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The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly...
The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for strategic and critical mineral resources. The SCM Assessment project is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment project, thousands of geochemical-sample analyses and locations from historical U.S. Bureau of Mines (USBM), U.S. Geological Survey (USGS), Bureau of Land Management (BLM), DGGS, Alaska Territorial Department of Mines, Alaska Division of Mines and...
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.
The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly...
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...
This report and digital data release presents 40 new geochemical analyses on historic U.S. Bureau of Mines (USBM) samples, including 33 rock and 7 heavy mineral concentrate (pan concentrate) samples. These samples were originally collected by the USBM as part of their critical and strategic minerals project, which investigated the rare-earth-element and uranium mineral potential of the Zane Hills area, northwestern Alaska. Historic USBM sample materials were retrieved by DGGS from the DGGS Geologic Materials Center (GMC), where the USBM samples were transferred as part of the federally funded Minerals Data and Information Rescue in Alaska (MDIRA) program in the late 1990s and early 2000s. The text and analytical...
This report and digital data release presents 131 new geochemical analyses on historic U.S. Bureau of Mines (USBM) samples, including 86 rock and 42 heavy mineral concentrate (pan concentrate) samples, as well as 3 samples of indeterminate type. Some of these samples were originally collected by the USBM from the Ray River watershed, and the Kanuti and Hodzana Rivers uplands, central Alaska, and a portion of the samples were collected as part of the National Uranium Resource Evaluation. Historic USBM sample materials were retrieved by DGGS from the DGGS Geologic Materials Center (GMC), where the USBM samples were transferred as part of the federally funded Minerals Data and Information Rescue in Alaska (MDIRA) program...
In 2016, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) and University of Alaska Fairbanks carried out a two-part geologic mapping and geochemical sampling project in the Tok River area of the Tanacross A-5 and A-6 quadrangles (June 12-26 and July 8-26). This report provides results of stream-sediment sampling for trace-element geochemistry. An initial suite of sediment samples was collected from streams draining known gold occurrences, including the Stibnite Creek and Noah prospects, and numerous prospects in the White Gold area. These samples were split in half and the two splits were sieved to -200 mesh and -80 mesh, respectively. The splits were then both analyzed to determine...
The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for strategic and critical mineral resources. The SCM Assessment project is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment project, thousands of geochemical-sample analyses and locations from historical U.S. Bureau of Mines (USBM), U.S. Geological Survey (USGS), Bureau of Land Management (BLM), DGGS, Alaska Territorial Department of Mines, Alaska Division of Mines and...
During the 2017 field season, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted geologic mapping and sampling of part of the Richardson Mining District southeast of Fairbanks, including parts of the Big Delta B-4, B-5, and C-5 quadrangles. The project area is about 30 miles west of the Pogo gold mine and covers the currently active Montecristo and Uncle Sam gold-exploration properties. The goal of DGGS's work in this area is to conduct a mineral-resource assessment and to build an improved understanding of the area's geology and controls on gold mineralization to facilitate industry exploration targeting. This report is based on 17 days of fieldwork completed June 23-July 3,...
This report and digital data release presents 326 new geochemical analyses on historic U.S. Bureau of Mines (USBM) samples, including 106 rock, 164 stream sediment, and 56 heavy mineral concentrate (pan concentrate) samples. These samples were originally collected by the USBM as part of a mineral-reconnaissance project in the Selawik Hills area of northwestern Alaska. Historic USBM sample materials were retrieved by DGGS from the DGGS Geologic Materials Center (GMC), where the USBM samples were transferred as part of the federally funded Minerals Data and Information Rescue in Alaska (MDIRA) program in the late 1990s and early 2000s. The text and analytical data and tables associated with this report are being released...
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...
Geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) and University of Alaska carried out a two-part geologic mapping and geochemical sampling project in the Tok River area of the Tanacross A-5 and A-6 quadrangles (June 12-26 and July 8-26). The Tok River area is adjacent to the Delta mineral belt volcanogenic massive-sulfide (VMS) district, the Peak gold-silver-copper skarn, and the structurally controlled gold and antimony mineralization in the Stibnite Creek and White Gold areas. The Tok River project area includes the Noah (also called Hona) prospect, an intrusion-related copper prospect. The combination of insufficient detailed geologic mapping, historical and current industry interest...
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.
This publication provides mercury injection capillary pressure (MICP) data for 36 outcrop samples collected from the Kaguyak, Naknek, and West Foreland formations in the Iniskin Peninsula region of Cook Inlet. The publication files provide: sample names, coordinates, and the formation from which samples were collected; per-sample pore aperture size distribution charts; formation pore volume graphs and data; pore system properties of each formation from which samples were analyzed; and correspondence from PetroTech Associates describing the methods used in MICP analyses of the samples, and a brief summary of the data
The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly...
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...
40Ar/39Ar analyses of igneous rocks from the Alaska Highway corridor between Delta Junction and the Canada border show a range of Cretaceous ages from about 68 Ma to about 112 Ma. The 25 samples fall into two broad age groups. The younger group ranges from about 68 Ma to 73 Ma; the older group ranges from a minimum age of about 84 Ma to about 103 Ma. One sample, a mafic dike, yielded an older age of about 112 Ma.
The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly...
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...
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