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U-Pb analyses were performed on igneous rocks from the Ray Mountains area of west-central Alaska. These new age analyses will allow us to better evaluate the geochronology of the granitic rocks that are the apparent source of the alluvial REE and tin resources. The plutonic samples have ages ranging from 98.0 +/- 0.9 Ma to 111.6 +/- 1.0 Ma. The sample location coordinates and analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files.
Tags: Age Dates,
Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results, All tags...
Bedrock,
Bedrock Geology,
Bettles Quadrangle,
Geochronology,
Geology,
Igneous Rocks,
Lab Methods,
Metals,
Mineral Assessment,
Mineral Deposit,
Mineral Resources,
Minerals,
Plutonic,
Polymetallic,
Rare Earth Elements,
Ray Mountains,
Sample Location,
Strategic and Critical Minerals Assessment Project,
Tin,
U-Pb,
Zircon,
geoscientificInformation, Fewer tags
This report provides detailed (1:63,360-scale) mapping of portions of U.S. Geological Survey Circle B-2 (1955), B-3 (1955), B-4 (1952), C-2 (1955), C-3 (1955), and C-4 (1952) quadrangles. The area is part of the Circle mining district and adjacent to the Fairbanks mining district. This report includes detailed geologic, structural, stratigraphic, and geochronologic data. Based on the resulting geologic maps, field investigations, and laboratory materials analyses, the project has also generated derivative maps of geologic construction materials and geologic hazards.
Tags: Aereal,
Aerial Photography,
Aeromagnetic Survey,
Age Dates,
Alaska, State of, All tags...
Alluvial Deposits,
Alluvium,
Amphibolite,
Ar-Ar,
Bedrock,
Bibliography,
Birch Creek,
C14,
Carbonates,
Circle Hot Springs,
Circle Mining District,
Circle Quadrangle,
Clastics,
Coal,
Colluvial Deposits,
Colluvium,
Conductivity Survey,
Conodonts,
Crooked Creek,
Electromagnetic Survey,
Fan,
Faulting,
Faults,
Fluvial,
Folding,
Fossils,
Geologic,
Geomorphology,
Glacial,
Glacial Deposits,
Glacial Drift,
Granite,
Hornblende,
Hornfels,
Igneous Rocks,
K-Ar,
Magnetite,
Major Oxides,
Mammoth Creek,
Mastodon Dome,
Metamorphic Grade,
Metamorphic Minerals,
Metamorphism,
Mineralogy,
Modal Analysis,
Petrography,
Plutonic,
Plutonic Hosted,
Porphyry,
Precious Metals,
Quartz,
Regional,
Regional Metamorphism,
Sample Location,
Sandstone,
Schist,
Sedimentary,
Structure,
Surficial,
Tectonics,
Terranes,
geoscientificInformation, Fewer tags
This Division of Geological & Geophysical Surveys (DGGS) Raw Data File presents U-Pb geochronology and Lu-Hf isotopic compositions, age-dating results, and additional trace-elemental composition of zircons from four granitoids sampled during investigations by DGGS geologists in the western Alaska Range and the Talkeetna Mountains. The purpose of the Lu-Hf and U-Pb isotopic study was to better understand the Jurassic through early Tertiary magmatic and tectonic evolution of the Alaska Range and the significance of that magmatism for the formation of metallic mineral deposits. The U-Pb isotopic data also serve to further refine the crystallization age of plutons, which were previously ambiguous in 40Ar/39Ar geochronology...
Tags: Age Dates,
Alaska Range,
Analyses,
Analyses and Sampling,
Analytical Lab Results, All tags...
Analytical Results,
Bedrock,
Geochemistry,
Geochronology,
Geologic,
Geology,
Geophysics,
Granite,
Hafnium,
Isotopes,
Lab Methods,
Lead,
Lime Hills Quadrangle,
Lutetium,
Methods,
Mineralogy,
Minerals,
Plutonic,
Plutons,
Resources,
Rocks,
STATEMAP Project,
Talkeetna Mountains,
Talkeetna Mountains Quadrangle,
Trace Elements,
U-Pb,
Uranium,
Zircon,
geoscientificInformation, Fewer tags
This report 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 Tanacross A-5 and A-6 quadrangles and adjoining areas. Our results indicate the Hona granodiorite pluton intruded the area in the Late Cretaceous between 76 and 71 Ma. We determined Cretaceous metamorphic ages from 126 to 121 Ma for hornblende, biotite, sericite and muscovite from multiple samples of upper greenschist to amphibolite grade rocks. This is consistent with regional argon results that imply this area is in the upper plate of the Yukon Tanana Terrane (Hansen and Dusel-Bacon, 1998). Basaltic andesite dikes...
Tags: 40Ar/39Ar,
Amphibolite,
Analyses,
Analyses and Sampling,
Analytical Lab Results, All tags...
Analytical Results,
Basalt,
Bedrock,
Crystals,
Exploration,
Faulting,
Geochronology,
Geologic,
Geology,
Gneiss,
Granite,
Granodiorite,
Greenschist,
Hornblende,
Igneous,
Isotopes,
Metamorphic,
Metamorphic Rocks,
Metamorphism,
Methods,
Mica,
Mineral Composition,
Mineral Prospect,
Mineralogy,
Minerals,
Muscovite,
Noah Prospect,
Plagioclase,
Plutonic,
Rocks,
Sample Location,
Sericite,
Shalosky Prospect,
Tanacross Quadrangle,
Tok,
Tok Mining District,
Tok River,
geoscientificInformation, Fewer tags
In conjunction with hosting field trips for the Association of American State Geologists 2016 annual meeting in Girdwood, Alaska, Alaska Division of Geological & Geophysical Surveys (DGGS) staff collected rock samples and obtained geochemical analysis from several readily accessible, but relatively unstudied outcrops. Samples were collected from Turnagain Arm (mile 104 Seward Highway), Whittier, Crow Pass, and Panorama Mountain (roughly mile 217 Parks Highway). Mineralized samples from veins and veinlets in granitic rocks from the Crow Pass and Whittier sites contain anomalous levels of gold ranging from 0.129 to 0.650 parts per million (ppm). Although none of the samples are from areas open to mineral entry, geochemical...
Tags: Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results,
Base Metals, All tags...
Bedrock,
Bedrock Geology,
Chemistry,
Economic Geology,
Exploration,
Geochemical Data,
Geochemical Surveys,
Geochemistry,
Geologic,
Geologic Map,
Geology,
Gold,
Gold Prospect,
Heavy Metals,
Igneous,
Igneous Rocks,
Lab Methods,
Magmatic Arc,
Major Oxides,
Metallogenesis,
Metals,
Mineral Assessment,
Mineral Deposit,
Mineral Development,
Mineral Localities,
Mineral Prospect,
Mineral Resources,
Mineralogy,
Minerals,
Mining,
Minor Oxides,
Ore Deposit,
Ores,
Petrology,
Plutonic,
Plutonic Hosted,
Plutonic Rocks,
Plutons,
Precious Metals,
Resource Assessment,
Resource Information,
Resources,
Sample Location,
Southcentral Alaska,
Trace Elements,
Trace Geochemical,
Trace Metals,
Whittier,
geoscientificInformation, Fewer tags
In conjunction with hosting field trips for the Association of American State Geologists 2016 annual meeting in Girdwood, Alaska, Alaska Division of Geological & Geophysical Surveys (DGGS) staff collected rock samples and obtained geochemical analysis from several readily accessible, but relatively unstudied outcrops. Samples were collected from Turnagain Arm (mile 104 Seward Highway), Whittier, Crow Pass, and Panorama Mountain (roughly mile 217 Parks Highway). Mineralized samples from veins and veinlets in granitic rocks from the Crow Pass and Whittier sites contain anomalous levels of gold ranging from 0.129 to 0.650 parts per million (ppm). Although none of the samples are from areas open to mineral entry, geochemical...
Tags: Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results,
Base Metals, All tags...
Bedrock,
Bedrock Geology,
Chemistry,
Economic Geology,
Exploration,
Geochemical Data,
Geochemical Surveys,
Geochemistry,
Geologic,
Geologic Map,
Geology,
Gold,
Gold Prospect,
Heavy Metals,
Igneous,
Igneous Rocks,
Lab Methods,
Magmatic Arc,
Major Oxides,
Metallogenesis,
Metals,
Mineral Assessment,
Mineral Deposit,
Mineral Development,
Mineral Localities,
Mineral Prospect,
Mineral Resources,
Mineralogy,
Minerals,
Mining,
Minor Oxides,
Ore Deposit,
Ores,
Petrology,
Plutonic,
Plutonic Hosted,
Plutonic Rocks,
Plutons,
Precious Metals,
Resource Assessment,
Resource Information,
Resources,
Sample Location,
Southcentral Alaska,
Trace Elements,
Trace Geochemical,
Trace Metals,
Whittier,
geoscientificInformation, Fewer tags
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