Dan River Group

The Dan River Group is a geologic group in Virginia and North Carolina associated with the initial rifting of the supercontinent Pangea. Consisting of nearly 15,000 feet of conglomerate, sandstone, and mudrock overlain in an unconformity on top of older metamorphic rocks that is in fault contact with, it is located on the southern end of a much larger rift valley sequence (the Newark Supergroup.) This together formed the Central Atlantic Magmatic Province (CAMP); an extremely large flood basalt eruption that occurred around 201 Ma, causing the Triassic-Jurassic extinction event. It preserves fossils dating back to the Triassic period.

Formations It contains six geological formations: Stoneville Formation (cyclical red mudstone). Sedimentary layer around 600 ft. Leaksville Formation (Predominantly red mudstone.) Cow Branch Formation (cyclical fossiliferous black/dark grey mudstone with rare coarser lithologies). Sedimentary thickness is around 545 ft. 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). Its thickness ranges between 524-2,000 feet in depth.

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 metamorphosis. The extent and volume of magma is unknown due to no exposed dikes or sills at the surface.

Dan River Group

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