Skip to main content
Advanced Search

Filters: partyWithName: Laurel G. Woodruff (X)

33 results (1s)   

View Results as: JSON ATOM CSV
thumbnail
This field trip examines the geology of rocks of the Keweenawan Supergroup (1 .1 Ga) and related intrusive rocks of the Midcontinent rift system (MRS) in the western part of the northern peninsula of Michigan. The combination of stops includes all formations of the Keweenawan Supergroup in this region. Examination of all described localities requires more than a single day and participants are encouraged to use this guidebook on their own to supplement the localities that will be visited on our one-day trip. Because of uncertainties of weather, road conditions, and remaining snow pack in early May in this region of very heavy snowfall, the stops that we will visitwill not be known until the date of the trip. Stops...
Categories: Publication; Types: Citation
thumbnail
This is a report of geochemical data from various media collected on Isle Royale, a large island in northeastern Lake Superior. Isle Royale became a national park in 1940 and was designated as a wilderness area in 1976.USGS sampling began in 1996 as part of a larger project on the Midcontinent Rift in the Lake Superior region. Data are given in nine Microsoft Excel spreadsheets. All the data are newly acquired by the USGS.
thumbnail
Magmatic sulfide deposits containing nickel (Ni) and copper (Cu), with or without (?) platinum-group elements (PGEs), account for approximately 60 percent of the world's Ni production and are active exploration targets in the United States and elsewhere. On the basis of their principal metal production, magmatic sulfide deposits in mafic rocks can be divided into two major types: those that are sulfide-rich, typically with 10 to 90 percent sulfide minerals, and have economic value primarily because of their Ni and Cu contents; and those that are sulfide-poor, typically with 0.5 to 5 percent sulfide minerals, and are exploited principally for PGE. Because the purpose of this deposit model is to facilitate the assessment...
Categories: Publication; Types: Citation; Tags: Open-File Report
thumbnail
Soil represents the largest store of mercury (Hg) in terrestrial ecosystems, and further study of the factors associated with soil Hg storage is needed to address concerns about the magnitude and persistence of global environmental Hg bioaccumulation. To address this need, we compared total Hg and methyl Hg concentrations and stores in the soil of different landscapes in two watersheds in different geographic settings with similar and relatively high methyl Hg concentrations in surface waters and biota, Fishing Brook, Adirondack Mountains, New York, and McTier Creek, Coastal Plain, South Carolina. Median total Hg concentrations and stores in organic and mineral soil samples were three-fold greater at Fishing Brook...
Categories: Publication; Types: Citation; Tags: PLoS ONE
thumbnail
The table contains oxide and cation compositions of olivine grains from drill core of the Duluth Complex, Minnesota. The oxides were determined by electron probe microanalysis (EPMA) and are reported in weight percent (wt%). The cations were calculated based on the oxide compositions and are reported in mole percent (mol%). Olivine is a magnesium iron orthosilicate mineral with the formula (Mg2+, Fe2+)2SiO4. Olivine forms a solid solution series with magnesium (Mg) at one end and iron (Fe) at the other. Forsterite (Mg2SiO4) is the magnesium endmember and fayalite (Fe2SiO4) is the iron endmember. Minor elements can substitute into the crystal structure, such as manganese (Mn) and nickel (Ni). To better understand...
thumbnail
Zn-, Pb-, Cu-, and Fe-bearing rocks of the Lion Hill area in western Vermont formed during the Early Cambrian by syngenetic sedimentary-exhalative and diagenetic replacement processes. Sphalerite, galena, chalcopyrite, pyrite, and, locally, magnetite form stratabound and broadly stratiform lenticular zones, -300 meters long and 25-50 meters thick, which are uneconomic at the present time. The lenses are structurally disrupted and metamorphosed to greenschist facies, probably due to the Taconic orogeny. Textural evidence suggests that mineralizing fluids permeated the sediments prior to lithification and that a dilatant fracture zone, possibly a feeder zone, contains some of the discordant veins at Lion Hill. The...
Categories: Publication; Types: Citation; Tags: Bulletin
thumbnail
We estimated copper (Cu) toxicity in surface water with high dissolved organic matter (DOM) for unmined mineralized watersheds of the Duluth Complex using the Biotic Ligand Model (BLM), which evaluates the effect of DOM, cation competition for biologic binding sites, and metal speciation. A sediment-based BLM was used to estimate stream-sediment toxicity; this approach factors in the cumulative effects of multiple metals, incorporation of metals into less bioavailable sulfides, and complexation of metals with organic carbon. For surface water, the formation of Cu-DOM complexes significantly reduces the amount of Cu available to aquatic organisms. The protective effects of cations, such as calcium (Ca) and magnesium...
Categories: Publication; Types: Citation
thumbnail
Titanium is a mineral commodity that is essential to the smooth functioning of modern industrial economies. Most of the titanium produced is refined into titanium dioxide, which has a high refractive index and is thus able to impart a durable white color to paint, paper, plastic, rubber, and wallboard. Because of their high strength-to-weight ratio and corrosion resistance, titanium metal and titanium metal alloys are used in the aerospace industry as well as for welding rod coatings, biological implants, and consumer goods.Ilmenite and rutile are currently the principal titanium-bearing ore minerals, although other minerals, including anatase, perovskite, and titanomagnetite, could have economic importance in the...
Categories: Publication; Types: Citation; Tags: Professional Paper
thumbnail
This report summarizes results of a study to establish water-quality and geochemical baseline conditions within a small watershed in the Lake Superior region. In 2008, the U.S. Geological Survey (USGS) completed a survey of water-quality parameters and soil and streambed sediment geochemistry of the 83 mi2 Huron River Watershed in the Upper Peninsula of Michigan. Streamflow was measured and water-quality samples collected at a range of flow conditions from six sites on the major tributaries of the Huron River. All water samples were analyzed for a suite of common ions, nutrients, and trace metals. In addition, water samples from each site were analyzed for unfiltered total and methylmercury once during summer low-flow...
thumbnail
In 1998 the U.S. Geological Survey (USGS) initiated a study to examine the natural regional environmental impact of sulfide mineralization exposed to episodic weathering and glaciation. The study focused on the Bend copper-gold massive sulfide deposit located in the Medford District of the Chequamegon National Forest in north central Wisconsin. The Bend massive sulfide deposit is a small, metal-rich sulfide body hosted by Paleoproterozoic metavolcanics. The mineralized horizon subcrops beneath 100-120 feet of glacial cover, and consists of massive pyrite and other sulfides. Bedrock and ore geochemistry are well characterized by analyses of diamond drill core provided to the USGS by Sharpe Energy and Resources. In...
Categories: Publication; Types: Citation; Tags: Open-File Report
thumbnail
In 2007, the U.S. Geological Survey initiated a low-density (1 site per 1600 km2, 4857 sites) geochemical and mineralogical survey of soil of the conterminous United States as part of the North American Soil Geochemical Landscapes Project. Three soil samples were collected, if possible, from each site; (1) a sample from a depth of 0 to 5 cm, (2) a composite of the soil A-horizon, and (3) a deeper sample from the soil C-horizon or, if the top of the C-horizon was at a depth greater than 100 cm, from a depth of approximately 80–100 cm. The < 2 mm fraction of each sample was analysed for a suite of 45 major and trace elements following near-total multi-acid digestion. The major mineralogical components in samples from...
thumbnail
Bedrock, forest floor, and mineral soil sampling in Voyageurs National Park (VNP), Minnesota in 2000 and 2001 is part of a multidisciplinary project that includes the U. S. Geological Survey, National Park Service, University of Wisconsin – La Crosse, Minnesota Pollution Control Agency, and the Minnesota Department of Natural Resources. The joint project is examining the distribution of mercury in age-1 perch, lake water, bedrock and soils for eighteen watersheds in the interior of VNP. The purpose of the project was to establish the background and baseline geochemistry for bedrock and soil in the region, and to determine terrestrial mercury sources and sinks in VNP.
Categories: Publication; Types: Citation; Tags: Open-File Report
thumbnail
In 2007, the U.S. Geological Survey, the Geological Survey of Canada, and the Mexican Geological Survey initiated a low-density (1 site per 1600 km2, 13323 sites) geochemical and mineralogical survey of North American soils (North American Soil Geochemical Landscapes Project). Sampling and analytical protocols were developed at a series of workshops in 20032004 and pilot studies were conducted from 20042007. The ideal sampling protocol at each site includes a sample from 05 cm depth, a composite of the soil A horizon, and a sample from the soil C horizon. The <2-mm fraction of each sample is analyzed for Al, Ca, Fe, K, Mg, Na, S, Ti, Ag, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Ga, In, La, Li, Mn, Mo, Nb, Ni, P, Pb,...
Categories: Publication; Types: Citation; Tags: Geoscience Frontiers
thumbnail
e of this research is to identify the solid-phase sources and geochemical mechanisms of release of As in aquifers of the Des Moines Lobe glacial advance. The overarching concept is that conditions present at the aquifer-aquitard interfaces promote a suite of geochemical reactions leading to mineral alteration and release of As to groundwater. A microprobe X-ray absorption spectroscopy (lXAS) approach is developed and applied to rotosonic drill core samples to identify the solid-phase speciation of As in aquifer, aquitard, and aquifer-aquitard interface sediments. This approach addresses the low solid-phase As concentrations, as well as the fine-scale physical and chemical heterogeneity of the sediments. The spectroscopy...
thumbnail
This report contains major- and trace-element concentration data for soil samples collected from 265 sites along two continental-scale transects in North America. One of the transects extends from northern Manitoba to the United States-Mexico border near El Paso, Tex. and consists of 105 sites. The other transect approximately follows the 38th parallel from the Pacific coast of the United States near San Francisco, Calif., to the Atlantic coast along the Maryland shore and consists of 160 sites. Sampling sites were defined by first dividing each transect into approximately 40-km segments. For each segment, a 1-km-wide latitudinal strip was randomly selected; within each strip, a potential sample site was selected...
Categories: Publication; Types: Citation; Tags: Open-File Report
thumbnail
The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue concentration and a total of 45 watershed and water chemistry parameters were evaluated for two separate years: 2005 and 2006. Results show agreement with other studies where watershed area, lake water pH, nutrient levels (specifically dissolved NO3−-N) and dissolved iron are important factors controlling and/or predicting fish THg level. Exceeding all was the strong dependence...
thumbnail
This report contains geochemical data gathered in the Ashland and Rice Lake 1 degree x 2 degree quadrangles in northern Wisconsin and adjacent parts of northern Michigan and Minnesota. The data, in part, is focused on the Chequamegon National Forest. Nine files are presented which contain more than 2,600 multi-element analyses of soils, stream sediments, and lake-bottom sediments.Data include a mixture of newly acquired data by the USGS and previously reported data from the National Uranium Resource Evaluation (NURE) program. The report thus provides a single-source summary in similar and consistent format of a majority of currently available analyses of surficial materials in this region. Files are presented in...
thumbnail
The U.S. Geological Survey began sampling in 2007 for a low-density (1 site per 1,600 square kilometers, 4,857 sites) geochemical and mineralogical survey of soils in the conterminous United States as part of the North American Soil Geochemical Landscapes Project. The sampling protocol for the national-scale survey included, at each site, a sample from a depth of 0 to 5 centimeters, a composite of the soil A horizon, and a deeper sample from the soil C horizon or, if the top of the C horizon was at a depth greater than 1 meter, a sample from a depth of approximately 80–100 centimeters. The <2-millimeter fraction of each sample was analyzed for a suite of 45 major and trace elements by methods that yield the total...
Categories: Publication; Types: Citation; Tags: Open-File Report
thumbnail
This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and...
thumbnail
Arsenic levels exceeding 10 μg/L are present in hundreds of private supply wells distributed over ten counties in eastern and southeastern Michigan. Most of these wells are completed in the Mississippian Marshall Sandstone, the principal bedrock aquifer in the region, or in Pleistocene glacial or Pennsylvanian bedrock aquifers. About 70% of ground water samples taken from more than 100 wells, have arsenic contents ≥10 μg/L with a maximum value of 220 μg/L. Water samples and continuous cores were taken from two test wells. Arsenic content of core samples ranges from <5 to more than 300 ppm, with the highest values found for pyritic black shales. Authigenic cements in the Marshall Sandstone include patchy authigenic...
Categories: Publication; Types: Citation


map background search result map search result map History and progress of the North American Soil Geochemical Landscapes Project, 2001-2010 The geochemical landscape of northwestern Wisconsin and adjacent parts of northern Michigan and Minnesota(geochemical data files) Bedrock, soil, and lichen geochemistry from Isle Royale National Park, Michigan Mercury in the soil of two contrasting watersheds in the eastern United States Geology of Keweenawan Supergroup Rocks near the Porcupine Mountains, Ontonagon and Gogebic Counties, Michigan Geochemical and mineralogical maps for soils of the conterminous United States A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in <i>Mineral Deposit Models for Resource Assessment</i> Oxide and Cation Compositions of Olivine Grains from Drill Core in the Duluth Complex, Minnesota Bedrock, soil, and lichen geochemistry from Isle Royale National Park, Michigan The geochemical landscape of northwestern Wisconsin and adjacent parts of northern Michigan and Minnesota(geochemical data files) Oxide and Cation Compositions of Olivine Grains from Drill Core in the Duluth Complex, Minnesota Geology of Keweenawan Supergroup Rocks near the Porcupine Mountains, Ontonagon and Gogebic Counties, Michigan Mercury in the soil of two contrasting watersheds in the eastern United States Geochemical and mineralogical maps for soils of the conterminous United States History and progress of the North American Soil Geochemical Landscapes Project, 2001-2010 A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in <i>Mineral Deposit Models for Resource Assessment</i>