequent erosion wore down the mountain chain and spread sediments both to the east and to the west. The immense region involved in the continental collision,
Svecofennian orogeny broad terms, regardless of details, it has been proposed that the Svecofennian orogeny involved more-less continuous subduction with subduction zones progressively migrating to the southwest. An alternative model postulates subduction included alternating extension and compression cycles, with the orogenic activity ceasing after the collision between the Fennoscandian Craton and the Sarmatian Craton. Prior to the onset of orogeny the Archean-aged craton of what is today northeastern Fennoscandia rifted creating an ocean basin, the "pre-Svecofennian Ocean", that then closed during the Svecofennian orogeny. The closure of this basin was indebted to subduction and resulted thus both in the formation of igneous