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 (Predominantly 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
- List of fossiliferous stratigraphic units in Virginia
- List of fossiliferous stratigraphic units in North Carolina
- Central Atlantic magmatic province
- Newark Supergroup
References
- ^ a b 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.
- ^ a b c 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.
- ^ 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.
- ^ a b "Geolex — CowBranch publications". ngmdb.usgs.gov. GNU records (USGS DDS-6; Reston GNULEX). Retrieved 22 October 2025.
- ^ 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.