2 new geologic maps published

Geologists completed two mapping projects this summer, one of which focuses on geologic hazards while the other characterizes the study area’s mineral and energy resources.

The preliminary surficial geologic map of the east half of the Jackson Lake 30' x 60' quadrangle highlights the Quaternary geology and geologic hazards in the area east of Jackson Hole. The map completes a larger effort of 1:100,000-scale mapping in the area. The Wyoming State Geological Survey (WSGS) last year mapped the west half of the quadrangle, which also focused on a better understanding of the region’s geologic hazards and Quaternary geology.

Read more about the east half of the Jackson Lake quadrangle map in the news release.

The preliminary geologic map of the Oil Mountain quadrangle, near Casper, provides updated information about the area’s stratigraphy and geologic structure, as well as potential resources of oil and gas, heavy-mineral sands, coal, uranium, bentonite, aggregate, and groundwater.

Read more about the Oil Mountain map in the news release.

The maps were completed using funding from the U.S. Geological Survey’s STATEMAP Program. The program is part of the National Cooperative Geologic Mapping Program. Geologists are in the field this summer gathering data for new maps funded through the program. Read about these projects below.

Teapot Sandstone of the Mesaverde Formation on the Oil Mountain quadrangle.

Summer fieldwork for new maps underway

This summer, WSGS geologists are working on two 1:100,000-scale geologic maps of quadrangles in western Wyoming, as well as a 1:24,000-scale geologic map in the southern part of the state. The projects are part of the U.S. National Cooperative Geologic Mapping Program (or STATEMAP) but involve different work and objectives. 

The first map will detail the surficial geology of the west half of The Ramshorn 30' x 60' quadrangle in Fremont and Park counties. The quadrangle encompasses portions of the northern Wind River Range, northwestern Wind River Basin, and southern Absaroka Range.

Generating data about landslides is a goal of the project. The Ramshorn quadrangle is in one of the most landslide-prone regions in the state; U.S. Highway 26/287 runs through the quadrangle between Dubois and Moran and has been damaged by unstable slopes in recent times.

The project will also provide detailed mapping of glacial, alluvial, and other surficial deposits that will contribute to understanding the regional Quaternary geologic history.

The Ramshorn quadrangle is one of two remaining 30' x 60' quadrangles in Wyoming without 1:00,000-scale surficial geologic mapping. This project will contribute to the WSGS’s long-term goal to map the entire state’s surficial geology at this scale.

The second mapping project underway this summer is of the Firehole Canyon 30' x 60' quadrangle in Sweetwater County, Wyoming; Daggett County, Utah; and Moffat County, Colorado. This map will be a compilation of the quadrangle’s bedrock geology. The project requires compiling previously published maps and converting more detailed mapping to a 1:100,000 scale.

The map will provide geologic data relevant to the economic resources within the southern Greater Green River Basin.

Geologists are also mapping the Phantom Lake 7.5' quadrangle in Carbon County. The mapping area is on the western flank of the Medicine Bow Mountains, about 17 miles southeast of Saratoga. This project continues the WSGS’s larger effort to map the mining districts in the Medicine Bow Mountains and will focus on documenting mineralization related to trends in regional structure and lithology.

Extensive geochronology and geochemical analysis of units within the map area will assist in identifying mineralization and potential deposits of critical and economic minerals and better establish age relationships between the Precambrian units. The final product will compile, refine, and contribute to previous mapping efforts in the area and will be published as a map series.

The three maps, once published, will be among more than 150 maps the WSGS has produced in the nearly three decades of involvement with the STATEMAP program.

WSGS geologist Kelsey Kehoe maps the Phantom Lake quadrangle.

Staff spotlight: Jim Rodgers

A series recognizing staff and their contributions

Jim Rodgers—Geologic Support, 16.5 years

What do you do at the WSGS? I support staff geologists on a wide range of projects. This might include data collection, software support, report layout, digitizing maps and well logs, and preparing figures for reports.  

What makes your job interesting? The thing that makes my job interesting is that I get to work on different types of projects with different geologists. One week I might work on an oil and gas project; the next week I am working with the geohydrologist on a water project. I am always learning something new and interesting about Wyoming’s geology.

What are some of your favorite geologic features in Wyoming and why? I would have to say areas in southwest Wyoming. This includes the Killpecker sand dunes of the Red Desert and the Flaming Gorge area. I grew up camping and fishing in these areas with my family and fell in love with the geology of the area at a young age.

Director's corner: Continental Divide

The summer heat may have some of us dreaming of a trip to a place with a nice cool ocean breeze, but to which ocean—west to the Pacific or east to the Atlantic? You could follow one of the many rivers that flow from Wyoming, because most of them eventually join the Pacific or Atlantic, depending on which side of the Continental Divide the river started.

The Continental Divide is a topographic hydrological feature (and an imaginary line shown on maps) that separates rivers traveling west to the Pacific from those going east and south to the Atlantic and the Gulf of Mexico. The Divide extends from northern Alaska (at the Bering Strait) to the tip of South America at the Strait of Magellan, passing through Wyoming from the northwest corner of the state to the southeast.

Two notable features on the Continental Divide in Wyoming are the Parting of the Waters and the Great Divide Basin.

The Parting of the Waters is at Two Ocean Pass, about 40 miles north of Moran in the Teton Wilderness. In this high-mountain meadow, North Two Ocean Creek splits into Pacific Creek and Atlantic Creek. The waters of Pacific Creek travel 1,353 miles to the Pacific Ocean via the Snake and Columbia rivers. Atlantic Creek water flows into the Yellowstone, Missouri, and Mississippi rivers to reach the Gulf of Mexico 3,488 miles downstream.

Here, fish can swim across the Continental Divide, moving from one side to the other. Biologists have found that Snake River cutthroat native to the Pacific drainage entered the Yellowstone River and Yellowstone Lake on the Atlantic side of the Divide by traveling through Two Ocean Pass. Recent research indicates that lake trout may have taken this same route to Yellowstone Lake. Because of its uniqueness the location was designated as a National Natural Landmark in 1965.

A more easily accessible location along the divide is the Great Divide Basin in southern Wyoming. The basin is in the Red Desert region, stretching from South Pass south to the Sierra Madre Range. Interstate 80 enters the Great Divide Basin just west of Rawlins and exits where it crosses the divide again near exit 154.

The Great Divide Basin is an “endorheic basin,” which means that none of the water within it drains to either ocean. It is an arid area of ephemeral streams, which flow only briefly and typically after rainfall, and alkali lakes with high concentrations of salts due to water evaporation and limited outflow. In the 1870s, travelers following the Oregon Trail and Overland Trail went around the basin, instead taking routes with fresh water at South Pass and Bridger Pass, respectively. Even today, hikers on the Continental Divide Trail are warned about the Great Divide Basin and advised to carry extra water to cross those 120 miles of high-desert trail.

There are many ways to beat the heat this summer. If a trip to the ocean is not in the cards, perhaps taking out a map, locating the Continental Divide, and visiting the headwaters of those paths to the ocean could be an alternative.

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

Interactive map shows state's geothermal resources

A new WSGS interactive map depicts Wyoming’s geothermal groundwater systems and other geothermal data for the state. Layers on the Wyoming Geothermal Map include an inventory of hot springs, wells, geothermal systems, and borehole bottom temperatures. Modeled estimates of geothermal potential and groundwater temperatures are included as well.

The data used on the new interactive map are available from the National Renewable Energy Laboratory, U.S. Geological Survey, Southern Methodist University Geothermal Laboratory, and WSGS.

Response to the online map has been positive, with more than a thousand views since it was launched at the start of summer. The map is free to use and will be updated periodically as new information becomes available.

Read more about the online map in the news release.