Shenandoah National Park Geology: A Billion Years of Rock in Virginia's Blue Ridge

The park's Geologic Resources Inventory report. National Park Service.

Shenandoah National Park runs along the crest of the Blue Ridge Mountains in Virginia, less than 145 km (90 mi) southwest of Washington, D.C., across Albemarle, Augusta, Greene, Madison, Page, Rappahannock, Rockingham and Warren counties.

• Authorized by Congress on May 22, 1926, to protect nationally significant natural and cultural resources, scenic beauty and designated wilderness in Virginia's northern Blue Ridge.
• About 80,580 hectares (199,117 acres) of mountains, forests and meadows and culturally and historically significant places.
• 805 km (500 mi) of hiking trails, including 163 km (101 mi) of the Appalachian Trail, and abundant, diverse wildlife.
• Historic landmarks include Skyland, Rapidan Camp and structures built by the Civilian Conservation Corps.

Four ages of rock

The park displays the geology and high-elevation hydrology of the Appalachians, one of the oldest mountain ranges on Earth. Its bedrock falls into four main groups:

Inside an ancient mountain belt

Structurally, the park straddles the Blue Ridge–South Mountain anticlinorium. Its steep high ground is made of resistant rock: Mesoproterozoic gneisses and granites, Neoproterozoic greenstones and metasedimentary rocks, and Cambrian quartzites or sandstones. Here visitors can examine the core of an ancient fold-and-thrust belt — and some of the oldest rocks in the eastern United States.

Old Rag Mountain. Image from the National Park Service's page.

Shenandoah belongs to the Blue Ridge Physiographic Province, and shares its geologic history and characteristic formations with a region far beyond the park.

Protected by law

• Fossils: all fossil resources in national parks are protected by the Paleontological Resources Preservation Act of 2009.
• Caves: all cave resources are protected by the Federal Cave Resources Protection Act of 1988.
• Abandoned mineral lands: old mine sites can be valuable cultural resources and habitat, but many are dangerous to visitors and wildlife and degrade water quality, landscapes and resources. Near them: Stay Out and Stay Alive.

Maps and reports

Bedrock geologic map of the park, from the Geologic Resources Inventory. National Park Service.

The NPS Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks:

• scoping summaries — records of the meetings where park staff and local geologists planned the mapping and the report;
• digital geologic maps for GIS software, with a user guide, and in newer products Google Earth and online map versions;
• reports on the park's setting, significance, notable features and processes, management issues and geologic history;
• posters — PDF views of the map data, often with aerial imagery or shaded relief.

Shenandoah's are in the NPS DataStore; its completed Soil Resources Inventory is there too. The park's own pages cover its geologic formations, mountains and rock outcrops.

Sources

Based on "NPS Geodiversity Atlas—Shenandoah National Park, Virginia," National Park Service, citing National Park Service (2016), Southworth and others (2009, 2010) and Thornberry-Ehrlich (2014); a work of the United States government in the public domain.