The Appalachian Mountains are estimated to be around 480 million years old, making them significantly older than the Rocky Mountains, which formed much more recently, approximately 80 million years ago.
The differences in age between these two mountain ranges can be attributed to their geological processes. The Appalachians were formed during the Paleozoic Era through the collision of tectonic plates and are characterized by their eroded peaks and rolling hills. In contrast, the Rockies are a younger range formed during the Laramide orogeny, which occurred during the late Cretaceous period, resulting in their more rugged and jagged features.
These variations in age not only reflect their formation processes but also the erosion and weathering that have occurred over millions of years, shaping their current landscapes.