Aquia Formation

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Aquia Formation
Stratigraphic range: Late Paleocene
~59.0–55.5 Ma
Thecachampsa crocodile coprolite (Aquia Formation, Upper Paleocene; Potomac River shores, King George County, northeastern Virginia, USA).jpg
coprolite (Aquia Formation; King George County, Virginia)
TypeGeological formation
Unit ofPamunkey Group
Sub-unitsPaspotansa & Piscataway Members
UnderliesNanjemoy Formation
OverliesBrightseat Formation
Thicknessup to 100 feet (30 m)
Lithology
PrimarySandstone
Location
LocationHopewell, Virginia
Coordinates38°18′N 77°18′W / 38.3°N 77.3°W / 38.3; -77.3Coordinates: 38°18′N 77°18′W / 38.3°N 77.3°W / 38.3; -77.3
Approximate paleocoordinates39°00′N 58°54′W / 39.0°N 58.9°W / 39.0; -58.9
RegionMaryland, New Jersey, Virginia
Country United States
ExtentUpper Chesapeake Bay-James River
Type section
Named forAquia Creek

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]

The Aquia formation was named for Aquia Creek where it is exposed in cliff faces along the banks.[2]

Geology[]

Lithology[]

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 occurs between 0 and 100 feet thick.[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]

Stratigraphy[]

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]

Age[]

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]

Fossils[]

Vertebrates[]

Bony fish[]

Chondrichthyes[]

Sharks[]
Rays[]

Reptiles[]

Crocodylians[]
Turtles[]

Mammals[]

Mammal fossils are extremely rare.[2]

Birds[]

Bird fossils are extremely rare.[2]

Molluscs[]

Gastropods[]

Bivalves[]

Cephalopods[]

  • marylandensis is present but uncommon.[19]

See also[]

References[]

  1. ^ a b c Geology of the National Capital Region - Field Trip Guidebook. Reston, Virginia: U.S. Geological Survey, Department of the Interior. 2004. p. 270.
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar http://phatfossils.com/Aquia%20Formation%20Paleocene%20of%20Maryland%20and%20Virginia.php
  3. ^ a b "Coastal Plain Rocks and Sediments". Geological Maps of Maryland. Maryland Geological Survey. 1968. Retrieved 21 January 2015.
  4. ^ a b Powars, D.S.; Bruce, T.S. (2000). The Effects Of The Chesapeake Bay Impact Crater On The Geological Framework And Correlation Of Hydrogeologic Units Of The Lower York-James Peninsula, Virginia. United States Geological Survey. Retrieved 22 January 2015.
  5. ^ Page, Richard A (1959). "The Questionable Age of the Aquia Formation". Journal of Paleontology. 33 (2): 347–350. JSTOR 1300764.
  6. ^ http://www.elasmo.com/frameMe.html?file=genera/cenozoic/sharks/abdounia.html&menu=bin/menu_genera-alt.html
  7. ^ a b c d e f g h i j k "Fossil Identification for the Potomac River".
  8. ^ a b "Potomac - Aquia Formation 3/15/18".
  9. ^ "Paleohypotodus?".
  10. ^ "Physogaleus secundus".
  11. ^ "Myliobatis".
  12. ^ "Thecachampsa".
  13. ^ "Trionyx".
  14. ^ "Turritella sp".
  15. ^ a b c d e f g h i Virginia Division of Mineral Resources (1912). Bulletin. p. 200. fossils of the aquia formation.
  16. ^ "Cucullaea Gigantea". 15 May 2010.
  17. ^ "Views of the Mahantango: Cucullaea gigantea pelecypod from the Aquia Formation". 11 August 2014.
  18. ^ a b "Ostrea compressirostra".
  19. ^ "Sanity check: It's a Nautilus, right?".
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