The Aquia Formation is a geologic sandstone formation that extends from the upper Chesapeake Bay to the James River near Hopewell, Virginia.[1] It consists of clayey, silty, very shelly, glauconitic sand.[1] Fossil records indicate that this stratigraphic unit was created during the Paleocene.[1]
Aquia Formation | |
---|---|
Stratigraphic range: Late Paleocene ~ | |
Type | Geological formation |
Unit of | Pamunkey Group |
Sub-units | Paspotansa & Piscataway Members |
Underlies | Nanjemoy Formation |
Overlies | Brightseat Formation |
Thickness | up to 100 feet (30 m) |
Lithology | |
Primary | Sandstone |
Location | |
Location | Hopewell, Virginia |
Coordinates | 38°18′N 77°18′W / 38.3°N 77.3°W |
Approximate paleocoordinates | 39°00′N 58°54′W / 39.0°N 58.9°W |
Region | Maryland, New Jersey, Virginia |
Country | United States |
Extent | Upper Chesapeake Bay-James River |
Type section | |
Named for | Aquia Creek |
The Aquia formation was named for Aquia Creek where it is exposed in cliff faces along the banks.[2]
When uncovered, it appears dark green to gray-green, argillaceous, with well sorted fine- to medium-grained sand and locally indurated shell beds.[3] It is between 0 and 100 feet thick in Maryland.[3] Quartz and phosphatic pebbles and/or very coarse glauconitic quartz sand mark the base of the unit.[4] A few hard streaks of shells or thin "rock" layers are often reported but appear to be more abundant in the sections south of the James River.[4]
The Aquia formation is overlain by the Nanjemoy Formation and overlies the Brightseat Formation.[5]
The Aquia formation is broken down into two members: the lower Piscataway member and upper Paspotansa member.[2]
The Aquia Formation is thought to be 59.0-55.5 million years old.[2] The Piscataway member is 59–56.25 million years old, and the Paspotansa member is 56–55.5 million years old.[2] This is the Paleocene period.
Older publications describe the Aquia as being of Eocene age.[6]
Mammal fossils are extremely rare.[2]
Bird fossils are extremely rare.[2]
fossils of the aquia formation.