Geologic Mapping

A geologic map displays the placement, distribution, characteristics, and age relationships of rock units, along with structural features, on a two-dimensional base map. Consequently, geologic maps are fundamental tools for locating, describing, and evaluating mineral, energy, and water resources. Geologic maps also show geologic hazards (such as fault zones, landslides, and flood plains) and are used extensively in land planning and development. These maps represent a geologist’s unique interpretation of the geology and geologic history of a locality. Scale, complexity, and subject can all vary from map to map.

Alan mapping along the foothills of the Bighorn Mountains
Alan Ver Ploeg mapping along the foothills of the Bighorn Mountains

  • Geologic Map of Wyoming
  • What We Do

    The geologic mapping and regional geology specialists at the Wyoming State Geological Survey (WSGS) investigate and provide information on the general geology, structural geology, and stratigraphy of Wyoming. These specialists have two main goals: (1) creating, compiling, and releasing new geologic mapping; and (2) disseminating data derived from existing geologic mapping, reports, and investigations. They prepare geologic maps within the framework of regional geology, a function essential to detailed studies of specific areas and the exploration, evaluation, and development of Wyoming’s mineral, energy, and water resources. Current WSGS geologic mapping projects address our long-range plan and serve three primary goals:

    1. Producing geologic maps to ensure and encourage responsible development of coalbed natural gas (CBNG) and associated ground and surface water protection needs in Wyoming;
    2. Mapping the more populated areas of the state to assist city and county planners in siting and land-use planning by providing geologic, hydrogeologic, and mineral resource information to ensure and encourage responsible development; and
    3. Mapping to characterize and assess mineral resources, to better understand geologic and hydrogeologic systems, and to advance scientific investigations and knowledge of Wyoming’s geology, thereby encouraging responsible use and conservation of the state’s energy and mineral resources.

    Projects

    Mapping projects that address these three goals are currently underway. The WSGS has finished 15 digital bedrock geologic maps and 15 digital surficial geologic maps at the 1:100,000 scale for northeastern Wyoming, including the Powder River Basin and surrounding area. This mapping effort supports both conventional oil and gas and CBNG activities. The WSGS also uses this mapping in a regional hydrologic/aquifer characterization study (see the Powder River Basin IMS). A new WSGS mapping project, initiated in June 2007, will support a regional aquifer/stratigraphic framework study pertaining to oil and gas exploration and development (including CBNG) in southwestern Wyoming. Mapping of surficial geologic deposits and geologic hazards in west-central Wyoming will aid planning and development along the Wind River Mountain front. The WSGS also plans to produce a bedrock geologic map of the Lander quadrangle to support exploration for and development of a number of industrial minerals, metals and precious stones, and water resources (to see all published WSGS mapping, visit the Online Store).

    Bedrock geologic map of Casper Mountain (from the Casper 1:100,000-scale Quadrangle, 2004. Map Series (MS) 65, WSGS publications).
    Bedrock geologic map of Casper Mountain (from the Casper 1:100,000-scale
    Quadrangle, 2004. Map Series (MS) 65, WSGS publications).

    Geologic Mapping at the WSGS

    A Brunton compass, protractor, rock hammer, and topographic maps will always be indispensable to a geologist, but today’s field gear also includes GPS units, laptops, complex drafting programs, and various tools used for remote sensing such as aerial photos and stereoscopes. These tools help WSGS geologists make the most precise geologic maps possible. All of the geologic maps at the WSGS are produced digitally using ArcGIS (Version 9.3, 10), allowing for easy and near-instantaneous map updates and revisions.

    STATEMAP Program

    Gardener Mountain anticline

    Since 1995, the WSGS has worked in conjunction with the federally-funded STATEMAP program. The STATEMAP Program (STATEMAP grant fact sheet), part of the U.S. Geological Survey’s National Cooperative Geologic Mapping Program (NCGMP), has significantly expanded and driven the mapping efforts of the WSGS. The WSGS has completed 94 map products (79 quadrangles at 100k and 15 quadrangles at 24k) using funding from the STATEMAP program (Index of maps completed under STATEMAP grant). The Mapping Group aims to map the entire state of Wyoming at the 1:100,000 scale, map areas of special interest at the 1:24,000 scale, and seam the 1:100,000-scale maps together to create a new bedrock geologic map of the entire state. The geologists working on geologic mapping and regional geology at the Wyoming State Geological Survey (WSGS) investigate and provide information about the general geology, structural geology, and stratigraphy of Wyoming. Geologists focus on one of two areas: (1) creating, compiling, and publishing new geologic maps; or (2) interpreting and disseminating data derived from existing geologic maps, reports, and investigations. When combined with a thorough understanding of Wyoming’s regional geology, geologic maps provide an essential foundation for detailed studies of specific areas, and for the exploration, evaluation, and development of Wyoming’s mineral, energy, and water resources. Geologic mapping and regional geology serve as a basis for many of the cooperative projects the WSGS undertakes.