Bedrock geologic map of the Eagle A-1 Quadrangle, Fortymile mining district

Szumigala, D.J.Newberry, R.J.Werdon, M.B.Athey, J.E.Flynn, R.L.Clautice, K.H.2002Bedrock geologic map of the Eagle A-1 Quadrangle, Fortymile mining districtgeodatabasePreliminary Interpretive ReportPIR 2002-1BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2864Geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted field investigations and geochemical rock sampling during the 1999, 2000, and 2001 field seasons to produce a 1:63,360 scale bedrock map of the Eagle A-1 Quadrangle, Alaska. Rock outcrop throughout the field area is limited; consequently, the map interpretation relies heavily on airborne magnetic and electromagnetic survey data and accompanying geochemical analysis of rock samples. Field investigations are part of a three-year mapping program to provide geologic ground truth for airborne geophysical surveys flown by DGGS in the Fortymile mining district during 1998. This work aims to build an improved understanding of the area's geology and controls on gold mineralization for purposes of exploration targeting and mineral-resource assessment. The complete report, geodatabase, and ESRI fonts and style files are available from the DGGS website: http://doi.org/10.14509/2864.This project and resulting map and data are intended to provide a geologic map and geologic interpretation of a portion of the Fortymile mining district at 1:63,360 scale. Previous published geologic maps at a 1:63,360 scale of this area have been reconnaissance-level maps or only covered portions of the quadrangle. Mapping at 1:63,360 scale or greater detail is needed to identify geologic features that may relate to more regional structures, geologic units, or mineralization. These detailed observations are also critical to test or use in tectonic models and this map also provides a geologic base in which to interpret geochemical results from the concurrent DGGS rock sampling program.This geodatabase is a digital geologic map produced by the Alaska Division of Geological & Geophysical Surveys. The features, fields, and allowable values for this geodatabase object are defined in Hendricks, M.D., Ekberg, P.G., Athey, J.E., Wyatt, W.C., Willingham, A.L., and Naibert, T.J., 2021, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 170, 10 p. https://doi.org/10.14509/30669, which is adapted from U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic maps: U.S. Geological Survey Techniques and Methods, Book 11, chap. B10, 74 p. https://doi.org//10.3133/tm11B10.2001ground conditioncompleteNone planned-142.011317-141.00000064.25310363.996231ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysBedrockBedrock Geologic MapBedrock GeologyBoundaryGeochronologyGeologic MapGeologyIgneous RocksKlondike SeriesMetamorphic RocksSTATEMAP ProjectThe Great DikeAlaska Division of Geological & Geophysical SurveysAlaska, State ofFortymile Mining DistrictFortymile RiverJack Wade JunctionMinchumina BasinSteele Creek DomeTaylor HighwayTop of the World HighwayAlaska Division of Geological & Geophysical SurveysFortymile River AssemblageNasina AssemblageSeventymile TerraneWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaCenozoicCretaceousDevonianJurassicMesozoicMississippianPaleozoicPennsylvanianPermianTertiaryTriassicThis 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 geologic mapping was funded by the Alaska State Legislature through a Capital Improvement Project (Alaska Airborne Geophysical/Geological Mineral Inventory Program) and the general fund and through the U.S. Geological Survey STATEMAP program under U.S. Department of the Interior, U.S. Geological Survey, National Cooperative Geologic Mapping Program assistance award 01HQAG0054. 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. DGGS student interns and volunteers providing field assistance include Bryan A. Finseth (1999), Mark Mccrary (1999), J.C. Grady (2000), W.C. Munley (2000), and M.R. Johnson (2001). Milton A. Wiltse provided technical review of the maps.DGGS StaffSzumigala, D.J.2000Alaska GeoSurvey News - Mineral-oriented geologic mapping of the Fortymile mining districtNewsletterNL 2000-3Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys9 phttps://doi.org/10.14509/14585Pinney, D.S.2001Engineering - geologic map of the Eagle A-2 Quadrangle, Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2001-3DFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2672Pinney, D.S.2001Surficial-geologic map of the Eagle A-2 Quadrangle, Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2001-3CFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2671Stevens, D.S.P.2012Engineering - geologic map of the Eagle A-1 Quadrangle, Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2002-1DFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/24544Stevens, D.S.P.Burns, P.A.C.2010Surficial-geologic map of the Eagle A-1 Quadrangle, Fortymile mining districtPreliminary Interpretive ReportPIR 2002-1CFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/22081Szumigala, D.J.Newberry, R.J.Werdon, M.B.Athey, J.E.Stevens, D.S.P.Flynn, R.L.Clautice, K.H.Craw, P.A.2002Geologic map of the Eagle A-1 Quadrangle, Fortymile mining districtPreliminary Interpretive ReportPIR 2002-1AFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2863Szumigala, D.J.Newberry, R.J.Werdon, M.B.Finseth, B.A.Pinney, D.S.Flynn, R.L.2000Major-oxide, minor-oxide, trace-element, and geochemical data from rocks collected in a portion of the Fortymile mining district, Alaska, 1999Raw Data FileRDF 2000-1 v. 1.0.1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys24 p., 2 sheets, scale 1:63,360https://doi.org/10.14509/2727Szumigala, D.J.Newberry, R.J.Werdon, M.B.Finseth, B.A.Pinney, D.S.2000Preliminary bedrock geologic map of a portion of the Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2000-6Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2734Szumigala, D.J.Werdon, M.B.Newberry, R.J.Athey, J.E.Clautice, K.H.Flynn, R.L.Grady, J.C.Munly, W.C.Johnson, M.R.2002Major-oxide, minor-oxide, trace-element, rare-earth element, trace geochemical, and coal quality data from rocks collected in the Eagle and Tanacross quadrangles, Alaska in 1999, 2000, 2001Raw Data FileRDF 2002-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys35 p., 1 sheet, scale 1:63,360https://doi.org/10.14509/2866Werdon, M.B.Newberry, R.J.Szumigala, D.J.Pinney, D.S.2001Geologic map of the Eagle A-2 Quadrangle, Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2001-3AFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2669Werdon, M.B.Newberry, R.J.Szumigala, D.J.2001Bedrock geologic map of the Eagle A-2 Quadrangle, Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2001-3BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/2670Werdon, M.B.Szumigala, D.J.Newberry, R.J.Grady, J.C.Munly, W.C.2000Major-oxide, minor-oxide, trace-element, rare-earth element, and geochemical data from rocks collected in Eagle and Tanacross quadrangles, Alaska in 2000Raw Data FileRDF 2000-4Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys29 p., 3 sheets, scale 1:63,360https://doi.org/10.14509/2729Certainty in attribute interpretation varies throughout the map and is scale dependant. Attribute fields within each feature class record the author's degree of confidence in the existence or identity of applicable features.All polygon features were topologically validated according to specifications of the AK GeMS geologic mapping schemaThis publication is a DGGS Preliminary Interpretive Report (PIR). This category is intended for the timely release of maps and reports with preliminary interpretation of geology or analytical data. It includes reports by DGGS staff, scientists from other organizations, and contractor reports containing technical interpretations of analytical data. Maps and reports have been reviewed by one or two people for technical content.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 author's degree of confidence in the location of applicable features.DGGS StaffGeoterrex-DighemStevens Exploration Management Corp.1999CD-ROM containing profile and gridded data and section lines of the 1998 geophysical survey data for part of the Fortymile mining district, Alaska, southern Eagle and northern Tanacross quadranglesPublic Data FilePDF 99-9Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 DVDhttps://doi.org/10.14509/1886paper1999publication dateDGGS Staff and others, 1999Bedrock mappingEkberg, 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/10.14509/30584digital2021publication dateEkberg, P.G. and others, 2021GeMS conversionFoster, H.L.1969Reconnaissance geology of the Eagle A-1 and A-2 quadrangles, AlaskaBulletinB 1271-GUnited StatesU.S. Geological Surveyp. G1-G30, 1 sheet, scale 1:63,360https://dggs.alaska.gov/pubs/id/365863360paper1969publication dateFoster, H.L., 1969Bedrock mappingGray, J.E.Riehle, J.R.1998Geologic studies in Alaska by the U.S. Geological Survey, 1996Professional PaperP 1595United StatesU.S. Geological Survey200 phttps://dggs.alaska.gov/pubs/id/4025paper1998publication dateGray, J.E. and Riehle, J.R., 1998Bedrock mappingHendricks, M.D.Ekberg, P.G.Athey, J.E.Wyatt, W.C.2020AK GeMS data dictionary: A description of the AK GeMS database schemaMiscellaneous PublicationMP 168Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveyshttps://doi.org/10.14509/30583digital2020publication dateHendricks, M.D. and others, 2020GeMS conversionNeuendorf, K.K.E.Mehl, J.P., Jr.Jackson, J.A.2011Glossary of GeologyAlexandria, VirginiaAmerican Geological Institute799 phttps://www.americangeosciences.org/pubs/glossarydigital2011publication dateNeuendorf, K.K.E. and others, 2011GeMS conversionNewberry, R.J.Layer, P.W.Burleigh, R.E.Solie, D.N.1998New 40Ar/39Ar dates for intrusions and mineral prospects in the eastern Yukon-Tanana terrane, Alaska; regional patterns and significanceProfessional PaperP 1595United StatesU.S. Geological Surveyp. 131-159https://dggs.alaska.gov/pubs/id/4120paper1998publication dateNewberry, R.J. and others, 1998, p. 131-159Bedrock mappingSzumigala, D.J.Newberry, R.J.Werdon, M.B.Athey, J.E.Flynn, R.L.Clautice, K.H.2002Bedrock geologic map of the Eagle A-1 Quadrangle, Fortymile mining districtPreliminary Interpretive ReportPIR 2002-1BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/286463360paper2002publication dateSzumigala, D.J. and others, 2002Bedrock mappingSzumigala, D.J.Newberry, R.J.Werdon, M.B.Athey, J.E.Stevens, D.S.P.Flynn, R.L.Clautice, K.H.Craw, P.A.2002Geologic map of the Eagle A-1 Quadrangle, Fortymile mining districtPreliminary Interpretive ReportPIR 2002-1AFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/286363360paper2002publication dateSzumigala, D.J. and others, 2002Bedrock mappingSzumigala, D.J.Newberry, R.J.Werdon, M.B.Finseth, B.A.Pinney, D.S.Flynn, R.L.2000Major-oxide, minor-oxide, trace-element, and geochemical data from rocks collected in a portion of the Fortymile mining district, Alaska, 1999Raw Data FileRDF 2000-1 v. 1.0.1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys24 p., 2 sheets, scale 1:63,360https://doi.org/10.14509/272763360paper2000publication dateSzumigala, D.J. and others, 2000Bedrock mappingSzumigala, D.J.Werdon, M.B.Newberry, R.J.Athey, J.E.Clautice, K.H.Flynn, R.L.Grady, J.C.Munly, W.C.Johnson, M.R.2002Major-oxide, minor-oxide, trace-element, rare-earth element, trace geochemical, and coal quality data from rocks collected in the Eagle and Tanacross quadrangles, Alaska in 1999, 2000, 2001Raw Data FileRDF 2002-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys35 p., 1 sheet, scale 1:63,360https://doi.org/10.14509/286663360paper2002publication dateSzumigala, D.J. and others, 2002Bedrock mappingU.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/30585digital2020publication dateU.S. Geological Survey National Cooperative Geologic Mapping Program, 2020GeMS conversionWalker, J.D.Geissman, J.W.Bowring, S.A.Babcock, L.E.2018Geologic Time Scale v. 5.0Boulder, COGeological Society of Americahttps://www.geosociety.org/documents/gsa/timescale/timescl.pdfdigital2018publication dateWalker, J.D. and others, 2018GeMS conversionWerdon, M.B.Newberry, R.J.Szumigala, D.J.2001Bedrock geologic map of the Eagle A-2 Quadrangle, Fortymile mining district, AlaskaPreliminary Interpretive ReportPIR 2001-3BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheet, scale 1:63,360https://doi.org/10.14509/267063360paper2001publication dateWerdon, M.B. and others, 2001Bedrock mappingWerdon, M.B.Szumigala, D.J.Newberry, R.J.Grady, J.C.Munly, W.C.2000Major-oxide, minor-oxide, trace-element, rare-earth element, and geochemical data from rocks collected in Eagle and Tanacross quadrangles, Alaska in 2000Raw Data FileRDF 2000-4Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys29 p., 3 sheets, scale 1:63,360https://doi.org/10.14509/272963360paper2000publication dateWerdon, M.B. and others, 2000Bedrock mappingWilson, F.H.Galloway, J.P.2002Studies by the U.S. Geological Survey in Alaska, 2000Professional PaperP 1662United StatesU.S. Geological Survey149 phttps://dggs.alaska.gov/pubs/id/4050paper2002publication dateWilson, F.H. and Galloway, J.P., 2002Bedrock mappingYeend, W.E.1996Gold placers of the historical Fortymile River region, AlaskaBulletinB 2125United StatesU.S. Geological Survey75 p., 1 sheet, scale 1:63,360https://dggs.alaska.gov/pubs/id/378163360paper1996publication dateYeend, W.E., 1996Bedrock mappingBedrock mapping - During the summers of 1999 through 2001, DGGS conducted a geologic field mapping project to provide geologic ground truth for airborne geophysical surveys flown in the Fortymile mining district in 1998. DGGS efforts are focused on determining and understanding the geologic framework of the Fortymile mining district, especially with respect to placer gold and lode mineral deposits. Fieldwork for bedrock investigations, including ridge traverses, roadcut investigations, and river exposures, was conducted for 374 person-days during the months of June through August in 1999 - 2001. Field notes and rock samples were collected at more than 3,880 stations throughout the quadrangle for bedrock investigations. Sixty person-days were spent on field investigations for the surficial geology. Bedrock mappers recorded observations on 1:50,000-scale topographic maps of the quadrangle. Stations were located using handheld GPS devices with location precision varying from 3 to 15 meters. Selected rock samples were analyzed for age and geochemical properties. Laboratory analyses were performed on rock samples collected during the fieldwork from July 1999 intermittently through April 2002. Published geochemical and age results are found in Newberry and others (1998), Szumigala and others (2000, 2002), Werdon and others (2000), Flynn and Newberry (2001), Layer and others (in prep.), and Day and others (in press). Unpublished laboratory results include petrographic work on thin sections and modal analysis of rock slabs stained for plagioclase and potassium feldspar. Results from major-oxide and trace-element geochemistry of igneous and metamorphic rocks were used to calculate CIPW Norms for use in classifying rocks according to established petrologic nomenclature. The map unit interpretation relies heavily on airborne magnetic and electromagnetic survey data and rock geochemistry.DGGS Staff and others, 1999Foster, H.L., 1969Gray, J.E. and Riehle, J.R., 1998Newberry, R.J. and others, 1998, p. 131-159Szumigala, D.J. and others, 2002Szumigala, D.J. and others, 2002Szumigala, D.J. and others, 2000Szumigala, D.J. and others, 2002Werdon, M.B. and others, 2001Werdon, M.B. and others, 2000Wilson, F.H. and Galloway, J.P., 2002Yeend, W.E., 19962001Digital cartography - Bedrock data were compiled on multiple layers of stable mylar at 1:50,000 scale, with some information plotted at 1:25,000 scale for more detail and later transferred to 1:50,000-scale mylar layers. Data were queried from Microsoft Access 2000 databases, imported into GIS software, and plotted on mylar at 1:50,000 scale to answer specific geologic questions. Relevant information from all mylar layers was compiled onto one stable mylar sheet with abundant control points. The bedrock-geologic map compilation mylar was scanned by a large-format scanner and saved as a TIFF image. The TIFF image was registered into MapInfo Professional 6.5 with multiple registration points, and a registration error of approximately 2.7 meters (RMS error) was obtained. Geologic contacts and unit polygons were digitized using MapInfo Professional 6.5. and ArcInfo 7.0.4. GPS values of point features were imported from spreadsheets and coded according to the attribute specifications.2001Technical review - The geologic map was evaluated for technical content by geologists familiar with the map area, and reviewer feedback was incorporated into the final product.2001Data release - The report and map were published, and GIS products were compiled and released in shapefile format.2001GeMS conversion - The geologic and geographic features portrayed in this data distribution package were organized and attributed according to the AK GeMS geologic mapping schema and derivative files using the USGS GeMS standard were created. These revised data packages replace files provided in the initial, 2002, release.Ekberg, P.G. and others, 2021Hendricks, M.D. and others, 2020Neuendorf, K.K.E. and others, 2011U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020Walker, J.D. and others, 20182021vectorUniversal Transverse Mercator70.999600-1410500000.0000000coordinate pair.00000001.00000001MetersNAD27Clarke 18666378206.40000000037294.978698199999997eagle_a1_bedrock_geology_ak_gems_db_pkggeodatabase, layer files, style files, and fontsAlaska Division of Geological & Geophysical SurveysAK GeMS geodatabase packageeagle_a1_bedrock_geology_fed_gems_db_pkggeodatabase, layer files, style files, and fontsAlaska Division of Geological & Geophysical SurveysFed GeMS geodatabase packageeagle_a1_bedrock_geology_fed_gems_shapefile_pkgshapefiles and open data filesAlaska Division of Geological & Geophysical SurveysFed GeMS shapefile packageAlaska 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