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NPS Geodiversity Atlas—Prince William Forest Park, Virginia

Geodiversity refers to the full variety of natural geologic (rocks, minerals, sediments, fossils, landforms, and physical processes) and soil resources and processes that occur in the park. A product of the Geologic Resources Inventory, the NPS Geodiversity Atlas delivers information in support of education, Geoconservation, and integrated management of living (biotic) and non-living (abiotic) components of the ecosystem.

image of gri report cover with photo of ranger on bridge
In-depth geologic information is contained in the baseline inventory products of the Geologic Resources Inventory, see table below.

Introduction

Prince William Forest Park (PRWI) is located approximately 56 km (35 mi) south of Washington, D.C., in Prince William County, Virginia. Originally established in 1933 as Chopawamsic Recreational Demonstration Area as part of President Franklin D. Roosevelt’s New Deal legislation, the park unit was later renamed on June 22, 1948. Encompassing approximately 6,507 hectares (16,081 acres), PRWI is home to the largest protected eastern Piedmont forest in the United States and offers recreational opportunities rooted in its legacy as a model for the New Deal-era recreational demonstration area (RDA) program, an initiative that built parks for the nation’s urban youth and families (National Park Service 2014). When the park unit was first established, the Civilian Conservation Corps (CCC) and Works Progress Administration (WPA) created programs to build a new type of park where low-income, inner-city children and families could escape the city and experience nature. Many of the CCC and WPA programs worked to reduce unemployment and teach job skills, as well as construct roads, bridges, dams, and cabin camps throughout the park. Today PRWI contains the largest concentration of CCC and WPA structures in the NPS.

Geologic Setting

Prince William Forest Park straddles the Fall Line, a transitional boundary between the eastern Piedmont province and the Atlantic Coastal Plain province. The landscape of PRWI is composed of rolling hills, narrow ridges, and steep-sloped valleys and ravines that are an expression of the underlying geology (Thornberry-Ehrlich 2009c). The bedrock of the park is an assemblage of volcanic, sedimentary, and plutonic rocks that were buried and metamorphosed during the Alleghenian Orogeny, then subsequently uplifted and eroded to a plateau (Figure 46; Southworth and Denenny 2006). The oldest bedrock underlying PRWI consists of Neoproterozoic–Cambrian mafic and ultramafic rocks located along and north of Quantico Creek. Early Paleozoic rocks are widely mapped throughout the park and include the Ordovician Lake Jackson pluton, Quantico Formation, Lunga Reservoir Formation, and Chopawamsic Formation. A belt of Silurian felsic igneous rocks has intruded the older metavolcanic and metasedimentary rocks of the Chopawamsic Formation in the eastern portion of PRWI. Sediments of the Coastal Plain form a veneer atop the bedrock of the park and include the Cretaceous Potomac Formation, Miocene terrace deposits, and Pleistocene fluvial and estuarine deposits. Younger, Quaternary surficial deposits mapped in PRWI consist of terrace deposits and alluvium.

Regional Geology

Prince William Forest is in the Piedmont and Coastal Plain Physiographic Provinces and shares its geologic history and some characteristic geologic formations with a region that extends well beyond park boundaries.

Maps and Reports

The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks. The products listed below are currently available for this park, check back often for updates as many maps, reports, and posters are still in progress.
  • Scoping summaries are records of scoping meetings where NPS staff and local geologists determined the park’s geologic mapping plan and what content should be included in the report.
  • Digital geologic maps include files for viewing in GIS software, a guide to using the data, and a document with ancillary map information. Newer products also include data viewable in Google Earth and online map services.
  • Reports use the maps to discuss the park’s setting and significance, notable geologic features and processes, geologic resource management issues, and geologic history.
  • Posters are a static view of the GIS data in PDF format. Newer posters include aerial imagery or shaded relief and other park information. They are also included with the reports.
  • Projects list basic information about the program and all products available for a park.

Source: Data Store Saved Search 3150. To search for additional information, visit the Data Store.

NPS Soil Resources Inventory project has been completed for Prince William Forest Park and can be found on the NPS Data Store.

Source: Data Store Saved Search 3101. To search for additional information, visit the Data Store.

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Prince William Forest Park

National Park Service Geodiversity Atlas

The servicewide Geodiversity Atlas provides information on geoheritage and geodiversity resources and values within the National Park System. This information supports science-based geoconservation and interpretation in the NPS, as well as STEM education in schools, museums, and field camps. The NPS Geologic Resources Division and many parks work with National and International geoconservation communities to ensure that NPS abiotic resources are managed using the highest standards and best practices available.


Prince William Forest Park

Last updated: July 15, 2024