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At least 541 records · Page 30Linked to original sources
USGS2002

Geologic Map of the Central Marysvale Volcanic Field, Southwestern Utah

The geologic map of the central Marysvale volcanic field, southwestern Utah, shows the geology at 1:100,000 scale of the heart of one of the largest Cenozoic volcanic fields in the Western United States. The map shows the area of 38 degrees 15' to 38 degrees 42'30' N., and 112 degrees to 112 degrees 37'30' W. The Marysvale field occurs mostly in the High Plateaus, a subprovince of the Colorado Plateau and structurally a transition zone between the complexly deformed Great Basin to the west and the stable, little-deformed main part of the Colorado Plateau to the east. The western part of the field is in the Great Basin proper. The volcanic rocks and their source intrusions in the volcanic field range in age from about 31 Ma (Oligocene) to about 0.5 Ma (Pleistocene). These rocks overlie sedimentary rocks exposed in the mapped area that range in age from Ordovician to early Cenozoic. The area has been deformed by thrust faults and folds formed during the late Mesozoic to early Cenozoic Sevier deformational event, and later by mostly normal faults and folds of the Miocene to Quaternary basin-range episode. The map revises and updates knowledge gained during a long-term U.S. Geological Survey investigation of the volcanic field, done in part because of its extensive history of mining. The investigation also was done to provide framework geologic knowledge suitable for defining geologic and hydrologic hazards, for locating hydrologic and mineral resources, and for an understanding of geologic processes in the area. A previous geologic map (Cunningham and others, 1983, U.S. Geological Survey Miscellaneous Investigations Series I-1430-A) covered the same area as this map but was published at 1:50,000 scale and is obsolete due to new data. This new geologic map of the central Marysvale field, here published as U.S. Geological Survey Geologic Investigations Series I-2645-A, is accompanied by gravity and aeromagnetic maps of the same area and the same scale (Campbell and others, 1999, U.S. Geological Survey Geologic Investigations Series I-2645-B).

IMAP↗
USGS2000

Neogene geomorphic and climatic evolution of the central San Juan Mountains, Colorado: K/Ar age and stable isotope data on supergene alunite and jarosite from the Creede mining district

K/Ar age determinations or supergene alunite and jarosite, formed during Neogene weathering of the epithermal silver and base-metal ores of the Creede mining district, have been combined with geologic evidence to estimate the timing of regional uplift of the southern Rocky Mountains and related canyon cutting. In addition, oxygen and hydrogen isotopic studies suggest climate changes in the central San Juan Mountains during the past 5 m.y. Alunite [ideally (K,Na)Al 3 (SO 4 ) 2 (OH) 6 ] and jarosite [ideally KFe 3 (SO 4 ) 2 (OH) 6 ] can be dated by K/Ar or 40 Ar/ 39 Ar techniques and both contain OH and SO 4 sites that enable four stable isotope analyses (δD, δ 18 O OH , and δ 34 S) to be made. This supergene alunite and jarosite formed by weathering of sulfide-rich ore bodies may record the evolution of the chemical and hydrologic processes affecting ancient oxidized acid ground water, as well as details of climate history and geomorphic evolution. Fine-grained (1-10 μm) supergene alunite and jarosite occur in minor fractures in the upper, oxidized parts of the 25 Ma sulfide-bearing veins of the Creede mining district, and jarosite also occurs in adjacent oxidized Ag-bearing clastic sediments. K/Ar ages for alunite range from 4.8 to 3.1 Ma, and for jarosite range from 2.6 to 0.9 Ma. The δD values for alunite and jarosite show opposite correlations with elevation, and values for jarosite correlate with age. Calculated δD H2O values of alunite fluids approach but are larger than those of present-day meteoric water. Calculated δD H2O values for jarosite fluids are more variable; the values of the youngest jarosites are lowest and are similar to those of present-day meteoric water in the district. The narrow δD-δ 18 O SO4 values of alunites reflects oxidation of sulfide below the water table. The greater range in these values for jarosites reflects oxidation of sulfide under vadose conditions. The ages of alunite mark the position of the paleo-water table at the end of a period of moderate erosion from ca. 25 to 5 Ma that exposed the tops of the ore bodies to oxidation. The younger jarosite formed in the vadose zone during or following subsequent canyon cutting related to regional uplift of the southern Rocky Mountains, The δD values suggest that climates in the area were similar to those of the present day prior to regional uplift but went through a warm period before returning to present conditions during or after regional uplift. The results of this study indicate that the combined stable and radiogenic isotope analysis of supergene alunite and jarosite has broad application in understanding climate and geomorphic evolution of selected areas.

Colorado↗
USGS2011

Development of industrial minerals in Colorado

Technology and engineering have helped make mining safer and cleaner for both humans and the environment. Inevitably, mineral development entails costs as well as benefits. Developing a mine is an environmental, engineering, and planning challenge that must conform to many Federal, State, and local regulations. Community collaboration, creative design, and best management practices of sustainability and biodiversity can be positive indicators for the mining industry. A better understanding of aesthetics, culture, economics, geology, climate, vegetation and wildlife, topography, historical significance, and regional land planning is important in resolving land-use issues and managing mineral resources wisely. Ultimately, the consuming public makes choices about product use (including water, food, highways, housing, and thousands of other items) that influence operations of the mineral industry. Land planners, resource managers, earth scientists, designers, and public groups have a responsibility to consider sound scientific information, society's needs, and community appeals in making smart decisions concerning resource use and how complex landscapes should change. An effort to provide comprehensive geosciences data for land management agencies in central Colorado was undertaken in 2003 by scientists of the U.S. Geological Survey and the Colorado Geological Survey. This effort, the Central Colorado Assessment Project, addressed a variety of land-use issues: an understanding of the availability of industrial and metallic rocks and minerals, the geochemical and environmental effects of historic mining activity on surface water and groundwater, and the geologic controls on the availability and quality of groundwater. The USDA Forest Service and other land management agencies have the opportunity to contribute to the sustainable management of natural aggregate and other mineral resources through the identification and selective development of mineral resources and the reclamation of mines on lands that they administer. The information in this Circular will help them carry out that task.

Colorado↗
USGS2010

Land-Use Analysis and Simulated Effects of Land-Use Change and Aggregate Mining on Groundwater Flow in the South Platte River Valley, Brighton to Fort Lupton, Colorado

Land use in the South Platte River valley between the cities of Brighton and Fort Lupton, Colo., is undergoing change as urban areas expand, and the extent of aggregate mining in the Brighton-Fort Lupton area is increasing as the demand for aggregate grows in response to urban development. To improve understanding of land-use change and the potential effects of land-use change and aggregate mining on groundwater flow, the U.S. Geological Survey, in cooperation with the cities of Brighton and Fort Lupton, analyzed socioeconomic and land-use trends and constructed a numerical groundwater flow model of the South Platte alluvial aquifer in the Brighton-Fort Lupton area. The numerical groundwater flow model was used to simulate (1) steady-state hydrologic effects of predicted land-use conditions in 2020 and 2040, (2) transient cumulative hydrologic effects of the potential extent of reclaimed aggregate pits in 2020 and 2040, (3) transient hydrologic effects of actively dewatered aggregate pits, and (4) effects of different hypothetical pit spacings and configurations on groundwater levels. The SLEUTH (Slope, Land cover, Exclusion, Urbanization, Transportation, and Hillshade) urban-growth modeling program was used to predict the extent of urban area in 2020 and 2040. Wetlands in the Brighton-Fort Lupton area were mapped as part of the study, and mapped wetland locations and areas of riparian herbaceous vegetation previously mapped by the Colorado Division of Wildlife were compared to simulation results to indicate areas where wetlands or riparian herbaceous vegetation might be affected by groundwater-level changes resulting from land-use change or aggregate mining. Analysis of land-use conditions in 1957, 1977, and 2000 indicated that the general distribution of irrigated land and non-irrigated land remained similar from 1957 to 2000, but both land uses decreased as urban area increased. Urban area increased about 165 percent from 1957 to 1977 and about 56 percent from 1977 to 2000 with most urban growth occurring east of Brighton and Fort Lupton and along major transportation corridors. Land-use conditions in 2020 and 2040 predicted by the SLEUTH modeling program indicated urban growth will continue to develop primarily east of Brighton and Fort Lupton and along major transportation routes, but substantial urban growth also is predicted south and west of Brighton. Steady-state simulations of the hydrologic effects of predicted land-use conditions in 2020 and 2040 indicated groundwater levels declined less than 2 feet relative to simulated groundwater levels in 2000. Groundwater levels declined most where irrigated land was converted to urban area and least where non-irrigated land was converted to urban area. Simulated groundwater-level declines resulting from land-use conditions in 2020 and 2040 are not predicted to substantially affect wetlands or riparian herbaceous vegetation in the study area because the declines are small and wetlands and riparian herbaceous vegetation generally are not located where simulated declines occur. See Report PDF for unabridged abstract.

Scientific Investigations Report↗
USGS1990

Geochemistry of batch-extract waters derived from spoil material collected at the Cordero coal mine, Powder River basin, Wyoming

Batch-mixing experiments to evaluate postmining water quality at the Cordero Mine were conducted by the U.S. Geological Survey during 1984 to 1985. Contact of groundwater from the spoil aquifer with fresh spoil material caused only small changes in major-element concentrations and in pH, unless sulfide oxidation or contact with soluble salts, such as epsomite, occurred. In contrast, large changes in major-element concentration resulted when water from the coal aquifer contacted the spoil material. Only three of seven reaction models considered to explain the water quality changes during the batch-mixing experiments were consistent with the thermodynamic and mineralogical data. The three models used to account for the observed water quality changes derived potassium from potassium feldspar; magnesium from chlorite or epsomite or both; sodium from cation exchange and halite; chloride from halite; silica from potassium feldspar and chlorite; sulfate from gypsum, or epsomite or both, and carbon from carbon dioxide. In general, water quality samples obtained from the batch-mixing experiments using water from the coal aquifer had smaller major-ion concentrations than the actual water quality in the spoil aquifer. These differences can be explained by the limited amount of efflorescent salt dissolution and volume of water used in the experiments. Correction ratios calculated for these experiments may be applied to batch-mixing experiments at other mines in the area, to predict postmining water quality. (USGS)

Water-Resources Investigations Report↗
USGS1984

Wilderness mineral potential: Assessment of mineral-resource potential in U.S. Forest Service lands studied in 1964-1984: Volume 1

Under the provisions of the Wilderness Act (Public Law 88-577, September 3, 1964) and subsequent related legislation, the U.S. Geological Survey (USGS) and the U.S. Bureau of Mines (USBM) have been conducting mineral surveys of wilderness and primitive areas, and of other national forest lands being considered for wilderness designation. The Wilderness Act directs that the results of these surveys are to be made available to the public and are to be submitted to the President and the Congress. This professional paper is a synopsis of the mineral surveys made from 1965 to 1983. It summarizes our current knowledge of mineral and energy resources and of the potential for the occurrence of undiscovered mineral and energy resources in 45 million acres of Federal lands, chiefly in national forests. This book, in two volumes, consists of 332 summary articles, arranged alphabetically by State, in which the mineral-resource potential of about 800 individual areas is discussed. The summaries of the mineral surveys were written during 1982-83, generally by those who made the surveys. Index maps of each state show the location of the areas studied, numerically keyed to an alphabetic list. The national distribution of the wilderness lands studied is shown on the frontispiece. Where lands were in proximity or were added to expand previously designated areas, they often are described in a single article. Each article begins with a short summary of the results of the mineral survey followed by a discussion of the character and geologic setting of the area. Mineral resources (if any) are discussed, and the potential for undiscovered mineral resources is assessed; these are keyed to the generalized geographic and geologic map of each area Areas that have geologic characteristics indicative of different degrees of potential for the occurrence of mineral resources are shown in shades of red on each map. Some articles have a section on suggestions for further study to better define the mineral-resource potential of the area A list of pertinent references (including many of the maps and reports prepared during the mineral survey) is provided at the end of each article. This introduction contains some basic concepts about mineral resources and mineral-resource potential to try to make the book more useful to those who are not familiar with the fields of earth science and mineral-resource assessments. The legislation dealing with the wilderness program is reviewed briefly, because this evolving legislation has imparted a continuing and changing influence on the mineral-resource surveys. The introduction concludes with a description of the publications of the Geological Survey that report in greater detail the results of the joint wilderness studies by the Geological Survey and the Bureau of Mines.

Alabama, Alaska, Arizona, Arkansas, California, Co↗
USGS2006

USGS Abandoned Mine Lands Research Presented at the NAAMLP Meeting in Billings, Mont., Sept. 25, 2006

The following talk was an invited presentation given at the National Association of Abandoned Mine Lands Programs meeting in Billings, Montana on Sept. 25, 2006. The objective of the talk was to outline the scope of the U.S. Geological Survey research, past, present and future, in the area of abandoned mine research. Two large Professional Papers have come out of our AML studies: Nimick, D.A., Church, S.E., and Finger, S.E., eds., 2004, Integrated investigations of environmental effects of historical mining in the Basin and Boulder mining districts, Boulder River watershed, Jefferson County, Montana: U.S. Geological Survey Professional Paper 1652, 524 p., 2 plates, 1 DVD, URL: http://pubs.er.usgs.gov/usgspubs/pp/pp1652 Church, S.E., von Guerard, Paul, and Finger, S.E., eds., 2006, Integrated Investigations of Environmental Effects of Historical Mining in the Animas River Watershed, San Juan County, Colorado: U.S. Geological Survey Professional Paper 1651, 1,096 p., 6 plates, 1 DVD (in press). Additional publications and links can be found on the USGS AML website at URL: http://amli.usgs.gov/ or are accessible from the USGS Mineral Resource Program website at URL: http://minerals.usgs.gov/.

Open-File Report↗
USGS2026

Vegetation cover and composition in environments surrounding uranium mines in the Grand Canyon ecosystem, Northern Arizona

Mining uranium from breccia-pipe deposits in the greater Grand Canyon region has occurred since the mid-1900s. However, possible ecosystem contamination with harmful levels of radionuclides may have occurred due to mining activities in the 21st century. In response, a 20-year Federal moratorium on new mining claims in the Grand Canyon watershed was initiated in 2012, to allow time to evaluate the potential effects of uranium exploration and mining on human health, wildlife, and water resources. This moratorium, nor the 2023 designation of the “Baaj Nwaavjo I’tah Kukveni–Ancestral Footprints of the Grand Canyon National Monument,” precludes operation or development of mining claims predating 2012. Vegetation is a core ecosystem component that may be affected by uranium mining (for instance, through uptake and storage of radionuclides from the air or soil) or may act as a vector of exposure to wildlife, livestock, and humans (for instance, via their consumption of contaminated plant tissues). To provide baseline information about the plant communities associated with uranium mines in the Grand Canyon region, the U.S. Geological Survey surveyed an approximately 200-meter-wide buffer surrounding four breccia-pipe deposits, each in a unique stage of mine development, and at one reference area (a livestock water tank) that underwent ground disturbance but contains no mineral deposits. We sectioned the buffer zones into 0.65–4.52 hectare plots, within which we (1) inventoried all plant species, (2) measured percent cover of plant species, plant functional groups, and ground surface types (dark cyanobacteria, lichen, moss, bedrock, rock, embedded litter, duff, plant bases, and bare soil) using line-point intercept, and (3) measured length and frequency of gaps between perennial plant canopies using canopy gap intercept. We found that plant composition at the mines and the reference area differed from one another but were all characteristic of expected regional vegetation patterns. We provide this data summary as potential baseline information for future research and management efforts.

Arizona↗
USGS1982

Full-time equivalency tracking system

To help meet the goals of the Surface-Mining Control and Reclamation Act of 1977, the U.S. Geological Survey is assessing the physical, chemical, and biological characteristics of surface water within the coal-mining region of southwestern Indiana. This report discussed benthic-invertebrate and periphytic-algal communities in streams draining homogeneous agricultural, forested, active/reclaimed-mine, and unreclaimed mine watersheds, and relates the biological communities to the physical and chemical characteristics of the streams. Alkalinity and pH were lower and the concentrations of dissolved solids, calcium, magnesium, sodium, potassium, sulfate, iron, manganese, aluminum, and zinc were higher in unreclaimed-mine watersheds than in the other land-use watersheds. Numbers and community diversity of benthic invertebrates were less at sites affected by mining than at agricultural or forested sites, owing to (1) synergistic effects of pH, metals, and unsuitable habitat and (2) lack of colonizing drift organisms because of the small drainage area upstream from the mined area. Only a few organisms , such as the caddisflies Cheumatopsyche and Hydrosyche and the chironomids Chironomus and Cricotopus were found in streams draining mine areas. (USGS)

Open-File Report↗
USGS2025

Critical minerals in mine waste

Introduction Critical minerals are commodities with vulnerable supply chains that play a vital role in supporting the United States’ economy, national defense and security, emerging technologies, and energy independence. The prosperity of our Nation depends on generating a resilient supply of domestic critical minerals; mine waste may be an untapped source of these commodities. Mine waste from centuries of legacy mining persist on the landscape and may contain critical minerals and other valuable commodities previously deemed uneconomic to recover. At modern mines, the financial viability of recovering byproduct critical minerals, which are not the primary target, may be marginal and can ultimately destine them to mine waste. Further, mine waste can be a liability for the mining company or, at legacy mines, the taxpayer because of its effect on the landscape. The U.S. Geological Survey (USGS) has several initiatives to evaluate critical mineral resources in various types of waste. This factsheet highlights studies of mine waste carried out by USGS scientists at the Geology, Energy & Minerals Science Center in collaboration with other science centers funded through the USGS Mineral Resources Program. Recovery of critical minerals from mine waste can aid in remediation efforts and increase domestic supply of vital mineral resources.

Fact Sheet↗
USGS1993

Mineral resource assessment of pegmatite minerals in the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina

Mineral resources of the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina, were assessed between 1984 and 1990 under the Conterminuous United States Mineral Assessment Program (CUSMAP) of the U.S. Geological Survey (USGS). The mineral resource assessments were made on the basis of geologic, geochemical, and geophysical investigations and on the distribution of mines, prospects, and mineral occurrences reported in the literature. This report is an assessment of the minerals associated with mica pegmatites in the Greenville quadrangle. It is based on the geology as mapped by Nelson and others (1989), on field studies conducted from 1952 to 1962 by the USGS for the Defense Minerals Exploration Administration (DMEA) and the concurrent examination of many of the known mica mines and prospects in Georgia, and on the published geologic literature and an unpublished report by K.H. Teague on file with the South Carolina Development Board, Division of Geology, in Columbia, S.C.

Georgia, North Carolina, South Carolina↗
USGS1975

Summary of references to mineral occurrences (other than mineral fuels and construction materials) in five quadrangles in West-Central Alaska (Hughes, Kotzebue, Melozitna, Selawik, Shungnak)

These summaries of references are designed to aid in library research on metallic and nonmetallic (other than mineral fuels and construction materials) mineral occurrences in 5 quadrangles in west-central Alaska. All references to published and open-filed reports of the Geological Survey, to most published and open-filed reports of the U.S. Bureau of Mines, and to most published reports of the State of Alaska Division of Geological and Geophysical Surveys and its predecessor State and Territorial agencies released before January 1, 1975, are summarized. Occasionally reports from other sources have been included; in such instances references have been summarized in greater detail than those to the kinds of reports listed above. Certain, mainly statistical, reports such as the annual Minerals Yearbook of the U.S. Bureau of Mines and the biennial and annual reports of the State of Alaska Division of Geological and Geophysical Surveys and its predecessor State and Territorial agencies are not included. This report is divided into three parts: a section made up of summaries of references arranged alphabetically first by quadrangle and second by occurrence name; a section that lists synonyms for names in the first section, claim names, and the names of operators and owners of mines and prospects; and a section that lists, by author, all references summarized in the first section.

Alaska↗
USGS1975

Summary of references to mineral occurrences (other than mineral fuels and construction materials) in Northern Alaska

These summaries of references are designed to aid in library research on metallic and nonmetallic (other than mineral fuels and construction materials) mineral occurrences in 11 quadrangles in northern Alaska. All references to published and open-filed reports of the Geological Survey, to most published and open-filed reports of the U.S. Bureau of Mines, and to most published reports of the State of Alaska Division of Geological and Geophysical Surveys and its predecessor State and Territorial agencies released before January 1, 1975. are summarized. Occasionally reports from other sources have been included; in such instances references have been summarized in greater detail than those to the kinds of reports listed above. Certain, mainly statistical reports such as the annual Minerals Yearbook of the U.S. Bureau of Mines and the biennial and annual reports of the State of Alaska Division of Geological and Geophysical Surveys and its predecessor State and Territorial agencies are not included. This report is divided into three parts: a section made up of summaries of references arranged alphabetically first by quadrangle and second by occurrence name; a section that lists synonyms for names in the first section, claim names, and the names of operators and owners of mines and prospects; and a section that lists, by author, all references summarized in the first section.

Alaska↗
USGS1983

Subsidence from underground mining; environmental analysis and planning considerations

Subsidence, a universal process that occurs in response to the voids created by extracting solids or liquids from beneath the Earth's surface, is controlled by many factors including mining methods, depth of extraction, thickness of deposit, and topography, as well as the in situ properties of the rock mass above the deposit. The impacts of subsidence are potentially severe in terms of damage to surface utility lines and structures, changes in surface-water and ground-water conditions, and effects on vegetation and animals. Although subsidence cannot be eliminated, it can be reduced or controlled in areas where deformation of the ground surface would produce dangerous or costly effects. Subsidence prediction is highly developed in Europe where there are comparatively uniform mining conditions and a long history of field measurements. Much of this mining has been carried out beneath crowded urban and industrial areas where accurate predictions have facilitated use of the surface and reduced undesirable impacts. Concerted efforts to understand subsidence processes in the United States are recent. Empirical methods of subsidence analysis and prediction based on local conditions seem better suited to the current state of knowledge of the varied geologic and topographic conditions in domestic coal mining regions than do theoretical/mathematical approaches. In order to develop broadly applicable subsidence prediction methods and models for the United States, more information is needed on magnitude and timing of ground movements and geologic properties.

Circular↗
USGS2014

Reanalysis of historical U.S. Geological Survey sediment samples for geochemical data from the western part of the Wrangellia terrane, Anchorage, Gulkana, Healy, Mt. Hayes, Nabesna, and Talkeetna Mountains quadrangles, Alaska

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 identify areas in Alaska with SCM potential. The USGS is also undertaking SCM-related geologic studies in Alaska through the federally funded Alaska Critical Minerals cooperative project. DGGS and USGS share the goal of evaluating Alaska’s strategic and critical minerals potential and together created a Letter of Agreement (signed December 2012) and a supplementary Technical Assistance Agreement (#14CMTAA143458) to facilitate the two agencies’ cooperative work. Under these agreements, DGGS contracted the USGS in Denver to reanalyze historical USGS sediment samples from Alaska. For this report, DGGS funded reanalysis of 1,682 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from an area covering the western half of the Wrangellia Terrane in the Anchorage, Gulkana, Healy, Mt. Hayes, Nabesna, and Talkeetna Mountains quadrangles of south-central Alaska (fig. 1). USGS was responsible for sample retrieval from the Denver warehouse through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract lab. The new geochemical data are published in this report as a coauthored DGGS report, and will be incorporated into the statewide geochemical databases of both agencies.

Alaska↗
USGS2015

Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the Inmachuk, Kugruk, Kiwalik, and Koyuk River drainages, Granite Mountain, and the northern Darby Mountains, Bendeleben, Candle, Kotzebue, and Solomon quadrangles, Alaska

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. As 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 identify areas in Alaska with SCM potential. The USGS is also undertaking SCM-related geologic studies in Alaska through the federally funded Alaska Critical Minerals cooperative project. DGGS and USGS share the goal of evaluating Alaska’s strategic and critical minerals potential and together created a Letter of Agreement (signed December 2012) and a supplementary Technical Assistance Agreement (#14CMTAA143458) to facilitate the two agencies’ cooperative work. Under these agreements, DGGS contracted the USGS in Denver to reanalyze historical USGS sediment samples from Alaska. For this report, DGGS funded reanalysis of 653 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from an area covering portions of the Inmachuk, Kugruk, Kiwalik, and Koyuk river drainages, Granite Mountain, and the northern Darby Mountains, located in the Bendeleben, Candle, Kotzebue, and Solomon quadrangles of eastern Seward Peninsula, Alaska (fig. 1). The USGS was responsible for sample retrieval from the National Geochemical Sample Archive (NGSA) in Denver, Colorado through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract lab. The new geochemical data are published in this report as a coauthored DGGS report, and will be incorporated into the statewide geochemical databases of both agencies.

Alaska↗
USGS2015

Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the Haines area, Juneau and Skagway quadrangles, southeast Alaska

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. As 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 identify areas in Alaska with SCM potential. The USGS is also undertaking SCM-related geologic studies in Alaska through the federally funded Alaska Critical Minerals cooperative project. DGGS and USGS share the goal of evaluating Alaska’s strategic and critical minerals potential and together created a Letter of Agreement (signed December 2012) and a supplementary Technical Assistance Agreement (#14CMTAA143458) to facilitate the two agencies’ cooperative work. Under these agreements, DGGS contracted the USGS in Denver to reanalyze historical USGS sediment samples from Alaska. For this report, DGGS funded reanalysis of 212 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from the Chilkat, Klehini, Tsirku, and Takhin river drainages, as well as smaller drainages flowing into Chilkat and Chilkoot Inlets near Haines, Skagway Quadrangle, Southeast Alaska. Additionally some samples were also chosen from the Juneau gold belt, Juneau Quadrangle, Southeast Alaska (fig. 1). The USGS was responsible for sample retrieval from the National Geochemical Sample Archive (NGSA) in Denver, Colorado through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract lab. The new geochemical data are published in this report as a coauthored DGGS report, and will be incorporated into the statewide geochemical databases of both agencies.

Alaska↗
USGS2015

Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the Kougarok area, Bendeleben and Teller quadrangles, Seward Peninsula, Alaska

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. As 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 identify areas in Alaska with SCM potential. The USGS is also undertaking SCM-related geologic studies in Alaska through the federally funded Alaska Critical Minerals cooperative project. DGGS and USGS share the goal of evaluating Alaska’s strategic and critical minerals potential and together created a Letter of Agreement (signed December 2012) and a supplementary Technical Assistance Agreement (#14CMTAA143458) to facilitate the two agencies’ cooperative work. Under these agreements, DGGS contracted the USGS in Denver to reanalyze historical USGS sediment samples from Alaska. For this report, DGGS funded reanalysis of 302 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from the Kougarok River drainage as well as smaller adjacent drainages in the Bendeleben and Teller quadrangles, Seward Peninsula, Alaska (fig. 1). The USGS was responsible for sample retrieval from the National Geochemical Sample Archive (NGSA) in Denver, Colorado through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract lab. The new geochemical data are published in this report as a coauthored DGGS report, and will be incorporated into the statewide geochemical databases of both agencies.

Alaska↗