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.