Geology of the Imuruk Lake area, Seward Peninsula, Alaska

Hopkins, D.M.1963Geology of the Imuruk Lake area, Seward Peninsula, AlaskageodatabaseBulletinB 1141-CUnited StatesU.S. Geological Surveyp. C1-C101, 2 sheetshttps://dggs.alaska.gov/pubs/id/3628Geology of the Imuruk Lake area, Seward Peninsula, Alaska, Bulletin 1141-C, presents a summary of the stratigraphy, glacial deposits, volcanic units, and late Cenozoic geologic history of the Imuruk Lake area on the Seward Peninsula. The sedimentary section includes a basal gravel more than 180 feet thick, a thin middle peaty lignite unit, and an upper gravel unit 3 to 90 feet thick. The middle unit contains mixed conifer and deciduous pollen similar to late Miocene and early Pliocene floras in Yakutia and the northern Alaska Range. The upper unit contains poplar and spruce or larch wood and may be early Pleistocene in age. Pleistocene deposits include glacial till and outwash of the Nome River (Illinoian) and Salmon Lake (Wisconsin) glaciations, windblown silt, stratified silt and peat, alluvial gravel, and lake sediments. Windblown silt mantles older bedrock, Kougarok gravel, and lava flows. Lake basins preserve three shoreline systems; the two older systems are warped, and the youngest is nearly horizontal. Drainage shifted from the Noxapaga River to the Kagruk River near the end of the Wisconsin glaciation. Late Cenozoic volcanic rocks cover much of the area. Five volcanic formations are distinguished by weathering profiles, frost brecciation, and silt cover: the Kagruk, Imaruk, Gosling, Camille, and Lost Jim units. Most lavas range from basalt to andesite, and a northwest trending belt produced inclusion bearing flows from shallow magma chambers. Volcanism likely occurred at intervals of several thousand years throughout late Cenozoic time. Late Cenozoic tectonic activity is recorded by warped surfaces, tilted lake basins, and fault scarps. Permafrost is widespread but thin where measured; permeable units contain thawed zones that store ground water in limestone, Kougarok gravel, lava flows, and flood plain gravel. Mineral resources include auriferous stream gravel, limonite, and diatomite. 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/3628.The purpose of this report is to document the stratigraphy, glacial deposits, volcanic units, geomorphic features, and late Cenozoic geologic history of the Imuruk Lake area on the Seward Peninsula. The information supports geologic mapping, interpretation of past environmental conditions, evaluation of permafrost and ground-water resources, and identification of local mineral resources. It provides a framework for understanding the development of sedimentary, volcanic, and glacial features and for guiding future geologic and land-use studies in the region.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/10.14509/30584.1963ground conditionCompleteNone planned-164.318714-162.73608265.89530665.310134ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAlluvialAlluviumAmphiboliteAndesiteApliteBasaltBasinsBedrockBedrock Geologic MapBedrock GeologyBiotiteContactCorrelationDioriteDriftFaultsFelsicFoldingFoldsGeologicGeologyGlacialGlacial TillGlaciationGneissGraniteGravelHornblendeIgneousIntrusiveLacustrineLacustrine DepositsLigniteLithologyMetalsMonzoniteNon-MetalsOutwashOutwash DepositsPeatPegmatiteQuartzRocksSandSchistSedimentSedimentarySiltSurficialTerraceTillVolcanicVolcanic DepositsVolcanic RocksVolcaniclasticVolcaniclastic DepositsAlaska Division of Geological & Geophysical SurveysAgnes LakeAmerican CreekAndesite CreekAndromeda ConeArizona CreekBerry CreekBilge CreekBlack ButteBlack CreekBlueberry DomeBurnt RiverBuzzard CreekCamille ConeCarex CreekCassiope ConeCaviar CreekCollins CreekCottonwood CreekCouncil Mining DistrictCrossfox ButteCygnus ConeDeep CreekDivide CreekDryas ConeErich LakeEsperanza CreekEureka CreekGoose CreekGosling ConeGranite BayGrouse CreekGrus ConeGull IslandsHannum CreekHoodoo HillHumboldt CreekImuruk LakeInmachuck RiverJoan LakeJune CreekKettle DomeKougarok Mining DistrictKoyuk RiverKugruk RiverKuzitrin LakeKuzitrin RiverLargo CreekLargo RidgeLava LakeLost Jim ConeMagnet CreekMinnie CreekMount BoyanMuskellunge CreekNelson CreekNimrod HillNoxapagaNoxapaga RiverNoyes CreekOld Glory CreekOlivine CreekPerry CreekPilgrim RiverPinnell RiverRecord CityRhododendron ConeSalix BaySandy LakeSkeleton ButteSkookum CreekSturgeon RidgeTrail CreekTurner CreekTwin CalderasVirginia ButteWinona CreekAlaska Division of Geological & Geophysical SurveysCamille BasaltGosling VolcanicsKugururok FormationLost Jim BasaltNome River GlaciationSalmon Lake GlaciationWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaCretaceousJurassicPaleozoicQuaternaryThis 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.Report and map credits include field assistance from A. T. Fernald, E. H. Muller, J. F. Seitz, R. S. Signfoos, W. B. Quay, and J. G. Sieh; logistical support from John Cross, D. H. Stewart, Charles Garnett, and John and Frank Whaley; radio support from CAA station KYTYK; technical review by M. P. Billings, R. F. Black, Kirk Bryan, R. E. Detterman, Maxim Guggisberg, T. W. V. Karlstrom, P. L. Killeen, Clyde Wahrhaftig, and J. R. Williams; and petrographic work by Joan P. Hopkins. 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.Herreid, G.H.1966Geology and geochemistry of the Inmachuk River map area, Seward Peninsula, AlaskaGeologic ReportGR 23Fairbanks, Alaska, United StatesAlaska Division of Mines and Minerals27 p., 1 sheet, scale 1:63,360https://doi.org/10.14509/352Manning, K.H.Stevens, D.L.1982The Chicago Creek and Norton Sound area coal exploration programs - 1982Public Data FilePDF 83-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys103 p., 9 sheetshttps://doi.org/10.14509/1032Retherford, R.M.Hinderman, T.K.Hawley, C.C.1986Preliminary feasibility study of a coal mine at Chicago Creek, Seward Peninsula, Alaska: summary reportReport of InvestigationRI 86-13Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys38 phttps://doi.org/10.14509/2412Robinson, M.S.Stevens, D.L.1984Geologic map of the Seward PeninsulaSpecial ReportSR 34Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:500,000https://doi.org/10.14509/2633Shallit, A.B.1941The placer deposits in the upper Kougarok, Seward Peninsula, AlaskaMiscellaneous ReportMR 44-2Fairbanks, Alaska, United StatesAlaska Territorial Department of Mines54 p., 7 sheetshttps://doi.org/10.14509/768Attribute 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 Bulletin (B), which present significant scientific data and interpretations of lasting value. Each Bulletin is considered complete for the scientific information it contains, and no additional chapters or companion volumes are required to understand the material presented.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 - The author conducted geologic mapping and field investigations across the Imuruk Lake area to document sedimentary, glacial, volcanic, and geomorphic features. Field crews measured gravel, silt, peat, and lava units; identified shoreline features; and documented permafrost, ground-water conditions, and mineral occurrences. Staff collected pollen, wood, and rock samples for laboratory analysis and completed petrographic descriptions of volcanic and sedimentary materials. Logistical support, transportation, and radio communication enabled access to field sites and coordination during both field seasons. Technical review and laboratory analysis refined geologic interpretations and supported development of the final dataset.1963Data 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 Mercator30.999600-1650500000.0000000coordinate pair.00000001.00000001MetersNAD27Clarke 18666378206.4294.9786982imuruk_lake_ak_gems_dbGeodatabase, layer files, style files, and fontsDGGS and USGSimuruk_lake_ak_gems_dbimuruk_lake_gems_dbGeodatabase, layer files, style files, and fontsDGGS and USGSimuruk_lake_gems_dbimuruk_lake_gems_geopackageSQLite Database fileDGGS and USGSimuruk_lake_gems_geopackageimuruk_lake_gems_shapefileShapefiles and open data filesDGGS and USGSimuruk_lake_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