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Gravel Deposits

Clay to boulder-size clasts primarily from igneous and metamorphic rocks of the central Black Hills. Also includes Phanerozoic lithic clasts and rare vertebrate fossils. Thickness up to 60 ft (18 m).
State South Dakota
Name Gravel Deposits
Geologic age Phanerozoic | Cenozoic | Tertiary
Primary rock type clay or mud
Secondary rock type silt
Other rock types sand; gravel
Lithologic constituents
Major
Sedimentary > Clastic > Conglomerate (Bed)
Map references
Martin, J. E., Sawyer, J. F., Fahrenbach, M. D., Tomhave, D. W., and Schulz, L. D., 2004, Geologic Map of South Dakota: South Dakota Geological Survey
Unit references
Martin, J. E., Sawyer, J. F., Fahrenbach, M. D., Tomhave, D. W., and Schulz, L. D., 2004, Geologic Map of South Dakota: South Dakota Geological Survey
Counties Custer - Fall River - Jackson - Pennington - Shannon