Multiple websites state that the mountain, which is in Colorado, was formed by an intrusion of magma about 1.4 billion years ago, forming a batholith.
On the other hand, the rocky mountains are said to have been formed only recently, perhaps 80 to 50 million years ago.
What then were the major forces that shaped the mountain? Did the batholith 1.4 billion years ago start thrusting the ground upward like a dome mountain, or did it remain flush underground until tectonic plate movement formed all of the rocky mountains?