Geochemical reanalysis of archival igneous rock pulp samples, Yukon-Tanana Upland, Alaska

Buchanan, J.W.2026Geochemical reanalysis of archival igneous rock pulp samples, Yukon-Tanana Upland, AlaskaspreadsheetRaw Data FileRDF 2026-16Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys4 p.https://doi.org/10.14509/32120Geochemical reanalysis of archival igneous rock pulp samples, Yukon-Tanana Upland, Alaska, Raw Data File 2026-16, presents results from the reanalysis of igneous rock samples collected by the Division of Geological and Geophysical Surveys (DGGS) during fieldwork conducted between 1997 and 2009 across the Yukon-Tanana Upland (YTU). Since 2019, the DGGS Mineral Resources Section has focused on the YTU as part of the United States Geological Survey Earth MRI program, which aims to modernize geologic mapping and improve understanding of areas with potential critical mineral resources. As part of this effort, DGGS submitted archived sample pulps stored at the DGGS Geologic Materials Center to the USGS Geology, Geophysics, and Geochemistry Science Center for modern geochemical analysis. A total of 278 pulps from previous DGGS projects, including the Salcha River-Pogo, Fortymile, Alaska Highway Corridor, Caribou Creek, and Rampart Mining District projects, were selected for reanalysis. The resulting major-, minor-, and trace-element data support interpretation of magmatic mineral systems and provide updated geochemical information that informs geologic mapping and broad tectonic interpretation across the YTU. These data and accompanying discussion are released as a DGGS Raw Data File, and all publication components are available from the DGGS website at: http://doi.org/10.14509/32120.The purpose of this dataset is to provide updated geochemical information that strengthens Alaska's ability to evaluate critical mineral resources and understand magmatic mineral systems in the Yukon-Tanana Upland. The reanalysis of archived DGGS rock samples supports statewide mineral resource assessments, improves geologic mapping, and helps guide future exploration and land-management decisions in Alaska.>geochemistry-download: Digital data available through the Alaska Geochemistry database online. Download files include data, analytical methods, and detection limits.2025ground conditionCompleteNone planned-150.939531-141.01921665.25633462.541677ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAnalysesAnalyses and SamplingAnalytical Lab ResultsAnalytical ResultsBase MetalsBedrockBedrock GeologyChemistryCopperCritical MineralsDGGSEarth MRIEconomic GeologyEconomic StudyExplorationGeochemical DataGeochemical SurveysGeochemistryGeologicGeologyGoldIgneousIgneous RocksIntrusion-hostedIntrusiveLab MethodsMajor OxidesMetallogenesisMetalsMetamorphicMetamorphic MineralsMetamorphic RocksMethodsMineral AssessmentMineral CompositionMineral Deposit ModelsMineral DevelopmentMineral ExplorationMineral ResourcesMineralogyMineralsMinor OxidesPlatinumPlatinum GoldPlatinum Group ElementsPlutonicPlutonic RocksPlutonsPrecious MetalsRare Earth ElementsReeResource AssessmentResource InformationResourcesRocksSample LocationStrategic MineralsTrace ElementsTrace GeochemicalTrace MetalsAlaska Division of Geological & Geophysical SurveysAirs HillAlder CreekAmerican CreekBeaver CreekBig LakeBoulder CreekBuckskin CreekCamp CreekCathedral BluffsCathedral RapidsCheneathda HillChicken CreekChisana Mining DistrictChisana RiverCircle Mining DistrictDeep CreekDennison ForkEliza LakeFairbanks Mining DistrictFish CreekFortymile Mining DistrictGardiner CreekGlacier CreekGoodpaster Mining DistrictGoodpaster RiverHot Springs Mining DistrictIndian CreekIngle CreekLadue RiverLilliwig CreekLost CreekMinook CreekMirror CreekMoose CreekNorthway JunctionOld Man CreekOmega CreekParadise HillPorcupine CreekRobertson RiverRoughtop MountainSalcha RiverSeattle CreekSheep CreekSilver CreekSonora CreekStevens CreekStonehouse CreekTanana RiverTenmile CreekTok Mining DistrictTok RiverUhler CreekUnanimous CreekUtah CreekVoss CreekWalker ForkWillow LakeYarger LakeThis 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.The author thanks Jaime Azain at the USGS Geology, Geophysics, and Geochemistry Science Center for help with sample coordination and discussion of data and laboratory methods. The analytical work was funded by the U.S. Geological Survey's Earth Mapping Resources Initiative (Earth MRI) analytical credits under cooperative agreement G23AC00372, and by the State of Alaska. Sample collection and shipping from the Geologic Materials Center were funded by the USGS National Geological and Geophysical Data Preservation Program (NGGDPP) under cooperative agreement G23AS00011. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the USGS. Mention of trade names or commercial products does not constitute their endorsement by the USGS.Solie, 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/10.14509/30038Szumigala, 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/10.14509/2864Werdon, M.B.Newberry, R.J.Athey, J.E.Szumigala, D.J.2004Bedrock geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, AlaskaReport of InvestigationRI 2004-1BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys19 p., 1 sheet, scale 1:63,360https://doi.org/10.14509/3209Werdon, M.B.Solie, D.N.Andrew, J.E.Freeman, L.K.Newberry, R.J.Szumigala, D.J.Elliott, B.A.2019Bedrock-geologic map, Alaska Highway corridor, Dot Lake to Tetlin Junction, AlaskaPreliminary Interpretive ReportPIR 2019-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys14 p., 2 sheets, scale 1:63,360https://doi.org/10.14509/30037Werdon, M.B.Solie, D.N.Newberry, R.J.Freeman, L.K.Elliott, B.A.Lessard, R.R.2019Bedrock-geologic map, Alaska Highway corridor, Little Gerstle River to Dot Lake, AlaskaPreliminary Interpretive ReportPIR 2019-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys12 p., 1 sheet, scale 1:63,360https://doi.org/10.14509/30036This publication is a DGGS Raw Data File (RDF). Reports in the RDF series present field data and analytical results with limited or no interpretation by DGGS staff or project collaborators. The report and accompanying data have been evaluated by project staff for general readability and logical consistency but have not undergone technical peer review. Information presented in this release is subject to change.Not applicableThis data release is complete.The location coordinates of each sample station were recorded with handheld recreational-grade GPS units, or location data were marked on paper topographic maps in the field and later digitized in GIS. GPS devices in use at that time had reported errors of approximately 30 m. GPS Selective Availability was in effect prior to 2000, and pre-2000 sites and digitized sites may have errors of up to 100 m. Sample locations were collected using the NAD27 datum and are reported here using the NAD83 datum.Sample collection - During field campaigns from 1997 to 2009, DGGS geologists collected 2â5â¯kg igneous wholeârock samples from targeted stations for geochemical analysis. The samples were selected from fresh surfaces that generally represent the exposed outcrop. The samples were geochemically analyzed soon after collection, and the returned sample pulps were stored at the DGGS Geologic Materials Center (GMC) in Anchorage, AK.2009Sample preparation - Geochemical samples were historically processed by several companies using different methods. All samples were crushed so that at least 70 percent of the material passed through a -10 mesh screen. Either a representative 200- or 250-gram split was crushed in a chrome-steel ring mill until 85 percent passed through either a -150 or -200 mesh screen. For this reanalysis, samples were retrieved from the GMC and sent to the USGS, where staff used a chrome-steel ring mill to reprocess pulp samples that had passed a -150 mesh screen, reducing the sample to 85 percent passing through a -200 mesh screen, ensuring all samples met lab standards.2024Geochemistry - All samples were analyzed using GGGSC analytical packages, with analytes and methods as summarized here. Major oxides (Al2O3, CaO, Cr2O3, Fe2O3, MgO, MnO, P2O5, K2O, SiO2, Na2O, TiO2, V2O5) and loss on ignition (LOI) were determined using the WDXRF-MAJORS package, in which 0.2 to 0.5 g of sample was fused with a lithium tetraborate/lithium metaborate mixture to form a homogeneous glass disk; LOI was measured gravimetrically at 1000 C, and the prepared disks were analyzed by wavelength-dispersion X-ray fluorescence with LOI included in matrix corrections. Gold, platinum, and palladium (in ppb) were analyzed using the FA_AU-PD-PT package, in which weighed samples were mixed with flux, fused with lead oxide at 1100 C, cupelled, and the resulting bead dissolved in HCl and HNO3 prior to analysis by inductively coupled plasma optical emission spectrometry (ICP-OES). A suite of trace elements (Ag, As, Ba, Be, Bi, Cd, Ce, Cr, Co, Cs, Cu, Ga, Ge, Hf, In, La, Li, Lu, Mn, Hg, Mo, Nb, Ni, Pb, Rb, Re, Sb, Sc, Se, Sn, Sr, Ta, Te, Tb, Tl, Th, U, V, W, Y, Yb, Zn, Zr in ppm) and major elements (Al, Ca, Fe, K, Mg, Na, P, S, Ti in percent) were analyzed using the AQUA-REGIA package, in which samples were digested in a 3:1 mixture of HCl and HNO3 suitable for low-sulfide, non-organic materials, and the resulting solutions were analyzed by ICP-MS and ICP-OES. Additional trace and major elements (Ag, As, Ba, Be, Bi, B, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Ga, Gd, Ge, Hf, Ho, In, La, Li, Lu, Mn, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sc, Sm, Sn, Sr, Ta, Tb, Th, Tl, Tm, U, V, W, Y, Yb, Zn, Zr in ppm; Al, Ca, Fe, K, Mg, P, Si, S, Ti in percent) were analyzed using the ICPOES_MS-61 package, in which samples were fused in glassy carbon crucibles with sodium peroxide (Na2O2), the resulting cake dissolved in HNO3, and the solutions analyzed by ICP-MS and ICP-OES.2025point0.00000010.0000001decimal degreesNAD83GRS 806378137298.257222101geochemistry-downloadDigital data available through the Alaska Geochemistry database online. Download files include data, analytical methods, and detection limits.Alaska Division of Geological & Geophysical Surveys (DGGS)geochemistry-downloadAlaska 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