40Ar/39Ar data, Styx River map area, Lime Hills C-1 Quadrangle, Alaska

This DGGS Raw Data File presents 40Ar/39Ar age dating results for selected igneous rocks encountered in the Styx River area of the western Alaska Range. Crystallization ages on biotite and hornblende from plutonic rocks range from about ~60 to ~63 Ma, while a sericite alteration age in plutonic rocks altered by a dike swarm also is around ~63 Ma. Sericite alteration associated with a copper-molybdenum porphyry ranges from ~10 to ~11 Ma. Analyses were performed by the University of Alaska Fairbanks Geochronology Laboratory, and results were reported by Paul Layer and Jeff Benowitz. This data release includes the following products: a summary of sample collection methods, the laboratory report, analytical data tables...

Tags: 40Ar/39Ar, Age Dates, Airborne Geophysical Survey, Alaska Range, Analyses and Sampling, All tags... Analytical Results, Ar-Ar, Bedrock Geology, Copper, Economic Geology, Faults, Fracturing, Geochronology, Geology, Gold, Hornblende, K-Feldspar, Lab Methods, Lime Hills Quadrangle, Mica, Mineral Deposit, Mineral Prospect, Mineralogy, Minerals, Mining, Mining Claims, Molybdenite, Muscovite, Ore Deposit Model, Plutonic Rocks, Plutons, Polymetallic Vein, Porphyry, Pyrite, Pyrrhotite, Quartz, Sample Location, Sericite, Sericite Alteration, Styx River, Volcanic Rocks, geoscientificInformation, Fewer tags

40Ar/39Ar data from rocks collected in the 2015 Wrangellia mineral assessment project area, Mount Hayes A-5, Mount Hayes B-6, and Talkeetna Mountains D-2 quadrangles, Alaska

This report presents 40Ar/39Ar step-heating geochronology results for igneous and metamorphic rocks from the Alaska Division of Geological & Geophysical Surveys' (DGGS) Wrangellia Mineral Assessment project, part of a multi-year effort focusing on improving the publicly available geoscientific information for the western Wrangellia terrane. The samples described in this report were selected and analyzed to improve our understanding of the geology and structural history of the Wrangellia Mineral Assessment project area. A metagabbro rock sample returned a Late Triassic crystallization age consistent with regional ages for Nikolai Greenstone-related magmatism; however, the two amphibole separates ages do not overlap,...

Tags: 40Ar/39Ar, Analyses, Analyses and Sampling, Analytical Lab Results, Analytical Results, All tags... Ar-Ar, Basalt, Bedrock, Bedrock Geology, Copper, Crystals, Geochronology, Geologic, Geology, Greenstone, Hayes, Hornblende, Igneous, Igneous Rocks, Interpretation, Lab Methods, Methods, Mica, Mineral Composition, Mineral Resources, Mineralogy, Minerals, Mount Hayes Quadrangle, Muscovite, Plutonic Rocks, Porphyry, Resources, Rocks, Sample Location, Strategic Minerals, Strategic and Critical Minerals Assessment Project, Stratigraphy, Structural Geology, Talkeetna, Talkeetna Mountains, Talkeetna Mountains Quadrangle, Thrust, Volcanic Rocks, geoscientificInformation, Fewer tags

Geologic map of the Circle mining district, Alaska

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

Geochemical reanalysis of rock and sediment samples from the Middle Fork and South Fork of the Salmon River collected in the mid-1960s through the early 1970s as part of the Idaho Primitive Area studies

This data release is a geochemical data set from the reanalysis of 23 rock and 85 sediment samples collected between 1966 and 1970 by the U.S. Geological Survey (USGS) for a series of studies investigating the mineral resources of the Idaho Primitive Area (Cater et al., 1973). The samples are from the upper Middle Fork Salmon River and the South Fork Salmon River, including the tributaries of East Fork of the South Fork and Porphyry Creek. The overall objective of this study is to characterize the regional impact of legacy mining for the Frank Church - River of No Return Wilderness Area. In 1980 the U. S. Congress passed the Central Idaho Wilderness Act which combined the Idaho Primitive Area, the Salmon Rivers...

Categories: Data; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Automatic Creek, Beansnapper Creek, Bear Creek, Big Chief Creek, Big Cottonwood Creek, All tags... Cabin Creek, Cache Creek, Cane Creek, Canyon Creek, Challis Volcanic Group, Colorado, Colt Creek, Cornish Creek, Cultus Creek, Dewey Mine, East Fork Indian Creek, East Fork South Fork Salmon River, East Fork Springfield Creek, East Fork Trail Creek, Forty-five Creek, Frank Church - River of No Return Wilderness Area, GGGSC, Geochemistry, Geology, Geophysics, and Geochemistry Science Center, Glass Mountain, Gunsight Formation, Idaho, Idaho Primitive Area, Indian Creek, Little Indian Creek, Little Loon Creek, Little Pistol Creek, Loon Creek, Luger Creek, MRP, Marble Creek, Mearney Creek, Middle Fork Indian Creek, Middle Fork Salmon River, Middle Fork terraces, Mineral Resources Program, North Fork Porphyry Creek, North Fork Wolf Fang Creek, Pistol Creek, Poee Creek, Porphyry Creek, Profile Creek, Pungo Creek, Rapid River, Ryan Creek, Salmon Rivers Breaks Primitive Area, Shrapnel Creek, Silver Plume, South Fork Salmon River, South Fork Wolf Fang Creek, Spring Creek, Springfield Creek, Sugar Creek, Sunnyside tuff, Tamarack Creek, Thirty-two Creek, Thunder Mountain Caldera, Trail Creek, Trigger Creek, Twenty-five Creek, USA, USGS Science Data Catalog (SDC), United States, Upper Middle Fork Salmon River, West Fork Little Loon Creek, West Fork Trail Creek, Wolf Fang Creek, alluvium, arsenic, atomic absorption analysis, atomic emission spectroscopy, biotite, carbonate rock, chemical analysis, clastic rock, conglomerate, copper, critical minerals, foliation, geochemistry, geology, gneiss, granite, granodiorite, hornblende, hornblende-biotite, hydride generation, lapilli tuff, mass spectroscopy, metallic mineral resources, migmatite, mineral deposits, mineral resources, mineralization, muscovite sulfides, muscovite-biotite, nonmetallic mineral resources, pebble conglomerate, phyllite, porphyry, quartz, rhyolite, rock drainage, sandstone, tributary, tuff, volcanic rock, Fewer tags

40Ar/39Ar ages from the Selawik A-2, A-3 and A-4 and Candle B-5 quadrangles, Alaska

40Ar/39Ar data from seven plutonic samples and one metamorphic sample collected during mineral assessment studies in 1991 show that various rock units in the Selawik Hills plutonic complex were emplaced in the order syenite/monzonite (nonfoliated, 106.6 ± 0.8 Ma; foliated, 101.7 ± 0.7 Ma; both on hornblende), followed by nepheline syenite (103.7 ± 0.8 Ma on hornblende) and then quartz monzonite (100.4 ± 3.7 Ma on biotite). 40Ar/39Ar data from Granite Mountain hornblendes yielded ages slightly older, but overlapping, those from Selawik Hills. In this suite, the silica-undersaturated phase appears to be younger (105.7 ±0.8 Ma) than the silica-saturated phase(s) (106.8 ± 0.8 Ma and 107.1 ± 0.8 Ma).

Tags: 40Ar/39Ar, Age Dates, Analytical Results, Ar-Ar, Candle Quadrangle, All tags... Geochronology, Granite, Granite Mountain, Hornblende, Igneous Rocks, Plutonic Rocks, Selawik Quadrangle, Fewer tags

40Ar/39Ar data from the Tok River area, Tanacross A-5 and A-6 quadrangles and adjoining areas, eastern Alaska Range

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