Thrust faults occur in the foreland basin which occur marginal to orogenic belts. Perhaps the most extreme form of orogenic uplift is a continental-continental crustal collision. Conditions producing widespread regionally metamorphosed rocks occur during an orogenic event. It represents a common type of regional pelitic orogenic metamorphism. Bursts of orogenic activity are divided by three angular unconformities in basin strata. The assembly of a supercontinent would have to show intercratonic orogenic belts. Intercratonic orogenic belts are characteristic of ocean basin closure. This occurs during uplift that is commonly associated with an orogenic event. They form as an isostatic response to an orogenic load. This continental collision resulted in several pivotal orogenic (mountain building) episodes. Erosion represents a subsequent phase of the orogenic cycle. The aulacogen terminates on contact with the Ouachita orogenic belt. Migration patterns flow away from the orogenic belt and into the cratonic interior. However, interpretation of orogenic belts can be difficult. The whole sequence may later be deformed and tilted by further orogenic activity.