NPS Geodiversity Atlas—Fort Pulaski National Monument, South Carolina

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.

fort veranda and interior grounds


Fort Pulaski National Monument (FOPU) is located between Savannah and Tybee Island along the Georgia coast in northeastern Chatham County. Proclaimed on October 15, 1924, FOPU encompasses approximately 2,275 hectares (5,623 acres) and occupies parts of Cockspur Island and McQueen’s Island (National Park Service 2016a). The national monument preserves Fort Pulaski, a 19th century masonry coastal fortification that was constructed to protect U.S. harbors following the War of 1812 (National Park Service 2016e). Built between 1829 and 1847, Fort Pulaski consists of 25 million bricks and a complex network of dikes, ditches, and drainage systems strategically located along the mouth of the Savannah River. The Battle of Fort Pulaski in 1862 demonstrated how new, experimental rifled artillery could breach the massive walls of the fort and forced the Confederate garrison stationed there to surrender within six weeks. Following the battle, Fort Pulaski became a safe refuge for freedom seekers until the close of the American Civil War. A significant portion of FOPU consists of undisturbed saltmarshes that are recognized as part of the National Oceanic and Atmospheric Administration’s national system of Marine Protected Areas for their critical ecological resources.

Geologic Setting

FOPU is situated in the Atlantic Coastal Plain physiographic province, a region characterized by gently sloping topography consisting of a series of marine terraces that decrease in age and elevation toward the Atlantic coast. The coastal islands of Georgia were built by Piedmont rivers draining into the Atlantic, deposited as landward migrating washover terraces that stabilized about 4.5 ka (Hayes 1988). The geology of FOPU is young, consisting of Quaternary fringe deposits, as well as Holocene beach sands and saltmarsh deposits. Quaternary fringe deposits are mapped on Cockspur Island on either side of the Fort Pulaski site and primarily occur along inland edges of intertidal to supratidal zones (Swezey et al. 2018). Holocene beach sands are mapped in the region of Goat Point and represent a depositional composite of former dune ridges and barrier stands. Saltmarsh deposits of black silty clay with lenses of fine-grained sand represent the most widely distributed unit within FOPU.

Regional Geology

Fort Pulaski National Monument is a part of the Sea Island Section of the Coastal Plain Physiographic Province 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 2862. To search for additional information, visit the Data Store.

NPS Soil Resources Inventory project has been completed for Fort Pulaski National Monument and can be found on the NPS Data Store.

Source: Data Store Saved Search 2930. To search for additional information, visit the Data Store.

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Fort Pulaski National Monument

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.

Fort Pulaski National Monument

Last updated: June 18, 2024