Scherr Formation

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Scherr Formation
Stratigraphic range: Late Devonian
Type sedimentary
Unit of Greenland Gap Group
Sub-units Minnehaha Springs Member
Underlies Foreknobs Formation
Overlies Brallier Formation
Thickness 1,004 ft (306 m) at type section
Lithology
Primary Shale
Other Siltstone
Location
Region Appalachian Mountains
Extent Pennsylvania, Maryland, Virginia, West Virginia
Type section
Named for Scherr, West Virginia
Named by J. M. Dennison, 1970

The Devonian Scherr Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia and West Virginia.

Description[edit]

The Scherr Formation consists predominantly of siltstone and shale. Lower part of unit includes considerable fine-grained sandstone, while upper two thirds contains almost no sandstone. It weathers light olive gray.[1]

Stratigraphy[edit]

Dennison (1970) renamed the old Chemung Formation the Greenland Gap Group and divided it into the lower Scherr Formation and the upper Foreknobs Formation. De Witt (1974) extended the Scherr and Foreknobs into Pennsylvania, but did not use the term Greenland Gap Group.[2]

Boswell, et al. (1987), does not recognize the Scherr and Foreknobs Formations in the subsurface of West Virginia and thus these formations are reduced from "group" to "formation" as the Greenland Gap Formation.[3]

The Minnehaha Springs Member is a "clastic bundle" consisting of interbedded medium gray siltstone and olive gray shale with some grayish-red siltstone and shale and some sandstone. It is interpreted as turbidites.[4] This same member is proposed to exist at the base of the Scherr's lateral equivalent, the Lock Haven Formation.[5]

Notable outcrops[edit]

Age[edit]

Relative age dating places the Scherr in the late Devonian.

References[edit]

  1. ^ Dennison, J.M., 1970, Stratigraphic divisions of Upper Devonian Greenland Gap Group ("Chemung Formation") along Allegheny Front in West Virginia, Maryland, and Highland County, Virginia: Southeastern Geology, v. 12, no. 1, p. 53-82.
  2. ^ de Witt, Wallace, Jr., 1974, Geologic map of the Beans Cove and Hyndman quadrangles and part of the Fairhope quadrangle, Bedford County, Pennsylvania: U.S. Geological Survey Miscellaneous Investigations Series Map, I-801, 6 p., 1 sheet, scale 1:24,000
  3. ^ Boswell, R.M., Donaldson, A.C., and Lewis, J.S., 1987, Subsurface stratigraphy of the Upper Devonian and Lower Mississippian of northern West Virginia: Southeastern Geology, v. 28, no. 2, p. 105-131.
  4. ^ Lyke, W.L., 1986, The stratigraphy, paleogeography, depositional environment, faunal communities, and general petrology of the Minnehaha Springs Member of the Scherr Formation: Southeastern Geology, v. 26, no. 3, p. 173-192.
  5. ^ Warne, A.G., and McGhee, G.R., Jr., 1991, Stratigraphic subdivisions of the Upper Devonian Scherr, Foreknobs, and Lock Haven Formations near the Allegheny Front of central Pennsylvania: Northeastern Geology, v. 13, no. 2, p. 96-109.