Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska

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Frequently anticipated questions:


What does this data set describe?

Title:
Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska
Abstract:
Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska, Preliminary Interpretive Report 2025-2, presents bedrock geologic mapping of a 7,988-sq-km (3,084-sq-mi) area north of the Richardson and Alaska highways between the communities of Salcha and Dot Lake in the Yukon-Tanana Uplands (YTU) of eastern Interior Alaska. The project's goals are: to better understand the geologic framework of known mineralization, to support the exploration and discovery of new mineral resources in the area, and to build scientific understanding of the geology of the YTU, one of Alaska's most active and important mineral belts. The project area has been a focus of gold exploration for several decades but also has additional significance for its potential to host critical minerals such as antimony, bismuth, tellurium, and tungsten. Project work was completed by Alaska Division of Geological & Geophysical Surveys (DGGS) staff and collaborators during the 2022 and 2023 summer field seasons and draws on additional published and unpublished work completed during prior years by DGGS, University of Alaska, and U.S. Geological Survey staff. The project area is divided into four geologic map sheets, listed from east to west: the Mount Harper-Middle Fork area, the Volkmar River-Healy River area, the Goodpaster River-Shaw Creek area, and the Richardson Mining District. The map units used across the four maps are described in this report. The complete report, geodatabase, and ESRI fonts and style files are available from the Alaska Division of Geological & Geophysical Surveys website: http://doi.org/10.14509/31648.
Supplemental_Information:
This geodatabase is organized according to the AK GeMS mapping schema Hendricks, M.D., Macpherson, A.E., Athey, J.E., Wyatt, W.C., Montayne, Simone, Buchanan, Wes, Rivera, P.G., and Steinleitner, A.M., 2024, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 170 v. 2, 13 p. https://doi.org/10.14509/31172. The distribution package includes ESRI fonts and style files, along with usage instructions. Further documentation of the symbology is provided by Ekberg, P.G., Hendricks, M.D., and Athey, J.E., 2021, AK GeMS symbology: A description of the AK GeMS style file: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 169, 7 p. 63.599164
  1. How might this data set be cited?
    Twelker, Evan, Newberry, R.J., Naibert, T.J., Wypych, Alicja, Gavel, M.M., Barrera, M.L., Szumigala, D.J., Truskowski, C.M., Muller, I.P., Fessenden, S.N., Blackwell, N.J., Harvey, D.A., and Wildland, A.D., 2025, Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska: Preliminary Interpretive Report PIR 2025-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 38 p
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -147.995666
    East_Bounding_Coordinate: -141.298396
    North_Bounding_Coordinate: 65.700812
    South_Bounding_Coordinate: 63.599164
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2022
    Ending_Date: 2026
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: geodatabase
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a vector data set.
    2. What coordinate system is used to represent geographic features?
      The map projection used is Alaska Albers.
      Projection parameters:
      Standard_Parallel: 55.0
      Standard_Parallel: 65.0
      Longitude_of_Central_Meridian: -154.0
      Latitude_of_Projection_Origin: 50.0
      False_Easting: 0
      False_Northing: 0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0000000030536018158500163
      Ordinates (y-coordinates) are specified to the nearest 0.0000000030536018158500163
      Planar coordinates are specified in meters
      The horizontal datum used is NAD83.
      The ellipsoid used is GRS 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222101.
  7. How does the data set describe geographic features?
    mount_harper_ak_gems_db
    Geodatabase, layer files, style files, and fonts (Source: DGGS)
    mount_harper_gems_db
    Geodatabase, layer files, style files, and fonts (Source: DGGS)
    mount_harper_gems_geopackage
    SQLite Database file (Source: DGGS)
    mount_harper_gems_shapefile
    Shapefiles and open data files (Source: DGGS)

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    We would like to thank Sean P. Regan and Melanie B. Werdon for thorough and constructive reviews of the geologic maps and accompanying map unit descriptions in this pamphlet. We gratefully acknowledge Doyon, Limited for access to its lands within the study area. Work in the Richardson Mining District benefited greatly from reports and information generated by exploration companies, current and former, that have worked in the area over the past three decades. In particular, we acknowledge the assistance of Dennis McDowell and Great American Minerals Exploration, Inc. (GAME), Peter Grieve and Koza Limited, Bill Cronk and Northern Empire Resources Corp., Phil St. George and Millrock Resources, and David Wright of Aurora Resource Exploration. This project was jointly funded by the State of Alaska and the U.S. Geological Survey Earth Mapping Resources Initiative (Earth MRI) through cooperative agreement G22AC00288. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Geological Survey. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey Conner Truskowski compiled the data into into the GeMS format and provided cartographic support. Ally M. Steinleitner quality controlled, and then finalized the GeMS database.
  3. To whom should users address questions about the data?
    Alaska Division of Geological & Geophysical Surveys
    GIS Manager
    3354 College Rd
    Fairbanks, AK
    USA

    907-451-5020 (voice)
    dggsgis@alaska.gov
    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays

Why was the data set created?

The Mount Harper bedrock geologic map seeks to understand the geologic framework of known mineralization, facilitate the exploration and discovery of new mineral resources, and advance scientific understanding of the YTU - one of Alaska's most dynamic and economically significant mineral belts. While gold exploration has been the primary focus in this area for several decades, its potential to host critical minerals such as antimony, bismuth, tellurium, and tungsten further elevates its importance.

How was the data set created?

  1. From what previous works were the data drawn?
    Hendricks, M.D. and others, 2024 (source 1 of 3)
    Hendricks, M.D., Macpherson, A.E., Athey, J.E., Wyatt, W.C., Montayne, Simone, Buchanan, Wes, Rivera, P.G., and Steinleitner, A.M., 2024, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Miscellaneous Publication MP 170 v. 2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 13 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
    Macpherson, A.E. and others, 2024 (source 2 of 3)
    Macpherson, A.E., Hendricks, M.D., and Athey, J.E., 2024, AK GeMS Symbology: A description of the AK GeMS Style File: Miscellaneous Publication MP 169 v. 2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 6 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
    U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020 (source 3 of 3)
    U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic maps: Techniques and Methods TM 11-B10, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 1 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
  2. How were the data generated, processed, and modified?
    Date: 2023 (process 1 of 2)
    Geologic mapping - The Alaska Division of Geological & Geophysical Surveys (DGGS) Mineral Resources Section staff and collaborators conducted bedrock geologic mapping of 7,988-sq-km (3,084-sq-mi) for the Mount Harper-Richardson project in the Yukon-Tanana Uplands (YTU) of eastern Interior Alaska during the 2022 and 2023 summer field seasons. Staff collected 3,178 rock stations, 407 geochemical samples, and 68 geochronology samples over 457 person-days of fieldwork. The Mount Harper-Richardson project includes four map areas with bedrock geology mapped at 1:100,000 scale.
    Date: 2026 (process 2 of 2)
    GIS analysis and digital cartography - This data distribution package's geologic and geographic features were organized and attributed according to the AK GeMS geologic mapping schema. The data were programmatically transformed to provide download options in three formats: (1) an AK GeMS data package that includes the complete AK GeMS database and associated files, (2) a GeMS data package that is a conversion of the AK GeMS database into the base GeMS standard published by the USGS, and (3) a shapefile data package that includes two simple shapefile representations of the data. Data sources used in this process:
    • Hendricks, M.D. and others, 2024
    • Macpherson, A.E. and others, 2024
    • U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020
  3. What similar or related data should the user be aware of?
    Buchanan, J.W., Wypych, Alicja, Barrera, M.L., Biegel, J.M., Gavel, M.M., Harvey, D.A., Ketcham, R.A., Muller, I.P., Naibert, T.J., Newberry, R.J., Regan, S.P., Szumigala, D.J., Twelker, Evan, and Wildland, A.D., 2025, Geochemical data from samples collected in 2023 for the Chena and Mount Harper projects, Big Delta, Circle, Fairbanks, and Eagle quadrangles, Alaska: Raw Data File RDF 2024-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 5 p
    Gavel, M.M., Twelker, Evan, Wypych, Alicja, Naibert, T.J., Newberry, R.J., Szumigala, D.J., Wildland, A.D., Barrera, M.L., Biegel, J.N., Harvey, D.A., Ketcham, R.A., Muller, I.P., and Regan, S.P., 2023, Field station locations and magnetic susceptibility data for the Chena-Pogo and Mount Harper projects, Big Delta and Circle quadrangles, Alaska, collected June-September 2023: Raw Data File RDF 2023-27, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Gavel, M.M., Twelker, Evan, Wypych, Alicja, Naibert, T.J., Newberry, R.J., Szumigala, D.J., Wildland, A.D., Barrera, M.L., Blackwell, N.J., Fessenden, S.N., Harvey, D.A., and Muller, I.P., 2023, Field station locations and magnetic susceptibility data collected in 2022 for the Mount Harper project, Eagle, Big Delta, and Mount Hayes quadrangles, Alaska: Raw Data File RDF 2023-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Truskowski, C.M., Heizler, M.T., Naibert, T.J., Newberry, R.J., Twelker, Evan, and Szumigala, D.J., 2025, 40Ar/39Ar geochronology data from the Big Delta, Eagle, and Mount Hayes quadrangles, Alaska: Raw Data File RDF 2025-11, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 21 p
    Wypych, Alicja, Twelker, Evan, Naibert, T.J., Gavel, M.M., Newberry, R.J., Szumigala, D.J., Wildland, A.D., Barrera, M.L., Harvey, D.A., Muller, I.P., Fessenden, S.N., and Blackwell, N.J., 2023, Geochemical data from samples collected in 2022 for the Mount Harper geologic mapping project, Big Delta, Mount Hayes, and Eagle quadrangles, Alaska: Raw Data File RDF 2023-24, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Attribute fields within each feature class are populated using the map symbology and corresponding applicable values from the GeMS and AK GeMS specifications. When known, certainty in attribute interpretation is indicated in the relevant fields. Attribute accuracy varies throughout the map and is scale-dependent.
  2. How accurate are the geographic locations?
    Certainty in feature boundaries or location varies throughout the map. Data fields within each feature class and the accompanying orientation and location confidence lookup tables record the authors' degree of confidence in the location of applicable features.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This publication is a DGGS Preliminary Interpretive Report (PIR). A PIR provides timely release of maps and reports with a preliminary interpretation of geology or analytical data. Several scientists familiar with the geology of map area reviewed this product for general readability and logical consistency, but it has not undergone technical peer review.
  5. How consistent are the relationships among the observations, including topology?
    All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Use_Constraints:
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  1. Who distributes the data set? (Distributor 1 of 1)
    State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
    3354 College Road
    Fairbanks, AK
    USA

    907-451-5020 (voice)
    907-451-5050 (FAX)
    dggspubs@alaska.gov
    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our website (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
  2. What's the catalog number I need to order this data set? PIR 2025-2
  3. What legal disclaimers am I supposed to read?
    The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity, whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requestor or anyone else exceed the fee paid for the electronic service or product.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 28-May-2025
Metadata author:
Simone Montayne
3354 College Road
Fairbanks, AK
USA

907-451-5020 (voice)
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.50 on Thu Aug 14 15:35:06 2025