Rockwell Formation

Rockwell Formation
Stratigraphic range: Late Devonian to Early Mississippian
Rockwell Formation at Sideling Hill, I-68 roadcut
Type	Sedimentary
Sub-units	Finzel Tongue,[1] Patton Shale, Riddlesburg Shale[2]
Underlies	Pocono Formation and Purselane Sandstone
Overlies	Hampshire Formation
Thickness	500 to 540 feet in WV,[3] 540 to 550 feet at Sideling Hill[4]
Lithology
Primary	Sandstone, shale, conglomerate
Location
Region	Appalachian Mountains
Extent	West Virginia, Maryland, Pennsylvania
Type section
Named for	Rockwell Run, West Virginia
Named by	Stose and Swartz, 1912[3]

The Rockwell Formation is a late Devonian and early Mississippian mapped bedrock unit in West Virginia, Maryland, and Pennsylvania, in the United States.

Description

The Rockwell Formation was described at its type section at Rockwell Run in West Virginia as soft arkosic sandstone, fine hard conglomerate, and buff hackly shale.^[3]

The formation was originally described in West Virginia by Stose and Swartz (1912).^[3] It was first described in Maryland by H. E. Vokes (1957),^[4] and later described in central Pennsylvania by C. R. Wood (1980).^[5]

Stratigraphy

The Rockwell is generally considered a Formation. At Formation rank, it has several members, including the Patton and Riddlesburg Shale Members,^[2] and the Finzel Tongue.^[1]

It has been reduced in rank to a member of the Price Formation in West Virginia.^[2]

The Rockwell is a lateral equivalent of the Huntley Mountain Formation and the Spechty Kopf Formation, as all three underlie the prominent Pocono Formation and its lateral equivalent, the Burgoon Sandstone.

Lessing, Dean, and Kulander (1992) mapped the Meadow Branch synclinorium in Berkeley County, West Virginia, and noted that the Rockwell is approximately 200 meters thick here and that a 2-meter thick diamictite is present near the base.^[6]

Outcrops of the Rockwell Formation in Pennsylvania (Norfolk Southern Railway, Horseshoe Curve)

See also

• Geology of Pennsylvania
• Huntley Mountain Formation

References

1. Dennison, J.M., Beuthin, J.D., and Hasson, K.O., 1986, Latest Devonian-earliest Carboniferous marine transgressions central and southern Appalachians, USA, IN Bless, M.J., and Streel, M., eds., Late Devonian events around the Old Red Continent; field conference in Aachen (FRG), with excursions in the Ardenne (Belgium), the Rheinisches Schiefergebirge (FRG) and in Moravia (USSR): Annales de la Societe Geologique de Belgique, Aachen, Federal Republic of Germany, April 6–14, 1986, v. 109, no. 1, p. 123-129.
2. Kammer, T.W., and Bjerstedt, T.W., 1986, Stratigraphic framework of the Price Formation (Upper Devonian-Lower Mississippian) in West Virginia: Southeastern Geology, v. 27, no. 1, p. 13-33.
3. Stose, G.W., and Swartz, C.K., 1912, Description of the Pawpaw and Hancock quadrangles (Maryland-West Virginia-Pennsylvania): U.S. Geological Survey Geologic Atlas of the United States, Pawpaw-Hancock folio, no. 179, p. 24.
4. Vokes, H.E., 1957, Geography and geology of Maryland: Maryland Geological Survey Bulletin, no. 19, p. 243.
5. Wood, C.R., 1980, Summary groundwater resources of Centre County, Pennsylvania: Pennsylvania Geological Survey Water Resource Report, 4th series, no. 48, p. 60.
6. Lessing, Peter, Dean, S.L., and Kulander, B.R., 1992, Stratigraphy and structure of Meadow Branch synclinorium, West Virginia: Southeastern Geology, v. 32, no. 3, p. 166-174.