Acadian orogeny Acadian orogeny The Acadian orogeny is a long-lasting mountain building event which began in the Middle Devonian, reaching a climax in the early Late Devonian. It was active for approximately 50 million years, beginning roughly around 375 million years ago, with deformational, plutonic, and metamorphic events extending into the Early Mississippian. The Acadian orogeny is the third of the four orogenies that created the Appalachian orogen and subsequent basin. The preceding orogenies consisted of the Potomac and Taconic orogeny, which followed a rift/drift stage in the Late Neoproterozoic. The Acadian orogeny involved the collision of a series of Avalonian continental
East African Orogeny supercontinent (today known as Rodinia), a process that eventually culminated in the relatively short-lived Gondwanan supercontinent. Two partly incomparable scenarios have been proposed for this assembly. In one model, the EAO evolved from an accretionary orogeny involving the amalgamation of arcs and evolved into a collisional orogeny when the Neoproterozoic continent Azania collided with the Congo-Tanzania-Bangweulu Block at . In another model, the assembly of East Gondwana was a multiphase process which included two main periods of orogenesis: the older EAO ( ) and the younger Kuunga Orogeny ( ). In the former scenario the Kuunga Orogeny of the latter