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At least 397 records · Page 22Linked to original sources
USGS1990

Map showing distribution of gold in stream-sediment samples, Richfield 1° x 2° quadrangle, Utah

This map of the Richfield 1° x 2° quadrangle, Utah, shows the regional distribution of gold in the less-than-0.180-mm (minus-80-mesh) fraction of stream sediments. It is part of a folio of maps of the Richfield 1° x 2° quadrangle, Utah, prepared under the Conterminuous United States Mineral Assessment Program. Other published geochemical maps in this folio are listed in the Selected References of this report. The Richfield quadrangle is located in west-central Utah and includes the eastern part of the Pioche-Marysvale igneous and mineral belt, which extends from the vicinity of Pioche in southeastern Nevada, east-northeastward for 155 miles into central Utah. The western two-thirds of the Richfield quadrangle is part of the Basin and Range province, whereas the eastern third is part of the High Plateaus of Utah, a subprovince of the Colorado Plateau. Bedrock in the northern part of the Richfield quadrangle consists predominantly of Late Proterozoic and Paleozoic sedimentary strata that were thrust eastward during the Sevier orogeny in Cretaceous time onto an autochthon of Mesozoic sedimentary rocks located in the eastern part of the quadrangle. The southern part of the quadrangle is largely underlain by Oligocene and younger volcanic rocks and related intrusions. Extensional tectonism in late Cenozoic time broke the bedrock terrain into a series of north-trending fault blocks; the uplifted mountain areas were eroded to various degrees and the resulting debris was deposited in adjacent basins. Most of the mineral deposits in the Pioche-Marysvale mineral belt were formed as a result of igneous activity in the middle and late Cenozoic time. A more complete description of the geology and a mineral-resource appraisal of the Richfield quadrangle appears in Steven and Morris (1984 and 1987). The regional sampling program was designed to define broad geochemical patterns and trends that can be utilized along with geological and geophysical data to assess the mineral-resource potential for this quadrangle. Reconnaissance geochemical surveys are valuable tools in mineral exploration, especially when used in conjunction with data obtained from other earth science disciplines. Identifying specific exploration targets generally involves additional, more detailed investigations.

Utah↗
USGS2003

Sediment-hosted copper deposits of the world: Deposit models and database

Introduction This publication contains four descriptive models and four grade-tonnage models for sediment hosted copper deposits. Descriptive models are useful in exploration planning and resource assessment because they enable the user to identify deposits in the field and to identify areas on geologic and geophysical maps where deposits could occur. Grade and tonnage models are used in resource assessment to predict the likelihood of different combinations of grades and tonnages that could occur in undiscovered deposits in a specific area. They are also useful in exploration in deciding what deposit types meet the economic objectives of the exploration company. The models in this report supersede the sediment-hosted copper models in USGS Bulletin 1693 (Cox, 1986, and Mosier and others, 1986) and are subdivided into a general type and three subtypes. The general model is useful in classifying deposits whose features are obscured by metamorphism or are otherwise poorly described, and for assessing regions in which the geologic environments are poorly understood. The three subtypes are based on differences in deposit form and environments of deposition. These differences are described under subtypes in the general model. Deposit models are based on the descriptions of geologic environments and physical characteristics, and on metal grades and tonnages of many individual deposits. Data used in this study are presented in a database representing 785 deposits in nine continents. This database was derived partly from data published by Kirkham and others (1994) and from new information in recent publications. To facilitate the construction of grade and tonnage models, the information, presented by Kirkham in disaggregated form, was brought together to provide a single grade and a single tonnage for each deposit. Throughout the report individual deposits are defined as being more than 2,000 meters from the nearest adjacent deposit. The deposit models are presented here as a PDF file. The database can be most conveniently read in FileMaker Pro. For those who do not have the FileMaker application, Microsoft-Excel, tab-delimited-ASCII and comma-separated-value files are included. The reader may be interested in a similar publication on porphyry copper deposits (Singer and others, 2005) also available online. The Google Earth image is not intended to be viewed at the highest possible magnification because the resolution of the database is plus or minus two kilometers. At extreme zoom settings, the deposit locations may not coincide with the Google-Earth images of the mine workings.

Open-File Report↗
USGS2025

Establishing historical baselines of arthropod assemblages using rodent paleomiddens

Aim Arthropods are under-represented in paleoecological studies but are critical agents in ecological processes. Despite rigorous documentation of diverse arthropod assemblages from ancient rodent (or paleo) middens worldwide, their use for studying ancient arthropod diversity has stalled in recent decades. Here, we review published studies to identify how paleomidden arthropods can be leveraged to address significant questions in ecology and synthesise spatiotemporal trends in ancient arthropod diversity. Location Global with a focus on the Americas. Time Period From ~40,000 to 100 years before present. Major Taxa Studied Fossil arthropods preserved in rodent paleomiddens. Methods We identified four primary objectives in ecology that can be advanced using paleomidden arthropod fossils: the reconstruction of ancient biodiversity, the elucidation of mechanisms and processes driving arthropod range shifts, the incorporation of arthropods into ancient trophic webs, and the assessment of adaptive responses to changing environments. Results We identified 20 papers reporting arthropod remains, of which 14 provided data suitable for quantitative analyses. Although no significant differences in arthropod community diversity were found across broad geographic regions, substantial differences in community structure were observed. In North America, we also detected a decline in arthropod diversity from 10 to 5 ka BP, driven primarily by the absence of high-diversity assemblages during this period. Main Conclusions Paleomidden arthropods remain an underutilised ecological resource that can be leveraged to improve the inferential scope of arthropod research across spatiotemporal gradients. Collaboration between paleo- and neoecologists could help expand the sampling of ancient and modern arthropod communities, particularly those associated with paleomiddens, to create high-resolution datasets spanning important periods in biogeographical history. Paleomidden arthropods will remain a fundamental component for understanding arthropod biodiversity changes in the past, present, and future.

Global Ecology and Biogeography↗
USGS2016

Assessing potential scour using the South Carolina bridge-scour envelope curves

Summary Bridge-scour equations presented in the Federal Highway Administration Hydraulic Engineering Circular No. 18 reflect the current state-of-the practice for predicting scour at bridges. Although these laboratory-derived equations provide an important resource for assessing scour potential, there is a measure of uncertainty when applying these equations to field conditions. The uncertainty and limitations have been acknowledged by laboratory researchers and confirmed in field investigations. Because of the uncertainty associated with bridge-scour equations, HEC-18 recommends that engineers evaluate the computed scour depths obtained from the equations and modify the resulting data if they appear unreasonable. Perhaps the best way to evaluate the reasonableness of predicted scour is to compare it to field measurements of historic scour. Historic field data show scour depths resulting from high flows and provide a reference for evaluating predicted scour. It is rare, however, that such data are available at or near a site of interest, making the evaluation of predicted scour as compared to field data difficult if not impossible. Realizing the value of historic scour measurements, the U.S. Geological Survey (USGS), in cooperation with the South Carolina Department of Transportation (SCDOT), conducted a series of three field investigations to collect historic scour data with the goal of understanding regional trends of scour at riverine bridges in South Carolina. Historic scour measurements, including measurements of clear-water abutment, contraction, and pier scour, as well as live-bed contraction and pier scour, were made at more than 200 bridges. These field investigations provided valuable insights into regional scour trends and yielded regional bridge-scour envelope curves that can be used as supplementary tools for assessing all components of scour at riverine bridges in South Carolina. The application and limitations of these envelope curves were documented in four reports. Because each report addresses different components of bridge scour, it was recognized that there was a need to develop an integrated procedure for applying the envelope curves to help assess scour potential at riverine bridges in South Carolina. The result of that effort is detailed in Benedict and others (2016) and summarized in this fact sheet.

South Carolina↗
USGS1984

Maps showing distribution of pH, copper, zinc, fluoride, uranium, molybdenum, arsenic, and sulfate in water, Richfield 1° x 2° quadrangle, Utah

These maps show the regional distribution of copper, zinc, arsenic, molybdenum, uranium, fluoride, sulfate, and pH in surface and ground water from the Richfield 1° x 2° quadrangle. This study supplements (Miller and others, 1984a-j) the regional drainage geochemical study done for the Richfield quadrangle under the U.S. Geological Survey’s Conterminuous United States Mineral Assessment Program (CUSMAP). Regional sampling was designed to define broad geochemical patterns and trends which can be used, along with geologic and geophysical data, to assess the mineral resource potential of the Richfield quadrangle. Analytical data used in compiling this report were published previously (McHugh and others, 1981). The Richfield quadrangle in west-central Utah covers the eastern part of the Pioche-Marysvale igneous and mineral belt that extends from the vicinity of Pioche in southeastern Nevada, east-northeastward for 250 km into central Utah. The western two-thirds of the Richfield quadrangle is in the Basin and Range Province, and the eastern third in the High Plateaus of Utah subprovince of the Colorado Plateau. Bedrock in the northern part of the Richfield quadrangle consists predominantly of latest Precambrian and Paleozoic sedimentary strata that were thrust eastward during the Sevier orogeny in Cretaceous time onto an autochthon of Mesozoic sedimentary rocks in the eastern part of the quadrangle. The southern part of the quadrangle is largely underlain by Oligocene and younger volcanic rocks and related intrusions. Extensional tectonism in late Cenozoic time broke the bedrock terrane into a series of north-trending fault blocks; the uplifted mountain areas were deeply eroded and the resulting debris deposited in the adjacent basins. Most of the mineral deposits in the Pioche-Marysvale mineral belt were formed during igneous activity in the middle and late Cenozoic time.

Utah↗
USGS2003

Sequence-Stratigraphic Analysis of the Regional Observation Monitoring Program (ROMP) 29A Test Corehole and Its Relation to Carbonate Porosity and Regional Transmissivity in the Floridan Aquifer System, Highlands County, Florida

An analysis was made to describe and interpret the lithology of a part of the Upper Floridan aquifer penetrated by the Regional Observation Monitoring Program (ROMP) 29A test corehole in Highlands County, Florida. This information was integrated into a one-dimensional hydrostratigraphic model that delineates candidate flow zones and confining units in the context of sequence stratigraphy. Results from this test corehole will serve as a starting point to build a robust three-dimensional sequence-stratigraphic framework of the Floridan aquifer system. The ROMP 29A test corehole penetrated the Avon Park Formation, Ocala Limestone, Suwannee Limestone, and Hawthorn Group of middle Eocene to Pliocene age. The part of the Avon Park Formation penetrated in the ROMP 29A test corehole contains two composite depositional sequences. A transgressive systems tract and a highstand systems tract were interpreted for the upper composite sequence; however, only a highstand systems tract was interpreted for the lower composite sequence of the deeper Avon Park stratigraphic section. The composite depositional sequences are composed of at least five high-frequency depositional sequences. These sequences contain high-frequency cycle sets that are an amalgamation of vertically stacked high-frequency cycles. Three types of high-frequency cycles have been identified in the Avon Park Formation: peritidal, shallow subtidal, and deeper subtidal high-frequency cycles. The vertical distribution of carbonate-rock diffuse flow zones within the Avon Park Formation is heterogeneous. Porous vuggy intervals are less than 10 feet, and most are much thinner. The volumetric arrangement of the diffuse flow zones shows that most occur in the highstand systems tract of the lower composite sequence of the Avon Park Formation as compared to the upper composite sequence, which contains both a backstepping transgressive systems tract and a prograding highstand systems tract. Although the porous and permeable layers are not thick, some intervals may exhibit lateral continuity because of their deposition on a broad low-relief ramp. A thick interval of thin vuggy zones and open faults forms thin conduit flow zones mixed with relatively thicker carbonate-rock diffuse flow zones between a depth of 1,070 and 1,244 feet below land surface (bottom of the test corehole). This interval is the most transmissive part of the Avon Park Formation penetrated in the ROMP 29A test corehole and is included in the highstand systems tract of the lower composite sequence. The Ocala Limestone is considered to be a semiconfining unit and contains three depositional sequences penetrated by the ROMP 29A test corehole. Deposited within deeper subtidal depositional cycles, no zones of enhanced porosity and permeability are expected in the Ocala Limestone. A thin erosional remnant of the shallow marine Suwannee Limestone overlies the Ocala Limestone, and permeability seems to be comparatively low because moldic porosity is poorly connected. Rocks that comprise the lower Hawthorn Group, Suwannee Limestone, and Ocala Limestone form a permeable upper zone of the Upper Floridan aquifer, and rocks of the lower Ocala Limestone and Avon Park Formation form a permeable lower zone of the Upper Floridan aquifer. On the basis of a preliminary analysis of transmissivity estimates for wells located north of Lake Okeechobee, spatial relations among groups of relatively high and low transmissivity values within the upper zone are evident. Upper zone transmissivity is generally less than 10,000 feet squared per day in areas located south of a line that extends through Charlotte, Sarasota, DeSoto, Highlands, Polk, Osceola, Okeechobee, and St. Lucie Counties. Transmissivity patterns within the lower zone of the Avon Park Formation cannot be regionally assessed because insufficient data over a wide areal extent have not been compiled.

Open-File Report↗
USGS2012

County-level estimates of nitrogen and phosphorus from commercial fertilizer for the Conterminous United States, 1987-2006

The U.S. Geological Survey’s National Water-Quality Assessment program requires nutrient input for analysis of the national and regional assessment of water quality. Detailed information on nutrient inputs to the environment are needed to understand and address the many serious problems that arise from excess nutrients in the streams and groundwater of the Nation. This report updates estimated county-level farm and nonfarm nitrogen and phosphorus input from commercial fertilizer sales for the conterminous United States for 1987 through 2006. Estimates were calculated from the Association of American Plant Food Control Officials fertilizer sales data, Census of Agriculture fertilizer expenditures, and U.S. Census Bureau county population. A previous national approach for deriving farm and nonfarm fertilizer nutrient estimates was evaluated, and a revised method for selecting representative states to calculate national farm and nonfarm proportions was developed. A national approach was used to estimate farm and nonfarm fertilizer inputs because not all states distinguish between farm and nonfarm use, and the quality of fertilizer reporting varies from year to year. For states that distinguish between farm and nonfarm use, the spatial distribution of the ratios of nonfarm-to-total fertilizer estimates for nitrogen and phosphorus calculated using the national-based farm and nonfarm proportions were similar to the spatial distribution of the ratios generated using state-based farm and nonfarm proportions. In addition, the relative highs and lows in the temporal distribution of farm and nonfarm nitrogen and phosphorus input at the state level were maintained—the periods of high and low usage coincide between national- and state-based values. With a few exceptions, nonfarm nitrogen estimates were found to be reasonable when compared to the amounts that would result if the lawn application rates recommended by state and university agricultural agencies were used. Also, states with higher nonfarm-to-total fertilizer ratios for nitrogen and phosphorus tended to have higher urban land-use percentages.

Scientific Investigations Report↗
USGS2003

Numerical simulation of ground-water flow in La Crosse County, Wisconsin, and into nearby pools of the Mississippi River

This report describes a two-dimensional regional screening model and two associated three-dimensional ground-water flow models that were developed to simulate the ground-water flow systems in La Crosse County, Wisconsin, and Pool 8 of the Mississippi River. Although the geographic extents of the three-dimensional models were slightly different, both were derived from the same geologic interpretation and regional screening model, and their calibrations were performed concurrently. The objectives of the La Crosse County (LCC) model were to assess the effects of recent (1990s) and potential future ground-water withdrawals and to provide a tool suitable to evaluate the effects of proposed water-management programs. The Pool 8 model objectives were to quantify the magnitude and distribution of ground-water flow into the Pool. The Wisconsin Geological and Natural History Survey and the U.S. Geological Survey developed the models cooperatively. The report describes: 1) the conceptual hydrogeologic model; 2) the methods used in simulating flow; 3) model calibration and sensitivity analysis; and 4) model results, such as simulation of predevelopment conditions and location and magnitude of ground-water discharge into Pool 8 of the Mississippi. Three aquifer units underlie the model area: 1) a shallow unconsolidated sand and gravel aquifer; 2) an upper bedrock aquifer, composed of Cambrian and Ordovician sandstone and dolomite; and 3) a lower bedrock aquifer composed of Cambrian sandstone of the Eau Claire Formation and the Mount Simon Formation. A shale layer that is part of the Eau Claire Formation forms a confining unit separating the upper and lower bedrock aquifers. This confining unit is absent in the Black River and parts of the La Crosse and Mississippi River valleys. Precambrian crystalline basement rock forms the lower base of the ground-water flow system. The U.S. Geological Survey ground-water flow model code, MODFLOW, was used to develop the La Crosse County (LCC) and Pool 8 ground-water flow models. Boundary conditions for the MODFLOW model were extracted from an analytic element screening model of the regional flow system surrounding La Crosse County. Model input was obtained from previously published and unpublished geologic and hydrologic data. Pumpages from municipal and high-capacity wells were also simulated. Model calibration included a comparison of modeled and field-measured water levels and field-measured base flows to simulated stream flows. At calibration, most measured water levels compared favorably to model-calculated water levels. Simulated streamflows at two targets were within 3 percent of estimated measured base flows. Mass balance results from the LCC and Pool 8 models indicated that 63 to 74 percent of ground water was from recharge and 19 to 26 percent was from surface-water sources. Ground-water flow out of the model was to rivers and streams (85 to 87 percent) and pumping wells (11 and 13 percent). The model demonstrates the effects of development on ground water in the study area. The maximum simulated water-level decline in the city of La Crosse metropolitan area is 9.3 feet. Simulated stream losses are similar to the amount of ground water pumped by wells. This indicates that ground water withdrawn by La Crosse County wells is water that under predevelopment conditions discharged to streams and lakes. The models provide estimates of the locations and amount of ground-water flow into Pool 8 and the southern portion of Pool 7 of the Mississippi River. Ground-water discharges into all areas of the pools, except along the eastern shore in the vicinity of the city of La Crosse and immediately downgradient from lock and dam 7 and 8. Ground-water flow into the pools is generally greatest around the perimeter with decreasing amounts away from the perimeter. An area of relatively high ground-water discharge extends out towards the center of Pool 7 from the upper reaches of the pool and may

Wisconsin↗
USGS2013

NW CSC annual report fiscal year 2013

The Northwest Climate Science Center (NW CSC) was established in 2010 as one of eight regional Climate Science Centers created by the Department of the Interior (DOI). The NW CSC encompasses Washing-ton, Oregon, Idaho, and western Montana and has overlapping boundaries with three Landscape Conservation Cooperatives (LCCs): the Great Northern, the Great Basin, and the North Pacific. With guidance from its Executive Stakeholder Advisory Committee (ESAC), the NW CSC and its partner LCCs are addressing the highest priority regional climate science needs of Northwest natural and cultural resource managers. Climate Science Centers tap into the scientific expertise of both the U.S. Geological Survey (USGS) and academic institutions. The NW CSC is supported by an academic consortium with the capacity to generate climate science and tools in a coordinated fashion, serving stakeholders across the Northwest region. This consortium is primarily represented by Oregon State University (OSU), the University of Id-ho (UI), and the University of Washington (UW). The academic consortium and USGS provide capabilities in climate science, ecology, impacts and vulnerability assessment, modeling, adaptation planning, and advanced information technology, all necessary to address and respond to climate change in the Northwest. University members also recruit and train graduate students and early-career scientists. This Annual Report summarizes progress for the goals set out in the NW CSC Strategic Plan for 2012-2015 (http://www.doi.gov/csc/northwest/upload/Northwest-CSC-Strategic-Plan.cfm) and the NW CSC Work-plan for Fiscal Year (FY) 2013 (October 1, 2012 through September 30, 2013). The report follows the structure of the Strategic Plan, which describes the five core services (Executive, Science, Data, Communications, and Education and Training) provided by the NW CSC in support of the stated vision: Our Vision: To become nationally recognized as a best-practice model for the provision of climate science and decision support tools to address conservation and management issues in the Pacific Northwest Region.

Report↗
USGS1997

Pesticides in surface waters: Current understanding of distribution and major influences

This report summarizes a comprehensive analysis of existing information on national and regional patterns of pesticide occurrence in surface waters of the United States and the major influences on the sources and transport of pesticides. It is one of a four-part series that synthesizes current knowledge and understanding of pesticides in the nation's water resources as part of the National Water Quality Assessment Program.

Fact Sheet↗
USGS2019

A probabilistic assessment methodology for carbon dioxide enhanced oil recovery and associated carbon dioxide retention

The U.S. Energy Independence and Security Act of 2007 authorized the U.S. Geological Survey (USGS) to conduct a national assessment of the potential volume of hydrocarbons recoverable by injection of carbon dioxide (CO 2 ) into known oil reservoirs with historical production. The implementation of CO 2 enhanced oil recovery (CO 2 -EOR) techniques could increase the U.S. recoverable hydrocarbon resource base. Use of anthropogenic CO 2 in the CO 2 -EOR process could reduce the amount of CO 2 released to the atmosphere by allowing a percentage of the injected CO 2 to remain in reservoir pore space once occupied by produced oil and water or by CO 2 dissolution in oil and water in the reservoir. The USGS has developed a new methodology for the national assessment of technically recoverable oil resources that may be produced by using current CO 2 -EOR technologies. The methodology relies on a proprietary reservoir-level database, the comprehensive resource database (CRD). The CRD incorporates commercially available geologic and engineering data, and USGS-defined play averages or province averages of reservoir data were used to populate incomplete records. Values from the CRD are used to estimate the original oil in place ( OOIP ) for each reservoir. The inputs are reviewed by USGS geologists, particularly when play or province averages have been used. Monte Carlo simulation is used to produce a numerical probability distribution for the OOIP for each reservoir, with the mean defined as the value of the OOIP in the CRD. A reservoir model (CO 2 Prophet, developed for the U.S. Department of Energy by Texaco, Inc.) is used to determine the incremental recovery factors for oil during the CO 2 -EOR process, on an individual reservoir basis. The model is also used to estimate the volume of CO 2 remaining in the reservoir after the CO 2 -EOR process is complete. Empirical decline curve analysis and comparison with data from published papers and reports on CO 2 -EOR projects are utilized to substantiate the simulation results. Numerical distributions of recovery factors are prepared for variations in the reservoir lithology (clastic or carbonate). The distribution of incremental oil is computed by multiplying the appropriate probability distribution of recovery factors by the individual reservoir distribution of the OOIP . A way to estimate the CO 2 remaining in the reservoir after the completion of the CO 2 -EOR process is also included in the methodology. Assessment results will be aggregated to play, petroleum province, regional, and national scales. This assessment methodology has been tested on the Horseshoe Atoll, Upper Pennsylvanian-Wolfcampian play in the Permian Basin Province in Texas; the play consists of 27 reservoirs having at least 2 billion barrels of OOIP that are amenable to the CO 2 -EOR process. The play was selected as a test case because CO 2 -EOR production data and published reports are available for several reservoirs within the play. Preliminary estimates of oil recoverable by implementation of miscible CO 2 -EOR are comparable to those reported in the literature and obtained by reservoir decline curve analysis.

Scientific Investigations Report↗
USGS2011

2010 Petroleum resource assessment of the National Petroleum Reserve in Alaska (NPRA): GIS play maps

This report provides digital geographic information systems (GIS) files of maps for each of the 24 plays considered in the U.S. Geological Survey (USGS) 2010 updated petroleum resource assessment of the National Petroleum Reserve in Alaska (NPRA) (Houseknecht and others, 2010). These are the sample plays evaluated in a previous USGS assessment of the NPRA (Bird and Houseknecht, 2002a), maps of which were released in pdf format (Bird and Houseknecht, 2002b). The 2010 updated assessment of the NPRA evaluated each of the previously used 24 plays based on new geologic data available from exploration activities and scientific research. Quantitative assessments were revised for 11 plays, and no revisions were made for 9 plays. Estimates of the volume of technically recoverable, undiscovered oil, and nonassociated gas resources in these 20 plays are reported elsewhere (Houseknecht and others, 2010). Four plays quantitatively assessed in 2002 were eliminated from quantitative assessment for reasons explained by Houseknecht and others (2010). The NPRA assessment study area includes Federal and native onshore land and adjacent State offshore areas. A map showing the areal extent of each play was prepared by USGS geologists as a preliminary step in the assessment process. Boundaries were drawn on the basis of a variety of information, including seismic reflection data, results of exploration drilling, and regional patterns of rock properties. Play boundary polygons were captured by digitizing the play maps prepared by USGS geologists.

Alaska↗
USGS1980

Distribution of modern benthic foraminifers on the New Jersey Outer Continental Shelf

We used samples from 21 stations within a 600 km2 area of the New Jersey Outer Continental Shelf to assess the effects of a hydrodynamic environment on the distribution and redistribution of benthic foraminifers. These samples show that, although the predominant genera (Elphidium, Cibicides, and Saccammina) are the same as those reported by other investigators for this region, the environmental factors that control the generic distribution are more complex than were previously postulated. Generic distribution patterns derived from this study are correlated with the bottom topography and sediment distribution as well as the temperature, salinity, and dissolved oxygen concentrations of the bottom waters. The six predominant species observed in the samples (and their phenotypic variants) are cryophilic forms known to occur in the Virginian and Nova Scotian biogeographic provinces and in Arctic waters. Species distribution patterns also correlate well with bottom topography and hydrographic factors, but may be modified by seasonal fluctuations in test production and by redistribution of dead tests. At most stations, specimens of Elphidium subarcticum were attached to quartz grains. This phenomenon, which has not been reported before, probably is an adaptation to a high-energy environment. The distribution pattern of Elphidium subarcticum along with those of the sessile species Webbinella concava and Vasiglobulina n.sp. corroborate sedimentological evidence that the accumulation of modern sediments in the area is negligible.

New Jersey↗
USGS2014

A guidance manual for assessing scour potential using the South Carolina bridge-scour envelope curves

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations of bridge scour in order to better understand regional trends of scour within South Carolina. The studies collected historic-scour data at approximately 200 riverine bridges including measurements of clear-water abutment, contraction, and pier scour, as well as live-bed contraction and pier scour. These investigations provided valuable insights for regional scour trends and yielded bridge-scour envelope curves for assessing scour potential associated with all components of scour at riverine bridges in South Carolina. The application and limitations of these envelop cureves were documents in three reports, Each repoort addresses different components of bridge scour and this, there is a need to develop an integrated procedure for applying the South Carolina bridge-scour envelope curves. To address this need, the U.S. Geological Survey and the South Carolina Department of Transportation initiated a cooperative effort to develop an integrated procedure and document the method in a guidance manual. In addition to developing the integrated procedure, field data from other investigations outside of South Carolina were used to verify the South Carolina bridge-source envelope curves.

South Carolina↗
USGS2011

Executive summary - Geologic assessment of coal in the Gulf of Mexico coastal plain, U.S.A.

The National Coal Resource Assessment (NCRA) project of the U.S. Geological Survey (USGS) has assessed the quantity and quality of the nation's coal deposits that potentially could be mined during the next few decades. For eight years, geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States: the Appalachian Basin, Illinois Basin, Northern Rocky Mountains and Great Plains, Colorado Plateau, and the western part of the Gulf of Mexico Coastal Plain (Gulf Coast) region (Figure 1). In particular, the NCRA assessed resource estimates, compiled coal-quality information, and characterized environmentally sensitive trace elements, such as arsenic and mercury, that are mentioned in the 1990 Clean Air Act Amendments (U.S. Environmental Protection Agency, 1990). The results of the USGS coal assessment efforts may be found at: http://energy.cr.usgs.gov/coal/coal-assessments/index.html and a summary of the results from all assessment areas can be found in Ruppert et al. (2002) and Dennen (2009). Detailed assessments of the major coal-producing areas for the Gulf Coast region along with reviews of the stratigraphy, coal quality, resources, and coalbed methane potential of the Cretaceous, Paleocene, and Eocene coal deposits are presented in this report (Chapters 5-10).

Gulf of Mexico coastal plain↗
USGS2013

National assessment of geologic carbon dioxide storage resources: Results

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resources ( TA SR ) for carbon dioxide (CO 2 ) in geologic formations underlying the onshore and State waters area of the United States. The formations assessed are at least 3,000 feet (914 meters) below the ground surface. The TA SR is an estimate of the CO 2 storage resource that may be available for CO 2 injection and storage that is based on present-day geologic and hydrologic knowledge of the subsurface and current engineering practices. Individual storage assessment units (SAUs) for 36 basins were defined on the basis of geologic and hydrologic characteristics outlined in the assessment methodology of Brennan and others (2010, USGS Open-File Report 2010–1127) and the subsequent methodology modification and implementation documentation of Blondes, Brennan, and others (2013, USGS Open-File Report 2013–1055). The mean national TA SR is approximately 3,000 metric gigatons (Gt). The estimate of the TA SR includes buoyant trapping storage resources ( B SR ), where CO 2 can be trapped in structural or stratigraphic closures, and residual trapping storage resources, where CO 2 can be held in place by capillary pore pressures in areas outside of buoyant traps. The mean total national B SR is 44 Gt. The residual storage resource consists of three injectivity classes based on reservoir permeability: residual trapping class 1 storage resource ( R1 SR ) represents storage in rocks with permeability greater than 1 darcy (D); residual trapping class 2 storage resource ( R2 SR ) represents storage in rocks with moderate permeability, defined as permeability between 1 millidarcy (mD) and 1 D; and residual trapping class 3 storage resource ( R3 SR ) represents storage in rocks with low permeability, defined as permeability less than 1 mD. The mean national storage resources for rocks in residual trapping classes 1, 2, and 3 are 140 Gt, 2,700 Gt, and 130 Gt, respectively. The known recovery replacement storage resource ( KRR SR ) is a conservative estimate that represents only the amount of CO 2 at subsurface conditions that could replace the volume of known hydrocarbon production. The mean national KRR SR , determined from production volumes rather than the geologic model of buoyant and residual traps that make up TA SR , is 13 Gt. The estimated storage resources are dominated by residual trapping class 2, which accounts for 89 percent of the total resources. The Coastal Plains Region of the United States contains the largest storage resource of any region. Within the Coastal Plains Region, the resources from the U.S. Gulf Coast area represent 59 percent of the national CO 2 storage capacity.

Circular↗
USGS1961

Occurrence of minor elements in water

Three basic studies, using spectrographic methods, have been used to establish the occurrence of minor elements in natural waters. One study, of oceanborne chemicals in principal rivers, has established a method for the quantitative analysis of many minor elements. Strontium, barium, lithium, rubidium, chromium, nickel, copper, lead, boron, titanium, molybdenum, manganese, and vanadium occur most frequently in measurable quantities. Reconnaissance of the strontium in surface waters of the United States, shows that surface waters in parts of northern and western Texas and southern New Mexico and Arizona are comparatively high in strontium. A study of minor elements in selected waters of California is continuing. Assessment of preliminary data on uranium and radium in waters is facilitated by grouping data for 10 geotectonic regions of the United States.

Circular↗