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A brief geological history of Cockspur Island at Fort Pulaski National Monument, Chatham County, Georgia

Fact Sheet 2018-3011

By:
ORCID iD , ORCID iD , and ORCID iD
https://doi.org/10.3133/fs20183011

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Abstract

Fort Pulaski National Monument is located on Cockspur Island in Chatham County, Georgia, within the Atlantic Coastal Plain province. The island lies near the mouth of the Savannah River, and consists of small mounds (hummocks), salt marshes, and sediment dredged from the river. A 1,017-foot (ft) (310-meter [m])-deep core drilled at Cockspur Island in 2010 by the U.S. Geological Survey revealed several sedimentary units ranging in age from 43 million years old to present. Sand and mud are present at drilling depths from 0 to 182 ft (56 m), limestone is present at depths from 182 ft (56 m) to 965 ft (295 m), and glauconitic sand is present at depths from 965 ft (295 m) to 1,017 ft (310 m). The limestone and the water within the limestone are referred to collectively as the Floridan aquifer system, which is the primary source of drinking water for the City of Savannah and surrounding communities. In addition to details of the subsurface geology, this fact sheet identifies the following geologic materials used in the construction of Fort Pulaski: (1) granite, (2) bricks, (3) sandstone, and (4) lime mud with oyster shells.

Suggested Citation

Swezey, C.S., Seefelt, E.L., and Parker, M., 2018, A brief geological history of Cockspur Island at Fort Pulaski National Monument, Chatham County, Georgia: U.S. Geological Survey Fact Sheet 2018‒3011, 4 p., https://doi.org/10.3133/fs20183011.

ISSN: 2327-6932 (online)

ISSN: 2327-6916 (print)

Study Area

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
A brief geological history of Cockspur Island at Fort Pulaski National Monument, Chatham County, Georgia
Series title:
Fact Sheet
Series number:
2018-3011
DOI:
10.3133/fs20183011
Year Published:
2018
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Eastern Energy Resources Science Center
Description:
4 p.
Country:
United States
State:
Georgia
County:
Chatham County
Other Geospatial:
Fort Pulaski National Monument
Online Only (Y/N):
N
Additional Online Files (Y/N):
N