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Hamilton Group
Geological Group in North America / From Wikipedia, the free encyclopedia
This article is about the geological structure. For other uses, see Hamilton Group (disambiguation).
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.
Quick Facts Hamilton Group or Millboro Shale, Type ...
Hamilton Group or Millboro Shale | |
---|---|
Stratigraphic range: Eifelian - Famennian | |
Type | Group |
Sub-units | Mahantango Formation
Skaneatales Formation
|
Underlies | Tully Limestone and Harrell Shale |
Overlies | Onondaga Limestone |
Thickness | up to 2,500 feet (800 m) |
Lithology | |
Primary | Shale |
Other | Limestone, Siltstone, Claystone |
Location | |
Region | Appalachian Basin of eastern North America |
Extent | Maryland, New York, Pennsylvania, Virginia, West Virginia and Ontario, Canada |
Type section | |
Named for | Hamilton, New York |
Named by | James Hall |
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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]
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