Geology of the Malaspina District, Gulf of Alaska Tertiary Province, Alaska

Metadata also available as - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
Geology of the Malaspina District, Gulf of Alaska Tertiary Province, Alaska
Abstract:
Geology of the Malaspina District, Gulf of Alaska Tertiary Province, Alaska, Open-File Report 61-101, presents the geology of the Malaspina district within the Gulf of Alaska Tertiary province, one of five maps compiled at a common scale to document an arcuate belt more than 300 miles long and 2 to 40 miles wide in which sedimentary rocks of Tertiary age were exposed or inferred beneath Quaternary deposits and glacial cover. Field studies in this province were conducted intermittently from 1944 to 1960 as part of the U.S. Geological Survey program of petroleum investigations in southern Alaska. The geology shown on two previously published maps of the Malaspina district was combined, revised, and plotted on an updated base, with a geologically complex area in the Samovar Hills also shown on a larger scale insert. Previously published descriptions of bedrock geology and surficial deposits apply to this compilation except where modified by new stratigraphic and structural interpretations. Rocks formerly assigned to a crystalline complex in part of the Samovar Hills were reinterpreted as a volcanic unit of probable Mesozoic age, consistent with correlations in adjoining districts. The crystalline complex north of the Chugach St. Elias fault was considered to include more metamorphosed equivalents of this volcanic unit and possibly older Paleozoic rocks. Newly collected fossils supported a Late Cretaceous age for the Yakutat Group, and rocks previously mapped as an early Tertiary siltstone sequence were reassigned to an undifferentiated sedimentary unit of Paleocene and Eocene age. Surficial deposits previously divided into fourteen units were simplified into four broader map units on the present compilation. 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 DGGS website: https://dggs.alaska.gov/pubs/id/10668.
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?
    Miller, D.J., 1961, Geology of the Malaspina District, Gulf of Alaska Tertiary Province, Alaska: Open-File Report OF 61-101, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 2 sheets, scale 1:96,000
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -141.516243
    East_Bounding_Coordinate: -139.439990
    North_Bounding_Coordinate: 60.400393
    South_Bounding_Coordinate: 59.638655
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1944
    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?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 7
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -141
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.000000
      False_Northing: 0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest .00000001
      Ordinates (y-coordinates) are specified to the nearest .00000001
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD27.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.9786982.
  7. How does the data set describe geographic features?
    malaspina_ak_gems_db
    Geodatabase, layer files, style files, and fonts (Source: DGGS and USGS)
    malaspina_gems_db
    Geodatabase, layer files, style files, and fonts (Source: DGGS and USGS)
    malaspina_gems_geopackage
    SQLite Database file (Source: DGGS and USGS)
    malaspina_gems_shapefile
    Shapefiles and open data files (Source: DGGS and USGS)

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?
    Kinney Engineering, LLC staff used scanned and georeferenced paper maps to digitize geologic features into an AK GeMS database. Chris Wyatt conducted quality control of this digitizing work and completed the creation of the 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?

The purpose of this report was to document the geologic mapping and stratigraphic interpretations of the Malaspina district within the Gulf of Alaska Tertiary province, based on field studies carried out between 1944 and 1960. The report preserved the geologic framework developed during early U.S. Geological Survey petroleum investigations and provided a consolidated record of mapping, unit correlations, and revisions made at that time. By integrating earlier maps, updating unit assignments using information then available, and simplifying surficial categories, the report served as a historical reference for regional geologic research, stratigraphic studies, and the development of geologic mapping practices in southern Alaska.

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: 1960 (process 1 of 2)
    Geologic mapping - Geologic mapping for this compilation was based on field studies completed between 1944 and 1960 as part of U.S. Geological Survey petroleum investigations in southern Alaska. Two previously published maps of the Malaspina district were combined, revised, and transferred to an updated base, with the complex Samovar Hills area shown on a larger scale insert. Published descriptions of bedrock and surficial units were incorporated except where modified by new stratigraphic and structural interpretations. Fossil data were used to refine ages of key units, several rock units were reassigned based on revised correlations, and surficial deposits were simplified from fourteen units to four broader map categories.
    Date: 2026 (process 2 of 2)
    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?
    Combellick, R.A., 1993, Geologic hazards in and near proposed state of Alaska oil and gas lease sale 79 (Cape Yakataga): Public Data File PDF 93-81, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 11 p
    Combellick, R.A., 1994, Geologic hazards in the Yakataga planning area, southeastern Alaska: an overview: Report of Investigation RI 94-29, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 9 p
    Combellick, R.A., and Long, W.E., 1983, Geologic hazards in southeastern Alaska: an overview: Report of Investigation RI 83-17, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 17 p
    Emond, A.M., Graham, G.R.C., Eden, Karsten, and Inc., Precision GeoServices, 2021, Icy Cape airborne magnetic geophysical survey, southeast Alaska: Geophysical Report GPR 2021-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p
    Hansen, R.A., and Combellick, R.A., 1998, Planning scenario earthquakes for southeast Alaska: Miscellaneous Publication MP 34, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 5 p
    Lyle, W.M., and Palmer, I.F., Jr., 1976, Stratigraphic study of the Gulf of Alaska tertiary province, northern Gulf of Alaska area: Alaska Open-File Report AOF 93, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 173 p., 23 sheets
    McGee, D.L., 1973, Gulf of Alaska petroleum seeps: Alaska Open-File Report AOF 32, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 9 p
    Motyka, R.J., and Moorman, M.A., 1987, Geothermal resources of southeast Alaska: Professional Report PR 93, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:1,000,000

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 U.S. Geological Survey Open-File Report (OF), which provide rapid public release of scientific information. The series includes interpretive reports, maps, supporting data, preliminary findings, interim computer programs, user guides, and bibliographies.
  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? OF 61-101
  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: 30-Jul-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 Thu Jul 30 16:10:25 2026