Identification_Information: Citation: Citation_Information: Originator: Gillis, R.J. Originator: Walser, S.L. Originator: Bernt, J.D. Originator: O'Sullivan, P.B. Publication_Date: 2026 Title: Zircon U-Pb geochronology for bedrock samples from the West Susitna STATEMAP project, southcentral, Alaska Geospatial_Data_Presentation_Form: spreadsheet Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2026-8 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 9 p. Online_Linkage: https://doi.org/10.14509/31972 Description: Abstract: Zircon U-Pb geochronology for bedrock samples from the West Susitna STATEMAP project, southcentral, Alaska, Raw Data File 2026-8, presents zircon uranium-lead (U-Pb) geochronologic data analyzed using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The Alaska Division of Geological & Geophysical Surveys (DGGS) staff collected ten samples for U-Pb dating during the 2024 field season as part of the West Susitna STATEMAP project. The project is a 1:50,000-scale geologic mapping initiative to characterize geology, assess geologic hazards, and investigate tectonic features within a region of increasing interest for resource development, alternative energy, and recreation. The study area lies in the West Susitna region of southcentral Alaska. It spans approximately 500 mi2 across the Tyonek C-3, C-4, D-4, and D-5 quadrangles, including approximately 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. Geochronological analyses were obtained to constrain the ages of mapped bedrock units and support tectonic interpretations in the map area. 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/10.14509/31972. Purpose: The purpose of this report is to present zircon U-Pb geochronologic data from ten samples collected during the 2024 West Susitna STATEMAP project to refine the ages of mapped bedrock units and strengthen tectonic interpretations within a 1:50,000-scale geologic mapping area in the West Susitna region of southcentral Alaska, providing geologic information that supports responsible resource development, infrastructure planning, hazard assessment, and long-term land use decision making for the State of Alaska. Supplemental_Information: >analytical data: Analytical lab data spreadsheets and accompanying data dictionary. >summary data: Summary data spreadsheet and accompanying data dictionary. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2024 Ending_Date: 2026 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -151.957742 East_Bounding_Coordinate: -151.064110 North_Bounding_Coordinate: 61.943743 South_Bounding_Coordinate: 61.641734 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Age Dates Theme_Keyword: Analyses Theme_Keyword: Analyses and Sampling Theme_Keyword: Analytical Lab Results Theme_Keyword: Analytical Results Theme_Keyword: Bedrock Theme_Keyword: Bedrock Geology Theme_Keyword: Chemistry Theme_Keyword: Dacite Theme_Keyword: DGGS Theme_Keyword: Engineering Geology Theme_Keyword: Gabbro Theme_Keyword: Geochronology Theme_Keyword: Geologic Theme_Keyword: Geologic Samples Theme_Keyword: Geology Theme_Keyword: Hornblende Theme_Keyword: Igneous Theme_Keyword: Igneous Rocks Theme_Keyword: Interpretation Theme_Keyword: Isotopes Theme_Keyword: LA-ICPMS Theme_Keyword: Lab Methods Theme_Keyword: Laser Ablation Theme_Keyword: Lead Theme_Keyword: Methods Theme_Keyword: Outcrop Theme_Keyword: Outcrop Samples Theme_Keyword: Petrogenesis Theme_Keyword: Provenance Theme_Keyword: Pyroclastics Theme_Keyword: Rhyolite Theme_Keyword: Rocks Theme_Keyword: Sample Location Theme_Keyword: STATEMAP Project Theme_Keyword: Tephra Theme_Keyword: Tephra Deposits Theme_Keyword: Tephrochronology Theme_Keyword: Tephrostratigraphy Theme_Keyword: Tuff Theme_Keyword: U-Pb Theme_Keyword: U-Pb Zircon Theme_Keyword: Uranium Theme_Keyword: Volcanic Theme_Keyword: Volcanic Deposits Theme_Keyword: Volcanic Rocks Theme_Keyword: Volcaniclastic Theme_Keyword: Volcaniclastic Deposits Theme_Keyword: Volcaniclastics Theme_Keyword: Zircon Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Bear Creek Place_Keyword: Beluga Mountain Place_Keyword: Canyon Creek Place_Keyword: Clear Creek Place_Keyword: Contact Creek Place_Keyword: Deep Creek Place_Keyword: Dickason Mountain Place_Keyword: Friday Creek Place_Keyword: Hayes River Place_Keyword: Redoubt Mining District Place_Keyword: Skwentna River Place_Keyword: Southcentral Alaska Place_Keyword: Talachulitna River Place_Keyword: Texas Creek Place_Keyword: Yentna Mining District Temporal: Temporal_Keyword_Thesaurus: Walker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of America Temporal_Keyword: Berriasian Temporal_Keyword: Cretaceous Temporal_Keyword: Eocene Temporal_Keyword: Miocene Temporal_Keyword: Neogene Temporal_Keyword: Paleocene Temporal_Keyword: Paleogene Temporal_Keyword: Serravallian Temporal_Keyword: Thanetian Temporal_Keyword: Ypresian 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: 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. Data_Set_Credit: The authors thank GeoSep Services, LLC for their contributions to data collection. This work was funded by the U.S. Geological Survey National Cooperative Geologic Mapping Program under STATEMAP Award Number: G23AC00584-01, 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. Cross_Reference: Citation_Information: Originator: Zechmann, J.M. Originator: Salisbury, J.B. Publication_Date: 2025 Title: Lidar-derived surface elevation data for Dickason Highlands, southcentral Alaska, collected August 14, 2024 Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2025-12 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 10 p Online_Linkage: https://doi.org/10.14509/31536 Cross_Reference: Citation_Information: Originator: Walser, S.L. Originator: Gillis, R.J. Originator: Bernt, J.D. Originator: Montayne, Simone Publication_Date: 2025 Title: Major-oxide and trace-element analyses of rock samples from the West Susitna area STATEMAP project, southcentral, Alaska Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2025-21 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/31725 Cross_Reference: Citation_Information: Originator: Zippi, P.A. Originator: Walser, S.L. Originator: Gillis, R.J. Originator: Montayne, Simone Publication_Date: 2025 Title: Palynological and thermal maturity analysis of outcrop samples from the West Susitna area STATEMAP project, southcentral, Alaska Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2025-27 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 3 p Online_Linkage: https://doi.org/10.14509/31734 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: 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. Logical_Consistency_Report: Not applicable Completeness_Report: This data release is complete. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Staff recorded geographic coordinates for sample stations using GPS-enabled tablets and smartphones running the ESRI Field Maps application, which typically provides positional accuracy within approximately 10 meters. All location data are reported in latitude and longitude using the WGS84 datum. Lineage: Process_Step: Process_Description: Field data collection - Stratigraphic profiles were selected for study in the field. They consisted of natural stream bank exposures or hand-dug pits. We scraped exposure surfaces clean with shovels and trowels to better expose the tephra deposits and associated buried soils, recorded the apparent vertical thickness of each unit, and collected samples of tephra and soil-organic matter for later analysis. Process_Date: 2022 Process_Step: Process_Description: Sample analysis - Researchers collected buried soil samples from 26 sites beneath major tephra layers, then dried and prepared them before sending them to the University of Georgia's Center for Applied Isotope Studies for radiocarbon analysis. In the lab, humic acids were isolated from the soils through sieving, acid treatment, alkaline extraction, precipitation, and drying, while peat samples underwent a similar cleaning process before combustion. Radiocarbon measurements were obtained using accelerator mass spectrometry, with isotopic ratios corrected for natural fractionation. Results were reported as percent modern carbon and as radiocarbon years before present (BP), based on a 5,568-year half-life. These uncalibrated dates were then converted to calendar ages using the CALIB 7.1 calibration program, which relies on tree-ring and other independently dated records. Final calibrated ages are expressed as cal BC, cal AD, or cal BP, corresponding directly to actual calendar years. Additional methodological detail and full analytical results are provided in the accompanying report. Process_Date: 2023 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.0000001 Longitude_Resolution: 0.0000001 Geographic_Coordinate_Units: decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS84 Ellipsoid_Name: WGS 84 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257223563 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: rdf2026-8-UPb-data.zip, rdf2026-8-UPb-data_dictionary.csv Entity_Type_Definition: Analytical lab data spreadsheets and accompanying data dictionary. Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: analytical data Detailed_Description: Entity_Type: Entity_Type_Label: rdf2026-8-UPb-summary.csv, rdf2026-8-UPb-summary-dictionary.csv Entity_Type_Definition: Summary data spreadsheet and accompanying data dictionary. Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: summary data Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: 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. Resource_Description: RDF 2026-8 Distribution_Liability: 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. Standard_Order_Process: Non-digital_Form: DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount. Fees: Contact DGGS for current pricing Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: spreadsheet Format_Version_Date: 20260302 Format_Information_Content: table Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/31972 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20260302 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Person: Simone Montayne Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Use_Constraints: If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys. Metadata_Extensions: Online_Linkage: https://dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions