Mineral Resources On-Line Spatial Data
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Geologic units in Petersburg City, Virginia
- Potomac Formation (Cretaceous) at surface, covers 3 % of this area
Potomac Formation - Pebbly, poorly sorted quartzo-feldspathic sand interbedded with sandy clay and silt; minor organic-rich clay and silt
- Chesapeake Group (Tertiary) at surface, covers 14 % of this area
Chesapeake Group - Fine- to coarse-grained sand, silt, clay; variably shelly and diatomaceous
- Lower Tertiary Deposits (Tertiary) at surface, covers 2 % of this area
Lower Tertiary Deposits - Glauconitic quartz sand and clay-silt, shelly in part, minor sandy limestone and limey sand; may include the following formations: Brightseat, Aquia, Marlboro, Nanjemay, and Piney Point (Pamunkey Group); and Old Church.
- Petersburg Granite (Mississippian) at surface, covers 3 % of this area
Petersburg Granite - Granite
- Bacons Castle Formation (Tertiary) at surface, covers 68 % of this area
Bacons Castle Formation - Gravel grading upward into sand and sandy clayey silt
- Quaternary and Tertiary Deposits (Tertiary-Quaternary) at surface, covers 7 % of this area
Quaternary and Tertiary Deposits - Tabb through Windsor Formations and alluvial/tidal prism deposits.
- Windsor Formation (Tertiary-Quaternary) at surface, covers 3 % of this area
Windsor Formation - Interbedded gravel, sand, silt, and clay; at altitudes to 85-95 ft. (top of unit).