George Washington Birthplace
George Washington Birthplace National Monument lies on the Northern Neck of Virginia between the Rappahannock and Potomac Rivers within the Atlantic Coastal Plain physiographic province. The Popes Creek watershed and its interaction with the Potomac River dominate the landscape at the park. The watershed includes several wetland areas including Longwood and Digwood swamps, a large estuary sheltered by a sand spit along the Potomac shoreline, and upland terraces and ravines.
In the area of George Washington Birthplace, the eastern United States is divided into 5 physiographic provinces with associated local subprovinces. These are, from east to west, the Atlantic Coastal Plain, the Piedmont Plateau, the Blue Ridge, the Valley and Ridge, and the Appalachian Plateaus provinces.
The Atlantic Coastal Plain province is primarily flat terrain with elevations ranging from sea level to about 100 m (300 ft) in Maryland. Sediments eroding from the Appalachian Highland areas to the west formed the wedge-shaped sequence of soft sediments that were deposited intermittently on the Atlantic Coastal Plain during periods of higher sea level over the past 100 million years. These sediments are now more than 2,438 m (8,000 ft) thick at the Atlantic coast and are continually reworked by fluctuating sea levels and the erosive action of waves along the coastline. Large streams and rivers in the Coastal Plain province, including the James, York, Rappahannock, and Potomac continue transporting sediment and extending the coastal plain eastward. Beyond the province to the east the submerged Continental Shelf province extends for another 121 km (75 miles).
The landscape at George Washington Birthplace is profoundly impacted by the deposition of Tertiary and younger sediments and the subsequent erosion of these units by evolving waterways. Popes Creek and its associated wetlands, estuaries, and tributaries are among the least engineered waterways in the Chesapeake Bay watershed. This natural riverine environment continues to cut terraces, entrench channels, shift bars and other sediments, and cut scarps and ravines as it responds to changes in climate, seasonal storms, and human influences.
Glaciers have also affected to geology of the area. Even though glaciers from the Pleistocene Ice Ages never reached the central Virginia area (the southern terminus was in northeastern Pennsylvania), the intermittent colder climates of the ice ages played a role in the formation of the landscape at George Washington Birthplace National Monument. Freeze and thaw cycles within unconsolidated terrace units homogenized bedding features. Cold climate subaerial deposits contain fossils such as mastodon teeth. Sea level fluctuations during ice ages throughout the Pleistocene caused the baselevel of many of the area’s rivers to change. During lowstands (sea level drops), the rivers eroded their channels exposing the deformed bedrock of the Piedmont Plateau to the west. During oceanic highstands, the river basins flooded and deposition resulted in deposits of beach sediments in the park area.
The youngest depositional units at George Washington Birthplace National Monument include thick sedimentary deposits of sand, gravel, silt and clays, which are often reworked from older units and redeposited on the landscape. Several sand and gravel bars, channel gravels, and paleoscarps are present across the mouth of Popes Creek. Associated with this watershed are marsh and swamp deposits, and shelly sands. Additionally, artificial fill from construction of roads, dams, bridges, landfills, and highways are present on the historical landscape at George Washington Birthplace National Monument. Some of these anthropogenic deposits are recording the historic evolution of the landscape, others are from recent developments within and surrounding the monument area.
A virtual park map is available on the park's map webpage.For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.
A photo album for this park can be found here.For information on other photo collections featuring National Park geology, please see the Image Sources page.
Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.
Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
9" x 10.75", paperback, 550 pages, full color throughout
The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!
Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.
General information about the park's research program is available on the park's research webpage.
For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.
The NPS maintains a searchable data base of research needs that have been identified by parks.
A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.
NPS Geology and Soils PartnersAssociation of American State Geologists
Geological Society of America
Natural Resource Conservation Service - Soils
U.S. Geological Survey
General information about the park's education and intrepretive programs is available on the park's education webpage.For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.