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Cook Inlet has been recognized as the second-largest petroleum province in Alaska, second only to the North Slope. The south-central Tyonek Quadrangle is an area of significant geologic interest because it is the only location in Cook Inlet where the entire producing stratigraphy of the basin is exposed on the surface. Additionally, this area encompasses the structural boundary between the forearc basin and its sediment source rocks. To better understand the petroleum system and the geologic relationships between the exhumed arc intrusive rocks and adjacent Cenozoic stratigraphy of the Cook Inlet forearc basin, during the summer of 2010 the Alaska Division of Geological & Geophysical Surveys conducted a federally-funded...
Tags: Alaska Range,
Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results, All tags...
Bedrock,
Bedrock Geology,
Chemistry,
Cook Inlet,
Cook Inlet Basin,
Exploration,
Geochemical Data,
Geochemical Surveys,
Geochemistry,
Geology,
Igneous,
Igneous Rocks,
Lab Methods,
Magmatic Arc,
Major Oxides,
Minor Oxides,
Neacola Mountains,
Petrology,
Resources,
Rocks,
STATEMAP Project,
Sample Location,
Tordrillo Mountains,
Trace Elements,
Trace Geochemical,
Tyonek,
Tyonek Quadrangle,
Volcanic,
Volcanic Arc,
Volcanic Rocks,
geoscientificInformation, Fewer tags
Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field survey, including mapping and sampling, in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles, Alaska, from June 16 through July 18, 2008. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. Interpretation and synthesis of this data has been presented in professional and trade meetings....
Tags: Alaska Range,
Bedrock,
Chute Creek,
Dry Creek,
Dry Creek prospect, All tags...
Fairbanks Quadrangle,
Geologic,
Geology,
Glory Creek,
Glory Creek prospect,
Healy Quadrangle,
Igneous,
Igneous Rocks,
Kansas Creek,
Minerals,
Red Mountain Creek,
Rocks,
Rogers Creek,
STATEMAP Project,
Sedimentary Rocks,
Sheep Creek,
Slide Creek,
Snow Mountain Gulch,
WTF (Western Tundra Flats) prospect,
Wood River,
geoscientificInformation, Fewer tags
Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
Tags: Active Volcanoes,
Age Dates,
Aleutian Arc,
Aleutian Islands,
Alluvial Deposits, All tags...
Analyses,
Analyses and Sampling,
Basalt,
Bedrock,
Bedrock Geology,
Caldera,
Chemistry,
Colluvium,
Erosion,
Fan,
Geochemical Data,
Geochemistry,
Geochronology,
Geologic,
Geologic Hazards,
Geologic Map,
Geological Process,
Geology,
Geomorphology,
Hazards,
Historic Eruption,
Igneous,
Kasatochi,
Lava Flow,
Mineralogy,
Petrographic,
Petrography,
Petrology,
Pumice,
Pyroclastics,
Rockfall,
Rocks,
Sample Location,
Slope Instability,
Slump,
Soils,
Surface,
Surficial,
Talus,
Tephra,
Topography,
Ultramafic,
Uplift,
Volcanic,
Volcanic Ash,
Volcanic Eruption,
Volcanic Rocks,
Volcaniclastics,
Volcanoes,
Volcanology,
geoscientificInformation, Fewer tags
This data release presents zircon U-Pb LA-ICP-MS geochronology from igneous rocks exposed in a coastal exposure at Ursus Head, Iliamna C-2 Quadrangle. Sills and dikes exposed in a coastal exposure at Ursus Head are deformed within the Bruin Bay fault zone. Common dikes intruding late Triassic Kamishak Formation strata composing the hanging-wall of the Bruin Bay fault are cut by numerous small-scale, low-angle, bedding-parallel, and high angle contractional faults. Sample 09MAW006A collected from one of many dikes deformed in the fault zone produced a uni-modal distribution of zircon ages of with a weighted mean of 206.92 +/-0.96 (2 sigma, n=47) and an MSWD of 1.1. Sample 09BG020C collected from a sill of more mafic...
Tags: 40Ar/39Ar,
Age Dates,
Analyses,
Analyses and Sampling,
Analytical Lab Results, All tags...
Analytical Results,
Ar-Ar,
Bedrock,
Bedrock Geology,
Contact Point,
Cook Inlet,
Cook Inlet Basin,
Fault Displacement,
Geochronology,
Geologic,
Geology,
Igneous,
Iliamna Quadrangle,
Isotopes,
Lab Methods,
Lead,
Methods,
Naknek,
Plagioclase,
Rocks,
Sample Location,
Stratigraphy,
Structural Geology,
Structure,
Tectonics,
U-Pb,
Uranium,
Ursus Head,
Volcanic,
Volcanic Rocks,
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) 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
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
This 1:50,000 scale geologic map describes the distribution of unconsolidated deposits, identifies local geologic hazards, and provides information about the depositional environment and basic engineering properties of common surficial-geologic materials in and around Shaktoolik, Alaska. Map units are the result of combined field observations and aerial imagery interpretation. A suite of local ground observations were collected over a two-week period in July 2011 by a helicopter-supported team of DGGS geologists and collaborators. Field investigations included soil test pits, sample collection, soil and rock description, oblique aerial photography, and documentation of landscape morphology.
Tags: Alluvial,
Alluvium,
Analyses and Sampling,
C14,
Clay, All tags...
Coastal,
Coastal and River,
Colluvium,
Conglomerate,
Construction Materials,
Engineering,
Engineering Geology,
Eolian,
Erosion,
Fan,
Flood,
Floodplain,
Fluvial,
Gelifluction,
Geochronology,
Geologic,
Geologic Hazards,
Geologic Map,
Geology,
Geomorphology,
Geotechnical,
Gravel,
Hazards,
Ice,
Image Interpretation,
Interpretation,
Inundation,
Lacustrine,
Lakes,
Meltwater,
Norton Bay Quadrangle,
Permafrost,
Permafrost and Periglacial,
Resource Assessment,
Resources,
Rocks,
Sand,
Sand and Gravel,
Sediment,
Sedimentation,
Shaktoolik,
Silt,
Slope,
Slump,
Surface,
Surficial,
Surficial Geologic Map,
Surficial Geology,
Terrace,
Thaw Lakes,
Thawing Permafrost,
Thermokarst,
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 data release presents 40Ar/39Ar step-heating geochronology results from rocks collected roughly 7 km southwest of Contact Point, Iliamna B-3 Quadrangle. Samples obtained from a felsic dike intruding the principal Bruin Bay fault plane near Contact Point produced biotite and plagioclase 40Ar/39Ar ages of 36.5 +/- 0.8 Ma and 31.5+/-0.7 Ma, respectively. The age dates inform stratigraphic, structural, and geochronologic studies along the western margin of lower Cook Inlet basin. The accompanying report also presents zircon U-Pb LA-ICP-MS geochronology results for dikes near Ursus Head.
Tags: 40Ar/39Ar,
Age Dates,
Analyses,
Analyses and Sampling,
Analytical Lab Results, All tags...
Analytical Results,
Ar-Ar,
Bedrock,
Bedrock Geology,
Contact Point,
Cook Inlet,
Cook Inlet Basin,
Fault Displacement,
Geochronology,
Geologic,
Geology,
Igneous,
Iliamna Quadrangle,
Isotopes,
Lab Methods,
Lead,
Methods,
Plagioclase,
Rocks,
Sample Location,
Stratigraphy,
Structural Geology,
Structure,
Tectonics,
U-Pb,
Uranium,
Ursus Head,
Volcanic,
Volcanic Rocks,
Zircon,
geoscientificInformation, Fewer tags
Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south-southwest of King Salmon, Alaska. This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks. The eruptive products of Chiginagak volcano record a history of chiefly andesite lava flows and associated block-and-ash flows. The oldest lavas exposed are Pleistocene in age and are found everywhere around the edifice except in the northeast sector, where Holocene lava flows dominate the landscape. Holocene activity has covered the northeast flank with rubbly-topped andesite lava flows that extend as far as 4.6 km from their source vent at the summit...
Tags: Alaska Peninsula,
Aleutian Range,
Analyses,
Chiginagak,
Gas, All tags...
Geochemistry,
Geochronology,
Geologic,
Geology,
Hazards,
Igneous,
Lahar,
Mount Chiginagak,
Neoglacial,
Pumice,
Rocks,
Sediment,
Sulfur,
Surface,
Surficial,
Tephra,
Ugashik Quadrangle,
Volcanic,
Volcanic Ash,
Volcanic Eruption,
Volcanic Gas,
Volcanic Rocks,
Volcaniclastic Deposits,
Volcaniclastics,
Volcanoes,
Volcanology,
Water,
geoscientificInformation, Fewer tags
Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys carried out a geological field survey, including mapping and sampling, in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2, and the Healy D-1 and D-2 quadrangles, Alaska, from June 16 through July 18, 2008. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geological mapping. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. To represent a typical lithology, igneous or possible meta-igneous samples were collected and analyzed...
Tags: Alaska Range,
Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results, All tags...
Bedrock,
Bedrock Geology,
Chemistry,
Chute Creek,
Dry Creek,
Fairbanks Quadrangle,
Geochemical Data,
Geochemical Surveys,
Geochemistry,
Geologic,
Geology,
Healy Quadrangle,
Igneous,
Igneous Rocks,
Kansas Creek,
Lab Methods,
Metamorphic Rocks,
Methods,
Mineral Assessment,
Mineralogy,
Minerals,
Red Mountain Creek,
Resource Assessment,
Resource Information,
Resources,
Rocks,
Rogers Creek,
STATEMAP Project,
Sample Location,
Sheep Creek,
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
This report presents 40Ar/39Ar step-heating geochronology results from a single outcrop of a mineralized near-trench intrusion exposed in a road cut near Whittier, Alaska. The outcrop is the best road-accessible occurrence of a Tertiary near-trench pluton in the region and is commonly visited by field trips, yet no prior geochronological data from this outcrop have been published. Two chronologically distinct intrusive bodies, the Paleogene Sanak-Baranof belt and the Eshamy-suite, are documented in the upper Cook Inlet area. Geochronological analysis of the two samples described in this report confirms that the Whittier road-cut intrusion and veins are coeval (53.0 +/- 0.3 Ma and 50.9 +/- 0.2 Ma, respectively) with...
Tags: 40Ar/39Ar,
Age Dates,
Analyses,
Analyses and Sampling,
Analytical Lab Results, All tags...
Analytical Results,
Ar-Ar,
Bedrock,
Bedrock Geology,
Geochronology,
Geologic,
Geology,
Igneous,
Igneous Rocks,
Isotopes,
Lab Methods,
Methods,
Mineralogy,
Rocks,
Sample Location,
Seward Quadrangle,
Volcanic Arc,
Volcanic Rocks,
Whittier,
geoscientificInformation, Fewer tags
Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south-southwest of King Salmon, Alaska. This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks. The eruptive products of Chiginagak volcano record a history of chiefly andesite lava flows and associated block-and-ash flows. The oldest lavas exposed are Pleistocene in age and are found everywhere around the edifice except in the northeast sector, where Holocene lava flows dominate the landscape. Holocene activity has covered the northeast flank with rubbly-topped andesite lava flows that extend as far as 4.6 km from their source vent at the summit...
Tags: Alaska Peninsula,
Aleutian Range,
Analyses,
Chiginagak,
Gas, All tags...
GeMS NCGMP09,
Geochemistry,
Geochronology,
Geologic,
Geology,
Hazards,
Igneous,
Lahar,
Mount Chiginagak,
Neoglacial,
Pumice,
Rocks,
Sediment,
Sulfur,
Surface,
Surficial,
Tephra,
Ugashik Quadrangle,
Volcanic,
Volcanic Ash,
Volcanic Eruption,
Volcanic Gas,
Volcanic Rocks,
Volcaniclastic Deposits,
Volcaniclastics,
Volcanoes,
Volcanology,
Water,
geoscientificInformation, Fewer tags
The Geologic Photos of Alaska database and online application contains photographs taken during and in support of Alaska Division of Geological & Geophysical Surveys (DGGS) projects. These photographs primarily document field sites and geomorphology statewide, usually in remote locations that are often impossible or prohibitively expensive to revisit. The database (http://maps.dggs.alaska.gov/photodb/) includes a variety of images such as field photos, photos of samples, and photomicrographs (photograph of a microscopic object) taken with the aid of a microscope.
Tags: Alaska Statewide Quadrangle,
Alaska, State of,
Analyses and Sampling,
Energy Resources,
Geologic, All tags...
Geologic Hazards,
Geologic Materials,
Geological Process,
Geology,
Geomorphology,
Glaciers,
Igneous Rocks,
Metamorphic Rocks,
Mineral Resources,
Resource Information,
Resources,
Rock Units,
Rocks,
Sample Location,
Sand and Gravel,
Sedimentary Rocks,
Structural Geology,
Structure,
Volcanic Rocks,
Volcanoes,
geoscientificInformation, Fewer tags
Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
Tags: Active Volcanoes,
Age Dates,
Aleutian Arc,
Aleutian Islands,
Alluvial Deposits, All tags...
Analyses,
Analyses and Sampling,
Basalt,
Bedrock,
Bedrock Geology,
Caldera,
Chemistry,
Colluvium,
Erosion,
Fan,
Geochemical Data,
Geochemistry,
Geochronology,
Geologic,
Geologic Hazards,
Geologic Map,
Geological Process,
Geology,
Geomorphology,
Hazards,
Historic Eruption,
Igneous,
Kasatochi,
Lava Flow,
Mineralogy,
Petrographic,
Petrography,
Petrology,
Pumice,
Pyroclastics,
Rockfall,
Rocks,
Sample Location,
Slope Instability,
Slump,
Soils,
Surface,
Surficial,
Talus,
Tephra,
Topography,
Ultramafic,
Uplift,
Volcanic,
Volcanic Ash,
Volcanic Eruption,
Volcanic Rocks,
Volcaniclastics,
Volcanoes,
Volcanology,
geoscientificInformation, Fewer tags
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