Stone Mountain State Park: Rock Formations

Each rock has a unique story about how it formed, and how the forces of erosion shape what it looks like today. While we don’t have any place we can see molten magma in North Carolina today, we do have places where, long ago, big pockets of magma cooled deep underground. After years and years of erosion, we can now see this igneous rock at the surface of the Earth. One location we can see this here in North Carolina is a granodiorite pluton called Stone Mountain.

Stone Mountain is about 700 feet tall, which is close to the size of two football fields stacked end to end. Stone Mountain consists of granodiorite, which is a combination of many different types of minerals, including gray quartz, white feldspar, black biotite mica, and amphibole. Over time, wind, water, and other forces gradually eroded softer layers of rock atop the granite block and exposed the outcrop we see today.

Student Resources:

Discover More (reading page) — Stone Mountain is a North Carolina Rockstar
Explore Outdoors — Backyard Geology
Glossary — Geology
Stone Mountain State Park Fact Sheet