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Filters: Tags: Structural geology (X) > partyWithName: Alaska Division of Geological & Geophysical Surveys (X)

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In 2006-2007, Alaska Division of Geological & Geophysical Surveys (DGGS) geologists traversed and collected rock samples from ridges on the north side of Granite Mountain in the Mount Hayes D-3 Quadrangle to supplement existing literature with additional details about the variations in texture, lithology and orientation of the 'Granite of Granite Mountain' (map unit grgm) described by Nokleberg and others (1992). The digital data files for this report provide station locations and observations recorded in the geologists' field notes. Outcrop observations describe fine- to medium-grained granodiorite and medium- to coarse-grained tonalite units which appear to be in contact with each other on the ridges north of...
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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...
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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,...
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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...
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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.
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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.


    map background search result map search result map Geologic notes on Granite Mountain, Mount Hayes D-3 Quadrangle, Alaska 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 Zircon U-Pb and 40Ar/39Ar results from dikes collected within the Bruin Bay fault zone, lower Cook Inlet Zircon U-Pb and 40Ar/39Ar results from dikes collected within the Bruin Bay fault zone, lower Cook Inlet Top Mesozoic unconformity subcrop map, Cook Inlet basin, Alaska Zircon U-Pb and 40Ar/39Ar results from dikes collected within the Bruin Bay fault zone, lower Cook Inlet 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 Top Mesozoic unconformity subcrop map, Cook Inlet basin, Alaska