{"action":"create","ckan_id":null,"date_created":"Sat, 04 Apr 2026 21:43:42 GMT","date_finished":null,"harvest_job_id":"b4f05016-c02c-40b9-a865-63417fc9765b","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"21b3c51a-5f3f-411f-aac8-041da0260bac","identifier":"https://dggs.alaska.gov/webpubs/metadata/RDF2023-23.xml","parent_identifier":null,"source_hash":"897ca455951c7c410ec5d56884ae2766d4ec11ba84510094028ead19a0606a77","source_raw":"Naibert, T.J.Heizler, M.T.Newberry, R.J.Twelker, EvanWypych, Alicja202340Ar/39Ar geochronology data from the Tanacross and Eagle quadrangles, AlaskacsvRaw Data FileRDF 2023-23Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys19 p.https://doi.org/10.14509/3108540Ar/39Ar geochronology data from the Tanacross and Eagle quadrangles, Alaska, Raw Data File 2023-23, provides 40Ar/39Ar geochronology data from igneous and metamorphic rocks in or adjacent to the DGGS Western Tanacross and Taylor Mountain geologic mapping project areas. Western Tanacross and Taylor Mountain geologic mapping projects aim to produce more accurate and integrated modern geologic maps and supporting datasets to promote mineral resource exploration in eastern Interior Alaska. The Tanacross and southern Eagle quadrangles are within the Yukon Tanana Uplands, which DGGS and USGS identified as having the potential to host deposits of multiple critical minerals, as well as gold, copper, molybdenum, lead, zinc, and silver. Most of the known mineralization in the region is related to Mesozoic-Paleogene magmatism. Igneous rocks intrude a composite metamorphic province that includes parautochthonous North America and the allochthonous Yukon Tanana Terrane, which are multiply deformed and apparently juxtaposed along low-angle faults. Samples were collected (2009, 2018, 2019, 2021) for 40Ar/39Ar geochronology to understand the crystallization ages of igneous rocks, the exhumation history of metamorphic rocks, and the timing of mineralization. The 22 40Ar/39Ar ages reported here include six mineralization/alteration ages, one volcanic crystallization age, seven metamorphic cooling ages from the Yukon-Tanana terrane (YTT), and eight metamorphic cooling ages from parautochthonous North American rocks (pNA). The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files. These data are available from the DGGS website: http://doi.org/10.14509/31085.The purpose of the Western Tanacross and Taylor Mountain projects is to produce more accurate, detailed, and modern geologic maps and supporting datasets that will promote mineral resource exploration in eastern Interior Alaska. The Tanacross and southern Eagle quadrangles are within the Yukon Tanana Uplands, which DGGS and USGS identified as having the potential to host deposits of multiple critical minerals, as well as gold, copper, molybdenum, lead, zinc, and silver.>data: Identification numbers, coordinates, sample descriptions, and summary ages of each sample; power output levels and resultant measurements from each sample run; and an index of the contents, format, and structure of the data.20212023ground conditionCompleteNone planned-143.839740-141.02599064.25582063.068960ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical Surveys40Ar/39ArAge DatesAlteration ProductsAnalysesAnalyses and SamplingAnalytical Lab ResultsAnalytical ResultsAr-ArAugen GneissBedrockBedrock GeologyDGGSExhumationExplorationGeochronologyGeologicGeologyIgneousIgneous RocksIsotopesK-FeldsparLab MethodsMetamorphicMetamorphic RocksMetamorphismMethodsMineral ResourcesMineralsOrthogneissRocksSample LocationSchistSkarnTrachybasaltVein DepositAlaska Division of Geological & Geophysical SurveysFortymile Mining DistrictGold CreekGoodpaster Mining DistrictIngle CreekLilliwig CreekMcElfish CreekMosquito Fork of the Fortymile RiverTaylor MountainTok Mining DistrictYukon-Tanana UplandAlaska Division of Geological & Geophysical SurveysChicken Metamorphic ComplexFortymile River AssemblageJarvis BeltLadue River UnitLake George AssemblageYukon-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 AmericaCretaceousJurassicMesozoicPaleozoicThis 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.U.S. Geological Survey EarthMRI funded sample collection and analyses for the Western Tanacross and Taylor Mountain projects awards G20AC00156 and G21AC10336 and State of Alaska capital project funds. Sample analyses for the compilation mapping in the eastern Yukon Tanana Upland were funded by USGS STATEMAP award G21AC10706. We are grateful to have had access to Doyon Limited lands within the study area. We thank the USGS for lending us core samples from the Fish prospect. 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.Gavel, M.M.Regan, S.P.Holland, MarkWildland, A.D.Wypych, AlicjaNaibert, T.J.Twelker, Evan2023U-Pb zircon geochronology of bedrock samples collected in the Eagle and Tanacross quadrangles, eastern AlaskaPreliminary Interpretive ReportPIR 2023-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys38 phttps://doi.org/10.14509/31013Solie, D.N.Werdon, M.B.Freeman, L.K.Newberry, R.J.Szumigala, D.J.Speeter, G.G.Elliott, B.A.2019Bedrock-geologic map, Alaska Highway corridor, Tetlin Junction, Alaska to Canada borderPreliminary Interpretive ReportPIR 2019-3Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys16 p., 2 sheets, scale 1:63,360https://doi.org/10.14509/30038Twelker, EvanNewberry, R.J.Wypych, AlicjaNaibert, T.J.Wildland, A.D.Sicard, K.R.Regan, S.P.Athey, J.E.Wyatt, W.C.Lopez, J.A.2021Bedrock geologic map of the Ladue River-Mount Fairplay area, Tanacross and Nabesna quadrangles, AlaskaReport of InvestigationRI 2021-5AFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveysp. 1-32, 1 sheet, scale 1:100,000https://doi.org/10.14509/30735Twelker, EvanNewberry, R.J.Wypych, AlicjaSicard, K.R.Naibert, T.J.2020Mineral occurrences in the Tok River area, eastern Alaska RangeReport of InvestigationRI 2020-8Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys49 phttps://doi.org/10.14509/30471Wypych, AlicjaHubbard, T.D.Naibert, T.J.Athey, J.E.Newberry, R.J.Sicard, K.R.Twelker, EvanWerdon, M.B.Willingham, A.L.Wyatt, W.C.Lockett, A.C.2021Northeast Tanacross geologic map and map units and descriptionsReport of InvestigationRI 2020-9BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveysp. 9-26, 1 sheet, scale 1:63,360https://doi.org/10.14509/30539This data set is being released into the DGGS Raw Data File series. The information has been examined by several geologists familiar with the study area, but the data and accompanying report have not been formally reviewed for technical content or for conformity to the editorial standards of DGGS. The originating lab can best answer questions about the analytical values or procedures.Not applicableThis data release is complete.Sample 21RN612 from the Fish prospect is from a drill core obtained by Rainer Newberry from the USGS. Sample location coordinates for the DGGS samples (in WGS84 datum) were obtained using GPS-enabled field tablets with a typical reported accuracy of about 10 meters.Fieldwork - DGGS field geologists collected fresh, unweathered samples from surface outcrops based on the presence of sufficiently large crystals appropriate for dating. Sample 21RN612 from the Fish prospect is from a drill core obtained by Rainer Newberry from the USGS. Sample location coordinates (in WGS84 datum) were obtained using GPS-enabled field tablets with a typical reported accuracy of +/- 10 meters. Samples were examined under a binocular microscope and/or in thin section to select unaltered mineral phases before sample preparation.2021Sample preparation - Twenty-seven samples were submitted to the New Mexico Geochronological Research Laboratory (NMGRL) in Socorro, New Mexico. Twenty-two samples yielded acceptable mineral separates for 40Ar/39Ar geochronology. Muscovite, biotite, phlogopite, hornblende, and sericite were separated from rock samples using standard magnetic, heavy liquid, and handpicking procedures. The samples were loaded into machined aluminum discs and irradiated for 20 hours at the USGS reactor in Denver, Colorado (NM-327), along with the Fish Canyon Tuff sanidine standard (FC-2; assigned age - 28.201 Ma; Kuiper and others, 2008) as a neutron flux monitor.2022Geochronology analysis - After irradiation, the samples and monitors were analyzed by step-heating with a defocused 810 nm diode laser. The samples were step-heated using between 10 and 17 increments, and most separates yielded moderate-quality to complex age-spectra patterns. Reactive gases were removed by a 45-second reaction with a SAES GP-50 getter at 450 degrees C, and gas was also exposed to a cold finger at -140 degrees C. The samples were analyzed in a Thermo-Fisher Scientific Helix MC-plus mass spectrometer at NMGRL. Total system blanks were 3.5 x 10^-17 mol 40Ar, 8 x 10^-18 mol 39Ar, 5 x 10^-19 mol 38Ar, 3 x 10^-18 mol 37Ar, 5 x 10^-19 mol 36Ar. Isotopic ratios were corrected for blank, radioactive decay, and mass discrimination but were not corrected for interfering reactions. Note: Complete list of references can be found in the accompanying report.2022point0.0000010.000001decimal degreesWGS84WGS 846378137298.257223563rdf2023-23-step-heating-data.csv, rdf2023-23-step-heating-data-dictionary.csv, rdf2023-23-summary-data.csv, rdf2023-23-summary-data-dictionary.csvIdentification numbers, coordinates, sample descriptions, and summary ages of each sample; power output levels and resultant measurements from each sample run; and an index of the contents, format, and structure of the data.Alaska Division of Geological & Geophysical Surveys (DGGS) and New Mexico Geochronological Research Laboratory (NMGRL)dataAlaska 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.RDF 2023-23The 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.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.Contact DGGS for current pricingcsv20231201tablehttps://doi.org/10.14509/31085Free download20231201Alaska Division of Geological & Geophysical SurveysSimone MontayneMetadata 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","source_transform":null,"status":"error"}