Current Projects

Mapping

STATEMAP Projects

Geologists at the Wyoming State Geological Survey (WSGS) are working on a pair of 1:100,000-scale geologic maps through the U.S. National Cooperative Geologic Mapping Program (STATEMAP) managed by the U.S. Geological Survey.

WSGS geoscientists are working on a pair of 1:00,000-scale bedrock geologic maps through the U.S. National cooperative Geologic Mapping Program (STATEMAP) managed by the U.S. Geological Survey.

The adjacent Red Desert Basin and Rawlins 30' x 60' quadrangles occupy nearly all of the Great Divide Basin, spanning an area between Rock Springs and Rawlins. Contained within both quadrangles are similar geologic units that share a deformation history related to the Laramide orogeny. With the exception of the Rawlins Uplift that hosts rocks that range from 2.6-billion-year-old granite and gneiss to less than 22-million-year-old sedimentary basin fill, most of the mapping area is blanketed by Cretaceous and Paleogene sedimentary strata deposited in shallow marine, nearshore, fluvial, and lacustrine environments.

These maps are key in the WSGS's effort to complete the mapping of Wyoming at the scale of 1:100,000, using modern digital methods following the Geologic Map Schema (GeMS) standards defined by the U.S. Geological Survey and used in most states. Digital maps at this scale are useful for regional geology and regional exploration for oil, gas, and minerals.

Both maps are partially funded through the U.S. Geological Survey’s STATEMAP program and are scheduled to be published in 2025. The WSGS has participated in this and related federal mapping programs for nearly 30 years, and to date has produced more than 160 geologic maps at the 1:24,000 and 1:100,000 scales.

Three Surficial Maps of Quads in Central Wyoming Underway

The WSGS is completing 1:100,000-scale surficial maps for the Riverton, Thermopolis, and Carter Mountain quadrangles in central Wyoming. Carter Mountain, and portions of the Thermopolis and Riverton quadrangles, were mapped previously by James Case and Laura Hallberg. Staff geologists are working to fill in unmapped areas based on available photography and elevation models. Publication of the maps will continue the WSGS initiative to complete 1:100,000-scale surficial mapping across Wyoming.

Minerals

Geochemistry and Geochronology Reconnaissance of the Medicine Bow Mountains

The WSGS is conducting an analytically intensive geochemistry and geochronology reconnaissance project in the Medicine Bows Mountains. The Medicine Bows have high potential for critical mineral deposits vital to U.S. growth and stability. The area’s complex geology, including the juxtaposition of the Archean Wyoming Province with the accreted Colorado Province terranes along the Cheyenne Belt and associated shear zones, multiple episodes of mafic and felsic intrusions, thick packages of metasediments and metavolcanics, possible later metamorphic events, and Laramide uplift, suggest that diverse mineral systems exist within the Medicine Bows.

Historical mining in the area has confirmed the existence of economically viable gold, silver, copper, platinum group elements, and minor uranium and rare earth element deposits. Historical mining efforts also noted the existence of metals now considered critical, the presence of which has been confirmed by subsequent scientific studies. However, geochemical data for the region are not available in a comprehensive public database. Pre-existing data are inconsistent in methodology, elements analyzed, spatial coverage, and public availability.

This project will develop and conduct an exhaustive sampling program to target areas of known and unknown mineralization in shear-hosted veins; layered mafic-ultramafic intrusions and associated felsic intrusions along the Cheyenne Belt; felsic intrusions, pegmatites, and vein systems in the accreted Proterozoic terranes; Precambrian sulfide-rich metasediments and metavolcanics; radioactive paleoplacers; and REE- and uranium-rich pegmatites. The study area encompasses the entire Wyoming portion of the Medicine Bow Mountains—a Precambrian-core Laramide uplift.

This project will directly complement the airborne magnetic and radiometric survey scheduled for summer 2023 in the Medicine Bow and eastern Sierra Madre mountains. The goal is an integrated understanding of the geochemical, structural, petrological, and deformational processes that make up regional mineral systems; this will have the potential to aid mineral exploration efforts not only in the Medicine Bows, but also in areas with a similar geologic history, such as the Sierra Madre range to the west and elsewhere along the trend of the Cheyenne Belt.

Potential critical minerals in the project area: antimony, arsenic, barium, beryllium, bismuth, cobalt, chromium, fluorspar, gallium, germanium, hafnium, indium, magnesium, manganese, nickel, platinum group elements, scandium, tantalum, tellurium, tin, vanadium, zinc, and zirconium.

Medicine Bows—Geophysics

A high-resolution magnetic and radiometric survey, designed to optimize coverage of geologic features of greatest interest, was flown in summer 2023 in the Medicine Bow Mountains. The effort focused on the Lake Owen Complex, a Paleoproterozoic layered mafic intrusion with known PGE mineralization, and the surrounding area that includes the Cheyenne Belt, which marks the southern margin of the Wyoming Province. The survey includes magnetic and radiometric data collected from a helicopter along flight lines spaced no wider than 200 meters and a nominal terrain clearance of 60–120 m. The mineral systems of interest in the survey area include mafic magmatic, magmatic rare earth elements, placer, porphyry Cu-Mo-Au, and volcanogenic seafloor. Potential critical mineral commodities: antimony, arsenic, barium, beryllium, bismuth, cobalt, chromium, fluorspar, gallium, germanium, hafnium, indium, magnesium, manganese, platinum group elements, rare earth elements, scandium, tantalum, tellurium, tin, vanadium, zinc, and zirconium. There is additional potential for silver, gold, cadmium, copper, iron, lanthanum, lead, molybdenum, thorium, uranium, and yttrium.

The resulting data collected from this survey will be released to the public in the coming months.

Please see the U.S. Geological Survey news release for more information about this geophysical survey.

Sierra Madre-Elkhead Mountains-Medicine Bow Mountains—Geophysics

A high-resolution magnetic and radiometric survey is currently being acquired in the greater Sierra Madre-Elkhead Mountains-Medicine Bow Mountains region along the Wyoming-Colorado border. The survey is funded by the USGS Earth MRI and is designed to meet complementary needs related to geologic mapping and mineral resource research. The survey design is coordinated with the WSGS, Colorado Geological Survey, and staff from the National Cooperative Geologic Mapping Program to optimize coverage of geologic features of greatest interest. The survey is also designed to adjoin and augment the Medicine Bow Mountains airborne magnetic and radiometric survey.

The effort is focused on the Cheyenne Belt corridor along the southern margin of the Archean Wyoming Province, a region that contains several known and suspected mineral systems of high interest for their critical mineral potential. There has been abundant past and current exploration and mining, although exploration efforts are hampered by a lack of high-quality geophysical data. Several fundamental questions on the region's structure and Paleoproterozoic tectonomagmatic evolution are also unresolved.

The airborne survey data are further expected to aid mapping of suspected Quaternary faults and elements of the geology important to groundwater resources in the Saratoga Valley. The planned survey includes magnetic and radiometric data collected from a helicopter along flight lines spaced 200 meters and a nominal terrain clearance of 100 m. Parts of the survey area may be suitable for a fixed-wing aircraft.

The mineral systems of interest in the survey area include Climax-type, mafic magmatic, magmatic rare earth elements, placer, porphyry copper-molybdenum-gold, and volcanogenic seafloor. Potential critical mineral commodities: antimony, arsenic, beryllium, bismuth, cobalt, chromium, fluorspar, hafnium, gallium, germanium, indium, magnesium, manganese, nickel, niobium, platinum group elements, rare earth elements, scandium, tantalum, tellurium, tin, vanadium, and zirconium. There is additional potential for cadmium, copper, gold, iron, molybdenum, lead, selenium, silver, vermiculite, and uranium.

Western Phosphate Field—Geochemistry

The WSGS is part of a four-state cooperative effort, administered by the Idaho Geological Survey and funded by the USGS Earth MRI program, to evaluate the enrichment of critical minerals in the Permian Phosphoria Formation. Exposures of this formation occur across 350,000 square kilometers in Idaho, Utah, Wyoming, and Montana, and it is one of the largest commercial resources of phosphate rock in the world. Mining of the Phosphoria Formation in this region, referred to as the Western Phosphate Field, has provided phosphorus for the fertilizer industry since the early 1900s.

The Phosphoria Formation formed within a marine chemocline system, and includes a succession of black organic-rich mudstones, siltstones, phosphorites, carbonates, and cherts deposited 265 million years ago on the western margin of North America. The richest phosphate deposits are in the Meade Peak and Retort members, which both display considerable lithologic and stratigraphic variability. Previous studies have shown that elevated levels of rare earth elements and other critical minerals are concentrated within phosphorites and black shales in these two members.

The project centers on collecting new geological and geochemical data primarily from the Meade Peak and Retort members. Data are being acquired along measured stratigraphic sections in the context of a basinwide framework and at locations considered strategic from a mineral resource or scientific standpoint (for example: suitable outcrops, mine exposures, and archived drill core). The objective is to construct geologic models that assess and delineate the critical mineral resource potential of the Western Phosphate Field in order to provide an enhanced understanding of marine chemocline mineral systems. Potential critical minerals in project area: chromium, fluorine, rare earth elements, and vanadium.

South Pass and Granite Mountains—Geophysics

A high-resolution magnetic and radiometric survey in the greater South Pass-Granite Mountains region in central Wyoming is now complete. The survey was designed to optimize coverage of geologic features of greatest interest and meet complementary needs related to geologic mapping, mineral resource research, and mapping of Quaternary faults.

The effort focuses on the areas encompassing and surrounding the Oregon Trail Structural Belt, which may represent the largely obscured boundary between the Beartooth-Bighorn magmatic zone and the southern accreted terranes. This region contains several known and suspected mineral systems of high interest for their critical mineral potential, and has been the subject of abundant past and current exploration and mining.

The area covers the South Pass-Atlantic City region, Rattlesnake Hills, Granite Mountains, and the Seminoe-Ferris mountains. Additionally, the airborne survey data are expected to aid in mapping and investigations along the North and South Granite Mountains faults, the Continental Fault, and other suspected Quaternary faults. The survey includes magnetic and radiometric data collected from a helicopter along flight lines spaced 200 meters and a nominal terrain clearance of 100 meters.

The mineral systems of interest in the survey area include alkalic porphyry, mafic magmatic, magmatic REE, metamorphic graphite, meteoric convection, orogenic gold, porphyry Cu-Mo-Au, and volcanogenic seafloor. Potential critical mineral commodities: aluminum, antimony, arsenic, barium, beryllium, bismuth, cobalt, chromium, fluorspar, gallium, germanium, graphite, hafnium, indium, manganese, niobium, nickel, platinum group elements, rare earth elements, scandium, tantalum, tin, tungsten, vanadium, zinc, and zirconium. There is additional potential for cadmium, copper, gold, iron, lead, mercury, molybdenum, phosphorus, selenium, silver, thorium, and yttrium.

The resulting data collected from this survey was released in February 2024.

Please see the U.S. Geological Survey news release for more information about this geophysical survey.

Water

Tensleep Sandstone Aquifer

WSGS hydrology staff have embarked on a compilation project focused on the Tensleep Sandstone aquifer—an important aquifer in Wyoming.

“One of the goals of this project is to gather in one place what is known about the Tensleep aquifer,” says WSGS hydrogeologist, Kurt Hinaman.

The Tensleep and its equivalent geologic formations occur statewide east of the Overthrust Belt and the Absaroka Range. They supply drinking and stock water along many basin margins in Wyoming. Additionally, the Tensleep is a reservoir for oil, and is one of the target aquifers in deep basins for the sequestration of carbon dioxide. Data about the Tensleep aquifer that will be covered in the publication include groundwater quality, porosity, permeability, surface recharge, oil field water injection, and oil field water production.