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NPS Geodiversity Atlas—Castillo de San Marcos National Monument, Florida

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.

fortress wall and bay beyond

Introduction

Castillo de San Marcos National Monument (CASA) is located along the northeastern coast of Florida in the city of St. Augustine in St. John’s County. Originally proclaimed as Fort Marion National Monument on October 15, 1924, the park unit was renamed on June 5, 1942 (National Park Service 2016a). CASA contains approximately 8 hectares (19 acres) and preserves the oldest masonry fortification in the continental United States. Constructed by the Spanish between 1672 and 1695, Castillo de San Marcos served as an outpost to protect maritime trade routes and represents one of the first permanent European settlements in the continental United States (National Park Service 2016b). Throughout its history, Castillo de San Marcos has been built upon, changed, and adapted to serve the needs of its numerous owners, which include the armies of Spain, Great Britain, the Confederate States of America, and the United States. The national monument protects 11 historic structures that consist of a moat that surrounds most of the fort, a ravelin (a triangular fortification), covered way, grassy glacis, City Gate pillars, seawall, water battery, hot shot furnace, and the reconstructed Cubo Line (defensive walls) (Brown 1997).

Geologic Setting

Situated in the Atlantic Coastal Plain physiographic province, the geology underlying CASA is characterized by a series of well-developed marine terraces that step down in elevation and age toward the Atlantic coast. These terraces document ancient shorelines that formed in response to sea level changes from the Pleistocene to the present (Colquhoun 1969; Richards et al. 1971). The geology of CASA is composed of young, Quaternary-age deposits consisting of beach ridges, dunes, and undifferentiated sediments. Although the Pleistocene Anastasia Formation is not exposed at CASA, Castillo de San Marcos is constructed of locally quarried coquina sourced from the unit.

Regional Geology

Castillo de San Marcos National Monument is a part 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 2802. To search for additional information, visit the Data Store.

NPS Soil Resources Inventory project has been completed for Castillo de San Marcos National Monument and can be found on the NPS Data Store.

Source: Data Store Saved Search 2753. To search for additional information, visit the Data Store.

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Castillo de San Marcos 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.


Castillo de San Marcos National Monument

Last updated: June 14, 2024