Dan River Group

Dan River Group
Stratigraphic range: Late Triassic
Type	Half graben rift basin; principle normal fault zone on the northwest basin margin. [1]
Unit of	Newark Supergroup
Sub-units	Stoneville Formation, Cow Branch Formation, Leaksville Formation, Dry Fork Formation, Walnut Cove Formation, Pine Hall Formation
Area	126,300 acres
Thickness	5,000-8,000 ft [1] [2]
Location
Region	Virginia, North Carolina
Country	United States
Type section
Named for	Dan River
Named by	Thayer (1970)

The Dan River Group is a geologic group in Virginia and North Carolina associated with the initial rifting of the supercontinent Pangea. It is located on the southern end of a much larger rift valley sequence (the Newark Supergroup) which together formed the Central Atlantic Magmatic Province (CAMP); an extremely large flood basalt eruption that occurred around 201 Ma. It preserves fossils dating back to the Triassic period. ^[3]

Formations

It contains six geological formations: ^[2]

• Stoneville Formation (cyclical red mudstone). Sedimentary layer around 600 ft. ^[4]
• Leaksville Formation (Predominatly red mudstone.)
• Cow Branch Formation (cyclical fossiliferous black/dark grey mudstone with rare coarser lithologies). Sedimentary thickness is around 545 ft. ^[4]
• Dry Fork Formation (cyclical tan/red sandstone and grey/purple/red mudstone)
• Walnut Cove Formation (cyclical black/grey mudstone, sandstone, and coal)
• Pine Hall Formation (coarse tan sandstone and red mudstone). It's thickness ranges between 524-2,000 feet in depth. ^[2]

Volcanism

While the exact extent of lava erupted in the Dan River formation is not known, there is evidence of diabase dikes/sills found here. These magma bodies heated the ground around them, causing sedimentary rocks and coal to alter; a process known as contact metamophisis. The extent and volume of magma is unknown due to no exposed dikes or sills at the surface. ^[5]

See also

• Earth sciences portal
• Illinois portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Virginia
• List of fossiliferous stratigraphic units in North Carolina
• Central Atlantic magmatic province
• Newark Supergroup

References

1. Reid, Jeffrey; Taylor, Kenneth (January 2013). "Mesozoic rift basins – Onshore North Carolina and southcentral Virginia, U.S.A.: Deep River and Dan River - Danville total petroleum systems (TPS) and assessment units (AU) for continuous gas accumulation". www.deq.nc.gov. North Carolina Geological Survey. Retrieved 22 October 2025.
2. Olsen, P. E.; Schlische, R. W; Gore, P. J. W. (1989). "GEOLOGY OF THE DAN RIVER-DANVILLE BASIN" (PDF). ldeo.columbia.edu. Field Guide to the Tectonics, stratigraphy, sedimentology, and paleontology of the Newark Supergroup, eastern North America. International Geological Congress. Archived (PDF) from the original on 2017-03-09. Retrieved 22 October 2025.
3. Ghatak, A.; Basu, A. R. (December 2012). "Central Atlantic Magmatic Province (CAMP): The Palisade Sill Connection". AGU Fall Meeting Abstracts. pp. DI53A–2371. Retrieved 22 October 2025.
4. "Geolex — CowBranch publications". ngmdb.usgs.gov. GNU records (USGS DDS-6; Reston GNULEX). Retrieved 22 October 2025.
5. Reid, Jeffery; Milici, Robert (8 November 2008). "Hydrocarbon Source Rocks in the Deep River and Dan River Triassic Basins, North Carolina" (PDF). pubs.usgs.gov. The USGS. Retrieved 22 October 2025.

• Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 25 March 2022. Retrieved 17 December 2021.