The Appalachian Orogeny is one of the geological mountain building events that created the Appalachian Mountains. This orogeny occurred about 325 million years ago and was caused by Africa colliding with North America at a time when these continents did not exist in their current forms. It applied massive stress on what is today the Eastern Seaboard of North America, forming a wide and high mountain chain. The Appalachians likely once reached elevations similar to those of the Alps, Andes, and the Rocky Mountains before they were eroded down to what they are today. The Appalachian Mountains are some of the oldest mountains in the world.
Age of the Mammals
About sixty-six million years ago, the Appalachian Mountains had been eroded to an almost flat plain. It was not until the region was uplifted during the Cenozoic Era (sixty-five million years ago to the present) that the distinctive topography of the Appalachian Mountains formed. Running across and through the ridge and valley region of the Appalachians is the New River which is believed to have existed before this second mountain building process began. This era is known as the ‘Age of the Mammals.’ This uplifting rejuvenated the streams, which rapidly responded by cutting downward into the ancient bedrock. Some streams flowed along weak layers that define the folds and faults created many millions of years earlier. Sinking Creek, a side stream of the New River, is an example of this process.
www.Ancient-Origins.net – Reconstructing the story of humanity’s past