WSGS Groundwater Group
Aquifer Systems in Wyoming
Aquifer systems in Wyoming can occur as any of the following.
- Unconsolidated deposits overlying bedrock formations. These may consist of river alluvial deposits, terrace deposits, eolian sand/silt deposits, glacial deposits, and lacustrine deposits, typically of Quaternary age.
- Volcanic rock formations ranging in age from Eocene to Quaternary. Most are located in northwestern Wyoming, in the Absaroka Mountains and Yellowstone National Park area.
- Upper Tertiary aquifers in Wyoming, including portions of the White River, Browns Park, Salt Lake, Split Rock, Moonstone, Arikaree, and Ogallala formations.
- Lower Tertiary aquifers generally located in Wyoming’s large structural basins. Examples include portions of the Fort Union, Evanston, Pinyon Conglomerate, Hoback, Ferris, Hanna, Wasatch, Green River, Battle Spring, Wind River, Wagon Bed, and Willwood formations.
- Triassic, Jurassic, Lower Cretaceous, and Upper Cretaceous aquifers generally located along the margins of structural basins and in the Overthrust Belt of western Wyoming. Examples include the Nugget Sandstone, Twin Creek Limestone, Muddy Sandstone, Newcastle Sandstone, and Fox Hills Sandstone, and the Chugwater, Jelm, Preuss, Stump, Cloverly, Lakota, Fall River, Bear River, Frontier, Mesaverde, Medicine Bow, Lance, and Ferris formations.
- Paleozoic aquifers commonly located along the flanks of mountain uplifts and in the Overthrust Belt of western Wyoming. Examples include the Casper Formation, Tensleep Sandstone, Madison Limestone, Hartville Formation, and Bighorn Dolomite.
- Precambrian aquifers commonly exposed at the ground surface in the cores of large mountain uplifts. These include both granitic and metamorphic crustal bedrock formations.