{"action":"create","ckan_id":null,"date_created":"Sat, 28 Mar 2026 21:13:07 GMT","date_finished":null,"harvest_job_id":"c87df6d4-55a4-4157-8f97-1f84fe294e8c","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"6c00209c-e50d-4724-b221-b41555a6d122","identifier":"https://dggs.alaska.gov/webpubs/metadata/RDF2025-1.xml","parent_identifier":null,"source_hash":"eeb50dc22b5a5ff1d372f31401eb12b68ccb5dca9394ca85216c4f7dd6a254eb","source_raw":"Layer, P.W.Drake, JeffreyAthey, J.E.Naibert, T.J.202540Ar/39Ar data from the northern Fairbanks mining district, Circle Quadrangle, AlaskacsvRaw Data FileRDF 2025-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys8 p.https://doi.org/10.14509/3147240Ar/39Ar data from the northern Fairbanks mining district, Circle Quadrangle, Alaska, Raw Data File 2025-1, presents 40Ar/39Ar step-heating geochronology results for igneous and metamorphic rocks from the Alaska Division of Geological & Geophysical Surveys' (DGGS) geologic mapping project in the northern Fairbanks mining district, covering parts of the Circle A-4, A-5, B-4, and B-5 quadrangles, Alaska. Field samples were collected by the DGGS Mineral Resources Section during a detailed geologic mapping campaign in June 2007. In addition to analytical data compiled in the geologic map for this area, other DGGS publications supporting geologic mapping in the northern Fairbanks mining district include geophysical data, geochemical data, and a planned U-Pb detrital zircon age report. The northern Fairbanks mining district map area lies within the Yukon-Tanana Upland in rocks that we interpret to correlate with the Cambrian to Late Proterozoic Fairbanks schist and the Wickersham Grit unit. These rocks are intruded by several phases of plutonism, of which two occur in the map area: Tertiary and Cretaceous plugs, dikes, and sills with characteristic geochemical signatures. The Cretaceous intrusions are regionally associated with placer- and lode-gold mines and occurrences. The age data in this report constrain the crystallization ages of igneous rocks, the potential timing of mineralization, and the cooling histories of metamorphic rocks in the map area. These data and report are available from the DGGS website: http://doi.org/10.14509/31472.This work furthers our understanding of potential mineral resources in the Circle A-4, A-5, B-4, and B-5 quadrangles of the northern Fairbanks mining district map area, which lies within Alaska's Yukon-Tanana Upland.>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.20072025ground conditionCompleteNone planned-146.450877-146.14276265.39804365.226045ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical Surveys40Ar/39ArAge DatesArsenopyriteBedrockCrystalsDGGSExplorationGeochronologyGeologicGeologyGranodioriteHornblendeMicaMineral AssessmentMineral CompositionMineral ResourcesMineralogyMineralsMonzograniteOutcrop SamplesPlutonsQuartzSample LocationSericiteSyeniteAlaska Division of Geological & Geophysical SurveysCircleFairbanks Mining DistrictWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaCenozoicCretaceousMesozoicPaleocenePaleogeneThis 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 Northern Fairbanks Mining District project is part of the State of Alaska's Airborne Geophysical/Geological Mineral Inventory (AGGMI) program, a special multi-year investment by the state to expand Alaska's geologic and mineral resources knowledge base, catalyze future private-sector mineral exploration and development, and guide state planning. AGGMI was funded by the Alaska State Legislature. Fieldwork for the project was also partially funded by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number 07HQAG0076. Additional funding was provided by 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.Athey, J.E.Freeman, L.K.Newberry, R.J.Werdon, M.B.Szumigala, D.J.Lessard, R.R.2022Bedrock geologic map of the northern Fairbanks mining district, Circle Quadrangle, AlaskaPreliminary Interpretive ReportPIR 2022-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys24 p., 1 sheet, scale 1:50,000https://doi.org/10.14509/30891Athey, J.E.Freeman, L.K.Werdon, M.B.Szumigala, D.J.Lessard, R.R.Newberry, R.J.Hansen, S.E.Jing, Liping2008Major-oxide, minor-oxide, and trace-element geochemical data from rocks and stream sediments collected in the northern Fairbanks mining district, Circle Quadrangle, Alaska in 2007Raw Data FileRDF 2008-1 v. 1.0.1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys41 phttps://doi.org/10.14509/15901Burns, L.E.Graham, G.R.C.Barefoot, J.D.Fugro Airborne SurveysStevens Exploration Management Corp.2019Northeast Fairbanks electromagnetic and magnetic airborne geophysical survey data compilationGeophysical ReportGPR 2018-11Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys12 phttps://doi.org/10.14509/30062Newberry, R.J.Bundtzen, T.K.Clautice, K.H.Combellick, R.A.Douglas, TomLaird, G.M.Liss, S.A.Pinney, D.S.Reifenstuhl, R.R.Solie, D.N.1996Preliminary geologic map of the Fairbanks mining district, AlaskaPublic Data FilePDF 96-16Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys17 p., 2 sheets, scale 1:63,360https://doi.org/10.14509/1740The accompanying report and data tables provide a discussion of processing methods. The tables contain measured values, calculated values, testing parameters, and statistical errors reported by the laboratory. Summary values are also included where applicable. Analytical results may include laboratory interpretations when an interpretive review is necessary for generating usable output. While the reports and data have been evaluated by project staff for general readability and logical consistency, the laboratory data may not have undergone technical peer review.Not applicableThis data release is complete.Sample location coordinates were obtained using recreational-grade GPS units, with a typical reported accuracy of about 10 meters. Coordinates are reported using the WGS84 datum. Hand samples and (or) thin sections were examined to select unaltered mineral phases before sample preparation.Sample collection - Samples from surface outcrops were collected by DGGS field geologists and were selected for dating based on the priority of information needed, presence of sufficiently large crystals appropriate for dating, and minimal weathering. Sample location coordinates were obtained using recreational-grade GPS units, with a typical reported accuracy of about 10 meters. Coordinates are reported using the WGS84 datum. Hand samples and (or) thin sections were examined to select unaltered mineral phases before sample preparation.2007Sample preparation - Five rock samples were submitted to the Geochronology Laboratory at the University of Alaska Fairbanks (UAF) for 40Ar/39Ar analysis. The samples were crushed, sieved to either 100-250 or 250-500 micron size fractions, and handpicked for biotite, hornblende, and sericite mineral phases. The monitor mineral MMhb-1 (Samson and Alexander, 1987) with an age of 513.9 Ma (Lanphere and Dalrymple, 2000) was used to monitor neutron flux and calculate the irradiation parameter J. The samples and standards were wrapped in aluminum foil and loaded into aluminum cans of 2.5 cm diameter and 6 cm height. The samples were irradiated in position 5c of the uranium-enriched research reactor at McMaster University in Hamilton, Ontario, Canada, for 20 megawatt-hours.2008Analytical methods - Upon their return from the reactor, the samples and monitors were loaded into 2-mm-diameter holes in a copper tray, which was then loaded in an ultra-high-vacuum extraction line. The monitors were fused, and samples heated, using a 6-watt argon-ion laser following the technique described in York and others (1981), Layer and others (1987), and Layer (2000). Argon purification was achieved using a liquid nitrogen cold trap and a SAES Zr-Al getter at 400 degrees C. The samples were analyzed in a VG-3600 mass spectrometer at the Geophysical Institute, University of Alaska Fairbanks. The argon isotopes measured were corrected for system blank and mass discrimination, as well as calcium, potassium, and chlorine interference reactions following procedures outlined in McDougall and Harrison (1999). System blanks generally were 2x10-16 mol 40Ar and 2x10-18 mol 36Ar, which are 10 to 50 times smaller than fraction volumes. Mass discrimination was monitored by running both calibrated air shots and a zero-age glass sample. These measurements were made on a weekly to monthly basis to check for changes in mass discrimination, with no significant variation observed during these intervals.2008point0.00000010.0000001decimal degreesWGS84WGS 846378137298.257223563rdf2025-1_ar_ar_step-heating-data.csv, rdf2025-1_ar_ar_summary-data-locations.csv, rdf2025-1_ar_ar_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.DGGS, UAFdataAlaska 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 2025-1The 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 pricingcsv20250224tablehttps://doi.org/10.14509/31472Free download20250224Alaska 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"}