Hamilton Group

This article is about the geological structure. For other uses, see Hamilton Group (disambiguation).
Hamilton Group or
Millboro Shale
Stratigraphic range: Eifelian - Famennian
TypeGroup
Sub-unitsMahantango Formation
Clearville Siltstone
Frame Shale
Donation Siltstone
Crooked Creek Shale
Backbone Ridge Siltstone
Chaneysville Siltstone
Gander Run Shale

Moscow Formation

North Evans limestone
Windom Shale
Kashong Shale
Tichenor Limestone

Ludlowville Formation

Jaycox Shale
Owasco Shale
Spafford Shale
Wanakah Shale, Ivy Point Shale
Ledyard Shale, Otisco Shale
Centerfield Limestone

Skaneatales Formation

Levanna Member
Stafford Limestone

Marcellus Formation

Otaka Creek Member
Cherry Valley Member
Union Spring Member
Tioga Bentonites
UnderliesTully Limestone and Harrell Shale
OverliesOnondaga Limestone
Thicknessup to 2,500 feet (800 m)
Lithology
PrimaryShale
OtherLimestone, Siltstone, Claystone
Location
RegionAppalachian Basin of
eastern North America
ExtentMaryland, New York, Pennsylvania, Virginia, West Virginia and Ontario, Canada
Type section
Named forHamilton, New York
Named byJames Hall

The Hamilton Group is a Devonian-age geological group which is located in the Appalachian region of the United States. It is present in New York, Pennsylvania, Maryland, Ohio, West Virginia, northwestern Virginia and Ontario, Canada,[1][2] and is mainly composed of marine shale with some sandstone.

There are two main formations encompassed by the group: the Mahantango Formation and the Marcellus Shale. In southwestern Virginia, where the two sub-units are not easily distinguishable, the Hamilton Group is broadly equivalent to the Millboro Shale or Millboro Formation.[3]

The group is named for the village of Hamilton, New York.[4][5] These rocks are the oldest strata of the Devonian gas shale sequence.[6]

Generalized stratigraphic nomenclature for the Middle Devonian strata in the Appalachian Basin.[7]
  1. ^ Ryder, R.T., Swezey, C.S., Crangle, R.D., Jr., and Trippi, M.T., 2008, Geologic cross section E-E’ through the central Appalachian Basin from the Findlay Arch, Wood County, Ohio, to the Valley and Ridge Province, Pendleton County, West Virginia: U.S. Geological Survey Scientific Investigations Map SIM-2985, 2 sheets with 48-page pamphlet. https://pubs.er.usgs.gov/publication/sim2985
  2. ^ Ryder, R.T., Trippi, M.H., Swezey, C.S., Crangle, R.D., Jr., Hope, R.S., Rowan, E.L., and Lentz, E.E., 2012, Geologic cross section C-C’ through the central Appalachian basin from near the Findlay Arch, north-central Ohio, to the Valley and Ridge Province, Bedford County, south-central Pennsylvania: U.S. Geological Survey Scientific Investigations Map SIM-3172, 2 sheets with 70-page pamphlet. https://pubs.er.usgs.gov/publication/sim3172
  3. ^ "Map Unit Descriptions" (PDF). Virginia Department of Mines, Minerals and Energy. 2007-09-28. Archived from the original (PDF) on 2008-02-11. Retrieved 2008-05-03.
  4. ^ Wood, G.H., Trexler, J.P., Kehn, T.M., (1964). Geology of the West-Central Part of the Southern Anthracite Field and Adjoining Areas, Pennsylvania. United States Geological Survey, C-46.
  5. ^ "Geolex — Hamilton".
  6. ^ Martin, John P. "The Middle Devonian Hamilton Group Shales in the Northern Appalachian Basin: Production and Potential". New York State Energy Research and Development Authority. Archived from the original on 2006-10-11. Retrieved 2008-04-02.
  7. ^ Milici, Robert C.; Swezey, Christopher S. (2006). "Assessment of Appalachian Basin Oil and Gas Resources: Devonian Shale–Middle and Upper Paleozoic Total Petroleum System" (PDF). Open-File Report Series 2006-1237. United States Geological Survey. Retrieved 2008-04-05.