When did the blue ridge mts come into existance?

best answer gets a 5When did the blue ridge mts come into existance?
The Blue Ridge mountains are part of the Valley and Ridge region of the Appalachians.





The Appalachians were formed during three orogenic events: the Taconic, the Acadian, and the Alleghenian, with the latter having the most effect on the entire mountain chain.





Read more: http://en.wikipedia.org/wiki/Alleghenian鈥?/a>





http://en.wikipedia.org/wiki/Geology_of_鈥?/a>





Basically, this mountain range is a result of Gondwanna converging into Laurentia.When did the blue ridge mts come into existance?
I do not think that the blue ridge mts are part of the valley and ridge, which is slightly to the west and north. I always understood the Blue Ridge mountains to be the core basement complex at the heart of the appalachians. the rocks themselves are precambrian in age, I think something similar to grenville, or about 1000 million years old. The Blue Ridge is what is left of a much larger mountain chain that formed during the collision of North America with Africa (and Europe further north), with a final stage ending sometime around 300 million years ago.





When the mountains wore down to where the Blue Ridge rocks became exposed is something I do not know, but many kilometers of rock had to erode to achieve today's situation.





I suppose that the appalachian orogeny (or sometimes called the allegheny orogeny, the last of the three ';appalachian'; events - Taconic, Acadian, Alleghenian) is when you would consider the mountains to have formed, and since then they have been slowly eroding away. What you see know is what is left of a mountain chain that 300 million years ago was probably something like the Himalayas are today.