Harpers Formation

Harpers Formation
Stratigraphic range: Cambrian
Harpers Schist. Shows older folded schistosity parallel to bedding cut by younger cleavage inclined to bedding.
TypeMetamorphic
Unit ofChilhowee Group
Sub-unitsSnowden Member (VA), Montalto Quartzite Member (PA)
UnderliesAntietam Formation
OverliesWeverton Formation
Lithology
PrimarySchist
OtherPhyllite, shale
Location
RegionAppalachia, Mid-Atlantic United States, and Southeastern United States
CountryUnited States
ExtentMaryland, Pennsylvania, Virginia,[1] West Virginia
Type section
Named forHarpers Ferry, West Virginia
Named byArthur Keith (1894)[2]
Photomicrograph of Harpers Schist

The Harpers Formation is a geologic formation in Maryland, Pennsylvania, Virginia, and West Virginia, consisting of schist, phyllite, and shale. It dates back to the early Cambrian period. It is considered part of the Chilhowee Group.

Notable exposures

The type section is in gorges of the Potomac River and the Shenandoah River at Harpers Ferry, West Virginia.

The Harpers Formation overlies the Ledger Formation (dolomite) due to a thrust fault in small roadside quarry (currently overgrown) on Pottery Hill, southwest of York, Pennsylvania.[3]

References

  1. ^ Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau
  2. ^ Arthur Keith, 1894. Harpers Ferry folio, Virginia, Maryland, West Virginia. United States Geological Survey Geologic atlas of the U.S. Folio 10. Field edition. Washington D.C., engraved and printed by the US Geological Survey. 5p., 5 maps. folio.
  3. ^ A. J. Stose and G. W. Stose, 1944. Geology of the Hanover-York district, U. S. Geological Survey Professional paper 204.


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