Waynesboro Formation

Waynesboro Formation
Stratigraphic range: Cambrian
Type Formation
Sub-units Red Run Member, Cavetown Member, and Chewsville Member
Underlies Elbrook Formation
Overlies Tomstown Dolomite
Lithology
Primary sandstone, dolomite, limestone
Other siltstone, shale
Location
Region Appalachia and Southeastern United States
Country  United States
Extent  Virginia[1],  Maryland,  Pennsylvania, and  West Virginia
Type section
Named for Waynesboro, Pennsylvania[2]

The Waynesboro Formation is a limestone, dolomite, and sandstone geologic formation in Virginia, Maryland, Pennsylvania and West Virginia.[2][3][4][5] It some areas it is composed of limestone and dolomite.[4] The Waynsboro Formation is one of the formations that make up the Shenandoah Valley. It dates back to the Cambrian period and is not considered fossiliferous.[3]

Description

The Waynesboro Formation is a predominantly limestone, dolomite, and sandstone formation that is found along the valley floor of the Shenandoah Valley.[3] It can also contain sometimes large beds of siltstone and shale.[2][3][4] The Waynesboro is often covered by gravel washes from surrounding mountains or by weathered debris from the formation itself, making finding outcrops for study difficult.[3][4] The formation is thought to represent a shallow marine depositional environment.[4] It was called the Watuga shale in parts of Virgina, but the name was abandoned in favor of the already established Waynesboro Formation.[3]

Members

The Waynesboro Formation was recognized as having three members in Virgina, Maryland, and Pennsylvania.[4][5] These members were later named the Red Run Member, the Cavetown Member, and the Chewsville Member. The Red Run Member is named after Red Run Creek near the Maryland-Pennsylvania state boundary, and forms the basal member of the formation. It consists of calcareous sandstone, sandy dolomite, and calcareous shale. Good exposures of the Cavetown Member are rare, but the member consists of limestone and dolomite with bioturbation with some interbedded sandstone. The youngest member of the Waynesboro Formation is the Chewsville Member, which is named after Chewsville, Maryland. It is composed of interbedded siltstone, sandstone, and shale and is considered the most distinctive member of the formation.[5]

References

  1. ↑ Read, J. Fred; Eriksson, Kenneth A. (2012). Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau (PDF). Virginia: Virginia Tech. Retrieved 30 June 2018.
  2. 1 2 3 Stose, George W. (1906). "The sedimentary rocks of South Mountain, Pennsylvania". Journal of Geology. 14: 209. Retrieved 30 June 2018.
  3. 1 2 3 4 5 6 King, Philip B. (1950). "Geology of the Elkton area, Virginia" (PDF). U.S. Geological Survey Professional Paper. 230: 30–32. Retrieved 30 June 2018.
  4. 1 2 3 4 5 6 Haynes, John T (1991). "Stratigraphy of the Waynesboro Formation (Lower and Middle Cambrian) near Buchanan, Botetourt County, Virginia" (PDF). Virginia Division of Mineral Resources Publication. 116: 1–34. Retrieved 30 June 2018.
  5. 1 2 3 Brezinski, David K. (1992). "Lithostratigraphy of the western Blue Ridge cover rocks in Maryland" (PDF). Maryland Geological Survey Report of Investigations. 55: 34–46. Retrieved 30 June 2018.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.