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Mineral Resources On-Line Spatial Data

Morrison Formation, Unkpapa Sandstone, Sundance Formation, and Gypsum Spring Formation

Morrison Formation (Late Jurassic)- Light-gray to green and variegatedred, brown, yellow, or lavender, silceous claystone, shale, and siltstone containing interbedded sandstone and fresh-water limestone lenses. Thickness up to 150 ft (46 m). Unkpapa Sandstone (Late Jurassic)- White, massive to thin-bedded, fine-grained, argillaceous sandstone. May be variegated to banded red, yellow, brown, or lavender. Thickness up to 267 ft (81 m). Sundance Formation (Late to Middle Jurassic)- Greenish-gray, yellow, tan, red to orange, and white, variegated, interbedded, fine- to coarse-grained sandstone, siltstone, clay, and limestone. Thickness 250-350 ft (76-107 m). Gypsum Springs Formation (Middle Jusassic)- Massive white gypsum and minor maroon siltstone and shale. Thickness up to 40 ft (12 m).
StateSouth Dakota
NameMorrison Formation, Unkpapa Sandstone, Sundance Formation, and Gypsum Spring Formation
Geologic agePhanerozoic | Mesozoic | Jurassic-Middle Jurassic-Late
Original map labelJms
Primary rock typesandstone
Secondary rock typesiltstone
Other rock typesclaystone; clay or mud; shale; limestone; evaporite
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Mudstone > Claystone (Bed)
Sedimentary > Clastic > Mudstone > Claystone (Bed)
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Chemical > Evaporite > Gypsum (Bed)
Sedimentary > Carbonate > Limestone (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
Geographic coverageButte - Custer - Fall River - Lawrence - Meade - Pennington

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