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

Geochemistry of some quaternary lavas from the Aleutian Arc and Mt. Wrangell

This publication contains previously unpublished geochemical analyses or re-analyses of lavas, magmatic inclusions, and a few gabbroic cumulate inclusions from Alaska volcanoes (Akutan, Augustine, Buzzard Creek, Dana, Douglas, Fourpeaked, Frosty, Great Sitkin, Iliamna, Kaguyak, Kiska, Okmok, Prindle Cone, Recheshnoi, Redoubt, Spurr, Ukinrek Maars, Vsevidof, Westdahl, Wrangell) collected by the authors and others over the past 35 years. It provides substantial data sets for three volcanoes (Vsevidof, Westdahl, and Douglas) for which little or no published data exist. All analyses were made by the GeoAnalytical laboratory at Washington State University in Pullman, WA. The ICP/MS data have been reduced using the 2006...

Tags: Adagdak, Adak, Akutan, Analyses, Analyses and Sampling, All tags... Analytical Lab Results, Analytical Results, Augustine, Augustine Volcano, Basalt, Bedrock, Bogoslof, Chemistry, Colorado Creek, Crater Peak, Crystals, Douglas, Faris Peak, Fourpeaked, Frosty, Frosty Peak, Geochemical Data, Geochemistry, Geochronology, Geologic, Geology, Glacier Creek, Hayes, Hazards, Ice, Iliamna, Iliamna Volcano, Jag Peak, Juneau, Kaguyak, Kansas Creek, Kasatochi, Katmai, Kiska, Maars, Mount Douglas, Mount Peulik, Mount Recheshnoi, Mount Spurr, Mount Wrangell, Mount Zanetti, Nikolski, Okmok, Okmok Caldera, Pavlof, Prindle Volcano, Redoubt, Redoubt Volcano, Rhyolite, Rocks, Sample Location, Spurr, Tanana, Tephra, The Sisters, Ukinrek, Ukinrek Maars, Uliaga, Umnak Island, Unimak, Volcanic, Volcanic Arc, Volcanic Rocks, Volcanoes, Volcanology, Vsevidof, Westdahl, Whittier, Wrangell, Yakutat, geoscientificInformation, 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