>>1402408Geologically the Appalachians are an older respectable formation, but it was formed from less impressive and less intense geologic events and weathering. The western half of North America is sliding across the largest continental crustal plate on Earth, creating massive volcanoes and tilting massive chunks of the plates forming 4000-6000m mountains. The weathering is more prominent in the west as well, less than 500k years ago quite possibly the largest peak in what would become the lower 48 of the US was actually a volcano in Arizona that lost over a thousand meters of elevation in its eruption (it was believed to be around 4800m). Another example of this intense weathering rate is the Vishnu base rocks at the bottom of the Grand Canyon which are 1.5-2 Gya (billion), but the canyon itself was opened less than 10 Mya by the Colorado river. There are either active or recently inactive volcanoes and hot spots in every state west of Texas, some of the older formations are up to 280 Mya (Permian).
