Great Smoky Mountains National Park - Geology

Geology

The majority of rocks in the Great Smoky Mountains National Park are Late Precambrian rocks that are part of the Ocoee Supergroup formation. This group consists of metamorphosed sandstones, phyllites, schists, and slate. Early Precambrian rocks are not only the oldest rocks in the park but also the dominant rock type in sites such as the Raven Fork Valley and upper Tuckasegee River between Cherokee and Bryson City. They primarily consist of metamorphic gneiss, granite, and schist. Cambrian sedimentary rocks can be found among the bottom of the Foothills to the northwest and in limestone coves such as Cades Cove. One of the most visited attractions in the mountains is Cades Cove which is a window or an area where older rocks made out of sandstone surround the valley floor of younger rocks made out of limestone.

The oldest rocks in the Smokies are the Precambrian gneiss and schists which were formed over a billion years ago from the accumulation of marine sediments and igneous rock. In the Late Precambrain period, the primordial ocean expanded and the more recent Ocoee Supergroup rocks formed from the accumulation of eroding land mass onto the continental shelf. At the end of the Paleozoic era, the ocean depostited a thick layer of marine sediments which left behind sedimentary rock. During the Ordovician period, the collision of North American and African plates initiated the Alleghenian orogeny that created the Appalachian range. The Mesozoic era was dictated by the rapid erosion of softer sedimentary rocks and re-exposed the older Ocoee Supergroup formations.