Bedrock geologic map of the Delta mineral belt, Tok mining district, Alaska

Dashevsky, S.S.Schaefer, C.F.Hunter, E.N.2003Bedrock geologic map of the Delta mineral belt, Tok mining district, AlaskageodatabaseProfessional ReportPR 122Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys122 p., 2 sheets, scale 1:63,360https://doi.org/10.14509/2923Bedrock geologic map of the Delta mineral belt, Tok mining district, Alaska, Professional Report 122, presents the first published, field scale map that shows the metamorphic rock units and mineralization of the Delta mineral belt, integrating decades of exploration data and new geologic interpretation. It incorporates extensive but previously unpublished reconnaissance mapping completed in the 1970s by RAA, Anaconda, and ACNC, including the 1:30,000 scale traverse maps that documented metamorphic lithologies before later protolith focused mapping obscured those details. Earlier regional syntheses, such as the 1982 protolith based map by Duke and Nauman and the 1985 metamorphic and tectonic framework by Duke, provided important foundations but lacked the petrographic and geochemical constraints needed for reliable correlation. Through new mapping, lithochemistry, geophysics, drilling, and radiometric dating, this report revises stratigraphic order, unit ages, contacts, and deposit relationships, producing a modern 1:63,360 scale geologic map that clarifies the distribution and setting of massive sulfide mineralization in the eastern Alaska Range. 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 Alaska Division of Geological & Geophysical Surveys website: http://doi.org/10.14509/2923.This geologic map provides updated bedrock geologic mapping of Alaska's Yukon-Tanana Upland regaion to support mineral-resource evaluation, improve understanding of the region's geologic framework, and inform studies of both known mineralization and critical-mineral potential. The resulting geologic information supports responsible resource development, guides land-management decisions, and strengthens the State of Alaska's understanding of its mineral-resource base.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/10.14509/3058419942026ground conditionCompleteNone planned-144.503735-143.74808563.39303663.096723ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAge DatesAlluvial DepositsAr-ArBedrockBedrock Geologic MapBedrock GeologyDikeExplorationFaultingFaultsFormationsGabbroGeMS DB L3 CompliantGeMS DB v2GeochemistryGeochronologyGeologicGeologic MapGeologyGlacial DepositsGold ProspectGraniteHistoric MineIgneousIgneous RocksLithologyMassive Sulfide DepositsMassive Sulfide OccurrenceMassive Sulfide ProspectMetamorphicMetamorphic RocksMetamorphismMetavolcanicsMineral DepositsMineral ProspectMineralsMiningPhyllitePlutonicPlutonic RocksPlutonsResource AssessmentRocksSchistU-PbUnconsolidated DepositsAlaska Division of Geological & Geophysical SurveysAlaska, State ofBlitz HillChistochina Mining DistrictDry Tok CreekMississippi ValleyRobertson RiverRumble CreekSheep CreekShindata CreekSlana RiverStibnite CreekTok GlacierTok Mining DistrictTok RiverTushtena PassWhite CreekAlaska Division of Geological & Geophysical SurveysDelta Mineral BeltDrum UnitHayes Glacier BeltJarvis BeltLagoon UnitMacomb BeltTiger UnitTok River UnitTushtena Pass UnitYukon-Tanana TerraneWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaCenozoicCretaceousDevonianJurassicMesozoicPaleozoicQuaternaryTertiaryTriassicThis 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).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.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease 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.The data in this report were generated through exploration work funded by American Copper and Nickel Company, with fieldwork carried out over five seasons by the authors and ACNC teams, building on earlier unpublished mapping by Resource Associates of Alaska and partner companies. Key ACNC contributors included Edward Hunter, Sam Dashevsky, Carl Schaefer, Katherine Bull, Noelle Shriver, Roderick MacInnes, and William Shalosky, with essential support from helicopter pilots Owen Jones and Walter Greaves and mountaineer-engineer Meine Huser. Additional expertise in lithochemical interpretation and geophysics was provided by David Burrows, Edward Pattisson, Bob Lo, and Pat McGowan, while Phil Rush guided the overall exploration strategy. Publication of these results was made possible through the cooperation of Grayd Resource Corporation and the Alaska Division of Geological and Geophysical Surveys, with further improvements from reviewers Rainer Newberry, Laurel Burns, Ellen Daley, Cynthia Dusel-Bacon, Karen Clautice, and Barry Hoffman. 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.Schaefer, C.F.Dashevsky, S.S.2001Whole-rock major oxide and trace element analyses for rock samples from the Delta Mineral Belt, Tok mining district, AlaskaRaw Data FileRDF 2001-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys3 p., 1 sheet, scale 1:63,360, 1 DVDhttps://doi.org/10.14509/2868Attribute 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.All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications.This publication is a DGGS Professional Report (PR). PRs present synthesized, broad-scale, high-level scientific interpretations that integrate extensive geological mapping and analytical research, often reflecting work conducted over many years. They undergo rigorous peer review and revision.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.Ekberg, P.G.Hendricks, M.D.Athey, J.E.2021AK GeMS symbology: A description of the AK GeMS style fileMiscellaneous PublicationMP 169Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys7 phttps://doi.org/10.14509/30584paper2021publication dateEkberg, P.G. and others, 2021GIS analysis and digital cartographyHendricks, M.D.Ekberg, P.G.Athey, J.E.Wyatt, W.C.Willingham, A.L.Naibert, T.J.2021AK GeMS data dictionary: A description of the Alaska geologic mapping schemaMiscellaneous PublicationMP 170Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys10 phttps://doi.org/10.14509/30669paper2021publication dateHendricks, M.D. and others, 2021GIS analysis and digital cartographyU.S. Geological Survey National Cooperative Geologic Mapping Program2020GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic mapsTechniques and MethodsTM 11-B10United StatesU.S. Geological Survey1 phttps://dggs.alaska.gov/pubs/id/30585paper2020publication dateU.S. Geological Survey National Cooperative Geologic Mapping Program, 2020GIS analysis and digital cartographyGeologic mapping - DGGS Mineral Resources Section staff conducted bedrock geologic mapping across the 14,530-sq-km Chena-Pogo project area during the 2023-2025 field seasons. During fieldwork, crews collected 4,800 bedrock observation stations, 429 geochemical samples, and 51 geochronology samples, and measured magnetic-susceptibility values to support map-unit characterization. In addition, previously published DGGS and USGS maps covering portions of the project area were compiled and modified by correlating original map units to those used in this publication, removing surficial deposits where present, simplifying geologic detail for display at 1:100,000 scale, and updating interpretations based on new field and analytical data. To organize the final mapping, the project was divided into four 1:100,000-scale map sheets (NW Chena, NE Chena, SW Chena, and SE Chena). Across these sheets, map units were standardized and described in the accompanying report. For GIS distribution, the four maps were combined into a single geologic map database formatted in both the Geologic Mapping Schema (GeMS) and the Alaska Geologic Mapping Schema (AK GeMS).2026Data 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.2026vectorUniversal Transverse Mercator60.999600-1470500000.0000000coordinate pair.00000001.00000001MetersNAD27Clarke 18666378206.4294.9786982delta_mineral_belt_ak_gems_dbGeodatabase, layer files, style files, and fontsDGGSdelta_mineral_belt_ak_gems_dbdelta_mineral_belt_gems_dbGeodatabase, layer files, style files, and fontsDGGSdelta_mineral_belt_gems_dbdelta_mineral_belt_gems_geopackageSQLite Database fileDGGSdelta_mineral_belt_gems_geopackagedelta_mineral_belt_gems_shapefileShapefiles and open data filesDGGSdelta_mineral_belt_gems_shapefileAlaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If 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.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions