NEWS RELEASE: Wyoming Geological Survey Summer 2017 Newsletter

Wyoming State Geological Survey Geo Notes banner image

Interpreting the past, providing for the future - summer 2017 newsletter

Exchanging office setting for field work

Erin Campbell and Jacob Carnes at Lake Owen, looking at Lake Owen Mafic complex.
WSGS geologists Erin Campbell and Jacob Carnes look at the Lake Owen Mafic complex during a field day at Lake Owen in southeast Wyoming.

If you stop by the WSGS office on a summer day, chances are some, if not all, staff geologists are away. That is because once temperatures warm and the last snowflake flies, desks and computers in their offices are set aside for a field notebook, GPS, compass and good hiking boots for rural terrain.

Field work is one of the most challenging, yet rewarding, aspects of being a WSGS geologist.

“The best part about field work is being able to figure out the puzzle,” says geologist Ranie Lynds. “Those ‘aha’ moments can come when mapping, when stumbling upon a key outcrop or when plotting or summarizing the data back in the office.”

Given Wyoming’s long winters and unpredictable falls and springs, geologists cram their summer months with field work, averaging 20 to 25 days. Depending on the project, it may be a 30-minute drive to the site or several hours, resulting in staying over in nearby towns or pitching a tent.

Regardless of the location, the purpose is the same – investigate rocks, such as outcrops, unconsolidated sediment, water or other geologic features.

“Field work is an essential part of any natural science,” WSGS geologist Jacob Carnes said.

This summer, teams of geologists are gathering data in the field to map quadrangles mainly in the southern and central portions of the state. The work is part of Statemap through the National Cooperative Geologic Mapping program. The primary objective of this program is to establish the geologic framework of areas vital to the welfare of individual states.

"Sometimes field work is the project, such as Statemap where we have a deliverable of a map,” says Lynds. “However, most of the time field work is in addition to  but an integral part of  a project and necessary to complete the project.”

Carnes says nearly every project he has worked on at the WSGS has involved field work in some capacity.

“For many of the mineral investigations we have completed over the last five years, such as rare earth elements, zeolites and phosphates, we have done field work to identify and describe specific mineral occurrences and to collect samples. This needs to be done before any lab analyses can be completed,” he explains. “Even for projects that are entirely office-based for Survey staff, like the geochronology map, we rely on field work and mapping of other geologists.”

A typical day in the field starts by being on site at about 8 a.m.

“Generally, we park the truck and start walking. We walk all day, measuring and describing rocks and outcrops as we go along,” Lynds says.

Geologists, including contractors hired for specific projects, return to their vehicle around 4-5 p.m. after walking five to eight miles. The long days are regardless of weather, including heat and snow. There’s also rattlesnakes to watch for, mud to avoid and hours of hiking that don’t always end with finding out the answer geologists are looking for.

“A lot of time, especially early in mapping projects, can be spent in utter confusion, which can be compounded with other factors like poor weather or physical exhaustion,” Carnes says.

Some projects require additional steps. For example, Carnes said this summer’s work on the Foxpark quadrangle in southeast Wyoming has involved more scouting of the area in their field vehicle to identify access and areas with good outcrops. This is due to dense vegetation.

But it’s critical to see the rocks in person.

“It is nearly impossible to understand a formation without seeing the rocks,” Lynds explains. “This allows the geologist to make his or her own interpretation of the depositional environment or the reason for mineralization, etc. Without field work, this could be blind guessing.”

Carnes agrees.

“It allows us to observe geologic features and relationships in their natural environment,” he adds. “It’s impossible to fully understand any given rock without information of its geologic context.”

Both Lynds and Carnes say it’s impossible to note the best areas to spend field days.

“Wyoming is a geologic wonderland. It is great pretty much anywhere,” Lynds says.

Ranie Lynds
WSGS geologist Ranie Lynds collects samples from the Mesaverde Group for detrital zircon U-Pb geochronology during recent field work in the Fort Steele quadrangle near Rawlins.

Northeast river basins groundwater technical memorandum

The river basins of northeastern Wyoming are among the most important drainages in the state; they collectively contain one quarter of the state’s surface area and much of its energy resources. The northeast river basins include the drainages of the Little Bighorn, Tongue, Powder, Little Powder, Belle Fourche, Little Missouri, Cheyenne and Upper Niobrara rivers.

Under contract to the Wyoming Water Development Office (WWDO), WSGS hydrologist Karl Taboga is developing a groundwater technical memo that defines the geographic extents of the area’s important aquifers and describes their hydraulic and chemical properties, recharge areas and estimated recharge rates. The project also identifies existing groundwater studies and future groundwater development opportunities to satisfy projected agricultural, municipal and industrial demands.

The technical memo represents an intensive collaborative effort among water resource professionals from the WSGS, the WWDO and the USGS. Additional contributors include the Wyoming State Engineer’s Office, the Water Resources Data System at the University of Wyoming, the Wyoming Department of Environmental Quality and the Wyoming Oil and Gas Conservation Commission.

Like previous river basin studies by the WSGS, this technical memorandum will provide the people of Wyoming with the most current and complete compilation of groundwater information available in a format that is understandable to water professionals and lay persons alike.

This report is scheduled to be published in 2018 and will be available on the Wyoming Water Development Office website and through the Wyoming River Basin Plan portal on the WSGS website.

New Wyoming Geochronology Map now available

The WSGS recently launched a geochronology map that presents Wyoming-specific data compiled from published and unpublished sources, in addition to data collected specifically for Survey projects. 

The new map is free to access and is intended to be a starting point for users interested in age data related to Wyoming. Jacob Carnes led the project.

Unconventional reservoir study in PRB

The Wyoming State Geological Survey (WSGS) oil and gas geologist Rachel Toner is investigating production trends from the Turner Sandstone Member of the Carlile Shale in the Powder River Basin. This is the second in a series of unconventional reservoir investigations that will look at how geology, completion techniques and/or a combination of both affect operators’ production. 

Toner published a similar project in May that investigated Codell Sandstone oil production trends in the northern portion of the Denver Basin in Laramie County. The Turner study will mirror the Codell report in its examination of production and completion practices, but will also include additional data collected by the WSGS for its National Coal Resource Data System project (NCRDS). The NCRDS data will be used to create isopach and structure contour maps and help further analyze how the geology of the Turner Sandstone influences hydrocarbon production.

The Turner Sandstone study is slated for completion in 2017. Next, Toner will be looking at the Frontier Formation (Wall Creek Member), Niobrara Formation, and eventually the Parkman, Sussex and Shannon sandstones.

PRB salinity investigation slated for fall completion

Groundwater quality, and subsequently the use(s) for which it is suited, varies widely throughout Wyoming. This is most evident in the large sedimentary structural basins, where the majority of the state’s population resides and the greater part of economic activity occurs. An aquifer may produce high-quality groundwater suited for human consumption at a basin’s margin while water pumped from the same aquifer a few miles basinward may be unfit for livestock usage. One measure of water quality is its “salinity.” Salinity is the amount of dissolved material that remains as residue after the liquid portion of a water sample evaporates.

WSGS hydrologist Karl Taboga is examining the occurrence of saline groundwaters suited to industrial uses at depths of 5,000 feet or less in the Powder River Basin. Industrial use of saline groundwater allows for the conservation of higher-quality waters for domestic, municipal and agricultural users. WSGS completed a similar analysis for the Denver-Julesburg Basin in 2016.

Chugwater quadrangle being mapped

WSGS geoscientists Jim Stafford and Andrea Loveland are spending the summer completing a bedrock geology map for the Chugwater 1:100,000 quadrangle in southeast Wyoming. 

A bedrock compilation effort for the quadrangle began in 2008 by the Survey, portions have been mapped by the U.S. Geological Survey (USGS) for Water Supply Papers and two 1:24,000-scale maps have been published in the northwestern corner.

The team will use these resources to construct a digital bedrock geologic map in an ArcGIS geodatabase. Stafford previously interpreted air photos to refine contact placement, edge-matched with adjacent 1:100,000-scale quadrangles.  Loveland will field check the map area to ground-truth formations and unit contact placement.

The Chugwater quadrangle bedrock map will complete bedrock mapping for the eastern edge of the state and will also complete bedrock mapping of the Denver Basin and High Plains Aquifer areas. Portions of two of Wyoming’s three Ground Water Control Areas are located within the Chugwater quadrangle, which means these well permits undergo additional scrutiny based on the groundwater in the area. Most of the groundwater wells are in unconfined aquifers, making the bedrock geology the primary driving factor in many of these areas. The Denver Basin has also been the subject of increased oil and gas drilling, which may increase as the geology of this region is better understood.