What mountain range is the oldest in North America?

The Appalachian Mountains are the oldest mountain range in North America, formed during the Paleozoic Era, roughly 480 million to 300 million years ago. Their age can be attributed to the processes of ancient continental collisions and the subsequent erosion that has shaped them over millions of years.

Unlike the younger, more rugged Rocky Mountains, which formed relatively recently due to tectonic activity associated with the uplifting of the Earth's crust during the last 65 million years, the Appalachians have been significantly eroded. This erosion has led to their characteristic worn-down peaks and gentle rolling hills, contrasting sharply with the sharper, more pronounced peaks found in younger ranges.

In comparison, the Sierra Nevada and the Cascade Range are also younger mountain ranges. The Sierra Nevada, primarily formed during the Laramide Orogeny around 100 million years ago, is still relatively young in geological terms. The Cascade Range is a volcanic mountain range that erupted as recently as the last few thousand years, further suggesting its youth in comparison to the Appalachians.

Understanding the geological history and processes involved in the formation of these mountain ranges highlights the significance of the Appalachian Mountains as the oldest and reveals details about the geological evolution of North America.