Palynological and thermal maturity analysis of outcrop samples from the West Susitna area STATEMAP project, southcentral, Alaska

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

Frequently anticipated questions:


What does this data set describe?

Title:
Palynological and thermal maturity analysis of outcrop samples from the West Susitna area STATEMAP project, southcentral, Alaska
Abstract:
Palynological and thermal maturity analysis of outcrop samples from the West Susitna area STATEMAP project, southcentral, Alaska, Raw Data File 2025-27, provides palynomorph assemblages, kerogen observations, thermal maturity estimates, age interpretations, and field station locations from samples collected by DGGS staff during the 2024 field season as part of the Alaska Division of Geological & Geophysical Surveys' (DGGS) West Susitna STATEMAP project. The project is a geologic mapping initiative at a 1:50,000 scale designed to characterize regional geology, assess geologic hazards, and investigate tectonic features in an area of growing interest for resource development, alternative energy, and recreation. The study area covers approximately 500 square miles in the West Susitna region of southcentral Alaska, spanning the Tyonek C-3, C-4, D-4, and D-5 quadrangles and including about 50 miles of the proposed West Susitna Access Corridor, which connects Anchorage to the Happy River Valley on the western margin of the Susitna Basin. Palynological assemblages and thermal-maturity data from siltstone and coal outcrop samples provide critical constraints on the basin's stratigraphic framework and burial history. The analyses refine age determinations, reconstruct depositional environments, and characterize kerogen types, thereby improving basin modeling and supporting regional geologic mapping, hazard assessment, and resource evaluation. These data are provided as a Raw Data File under an open end-user license and are available on the DGGS website: http://doi.org/10.14509/31734.
Supplemental_Information:
palynology-summary:    Detailed metadata for geological and palynological samples, including identifiers, lithology, location, age interpretations, organic matter analysis, and paleoenvironmental insights derived from palynomorph assemblages.	
palynomorph-inventory:    Palynological count data documenting observed frequency and botanical classification.
  1. How might this data set be cited?
    Zippi, P.A., Walser, S.L., Gillis, R.J., and Montayne, Simone, 2025, Palynological and thermal maturity analysis of outcrop samples from the West Susitna area STATEMAP project, southcentral, Alaska: Raw Data File RDF 2025-27, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -151.761436
    East_Bounding_Coordinate: -151.362319
    North_Bounding_Coordinate: 61.826902
    South_Bounding_Coordinate: 61.673963
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2025
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: spreadsheet
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a point data set.
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is WGS84.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    rdf2025-27_palynology-summary-data.csv, rdf2025-27_palynology-summary-data-dictionary.csv
    Detailed metadata for geological and palynological samples, including identifiers, lithology, location, age interpretations, organic matter analysis, and paleoenvironmental insights derived from palynomorph assemblages. (Source: DGGS)
    rdf2025-27_palynomorph-inventory-data.csv, rdf2025-27_palynomorph-inventory-data-dictionary.csv
    Palynological count data documenting observed frequency and botanical classification. (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?
    This work was funded by the U.S. Geological Survey National Cooperative Geologic Mapping Program under STATEMAP award number G23AC00584, 2023, 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 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 or by any branch or employee of the State of Alaska.
  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?

Palynological assemblages and thermal maturity data derived from siltstone and coal outcrop samples provide critical constraints on the stratigraphic framework and burial history of the Susitna Basin. These analyses refine age determinations, depositional environment reconstructions, and kerogen type characterization, thereby improving basin modeling and supporting 1:50,000-scale geologic mapping. The results directly inform hazard assessment, resource evaluation, and infrastructure planning along the proposed West Susitna Access Corridor. By integrating palynological inventories with organic matter maturity indices, the dataset enhances the State of Alaska's ability to evaluate hydrocarbon potential, assess geologic hazards, and develop sustainable land-use and energy strategies in a region of increasing strategic importance.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2025 (process 1 of 3)
    Sample selection - Researchers collected samples from mudstone, shaly coal, and unconsolidated clayey sediment. When conditions allowed, they removed several centimeters of weathered outcrop material to access fresh material. Each sample location was documented with GPS coordinates, lithologic descriptions, and geologic context.
    Date: 2025 (process 2 of 3)
    Preparation - Global Geolab Limited (Medicine Hat, Alberta) processed all samples using standard palynological preparation techniques. Carbonates and silicates were removed with acid treatments, residues were cleaned and separated, sieved through a 7‑μm mesh, and mounted on microscope slides for transmitted light analysis. Additional details on laboratory methods and data reduction are provided in the accompanying report.
    Date: 2025 (process 3 of 3)
    Analytical methods - Palynological, kerogen, and spore color analyses were conducted using a Zeiss Axio Imager microscope with advanced illumination and oil-immersion objectives at 500X magnification. Palynomorph occurrence data were collected to establish relative abundance, with additional scanning for rare stratigraphically significant taxa. Kerogen residues were separated through acid demineralization and oxidation, and vitrinite reflectance and maximum temperatures were estimated using the thermal alteration index (TAI) from suitable spores. Age zones follow Cook Inlet palynostratigraphic terminology, and paleoenvironmental interpretations were based on pollen/spore group dominance, kerogen type abundance, and lithological context. Additional details on laboratory methods and data reduction are provided in the accompanying report.
  3. What similar or related data should the user be aware of?
    Bliss, A.K., Hock, Regine, Wolken, G.J., Whorton, E.N., Aubry-Wake, Caroline, Braun, Juliana, Gusmeroli, Alessio, Harrison, W.D., Hoffman, Andrew, and Liljedahl, A.K., 2019, Glaciers and climate of the upper Susitna Basin, Alaska; supporting data: Raw Data File RDF 2019-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 6 p
    Daanen, R.P., Wolken, G.J., and Herbst, A.M., 2020, High-resolution lidar data from the west Susitna area, southcentral, Alaska: Raw Data File RDF 2020-5, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 7 p
    Gillis, R.J., 2015, Overview of 2014 energy-focused field studies in Susitna basin, south-central Alaska, and preliminary results: Preliminary Interpretive Report PIR 2015-3-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 1-4
    Gillis, R.J., Herriott, T.M., and Tsigonis, R.M., 2015, Preliminary results of reconnaissance structural studies of the western Susitna basin, south-central Alaska: Preliminary Interpretive Report PIR 2015-3-5, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 25-34
    Gillis, R.J., Stanley, R.G., LePain, D.L., Mauel, D.J., Herriott, T.M., Helmold, K.P., Peterson, C.S., Wartes, M.A., and Shellenbaum, D.P., 2013, Status of a reconnaissance field study of the Susitna basin, 2011: Preliminary Interpretive Report PIR 2013-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 8 p
    Harun, N.T., LePain, D.L., Tsigonis, R.M., Helmold, K.P., and Stanley, R.G., 2015, Reconnaissance coal study in the Susitna basin, 2014: Preliminary Interpretive Report PIR 2015-3-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 19-24
    LePain, D.L., Stanley, R.G., Harun, N.T., Helmold, K.P., and Tsigonis, R.M., 2015, Reconnaissance stratigraphic studies in the Susitna basin, Alaska, during the 2014 field season: Preliminary Interpretive Report PIR 2015-3-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 5-10
    Stevens, D.S.P., Solie, D.N., Bachmann, E.N., and Wright, T.C., 2015, Geospatial database: Compiled geologic mapping in the area of the proposed Susitna-Watana hydroelectric project, south-central Alaska: Miscellaneous Publication MP 156, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Walser, S.L., Gillis, R.J., Bernt, J.D., and Montayne, Simone, 2025, Major-oxide and trace-element analyses of rock samples from the West Susitna area STATEMAP project, southcentral, Alaska: Raw Data File RDF 2025-21, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 2 p

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

  1. How well have the observations been checked?
    The accompanying report and data tables provide a comprehensive discussion of processing methods, with errors reported in the tables where applicable. This data is being released as part of the DGGS RDF series, which includes content describing approved techniques and methods for the collection, storage, visualization, analysis, and interpretation of scientific data. While the information has been reviewed by several geologists familiar with the study area, the data and report have not undergone formal review for technical content or conformity to DGGS editorial standards. For inquiries regarding analytical values or procedures, the originating lab is the best point of contact.
  2. How accurate are the geographic locations?
    Location data for field stations were collected using GPS-enabled tablets or smartphones running the Esri Field Maps app. Data were merged into an ArcGIS geodatabase. The devices have a reported error of 10-12 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This data release is complete.
  5. How consistent are the relationships among the observations, including topology?
    Not applicable

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? RDF 2025-27
  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: 18-Nov-2025
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 Nov 18 16:07:47 2025