NEWS RELEASE: Wyoming Geological Survey Winter 2021 Newsletter

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Interpreting the past, providing for the future - winter 2021 newsletter

Geologists discover unmapped portion of Greys River fault, report of findings underway

Wyoming State Geological Survey (WSGS) geologists are preparing a report focused on an unmapped portion of the Greys River fault in northwestern Wyoming. Geologists had discovered the area while mapping the surficial geology in the Jackson 30' x 60' quadrangle in 2016.  

The WSGS revisited the unmapped northern extent of the Greys River fault in 2019 to conduct an in-depth study as part of a larger mapping project. Additional aerial photography interpretation, field investigation, and high-resolution ground models were used to better define the extent and characteristics of the fault. This work resulted in WSGS Open File Report 2020-5, the Preliminary Surficial Geologic and Landslide Maps of the Blind Bull Creek and Pickle Pass Quadrangles, Lincoln County, Wyoming.

The WSGS is currently preparing a Report of Investigations related to the findings of the work completed in 2019. The publication will focus on the previously unmapped section of the fault, describing surface characteristics, geomorphic relationships, and general seismic history. The report will create new information that will be used to model the seismic hazards in the area.

Upper Blind Trail Creek

Fault scarp in part of the newly-mapped section, Upper Blind Trail Creek.

Latest study in groundwater salinity series centers on Greater Green River Basin

The WSGS published a study in December about groundwater salinity in the Greater Green River Basin. The new report is part of an ongoing series led by WSGS hydrogeologist Karl Taboga that focuses on water quality in some of the state’s energy-producing basins.

Groundwater resources are more limited in the Greater Green River Basin than elsewhere in Wyoming, making it important to conserve fresher waters for domestic and agricultural use by using saline water for energy development and mining, whenever possible, says Taboga.

“Salinity” is the amount of dissolved material that remains as residue after the liquid portion of a water sample evaporates. Salinity is one way to determine whether groundwater resources are suited for human or agriculture use. In Wyoming, saline groundwater is encountered most frequently as a byproduct of oil and gas exploration in deep basin aquifers.

Other reports in the salinity series are about the Denver-Julesburg and Powder River basins. The WSGS also published a statewide report regarding saline waters. All reports are available as free downloads from the WSGS website.

Newest information pamphlet details geology in Boysen State Park

Boysen State Park

The WSGS continues adding to the information pamphlets series about geology found in Wyoming’s state parks, the latest focusing on Boysen.

Boysen State Park sits in the middle of the state near Shoshoni and is the southern gateway to Wind River Canyon, which hosts its own unique geologic features. Boysen Reservoir covers most of the park’s grounds. Boysen State Park sits at the northern edge of the Wind River Basin and on the southern flank of the Owl Creek Mountains. Faults, 3-billion-year-old rocks, and the Great Unconformity can also be found in and around the park.

Other Wyoming state park pamphlets available are Buffalo Bill, Glendo, Edness K. Wilkins, Bear River, Keyhole, Guernsey, Seminoe, and Curt Gowdy. The series will conclude with a Hot Springs State Park pamphlet that is nearing publication.

State park pamphlets are free. In addition to the downloadable pamphlets available through the links mentioned above, hard copies can be picked up at the WSGS office on the University of Wyoming campus in Laramie and at park visitor centers.

Staff spotlight: Rachel Toner

Rachel Toner

A series recognizing staff and their contributions 

Rachel Toner—senior oil and gas geologist, 8 years of service 

What do you do at the WSGS: My tasks are pretty varied—they range from characterizing oil and gas reservoirs in the Powder River and Denver basins, to assisting with oil and gas production and price forecasts, to fieldwork and mapping of 1:24,000-scale quadrangles. As part of the WSGS’s participation in the federal EarthMRI initiative, I’ve also been researching Wyoming’s potential critical minerals resources. To support this research, I will be continuing to map and sample in the Medicine Bow Mountains, which has significant metal deposits. I use GIS extensively in all my projects to analyze and organize data and to create maps that spatially display the state’s bedrock and subsurface geology.

What makes your job interesting: I’m very lucky to have a job where I can work on a wide variety of challenging but fun projects, in a state with such diverse geology, and as part of a team of talented coworkers. I’m constantly learning and am never bored!

How does your job help Wyoming: All of my publications, maps, presentations, and direct inquiries have the explicit goal of benefiting the state of Wyoming. By publishing my projects’ geologic data and by creating tools for visualizing and analyzing that data, it hopefully helps spread the word on how important oil, gas, and mineral resources are to Wyoming’s economy.

What are some of your favorite geologic features in the state: There’s amazing geology everywhere in Wyoming, so it’s hard to choose favorites. If pressed, I would say Tongue River Canyon in the Bighorn Mountains, the Fremont Canyon/Alcova reservoir area, and the Leucite Hills volcanics and Flaming Gorge scenic byway in southwestern Wyoming. Closer to home, recent projects have given me an appreciation for the geologic complexity, diversity, and mineral resources of the Medicine Bow Mountains.

Director's corner: Wyoming glaciers

Director's corner take 2

As we brave our way through a Wyoming winter, let's talk about things cold and icy—like glaciers.

Wyoming is home to the largest glacier in the Rocky Mountains and the second largest in the continental United States. Gannett Glacier lies in the Wind River Range in central Wyoming, northeast of Gannet Peak (the highest peak in the state). The glacier is currently about 3.3 square kilometers (1.27 square miles) in area; it was 4.6 square kilometers (1.78 square miles) in 1950, making it a retreating glacier. Glaciers are constantly accumulating ice at their head and melting at their terminus (foot). When the amount of melt is higher than the amount of ice formation, the glacier shrinks and retreats.

There are 38 named glaciers across Wyoming. Most of them are in the Wind River Range, with a few in the Teton and Absaroka ranges. Evidence of past glaciation does, however, exist in many mountainous areas across the state and can be found by looking for clues left by the long-gone glaciers.

Glaciers carve out characteristic U-shaped valleys (an example is Sinks Canyon, near Lander), as opposed to the V-shaped valleys created by rivers. Rocks left behind by glaciers can be distinctive in several ways as well. As glaciers retreat, they leave behind mounds of sediment in features called moraines. This sediment, known as glacial till, can vary widely in composition and size because glaciers pick up everything the ice passes over, including very large boulders. As rocks are carried along within a glacier, they bump and slide past each other. This action can create striations (long linear groves), chatter marks (impact marks), and other evidence of their movement. The rocks in the glacier also grind against one another, creating a fine powder called glacial flour. This glacial flour is very light and stays suspended when it enters glacial lakes and streams. The light reflecting off the particles gives glacial meltwater its characteristic light-blue and green color.

The most scenic features left behind by glaciers are glacial lakes. These lakes can be high in the mountains and are often deep and clear.  As the glaciers receded, they left moraines surrounded by steep mountain terrain. In many cases the moraines trapped water, creating lakes in dramatic alpine settings.  A trip to the high country usually involves a visit to a glacial lake, which we can all look forward to next summer. 

--Dr. Erin Campbell, WSGS Director and State Geologist


In the Absaroka Mountains near the Continental Divide.

Snapshot of state's oil and gas resources in 2020 now available

The Survey’s annual report—Oil and Natural Gas Resources of Wyoming—is now available as a free download from the WSGS website. The four-page publication summarizes major events that occurred in the state’s oil and natural gas industry throughout last year.

Specifically, the report outlines 2020’s supply and demand difficulties, as well as offers a snapshot of where Wyoming is now and where it is going with regard to its largest industry. The summary is accompanied by charts showing U.S. commercial crude oil stocks, natural gas available to the marketplace in underground storage, crude oil and natural gas prices, and a timeline of Wyoming crude oil and natural gas production from 1950 through 2020.

More information about the report can be found in the news release.

More data added to Yellowstone geology interactive map

As the body of scientific data on Yellowstone expands, so too will the Geology of Yellowstone Map. The WSGS recently completed an update to the online map, adding new layers and revising several more to reflect the most current data.

Visitors to the map, developed in 2020, will now find new layers for seismic stations, GPS stations, temperature sensors, tiltmeters, stream gages, and SNOTEL sites (all within the monitoring group); water isotope samples and thermal infrared satellite imagery (thermal features group); and landforms (Quaternary surficial geology group). Additionally, recent data have been incorporated to update the thermal areas and gas samples layers within the thermal features group. The data for these map additions were provided by, among others, the University of Utah, U.S. Geological Survey, National Park Service, and UNAVCO.

The Geology of Yellowstone Map can be accessed through the direct link or via the interactive maps panel on the WSGS homepage. An initial welcome screen explains some of the map functions, after which users are free to explore the more than 100 layers contained in the map.

To learn more about the online map’s 2020 launching, see the news release.

The WSGS earns awards for news releases

The WSGS earned two awards for news release writing at the annual Wyoming Press Association virtual convention in January.

The August news release about a new study of the Upper Cretaceous stratigraphy of the Powder River Basin earned a second-place award. Judges noted the release helped geology seem approachable for those outside the field.

Another second-place win was awarded in the information campaign category for the Survey's news release about the October ShakeOut earthquake drill.

The WSGS is an associates member of the press association, which is primarily composed of members of Wyoming newspapers.

A look back: WSGS publications released last year

Geology of Glendo State Park pamphlet

2019 oil and natural gas summary report

Geology of Buffalo Bill State Park 

Chugwater 30' x 60' quadrangle in Goshen, Platte, and Laramie counties, Wyoming, and Scotts Bluff and Banner counties, Nebraska

STATEMAP geologic maps

Geology of Yellowstone Map

Groundwater salinity in Wyoming

Data release of reprocessed select national uranium resources evaluation program samples in Wyoming

Upper Cretaceous strata in the Powder River Basin: Formation tops database, structure and thickness contour maps, and associated well data

Groundwater atlas update

Geology of Wyoming postcard

Groundwater salinity in the Greater Green River Basin

You asked ...

Is the mineral galena found in Wyoming?

Question: “I love galena! Can you find it in Wyoming?”

Answer from WSGS Bulletin 72: Galena is a sulfide mineral often found with copper, zinc, and silver. It forms soft, lead-gray cubes and masses that have a noticeably high heft. It has subconchoidal fracture and a lead gray streak. Galena has been found in Wyoming, including at the Esterbrook mine in the northern Laramie Mountains. Historical reports indicate that the mine workings intersected 6-ft-wide ore shoots of solid galena. There was a report in 1937 that galena was found with a variety of ore minerals in the Sunlight district in the Absaroka Range. At Black Butte in the Black Hills, minor amounts of galena occur with hemimorphite, minor fluorite, jasper, and wulfenite. A minor amount of agentiferous galena is found at the Albion mine on Copper Hill in the Medicine Bow Mountains. To learn more about galena and where it is found in Wyoming, see page 79 of Bulletin 72.

Questions for “You asked ...” are from social media followers. Be sure to follow the WSGS on Facebook, Instagram, and Twitter for interesting tidbits about Wyoming geology.