Wacke member

Unit symbol: Dbfw
Age range Upper Devonian (393.3 to 358.9 Ma)
Lithology: Sedimentary
Group name: Beaucoup Formation, undivided
Gray and green, thin-bedded wacke, brown and gray sandstone and quartzite, siltstone, shale, and calcareous sandstone and shale. Contains coquina lenses (Brosgé and others, 2000). Apparently contains less green shale and siltstone, and more calcareous sandstone, than wacke member of Hunt Fork Shale (unit Degh) (Brosgé and others, 1979). Contains Late Devonian (Frasnian) brachiopods, pelecypods, crinoids, and corals (Brosgé and others, 1979; 2001). Includes wacke member of Rocks of Whiteface Mountain of Dillon and others (1986), which consist of fine-grained wacke, graywacke, calcareous shale-chip and granule conglomerate with some volcanic clasts, and thin fossiliferous limestone

Source map information

Source map Mayfield, C.F., and Tailleur, I.L., 1978, Bedrock geology map of the Ambler River quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-120-A, 1 sheet, scale 1:250,000.
Symbol MzPzfw
Unit name Felspathic wacke
Description Calcareous felspathic volcanic wacke containing a few intercalated phyllite and limestone beds; mostly fine-grained gray green sandstone and siltstone
Lithology Sedimentary

Correlated geologic units

Label Dbfw
Description Wacke member of Beaucoup Formation
Geologic age Middle-Devonian to Late-Devonian
Geologic setting Sedimentary, undivided
Lithology Form Importance
Conglomerate-mudstone < Mixed-clastic < Clastic < Sedimentary Bed Major