Identification_Information: Citation: Citation_Information: Originator: Bundtzen, T.K. Originator: Laird, G.M. Publication_Date: 1980 Title: Preliminary geology of the McGrath - upper Innoko River area, western interior Alaska Geospatial_Data_Presentation_Form: geodatabase Series_Information: Series_Name: Alaska Open-File Report Issue_Identification: AOF 134 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 39 p., 2 sheets Online_Linkage: https://doi.org/10.14509/53 Description: Abstract: Preliminary geology of the McGrath - upper Innoko River area, western interior Alaska, Alaska Open-File Report 134, presents results of geologic mapping and resource assessment across approximately 900 square miles in parts of the McGrath, Iditarod, and Ophir 1:250,000 quadrangles of western interior Alaska. DGGS staff completed a total of ninety-four field days in 1972, 1978, and 1979. The map area contains a Late Paleozoic chert-argillite-limestone unit, Early(?) Cretaceous limy sandstone and impure limestone, and a thick section of mid- to Late Cretaceous lithic sandstone, siltstone, shale, and conglomerate. Layered sedimentary rocks form low, rounded ridges, and igneous complexes and associated hornfels form steep massifs. Bedrock exposures are limited below timberline but are well developed along stream bluffs and in the Beaver Mountains. Late Cretaceous alkaline plutonic complexes, dike swarms, and associated mafic volcanic rocks intrude and overlie the layered units. Surficial deposits include glacial, eolian, alluvial, and colluvial sediments. Dominant structures consist of northeast-trending folds and high-angle faults. Placer gold deposits occur in modern and older stream terraces in the Ophir mining area and the Candle Hills. Gold placers are associated with basaltic-to-rhyolitic dike swarms and faults that cross stream channels. The dike swarms contain anomalous concentrations of gold, nickel, yttrium, chromium, and zirconium, and fractures in plutons and nearby hornfels zones locally contain anomalous base and precious metals interpreted as probable lode sources for gold placers in the Candle Hills. The geologic relationships recorded by this map have important implications for understanding mineral resources and guiding future exploration throughout this region of Alaska. 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://doi.org/10.14509/53. Purpose: This report provides geologic mapping and resource information for parts of the McGrath, Iditarod, and Ophir 1:250,000 quadrangles of western interior Alaska. The mapping improves understanding of bedrock geology, surficial deposits, and structural features, and documents the distribution and geologic controls of placer gold deposits in the Ophir mining precinct and Candle Hills. These data support mineral resource evaluation, land management, and future geologic investigations in the region. 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. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1972 Ending_Date: 1979 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -157.182321 East_Bounding_Coordinate: -155.504112 North_Bounding_Coordinate: 63.175279 South_Bounding_Coordinate: 62.719700 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Alluvial Theme_Keyword: Alluvium Theme_Keyword: Analyses Theme_Keyword: Andesite Theme_Keyword: Antimony Theme_Keyword: Argillite Theme_Keyword: Arsenic Theme_Keyword: Augite Theme_Keyword: Barite Theme_Keyword: Basalt Theme_Keyword: Bedrock Theme_Keyword: Bedrock Geology Theme_Keyword: Biotite Theme_Keyword: Bismuth Theme_Keyword: Brachiopods Theme_Keyword: Breccia Theme_Keyword: Chemistry Theme_Keyword: Chert Theme_Keyword: Chlorite Theme_Keyword: Chromite Theme_Keyword: Chromium Theme_Keyword: Cinnabar Theme_Keyword: Clay Theme_Keyword: Clinopyroxene Theme_Keyword: Colluvium Theme_Keyword: Conglomerate Theme_Keyword: Dacite Theme_Keyword: Dike Theme_Keyword: Diorite Theme_Keyword: Dredge Theme_Keyword: Drift Theme_Keyword: Energy Theme_Keyword: Environment Theme_Keyword: Eolian Theme_Keyword: Erosion Theme_Keyword: Exploration Theme_Keyword: Fan Theme_Keyword: Faults Theme_Keyword: Felsic Theme_Keyword: Felsite Theme_Keyword: Flysch Theme_Keyword: Folding Theme_Keyword: Folds Theme_Keyword: Fossils Theme_Keyword: Fracture Theme_Keyword: Garnet Theme_Keyword: Gastropods Theme_Keyword: Generalized Theme_Keyword: Geochemistry Theme_Keyword: Geochronology Theme_Keyword: Geologic Theme_Keyword: Geology Theme_Keyword: Glacial Theme_Keyword: Glaciation Theme_Keyword: Gold Theme_Keyword: Gossan Theme_Keyword: Graphite Theme_Keyword: Gravel Theme_Keyword: Graywacke Theme_Keyword: Greisen Theme_Keyword: Helminthopsis Theme_Keyword: Hornfels Theme_Keyword: Igneous Theme_Keyword: Ilmenite Theme_Keyword: Inoceramus Theme_Keyword: Interpretation Theme_Keyword: Intrusive Theme_Keyword: Jasper Theme_Keyword: Lead Theme_Keyword: Limestone Theme_Keyword: Lithology Theme_Keyword: Lode Theme_Keyword: Loess Theme_Keyword: Magnetite Theme_Keyword: Manganese Theme_Keyword: Marine Theme_Keyword: Megafossils Theme_Keyword: Meltwater Theme_Keyword: Mercury Theme_Keyword: Metals Theme_Keyword: Metamorphic Theme_Keyword: Mineral Assessment Theme_Keyword: Mineral Deposits Theme_Keyword: Mineral Development Theme_Keyword: Mineral Exploration Theme_Keyword: Mineral Localities Theme_Keyword: Mineral Resources Theme_Keyword: Mineralogy Theme_Keyword: Minerals Theme_Keyword: Mining Theme_Keyword: Molybdenum Theme_Keyword: Monzonite Theme_Keyword: Mudstone Theme_Keyword: Nickel Theme_Keyword: Nonmarine Theme_Keyword: Olivine Theme_Keyword: Ore Theme_Keyword: Orogeny Theme_Keyword: Orthoquartzite Theme_Keyword: Outcrop Theme_Keyword: Outwash Theme_Keyword: Paleobotany Theme_Keyword: Paleocurrent Theme_Keyword: Paleontology Theme_Keyword: Petrology Theme_Keyword: Phyllite Theme_Keyword: Placer Theme_Keyword: Plagioclase Theme_Keyword: Platinum Theme_Keyword: Plutonic Theme_Keyword: Plutons Theme_Keyword: Pyrite Theme_Keyword: Quartz Theme_Keyword: Resources Theme_Keyword: Rhyolite Theme_Keyword: Rocks Theme_Keyword: Sand Theme_Keyword: Sandstone Theme_Keyword: Scheelite Theme_Keyword: Sediment Theme_Keyword: Sedimentary Theme_Keyword: Shale Theme_Keyword: Shear Theme_Keyword: Shonkinite Theme_Keyword: Siderite Theme_Keyword: Silt Theme_Keyword: Siltstone Theme_Keyword: Silver Theme_Keyword: Slate Theme_Keyword: Slope Theme_Keyword: Stratigraphy Theme_Keyword: Stream Sediments Theme_Keyword: Structure Theme_Keyword: Sulfides Theme_Keyword: Surface Theme_Keyword: Surficial Theme_Keyword: Syenite Theme_Keyword: Tailings Theme_Keyword: Talus Theme_Keyword: Tephra Theme_Keyword: Terrace Theme_Keyword: Thermokarst Theme_Keyword: Thorium Theme_Keyword: Till Theme_Keyword: Tourmaline Theme_Keyword: Transportation Theme_Keyword: Trenching Theme_Keyword: Tuff Theme_Keyword: Tungsten Theme_Keyword: Turbidity Theme_Keyword: Uplift Theme_Keyword: Uranium Theme_Keyword: Vanadium Theme_Keyword: Volcanic Theme_Keyword: Volcaniclastic Theme_Keyword: Yttrium Theme_Keyword: Zinc Theme_Keyword: Zirconium Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Anvil Creek Place_Keyword: Beaver Creek Place_Keyword: Beaver Mountains Place_Keyword: Beef Steak Creek Place_Keyword: Billy Goat Creek Place_Keyword: Brown Creek Place_Keyword: California Creek Place_Keyword: Camp Creek Place_Keyword: Canadian Creek Place_Keyword: Candle Creek Place_Keyword: Candle Hills Place_Keyword: Candle Placer Place_Keyword: Carl Creek Place_Keyword: Cash Creek Place_Keyword: Crater Mountain Place_Keyword: Dodge Creek Place_Keyword: Dollar Creek Place_Keyword: Dome Creek Place_Keyword: Ester Creek Place_Keyword: French Joe Mountain Place_Keyword: Ganes Creek Place_Keyword: Goldbottom Creek Place_Keyword: Harrell Island Place_Keyword: Independence Creek Place_Keyword: Innoko Mining District Place_Keyword: Innoko River Place_Keyword: Katlitna River Place_Keyword: Kuskokwim Mountains Place_Keyword: Kuskokwim River Place_Keyword: Last Chance Creek Place_Keyword: Lincoln Creek Place_Keyword: Maiden Creek Place_Keyword: Moore City Place_Keyword: Mount Joaquin Place_Keyword: Naden Creek Place_Keyword: Ophir Place_Keyword: Ophir Creek Place_Keyword: Ready Bullion Creek Place_Keyword: Rex Creek Place_Keyword: Roundabout Mountain Place_Keyword: Roundabout Mountains Place_Keyword: Spalding Creek Place_Keyword: Spruce Creek Place_Keyword: Steak Creek Place_Keyword: Steel Creek Place_Keyword: Sunset Creek Place_Keyword: Takotna Place_Keyword: Takotna Mountain Place_Keyword: Takotna River Place_Keyword: Tamarack Creek Place_Keyword: Tatalina River Place_Keyword: Tolstoi Creek Place_Keyword: Tolstoi Lake Place_Keyword: Warner Creek Place_Keyword: Wilson Lake Place_Keyword: Windy Creek Place_Keyword: Yankee Creek 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: Cretaceous Temporal_Keyword: Paleozoic Temporal_Keyword: Phanerozoic Temporal_Keyword: Quaternary 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: Thomas K. Bundtzen led the project and was assisted by Gregory M. Laird during all three seasons, and by Virginia F. Ferrell, Nicki D. Coursey, and Karen S. Emmel in 1979. Specialists contributed fossil locality data, paleocurrent measurements, K-Ar age determinations, geochemical analyses, gold production figures, and uranium and thorium analyses. Additional geological comparisons were provided by U.S. Geological Survey staff familiar with nearby quadrangles. Long-time local residents shared information on past mineral activity, and the Rossander mining camp on Yankee Creek served as the 1979 base camp. The report was reviewed by DGGS staff. This map was converted to GeMS or digitized into GeMS by Kinney Engineering, LCC., quality controlled, and then finalized by DGGS staff (Chris Wyatt and Mike Hendricks). 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. Cross_Reference: Citation_Information: Originator: Bundtzen, T.K. Originator: Laird, G.M. Publication_Date: 1982 Title: Geologic map of the Iditarod D-2 and eastern D-3 quadrangles, Alaska Series_Information: Series_Name: Geologic Report Issue_Identification: GR 72 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 1 sheet, scale 1:63,360 Online_Linkage: https://doi.org/10.14509/432 Cross_Reference: Citation_Information: Originator: Bundtzen, T.K. Originator: Laird, G.M. Publication_Date: 1983 Title: Geologic map of the Iditarod D-1 Quadrangle, Alaska Series_Information: Series_Name: Professional Report Issue_Identification: PR 78 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 1 sheet, scale 1:63,360 Online_Linkage: https://doi.org/10.14509/2252 Cross_Reference: Citation_Information: Originator: Bundtzen, T.K. Originator: Laird, G.M. Publication_Date: 1983 Title: Geologic map of the McGrath D-6 Quadrangle, Alaska Series_Information: Series_Name: Professional Report Issue_Identification: PR 79 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 1 sheet, scale 1:63,360 Online_Linkage: https://doi.org/10.14509/2253 Cross_Reference: Citation_Information: Originator: Bundtzen, T.K. Originator: Laird, G.M. Publication_Date: 1983 Title: Preliminary geology of the northeastern Iditarod C-3 Quadrangle, Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 83-13 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 1 sheet, scale 1:63,360 Online_Linkage: https://doi.org/10.14509/2352 Cross_Reference: Citation_Information: Originator: Bundtzen, T.K. Originator: Laird, G.M. Originator: Lockwood, M.S. Publication_Date: 1988 Title: Geologic map of the Iditarod C-3 Quadrangle, Alaska Series_Information: Series_Name: Professional Report Issue_Identification: PR 96 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 13 p., 1 sheet, scale 1:63,360 Online_Linkage: https://doi.org/10.14509/2277 Cross_Reference: Citation_Information: Originator: Burns, L.E. Originator: Graham, G.R.C. Originator: Barefoot, J.D. Originator: Naibert, T.J. Originator: Fugro Airborne Surveys Corp. Publication_Date: 2019 Title: Iditarod electromagnetic and magnetic airborne geophysical survey data compilation Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2019-15 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 15 p Online_Linkage: https://doi.org/10.14509/30222 Cross_Reference: Citation_Information: Originator: Burns, L.E. Originator: Graham, G.R.C. Originator: Barefoot, J.D. Originator: Naibert, T.J. Originator: CGG Originator: Fugro Airborne Surveys Corp. Publication_Date: 2019 Title: Fox Hills electromagnetic and magnetic airborne geophysical survey data compilation Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2018-6 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 14 p Online_Linkage: https://doi.org/10.14509/29820 Cross_Reference: Citation_Information: Originator: Fusso, L.A. Originator: Petersen, E.I. Originator: Emond, A.M. Originator: EON Geosciences Inc. Publication_Date: 2026 Title: Kuskokwim airborne magnetic and radiometric geophysical survey, Ganes Creek, Alaska (2026) Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2026-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 16 p Online_Linkage: https://doi.org/10.14509/31746 Cross_Reference: Citation_Information: Originator: Fusso, L.A. Originator: Petersen, E.I. Originator: Emond, A.M. Originator: EON Geosciences Inc. Publication_Date: 2026 Title: Kuskokwim airborne magnetics and radiometric geophysical survey, McGrath, Alaska Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2026-2 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 17 p Online_Linkage: https://doi.org/10.14509/31804 Cross_Reference: Citation_Information: Originator: Meyer, J.F. Originator: Krouskop, D.L. Publication_Date: 1986 Title: Preliminary gravity data of the Minchumina basin, southcentral Alaska Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 86-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 14 p., 2 sheets, scale 1:500,000 Online_Linkage: https://doi.org/10.14509/2400 Cross_Reference: Citation_Information: Originator: Petersen, E.I. Originator: Fusso, L.A. Originator: Geotech Ltd. Originator: Aqua Geo Frameworks LLC Publication_Date: 2026 Title: Candle Hills airborne electromagnetic survey, Kuskokwim region, Alaska Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2026-3 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/10.14509/31963 Cross_Reference: Citation_Information: Originator: Reger, R.D. Originator: Campbell, K.M. Originator: Stevens, D.S.P. Originator: Smith, R.L. Publication_Date: 2003 Title: Survey of geology, geologic materials, and geologic hazards in proposed access corridors in the Ophir Quadrangle, Alaska Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 100 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 5 sheets, scale 1:250,000 Online_Linkage: https://doi.org/10.14509/3286 Cross_Reference: Citation_Information: Originator: Reger, R.D. Originator: Cruse, G.R. Originator: Stevens, D.S.P. Originator: Smith, R.L. Publication_Date: 2003 Title: Survey of geology, geologic materials, and geologic hazards in proposed access corridors in the Iditarod Quadrangle, Alaska Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 76 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 4 sheets, scale 1:250,000 Online_Linkage: https://doi.org/10.14509/2930 Cross_Reference: Citation_Information: Originator: Reger, R.D. Originator: Stevens, D.S.P. Originator: Cruse, G.R. Originator: Livingston, H.R. Publication_Date: 2003 Title: Survey of geology, geologic materials, and geologic hazards in proposed access corridors in selected quadrangles, Alaska Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 129 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 72 p Online_Linkage: https://doi.org/10.14509/2946 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: 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. Logical_Consistency_Report: All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications. Completeness_Report: This publication is a DGGS Alaska Open-File Report (AOF). An AOF contains reports of research by DGGS personnel. Its objective was to make information available to the public as soon as possible, and therefore reports of this series were not subjected to rigorous critical review and formal editing and did not use professional cartographic services. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: 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. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Ekberg, P.G. Originator: Hendricks, M.D. Originator: Athey, J.E. Publication_Date: 2021 Title: AK GeMS symbology: A description of the AK GeMS style file Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 169 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 7 p Online_Linkage: https://doi.org/10.14509/30584 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2021 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Ekberg, P.G. and others, 2021 Source_Contribution: GIS analysis and digital cartography Source_Information: Source_Citation: Citation_Information: Originator: Hendricks, M.D. Originator: Ekberg, P.G. Originator: Athey, J.E. Originator: Wyatt, W.C. Originator: Willingham, A.L. Originator: Naibert, T.J. Publication_Date: 2021 Title: AK GeMS data dictionary: A description of the Alaska geologic mapping schema Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 170 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/10.14509/30669 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2021 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Hendricks, M.D. and others, 2021 Source_Contribution: GIS analysis and digital cartography Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey National Cooperative Geologic Mapping Program Publication_Date: 2020 Title: GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic maps Series_Information: Series_Name: Techniques and Methods Issue_Identification: TM 11-B10 Publication_Information: Publication_Place: United States Publisher: U.S. Geological Survey Other_Citation_Details: 1 p Online_Linkage: https://dggs.alaska.gov/pubs/id/30585 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2020 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020 Source_Contribution: GIS analysis and digital cartography Process_Step: Process_Description: Geologic mapping - DGGS completed geologic mapping during ninety-four field days in 1972, 1978, and 1979. Mapping documented bedrock lithologies, intrusive and volcanic relationships, structural features, and surficial deposits across parts of the McGrath, Iditarod, and Ophir quadrangles. Field investigations included measurement of paleocurrent indicators, identification of fossil localities, and collection of rock and sediment samples for geochemical and age-dating analyses. Supporting data included fossil identifications, K-Ar age determinations, and uranium and thorium analyses. Information on historical mineral activity was gathered from local residents, and geological comparisons with nearby quadrangles were incorporated into final interpretations. Process_Date: 1979 Process_Step: Process_Description: 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. Process_Date: 2026 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: vector Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 4 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -159 Latitude_of_Projection_Origin: 0 False_Easting: 500000.000000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: .00000001 Ordinate_Resolution: .00000001 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: NAD27 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.9786982 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: mcgrath_upper_innoko_river_ak_gems_db Entity_Type_Definition: Geodatabase, layer files, style files, and fonts Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: mcgrath_upper_innoko_river_ak_gems_db Detailed_Description: Entity_Type: Entity_Type_Label: mcgrath_upper_innoko_river_gems_db Entity_Type_Definition: Geodatabase, layer files, style files, and fonts Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: mcgrath_upper_innoko_river_gems_db Detailed_Description: Entity_Type: Entity_Type_Label: mcgrath_upper_innoko_river_gems_geopackage Entity_Type_Definition: SQLite Database file Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: mcgrath_upper_innoko_river_gems_geopackage Detailed_Description: Entity_Type: Entity_Type_Label: mcgrath_upper_innoko_river_gems_shapefile Entity_Type_Definition: Shapefiles and open data files Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: mcgrath_upper_innoko_river_gems_shapefile 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: AOF 134 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: geodatabase Format_Information_Content: geologic map Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/53 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20260730 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