Paleozoic Era (540 - 250 million years ago) Early Paleozoic: Shallow seas covered the region. Sand, silt, and mud settled in layers and eventually became sandstone, shale, and limestone. These layers now make up much of the sedimentary rock in the park.

Late Paleozoic - Appalachian Mountain Building (310 - 254 million years ago) Alleghenian Orogeny (about 300 million years ago): Huge tectonic forces caused by the collision of North America and Africa (during the formation of the supercontinent Pangea) led to a massive mountain-building event. The pressure folded, faulted, and uplifted the rocks layers, creating the early Appalachian Mountains, including the Smokies.

Mesozoic Era (250-65 million years ago)-The mountains began to erode, and no major geological formation events occurred during this time 

Cenozoic Era (65 million years ago to present) Continued uplift and erosion: The landscape kept evolving. though the Smokies aren't as tall as the Rockies, they remain dramatic due to deep valleys and ridges.

Glacier periods: While glaciers didn't reach the Smokies, the Ice Ages influenced the climate and ecosystems, helping create the region's famous biodiversity.