Reconnaissance engineering geology for the selection of highway route from Talkeetna to McGrath, Alaska

Weber, F.R.1961Reconnaissance engineering geology for the selection of highway route from Talkeetna to McGrath, AlaskageodatabaseOpen-File ReportOF 61-169United StatesU.S. Geological Survey2 sheets, scale 1:250,000https://dggs.alaska.gov/pubs/id/10671Reconnaissance engineering geology for the selection of highway route from Talkeetna to McGrath, Alaska, Open-File Report 61-169, evaluates a potential highway corridor between Talkeetna and McGrath to support planning for expansion of Alaska's highway system. Field checks were completed in 1959 and 1960, and aerial photographs were used to map bedrock and surficial deposits throughout the corridor. The study provides a general geologic basis for identifying possible road routes and focuses on conditions that may influence construction. The area includes parts of the lower Susitna River valley, a narrow band across the Alaska Range, and a broad region to the northwest. Two eastern access options were examined: a route west from Talkeetna along the Petersville Road toward Rainy Pass, and a route west from Flat Lake that parallels the historic Iditarod Trail along the Susitna, Yentna, and Skwentna Rivers. Bedrock interpretation draws on published geologic reports, and geologic information for the Farewell-McGrath area is based largely on the work of Arthur T. Fernald. Geologic units were delineated primarily from aerial photographs and transferred to topographic maps; boundaries are approximate. Surficial materials important for engineering evaluation include flood plain and terrace alluvium, alluvial fans and aprons, bog deposits, talus and localized mass-movement debris, active and inactive glacial outwash, outwash fans, alpine and end moraines, multiple varieties of ground moraine, silt and colluvium over bedrock, poorly and well consolidated sedimentary rocks, granitic intrusive rocks, and volcanic rocks. Glaciation strongly affected the Susitna drainage, where large glaciers once filled the valley and overtopped nearby hills and low mountains. Older drift is commonly mantled by windblown silt. In the Kuskokwim drainage, valley glaciers advanced roughly 20 miles from the mountain front, leaving arcuate end moraines and outwash fans. Eolian sand and silt are widespread north of the range. Permafrost is sporadic in the Susitna area but widespread on the Kuskokwim side, where it must be considered in road design. Seasonal frost action can be intense in poorly drained, fine-grained sediments throughout the corridor. 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://dggs.alaska.gov/pubs/id/10671.The purpose of this study was to supply early geologic and engineering information needed to evaluate possible highway routes between Talkeetna and McGrath. The work used aerial photograph interpretation and field checks completed in 1959 and 1960 to identify terrain conditions that could have affected road construction. The results supported the State of Alaska by helping assess long-range transportation options across remote terrain, improving planning for future access to communities, resource areas, and regional corridors.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/10.14509/30584.1960ground conditionCompleteNone planned-155.780385-149.84580463.02671561.429066ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysGeMS DB L3 CompliantGeMS DB v2AerialAlluvialAlluviumBedrockColluviumDriftEngineeringEngineering GeologyEolianFanFelsicFloodGeologicGeologyGlacialGlaciationGlaciersIceIgneousInterpretationIntrusiveMorainesMountainOutwashPeatPermafrostPermafrost and PeriglacialResourcesRocksSandSedimentSedimentarySiltSlope InstabilitySurficialTalusTerraceTillVolcanicAlaska Division of Geological & Geophysical SurveysAlaskaAlexander CreekAlpineBear CreekBeaver CreekBirch CreekBlackwater CreekBonanza CreekBoulder CreekCandle CreekCanyon CreekChickak RiverChulitna RiverClear CreekCoal CreekDalzell CreekDeep CreekDeepbank CreekDillinger RiverDivide CreekDome CreekEightmile CreekFish CreekGlacier CreekGold CreekHappy RiverHayes RiverKahiltna RiverKichatna RiverKuskokwim RiverMcGrathNakochna RiverPetersvilleRedoubt Mining DistrictSalmon RiverSkwentnaSunshineSusitnaSusitna RiverTakotna RiverTalachulitna RiverTalkeetnaTalkeetna LakesTalkeetna RiverTatalina RiverTatina RiverTokositna RiverTonzona RiverTrapper CreekValdez Creek Mining DistrictYentna Mining DistrictYentna RiverThis 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

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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.This map was converted to GeMS or digitized into GeMS by Kinney Engineering, LCC., quality controlled, and then finalized by DGGS staff (Chris Wyatt). 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.Bundtzen, T.K.Laird, G.M.1980Preliminary geology of the McGrath - upper Innoko River area, western interior AlaskaAlaska Open-File ReportAOF 134Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys39 p., 2 sheetshttps://doi.org/10.14509/53Bundtzen, T.K.Laird, G.M.1983Geologic map of the McGrath D-6 Quadrangle, AlaskaProfessional ReportPR 79Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2253Bundtzen, T.K.Harris, E.E.Gilbert, W.G.1997Geologic map of the eastern half of the McGrath Quadrangle, AlaskaReport of InvestigationRI 97-14AFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys34 p., 1 sheet, scale 1:125,000https://doi.org/10.14509/2549Kline, J.T.Pinney, D.S.1997Derivative map of the geologic materials and hazards in the eastern half McGrath Quadrangle, AlaskaReport of InvestigationRI 97-14BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:125,000https://doi.org/10.14509/2550Walser, S.L.Gillis, R.J.Bernt, J.D.Salisbury, J.B.Diaz, A.V.Hubbard, T.D.2026Geologic map of the West Susitna area, parts of the Tyonek C-3, C-4, D-4, and D-5 quadrangles, AlaskaPreliminary Interpretive ReportPIR 2026-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys10 p., 2 sheets, scale 1:50,000https://doi.org/10.14509/32075Attribute 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 U.S. Geological Survey Open-File Report (OF), which provide rapid public release of scientific information. The series includes interpretive reports, maps, supporting data, preliminary findings, interim computer programs, user guides, and bibliographies.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 - Aerial photographs were examined to identify bedrock, surficial deposits, glacial features, and terrain conditions relevant to highway route evaluation. Photo interpretation was supported by field checks completed in 1959 and 1960. Geologic units were delineated on the photographs, transferred to topographic maps, and classified according to engineering significance. Surficial materials were grouped into alluvial, bog, colluvial, mass-movement, glacial, eolian, and bedrock units to support assessment of construction conditions. Boundaries were considered approximate due to the reconnaissance nature of the work.1960Data 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 Mercator50.999600-1530500000.0000000coordinate pair.00000001.00000001MetersNAD27Clarke 18666378206.4294.9786982talkeetna_to_mcgrath_ak_gems_dbGeodatabase, layer files, style files, and fontsDGGS and USGStalkeetna_to_mcgrath_ak_gems_dbtalkeetna_to_mcgrath_gems_dbGeodatabase, layer files, style files, and fontsDGGS and USGStalkeetna_to_mcgrath_gems_dbtalkeetna_to_mcgrath_gems_geopackageSQLite Database fileDGGS and USGStalkeetna_to_mcgrath_gems_geopackagetalkeetna_to_mcgrath_gems_shapefileShapefiles and open data filesDGGS and USGStalkeetna_to_mcgrath_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