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Miocene Rocks

MIOCENE ROCKS--Southwest Wyoming: Southern Rock Springs uplift--Pale-green to tan tuffaceous sandstone and claystone of Miocene(?) age. Conglomerate of uncertain correlation locally at base. Saratoga Valley and west and southwest to Colorado--White massive soft tuffaceous sandstone and lesser amounts of white marl; lower part conglomeratic. Underlies North Park Formation in Saratoga Valley. To the west and southwest is called Browns Park Formation. Rawlins area--White massive soft tuffaceous sandstone; Central Wyoming: White soft tuffaceous sandstone. Locally derived conglomerate in upper and lower parts of sequence; in places lower conglomeratic sequence may be of Oligocene age. In Granite Mountains K/Ar age of tuff in lower part of sandstone sequence about 17 Ma and fission-track age of lower conglomerate about 24 Ma.
State Wyoming
Name Miocene Rocks
Geologic age Phanerozoic | Cenozoic | Tertiary | Miocene
Primary rock type sandstone
Secondary rock type conglomerate
Other rock types claystone
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Tuffaceous)
Minor
Unconsolidated > Marl
Sedimentary > Clastic > Mudstone > Claystone
Sedimentary > Clastic > Conglomerate
Igneous > Volcanic (Pyroclastic, tuff)
Incidental
Sedimentary > Carbonate > Marlstone
Map references
Love, J.D. and Christiansen, Ann Coe, 1985, Geologic Map of Wyoming: U.S. Geological Survey.
Unit references
Love, J.D. and Christiansen, Ann Coe, 1985, Geologic Map of Wyoming: U.S. Geological Survey.
Counties Carbon - Fremont - Natrona - Sweetwater