Mercury injection capillary pressure results from Middle and Upper Jurassic outcrop samples in the Iniskin Peninsula area of lower Cook Inlet, Alaska

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Frequently anticipated questions:

What does this data set describe?

Title:
Mercury injection capillary pressure results from Middle and Upper Jurassic outcrop samples in the Iniskin Peninsula area of lower Cook Inlet, Alaska
Abstract:
Mercury injection capillary pressure results from Middle and Upper Jurassic outcrop samples in the Iniskin Peninsula area of lower Cook Inlet, Alaska, Raw Data File 2025-10, provides mercury-injection capillary pressure (MICP) analysis performed for 53 outcrop samples collected from three measured sections. Six samples are from the Gaikema Sandstone of the Middle Jurassic Tuxedni Group; 47 samples are from the Paveloff Siltstone of the Middle Jurassic Chinitna Formation; 1 additional sample collected in 2009 (09BG010) from the lower sandstone member of the Upper Jurassic Naknek Formation is also included in this report. The MICP analysis determines the pore system properties using bulk volume, pore volume, and pore system size distribution. These data are useful in evaluating the hydrocarbon or carbon dioxide seal capacity of rocks. These data and report are available from the DGGS website: http://doi.org/10.14509/31522.
Supplemental_Information: 
MICP-data:    Analytical lab data and accompanying data dictionary	
sample-summary:    Summary data spreadsheet and accompanying data dictionary
  1. How might this data set be cited?
    Qureshi, K.A., and Associates, PetroTech, 2025, Mercury injection capillary pressure results from Middle and Upper Jurassic outcrop samples in the Iniskin Peninsula area of lower Cook Inlet, Alaska: Raw Data File RDF 2025-10, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 30 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -153.280755
    East_Bounding_Coordinate: -153.168321
    North_Bounding_Coordinate: 59.816305
    South_Bounding_Coordinate: 59.662582
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2013
    Ending_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 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?
    rdf2025_10-MICP-data.zip, rdf2025_10-MICP-data-dictionary.csv
    Analytical lab data and accompanying data dictionary (Source: DGGS and PetroTech Associates)
    rdf2025_10-sample-summary.csv, rdf2025_10-sample-summary-data-dictionary.csv
    Summary data spreadsheet and accompanying data dictionary (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 STATEMAP bedrock geologic map of the Iniskin Peninsula area, lower Cook Inlet, Alaska (grant no. G13AC00157, 2013) and the State of Alaska Cook Inlet Basin Analysis Capital Improvement Project (CIP). We thank the field geologists who collected most of the samples used in this study, Simone Montayne for her assistance with metadata, and Melanie Werdon for her review.
  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?

Cook Inlet basin analysis program aimed at developing a better understanding of the near-margin stratigraphic and structural components of the Cook Inlet petroleum system. These data are useful in evaluating the hydrocarbon or carbon dioxide seal capacity of rocks.

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: 2013 (process 1 of 3)
    Sample collection - DGGS field geologists collected samples from surface outcrops for MICP analysis. Sample location coordinates were obtained using recreational-grade GPS units, with a typical reported accuracy of about 10 meters. Data were merged into an ArcGIS geodatabase. Coordinates were reported using the WGS84 datum. Coordinates conversion was performed from NAD27 to NAD83 in ArcGIS Pro. Sample number corresponds to measured section number and the sample position (meters above base of section) in each measured section. Coordinates refer to the base of the measured section.
    Date: 2023 (process 2 of 3)
    Sample preparation - To carry out the MICP analysis, a representative portion of each sample was trimmed to fit the sample holders and examined under reflected light microscopy to note any irregularities that might affect the data quality. The rock surfaces were cleaned of any mud or dust, and the samples were then dried to a constant weight in a low-temperature oven before being analyzed. Samples were sent for analysis to PetroTech in Houston, Texas. During capillary pressure testing, the volume of mercury injected was measured at 118 pressure points from 1.64 to 59,500 pounds per square inch absolute (psia). These data were then corrected for closure. The closure volume is the amount of mercury intrusion that occurs as the mercury conforms to the sample surface, filling any irregularities, prior to entering the pore system.
    Date: 2023 (process 3 of 3)
    Analytical methods - During capillary pressure testing, the volume of mercury injected was measured at 118 pressure points from 1.64 to 59,500 pounds per square inch absolute (psia). These data were then corrected for closure. The closure volume is the amount of mercury intrusion that occurs as the mercury conforms to the sample surface, filling any irregularities, prior to entering the pore system.
  3. What similar or related data should the user be aware of?
    Betka, P.M., and Gillis, R.J., 2014, Preliminary characterization of brittle deformation on the Iniskin Peninsula: Implications for the kinematic history of the Bruin Bay fault system, lower Cook Inlet, Alaska: Preliminary Interpretive Report PIR 2014-5, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 14 p
    Gillis, R.J., 2014, Cook Inlet program 2013 field studies: Observations and preliminary interpretations from new 1:63,360-scale geologic mapping of the Iniskin Peninsula, lower Cook Inlet, Alaska: Preliminary Interpretive Report PIR 2014-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 31 p
    Gillis, R.J., Wartes, M.A., Herriott, T.M., Bull, K.F., Decker, P.L., and Betka, P.M., 2014, Overview of new 1:63,360-scale geologic mapping of the Iniskin Peninsula, lower Cook Inlet, Alaska: Preliminary Interpretive Report PIR 2014-2-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 3-6
    Helmold, K.P., and Stanley, R.G., 2015, Petrology and reservoir quality of the Gaikema Sandstone: Initial impressions: Preliminary Interpretive Report PIR 2015-5-7, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 43-48
    Herriott, T.M., 2016, Introduction to petroleum-related geologic studies in lower Cook Inlet during 2015, Iniskin-Tuxedni region, south-central Alaska: Preliminary Interpretive Report PIR 2016-1-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 1-8
    Herriott, T.M., and Wartes, M.A., 2014, Brief overview of geologic mapping of the Middle Jurassic Chinitna Formation and Upper Jurassic Naknek Formation in the Tilted Hills, Iniskin Peninsula, Cook Inlet, Alaska: Preliminary Interpretive Report PIR 2014-2-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 7-11
    Herriott, T.M., 2016, Petroleum-related geologic studies in lower Cook Inlet during 2015, Iniskin-Tuxedni region, south-central Alaska: Preliminary Interpretive Report PIR 2016-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 78 p
    Loveland, A.M., and Associates, PetroTech, 2013, Mercury injection capillary pressure (MICP) results from outcrop samples in the Naknek Formation, Iniskin Peninsula, Alaska: Raw Data File RDF 2013-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p
    Loveland, A.M., and Associates, PetroTech, 2014, Mercury injection capillary pressure results from outcrop samples in the Kaguyak, Naknek, and West Foreland formations, Iniskin Peninsula region, Alaska: Raw Data File RDF 2014-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 5 p
    Stanley, R.G., Helmold, K.P., and LePain, D.L., 2015, Storm-influenced deltaic deposits of the Middle Jurassic Gaikema Sandstone in a measured section of the northern Iniskin Peninsula, Cook Inlet basin, Alaska: Preliminary Interpretive Report PIR 2015-5-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 29-42
    Wartes, M.A., and Herriott, T.M., 2014, A new occurrence of oil-stained rocks within a small fault zone involving the Middle Jurassic Cynthia Falls Formation, Tuxedni Group, northern Iniskin Peninsula: Preliminary Interpretive Report PIR 2014-2-5, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 23-27
    Wartes, M.A., and Herriott, T.M., 2014, Discovery of oil-stained sandstone within the Chinitna Formation, northern Iniskin Peninsula: Preliminary Interpretive Report PIR 2014-2-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: p. 29-31

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?
    Sample location coordinates were obtained using recreational-grade GPS units, with a typical reported accuracy of about 10 meters. Data were merged into an ArcGIS geodatabase. Coordinates were reported using the WGS84 datum. Coordinates conversion was performed from NAD27 to NAD83 in ArcGIS Pro. Sample number corresponds to measured section number and the sample position (meters above base of section) in each measured section. Coordinates refer to the base of the measured section.
  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 2025-10
  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-Jun-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 Thu Jul 03 19:10:09 2025