Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska

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Frequently anticipated questions:


What does this data set describe?

Title:
Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska
Abstract:
Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska, Professional Paper 1776-A, provides the results of geologic mapping and petrologic analysis of a 68-63 Ma epizonal, composite biotite-granite stock. The pluton consists of two compositionally similar porphyritic biotite-granite phases whose contrasting textures reflect differing emplacement histories. Fractional crystallization of these magmas produced a minor volume of fine-grained residual granite that, although distinctly more felsic, shows limited enrichment in trace elements or volatiles. Mineral deposits in the region are dominated by placer occurrences, likely sourced from vein systems in the surrounding country rocks rather than from hydrothermal activity associated with pluton crystallization. Geologic evidence indicates that the Taylor Mountains pluton formed through partial melting of continental crust in a high heat-flow environment during the waning stages of Late Cretaceous subduction beneath interior Alaska. This map was published by the USGS and has been scanned, digitized, and attributed by DGGS staff. The dataset provides geologic, structural, stratigraphic, and geochronologic information organized according to the GeMS and AK GeMS mapping schemas. The complete report, geodatabase, and ESRI fonts and style files are available from the Alaska Division of Geological & Geophysical Surveys website: https://dggs.alaska.gov/pubs/id/24047.
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. https://doi.org/10.14509/30584
  1. How might this data set be cited?
    Hudson, T.L., Miller, M.L., Klimasauskas, E.P., and Layer, P.W., 2010, Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska: Professional Paper P 1776-A, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 13 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -157.494883
    East_Bounding_Coordinate: -157.338946
    North_Bounding_Coordinate: 60.967378
    South_Bounding_Coordinate: 60.902996
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2005
    Ending_Date: 2025
    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?
    taylor_mountains_pluton_ak_gems_db
    Geodatabase, layer files, style files, and fonts (Source: DGGS)
    taylor_mountains_pluton_gems_db
    Geodatabase, layer files, style files, and fonts (Source: DGGS)
    taylor_mountains_pluton_gems_geopackage
    SQLite Database file (Source: DGGS)
    taylor_mountains_pluton_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?
    Amy E. Macpherson scanned and georeferenced the paper map to digitize geologic features into an AK GeMS database. Ally M. Steinleitner implemented final database quality control and packaging. This geologic map (or report or conversion or product, etc.) was funded by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G24AC00521, 2024, and the State of Alaska General Fund. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.
  3. To whom should users address questions about the data?
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    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 (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.

Why was the data set created?

This dataset provides a modern digital version of the original USGS geologic map of the Taylor Mountains area, enabling broader use of the information in current geologic, land-management, and resource-assessment workflows. By organizing the data into standardized GeMS and AK GeMS formats, it supports consistent interpretation of the region's geologic framework, mineral potential, and tectonic history. Making these data accessible in a GIS-ready form benefits Alaskans by improving the quality of information available for mineral exploration, infrastructure planning, environmental evaluation, and community decision-making.

How was the data set created?

  1. From what previous works were the data drawn?
    Ekberg, P.G. and others, 2021 (source 1 of 3)
    Ekberg, P.G., Hendricks, M.D., and Athey, J.E., 2021, AK GeMS symbology: A description of the AK GeMS style file: Miscellaneous Publication MP 169, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 7 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
    Hendricks, M.D. and others, 2021 (source 2 of 3)
    Hendricks, M.D., Ekberg, P.G., Athey, J.E., Wyatt, W.C., Willingham, A.L., and Naibert, T.J., 2021, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Miscellaneous Publication MP 170, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 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: 2005 (process 1 of 3)
    Geologic mapping - USGS geologists conducted field mapping of the Taylor Mountains area, documenting lithologic units, structural features, and intrusive relationships at detailed map scale. They recorded observations on aerial photographs and topographic bases, collected representative samples, and delineated geologic contacts and structural trends directly in the field. The team integrated field notes, sample data, and photogeologic interpretations to compile the original geologic map that forms the basis of this digital dataset.
    Date: 2025 (process 2 of 3)
    Geologic map conversion - DGGS staff scanned the original USGS paper map at high resolution, georeferenced it to modern coordinate standards, and digitized geologic contacts, structures, and map-unit polygons. They attributed all features following GeMS and AK GeMS schemas and completed quality-control checks for accuracy and schema compliance.
    Date: 2025 (process 3 of 3)
    Data packaging - DGGS organized and attributed the geologic and geographic features according to the AK GeMS schema, then programmatically transformed the data into four distribution formats: (1) an AK GeMS data package containing the full database and supporting files, (2) a GeMS data package converted to the USGS base standard, (3) a SQLite database file, and (4) a simplified shapefile package with shapefile representations of the data.
  3. What similar or related data should the user be aware of?

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 USGS Professional Paper(P), which is the premier series of the USGS. It consists of comprehensive reports of wide and lasting interest and scientific importance, characterized by thoroughness of study and breadth of scientific or geographic coverage.
  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)
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    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 (https://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? P 1776-A
  3. What legal disclaimers am I supposed to read?
    The State of Alaska makes no expressed 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.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 01-Sep-2026
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Attn: Simone Montayne
Metadata Manager
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
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.50 on Tue Sep 01 17:36:34 2026