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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
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 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
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 map shows the subcrop pattern of the Mesozoic rock units present at the top Mesozoic unconformity (also commonly referred to as the base Tertiary unconformity) in Cook Inlet basin, Alaska. The subcrop is projected onto the top Mesozoic unconformity depth surface of Cook Inlet basin, Alaska, published by Shellenbaum and others (2010). Publicly available geologic and geophysical data from multiple sources were collected, interpreted, and integrated into the subcrop map. Formation picks at the top Mesozoic unconformity were determined for 109 wells. Mesozoic horizons from two regional marine two-dimensional (2-D) seismic datasets (approximately 3,300 miles) were interpreted. Eight map units were established for...
Tags: Anchorage,
Anchorage Quadrangle,
Bedrock Geologic Map,
Bedrock Geology,
Bibliography, All tags...
Biostratigraphy,
Cook Inlet,
Cook Inlet Basin,
Core Logs,
Correlation,
Depth Interpretation,
Drill Logs,
Drilling,
Energy,
Energy Resources,
Folds,
Forearc Basin,
Geologic,
Geologic Map,
Geology,
Geophysical Logs,
Geophysics,
Gis,
Homer,
Hydrocarbon,
Hydrocarbon Potential,
Igneous Rocks,
Iliamna Quadrangle,
Iniskin Bay,
Inoceramus,
Interpretation,
Kenai,
Kenai Peninsula,
Kenai Quadrangle,
Lake Clark Quadrangle,
Matanuska River,
Matanuska Valley,
Metamorphic Rocks,
Mount Katmai Quadrangle,
Oil Basins,
Oil and Gas,
Oil and Gas Basin,
Palmer,
Palynology,
Petroleum,
Petroleum Basin Study,
Port Graham,
Reservoir,
Resources,
Rock Units,
Saddle Mountain,
Sedimentary Rocks,
Seismic Interpretation,
Seldovia,
Seward,
Seward Quadrangle,
Source Rock,
Southcentral Alaska,
Stratigraphy,
Strike-Slip,
Structural Geology,
Structure,
Structure Contours,
Structure Map,
Subsurface,
Surface,
Susitna River,
Talkeetna Mountains Quadrangle,
Talkeetna Quadrangle,
Thrust,
Tuxedni Bay,
Tyonek,
Tyonek Quadrangle,
Unconformity,
Volcanic Rocks,
Wasilla,
Well Logs,
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) Talkeetna Mountains C-4 Quadrangle and Adjoining Areas geologic mapping project. Hornblende-bearing gabbro returned a Late Triassic crystallization age consistent with regional results for Nikolai Greenstone-related magmatism. We determined Early Jurassic metamorphic ages for hornblende and sericite from two samples of upper greenschist to amphibolite grade metavolcanic rocks. Our results indicate that a granodiorite pluton intruding Wrangellia in the study area has a Middle Jurassic age consistent with the Talkeetna Arc, indicating that the Wrangellia...
Tags: 40Ar/39Ar,
Age Dates,
Analyses,
Analyses and Sampling,
Analytical Lab Results, All tags...
Analytical Results,
Ar-Ar,
Bedrock,
Bedrock Geology,
Geochronology,
Geology,
Lab Methods,
Plutonic Rocks,
Plutons,
STATEMAP Project,
Sample Location,
Strategic and Critical Minerals Assessment Project,
Talkeetna Mountains Quadrangle,
Volcanic,
Volcanic Arc,
Volcanic Rocks,
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
The Iniskin-Tuxedni Bay area contains excellent exposures of nearly all of the lower Cook Inlet Mesozoic succession, including most of the stratigraphic sections that define the interval and the petroleum source rocks that comprise the basin. An underdeveloped understanding of the Mesozoic petroleum system has led the Alaska Department of Natural Resources' Division of Geological & Geophysical Surveys and Division of Oil and Gas, and the U.S. Geological Survey to collaborate on a multi-year project that includes two major mapping campaigns. Geologic mapping between Chinitna Bay and the Johnson River during the 2015 field season encompassed volcanic arc rocks northwest of the Bruin Bay fault system, and Mesozoic...
Tags: Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results,
Chemistry, All tags...
Chitina,
Cook Inlet,
Geochemical Data,
Geochemistry,
Geology,
Igneous,
Igneous Rocks,
Iliamna,
Kenai,
Lab Methods,
Magmatic Arc,
Major Oxides,
Minor Oxides,
STATEMAP Project,
Sample Location,
Trace Elements,
Volcanic,
Volcanic Arc,
Volcanic Rocks,
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
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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