The Appalachian mountains were built by a series of 3 orogenies (collisions).
The Appalachian orogenic belt is an ancient mountain range that stretches from Newfoundland, Canada, in the north, to Alabama in the south, across a distance of more than 3,000 km (1,860 miles), along the eastern edge of North America. James Dana and James Hall developed the geosynclinal theory of mountain development in the Appalachians in the late 19th century; currently, the plate tectonic theory is used instead. Three Appalachian orogenies were created as a result of these collisions: the Taconic in the Middle Ordovician (472 million years ago), the Acadian in the Middle to Late Devonian (390 million to 370 million years ago), and the Alleghenian in the Late Carboniferous to Permian (300 million to 250 million years ago).
To learn more about Appalachian Mountain, Visit:
https://brainly.com/question/1746571
#SPJ4
