SEARCH · USGS Science

Results for “Technology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources

USGS1991

Morphological development of the Florida Escarpment: Observations on the generation of time transgressive unconformities in carbonate terrains

An unconformity of 100 m.yr magnitude continues to form on the western edge of the Florida-Bahama Platform, near 26??N, where distal Mississippi Fan sediments are progressively burying the Florida Escarpment. Multiple perspectives of the developing unconformity's morphology are revealed using available technologies including GLORIA images of the entire platform's edge, Seabeam bathymetric contours, and Deep-Tow's high resolution side-scan data calibrated with bottom photographs. The structure and stratigraphy of the buried escarpment and the associated unconformity are resolved by airgun, sparker, and Deep-Tow's 4 kHz seismic reflection data; we summarize the morphological data on the exposed part of the unconformity and the sedimentary deposits accumulating in the basin above the unconformity. The exposed cliff face is composed of a staircase of bedding-plane terraces which are developed along joint planes. The terraces extend 100-1000 m along the escarpment's face, and the intervening vertical walls are up to 100 m high. The jointed morphology of this Mesozoic limestone cliff apparently reflects erosional exposure of its interior anatomy rather than its accretionary shape. The change in slope between the platform face and the abyssal plain is very abrupt. In places along the contact between the escarpment and fan sediments, reduced chemical-charged brine seeps occur, which locally cause carbonate dissolution and precipitation, sulfide mineralization, and the deposition of a fossiliferous and organic carbon-rich lens associated with chemosynthetic communities. These seep deposits and escarpment-derived megabreccias intercalate with basinal sediments that overlie the unconformity. Because surface seismic reflection data do not produce images of the escarpment's face that closely reflect the exposed escarpment's morphology, they must also be of limited value in characterizing the surface of similar steeply dipping buried escarpments. Thus, the downslope extent of the heavily eroded platform edge is unclear.

Florida↗

USGS1981

Trace elemental analysis of bituminuos coals using the Heidelberg proton microprobe

Trace elements in coal can occur as components of either the organic constituents (macerals) or the inorganic constituents (minerals). Studies of the concentrations and distribution of the trace elements are vital to understanding the geochemical millieu in which the coal was formed and in evaluating the attempts to recover rare but technologically valuable metals. In addition, information on the trace element concentrations is important in predicting the environmental impact of burning particular coals, as many countries move toward greater utilization of coal reserves for energy production. Traditionally, the optical and the electron microscopes and more recently the electron microprobe have been used in studying the components of coal. The proton-induced X-ray emission (PIXE) microprobe offers a new complementary approach with an order of magnitude or more better minimum detection limit. We present the first measurements with a PIXE microprobe of the trace element concentrations of bituminous coal samples. Elemental analyses of the coal macerals-vitrinite, exinite, and inertinite-are discussed for three coal samples from the Eastern U.S.A., three samples from the Western U.S.A., and one sample from the Peoples Republic of China. ?? 1981.

Nuclear Instruments and Methods↗

USGS1981

Computer-assisted photogrammetric mapping systems for geologic studies-A progress report

Photogrammetry has played an important role in geologic mapping for many years; however, only recently have attempts been made to automate mapping functions for geology. Computer-assisted photogrammetric mapping systems for geologic studies have been developed and are currently in use in offices of the Geological Survey of Greenland at Copenhagen, Denmark, and the U.S. Geological Survey at Denver, Colorado. Though differing somewhat, the systems are similar in that they integrate Kern PG-2 photogrammetric plotting instruments and small desk-top computers that are programmed to perform special geologic functions and operate flat-bed plotters by means of specially designed hardware and software. A z-drive capability, in which stepping motors control the z-motions of the PG-2 plotters, is an integral part of both systems. This feature enables the computer to automatically position the floating mark on computer-calculated, previously defined geologic planes, such as contacts or the base of coal beds, throughout the stereoscopic model in order to improve the mapping capabilities of the instrument and to aid in correlation and tracing of geologic units. The common goal is to enhance the capabilities of the PG-2 plotter and provide a means by which geologists can make conventional geologic maps more efficiently and explore ways to apply computer technology to geologic studies. ?? 1981.

Photogrammetria↗

USGS1986

Regional resource depletion and industry activity: The case of oil and gas in the Gulf of Mexico

Stable and declining oil and gas prices have changed the industry's price expectations and, along with depletion of promising exploration prospects, has resulted in reduced exploration. Even with intensive additional exploration, production in most U.S. areas is expected to decline. What does this imply for the drilling and petroleum industry suppliers in particular regions? How should planners in government and the private sector project and incorporate the consequences of these changes in their strategies? This paper answers these questions for the industry operating in the offshore Gulf of Mexico. Future oil and gas production, as well as demand for offshore drilling and production facilities, are shown to depend on the size distribution of undiscovered fields, their associated production costs, and oil and gas prices. Declining well productivity is a consequence of development of progressively smaller fields so that long-run drilling demand should not decline in proportion to the expected production decline. Calculations show a substantial payoff to the drilling industry, in terms of potential demand increases, if it can develop and implement cost reducing technologies. Implications of these results for other offshore producing areas such as the North Sea are also discussed.

Socio-Economic Planning Sciences↗

USGS1990

The occurrence and distribution of trace metals in the Mississippi River and its tributaries

Quantitative and semiquantitative analyses of dissolved trace metals are reported for designated sampling sites on the Mississippi River and its main tributaries utilizing depth-integrated and width-integrated sampling technology to collect statistically representative samples. Data are reported for three sampling periods, including: July-August 1987, November-December 1987, and May-June 1988. Concentrations of Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Pb, Sr, Tl, U, V, and Zn are reported quantitatively, with the remainder of the stable metals in the periodic table reported semiquantitatively. Correlations between As and V, Ba and U, Cu and Zn, Li and Ba, and Li and U are significant at the 99% confidence level for each of the sampling trips. Comparison of the results of this study for selected metals with other published data show generally good agreement for Cr, Cu, Fe, and Zn, moderate agreement for Mo, and poor agreement for Cd and V.

Science of Total Environment↗

USGS1976

Resource data bases-Resource assessment

The U.S. Geological Survey's Office of Resource Analysis is developing computer methods for the handling of mineral-resources data in order to provide improved means for addressing and manipulating data. These methods include: computerized data files and predictive resource models. Data files contain the raw or disaggregated information on mineral deposits and commodities. One operational data file is CRIB (Computerized Resources Information Bank) which is a general purpose inventory and reference file on metallic and nonmetallic mineral deposits. A computer file on resources should contain detailed information on the following main categories: record identification, name and location, description of deposit, analytical data, and production/reserves. A resource model employs postulates and inferences in conjunction with the data to make predictions about resources-as key variables concerning a mineral commodity are changed. The objective is to estimate the availability of minerals including: geological availability (occurrence models), technological availability (exploration and beneficiation models), and economic availability (economics models). ?? 1976.

Computers & Geosciences↗

USGS1984

Feasibility of saltwater gradient ponds as a heat supply for hatchery rearing water

Salt gradient solar collector ponds are economically feasible as a source of heat energy for hatchery rearing water. A pond 3 m deep and covering an area of 5000 m 2 will supply approximately 2800 GJ of energy over a three-month period — enough for a one-year smolt program in an Atlantic salmon hatchery. The cost to construct such a pond is approximately $173,000, or the equivalent of seven years' fuel bills using conventional heating equipment. Although the technology is new and not entirely understood, existing ponds have proven to be relatively problem free and require only minimum maintenance.

Aquacultural Engineering↗

USGS1984

Geology of the Devonian black shales of the Appalachian Basin

Black shales of Devonian age in the Appalachian Basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. The recent energy shortage prompted the U.S. Department of Energy through the Eastern Gas Shales Project of the Morgantown Energy Technology Center to underwrite a research program to determine the geologic, geochemical, and structural characteristics of the Devonian black shales in order to enhance the recovery of gas from the shales. Geologic studies by Federal and State agencies and academic institutions produced a regional stratigraphic network that correlates the 15 ft black shale sequence in Tennessee with 3000 ft of interbedded black and gray shales in central New York. These studies correlate the classic Devonian black shale sequence in New York with the Ohio Shale of Ohio and Kentucky and the Chattanooga Shale of Tennessee and southwestern Virginia. Biostratigraphic and lithostratigraphic markers in conjunction with gamma-ray logs facilitated long-range correlations within the Appalachian Basin. Basinwide correlations, including the subsurface rocks, provided a basis for determining the areal distribution and thickness of the important black shale units. The organic carbon content of the dark shales generally increases from east to west across the basin and is sufficient to qualify as a hydrocarbon source rock. Significant structural features that involve the black shale and their hydrocarbon potential are the Rome trough, Kentucky River and Irvine-Paint Creek fault zone, and regional decollements and ramp zones.

Kentucky, Maryland, New York, Ohio, Pennsylvania, ↗

USGS1996

A passive integrated transponder (PIT) tag system for monitoring fishways

An application of passive integrated transponder (PIT) technology was used to monitor movements of adult American shad ( Alosa sapidissima ), blueback herring ( A. aestivalis ) and gizzard shad ( Dorosoma cepedianum ) in two experimental fishways. Tag reading efficiency was between 88–96%, detection ranges were 50–100 cm from orifices of 3100–9600 cm 2 , and read rates were 5–7 Hz. The system was limited by the amount of time that tags were exposed to the energize/detect zone, and by simultaneous presences of large numbers of tags within this zone.

Fisheries Research↗

USGS1982

Recommended procedures and techniques for the petrographic description of bituminous coals

Modern coal petrology requires rapid and precise description of great numbers of coal core or bench samples in order to acquire the information required to understand and predict vertical and lateral variation of coal quality for correlation with coal-bed thickness, depositional environment, suitability for technological uses, etc. Procedures for coal description vary in accordance with the objectives of the description. To achieve our aim of acquiring the maximum amount of quantitative information within the shortest period of time, we have adopted a combined megascopic-microscopic procedure. Megascopic analysis is used to identify the distinctive lithologies present, and microscopic analysis is required only to describe representative examples of the mixed lithologies observed. This procedure greatly decreases the number of microscopic analyses needed for adequate description of a sample. For quantitative megascopic description of coal microlithotypes, microlithotype assemblages, and lithotypes, we use (V) for vitrite or vitrain, (E) for liptite, (I) for inertite or fusain, (M) for mineral layers or lenses other than iron sulfide, (S) for iron sulfide, and (X 1 ), (X 2 ), etc. for mixed lithologies. Microscopic description is expressed in terms of V representing the vitrinite maceral group, E the exinite group, I the inertinite group, and M mineral components. volume percentages are expressed as subscripts. Thus (V) 20 (V 80 E 10 I 5 M 5 ) 80 indicates a lithotype or assemblage of microlithotypes consisting of 20 vol. % vitrite and 80% of a mixed lithology having a modal maceral composition V 80 E 10 I 5 M 5 . This bulk composition can alternatively be recalculated and described as V 84 E 8 I 4 M 4 . To generate these quantitative data rapidly and accurately, we utilize an automated image analysis system (AIAS). Plots of VEIM data on easily constructed ternary diagrams provide readily comprehended illustrations of the range of modal composition of the lithologic units making up a given coal bed. The use of bulk-specific-gravity determinations is alo recommended for identification and characterization of the distinctive lithologic units. The availability of an AIAS also enhances the capability to acquire textural information. Ranges of size of maceral and mineral grains can be quickly and precisely determined by use of an AIAS. We assume that shape characteristics of coal particles can also be readily evaluated by automated image analysis, although this evaluation has not yet been attempted in our laboratory. Definitive data on the particulate mineral content of coal constitute another important segment of petrographic description. Characterization of mineral content may be accomplished by optical identification, electron microprobe analysis, X-ray diffraction, and scanning and transmission electron microscopy. Individual mineral grains in place in polished blocks or polished this sections, or separated from the coal matrix by sink-float methods are studied by analytical techniques appropriate to the conditions of sampling.

International Journal of Coal Geology↗

USGS1981

Objectives, accomplishments, and future plans of IGCP project 143, remote sensing and mineral exploration

The International Geological Correlation Programme (IGCP) is a worldwide cooperative research programme that began in 1974 under the auspices of the International Union of Geological Sciences. Because of the global availability of Earth resources data collected by satellites and the great interest among geologists in taking advantage of these new sources of information, a project was begun in 1976 to improve the rate of technology transfer in the field of remote-sensing exploration for energy and mineral resources. Conducting joint workshops in cooperation with COSPAR has been an important part of this project. It is to be hoped the project will improve our capability to explore, identify, and develop new resources to meet the burgeoning demands of society. ?? 1981.

Advances in Space Research↗

USGS1983

Maps for the nation: The current federal mapping establishment

The U.S. Government annually produces an estimated 53,000 new maps and charts and distributes about 160 million copies. A large number of these maps are produced under the national mapping program, a decentralized Federal/State cooperative approach to mapping the country at standard scales. Circular A-16, issued by the Office of Management and Budget in 1953 and revised in 1967, delegates the mapping responsibilities to various federal agencies. The U.S. Department of the Interior's Geological Survey is the principal federal agency responsible for implementing the national mapping program. Other major federal map producing agencies include the Departments of Agriculture, Commerce, Defense, Housing and Urban Development, and Transportation, and the Tennessee Valley Authority. To make maps and mapping information more readily available, the National Cartographic Information Center was established in 1974 and an expanded National Map Library Depository Program in 1981. The most recent of many technological advances made under the mapping program are in the areas of digital cartography and video disc and optical disc information storage systems. Future trends and changes in the federal mapping program will involve expanded information and customer service operations, further developments in the production and use of digital cartographic data, and consideration of a Federal Mapping Agency.

Government Publications Review↗

USGS1994

US North Slope gas and Asian LNG markets

Prospects for export of liquified natural gas (LNG) from Alaska's North Slope are assessed. Projected market conditions to 2010 show that new LNG capacity beyond announced expansions will be needed to meet regional demand and that supplies will probably come from outside the region. The estimated delivered costs of likely suppliers show that Alaska North Slope gas will not be competitive. The alternative North Slope gas development strategies of transport and sale to the lower 48 states and use on the North Slope for either enhanced oil recovery or conversion to liquids are examined. The alternative options require delaying development until US gas prices increase, exhaustion of certain North Slope oil fields, or advances occur in gas to liquid fuels conversion technology.

Resources Policy↗

USGS1992

Decomposition techniques

Sample decomposition is a fundamental and integral step in the procedure of geochemical analysis. It is often the limiting factor to sample throughput, especially with the recent application of the fast and modern multi-element measurement instrumentation. The complexity of geological materials makes it necessary to choose the sample decomposition technique that is compatible with the specific objective of the analysis. When selecting a decomposition technique, consideration should be given to the chemical and mineralogical characteristics of the sample, elements to be determined, precision and accuracy requirements, sample throughput, technical capability of personnel, and time constraints. This paper addresses these concerns and discusses the attributes and limitations of many techniques of sample decomposition along with examples of their application to geochemical analysis. The chemical properties of reagents as to their function as decomposition agents are also reviewed. The section on acid dissolution techniques addresses the various inorganic acids that are used individually or in combination in both open and closed systems. Fluxes used in sample fusion are discussed. The promising microwave-oven technology and the emerging field of automation are also examined. A section on applications highlights the use of decomposition techniques for the determination of Au, platinum group elements (PGEs), Hg, U, hydride-forming elements, rare earth elements (REEs), and multi-elements in geological materials. Partial dissolution techniques used for geochemical exploration which have been treated in detail elsewhere are not discussed here; nor are fire-assaying for noble metals and decomposition techniques for X-ray fluorescence or nuclear methods be discussed.

Journal of Geochemical Exploration↗

USGS1995

Graphical and PC-software analysis of volcano eruption precursors according to the Materials Failure Forecast Method (FFM)

The Materials Failure Forecasting Method for volcanic eruptions (FFM) analyses the rate of precursory phenomena. Time of eruption onset is derived from the time of “failure” implied by accelerating rate of deformation. The approach attempts to fit data, Ω, to the differential relationship Ω Ω ¨ = A Ω ˙ "> ¨ = AΩ˙ , where the dot superscript represents the time derivative, and the data Ω may be any of several parameters describing the accelerating deformation or energy release of the volcanic system. Rate coefficients, A and α, may be derived from appropriate data sets to provide an estimate of time to “failure”. As the method is still an experimental technique, it should be used with appropriate judgment during times of volcanic crisis. Limitations of the approach are identified and discussed. Several kinds of eruption precursory phenomena, all simulating accelerating creep during the mechanical deformation of the system, can be used with FFM. Among these are tilt data, slope-distance measurements, crater fault movements and seismicity. The use of seismic coda, seismic amplitude-derived energy release and time-integrated amplitudes or coda lengths are examined. Usage of cumulative coda length directly has some practical advantages to more rigorously derived parameters, and RSAM and SSAM technologies appear to be well suited to real-time applications. One graphical and four numerical techniques of applying FFM are discussed. The graphical technique is based on an inverse representation of rate versus time. For α = 2, the inverse rate plot is linear; it is concave upward for α < 2 and concave downward for α > 2. The eruption time is found by simple extrapolation of the data set toward the time axis. Three numerical techniques are based on linear least-squares fits to linearized data sets. The “linearized least-squares technique” is most robust and is expected to be the most practical numerical technique. This technique is based on an iterative linearization of the given rate-time series. The hindsight technique is disadvantaged by a bias favouring a too early eruption time in foresight applications. The “log rate versus log acceleration technique”, utilizing a logarithmic representation of the fundamental differential equation, is disadvantaged by large data scatter after interpolation of accelerations. One further numerical technique, a nonlinear least-squares fit to rate data, requires special and more complex software. PC-oriented computer codes were developed for data manipulation, application of the three linearizing numerical methods, and curve fitting. Separate software is required for graphing purposes. All three linearizing techniques facilitate an eruption window based on a data envelope according to the linear least-squares fit, at a specific level of confidence, and an estimated rate at time of failure.

Journal of Volcanology and Geothermal Research↗

USGS1987

Inter-laboratory comparison of X-ray fluorescence analyses of eruptive products of El Chichón Volcano, Chiapas, Mexico

An inter-laboratory comparison has been made of X-ray fluorescence analyses of 10 samples of lava and pumices from El Chichón Volcano, Chiapas, Mexico. Some determinations of major-element constituents agree within analytical uncertainty, whereas others exchibit significant bias. Analyses carried out at the Michigan Technological University (MTU) laboratory are systematically lower in MgO (26–48%), Fe total (5–18%), CaO (4–15%) and higher in K 2 O (0–15%) than analyses made at the U.S. Geological Survey (USGS) Denver laboratory. These differences are ascribed in part to a complex combination of calibration assumptionsand mineralogical and particle-size effects inherent in the use of pressed rock-powder pellets in the analytical procedure of the MTU laboratory. Other, but as yet unknown, differences in sample preparation and/or analytical technique may also be important; effects related to natural sample inhomogeneityare believed to be insignificant. The inter-laboratory differences in the analytical data complicated accurate assessment of whether El Chichón magmas have changed composition during the past 300 000 a. Knowledge of such change is needed for understanding petrogenetic history and for such related studies as evaluation of volcanic hazards.

Applied Geochemistry↗

USGS2014

Deep-ocean ferromanganese crusts and nodules

Ferromanganese crusts and nodules may provide a future resource for a large variety of metals, including many that are essential for emerging high- and green-technology applications. A brief review of nodules and crusts provides a setting for a discussion on the latest (past 10 years) research related to the geochemistry of sequestration of metals from seawater. Special attention is given to cobalt, nickel, titanium, rare earth elements and yttrium, bismuth, platinum, tungsten, tantalum, hafnium, tellurium, molybdenum, niobium, zirconium, and lithium. Sequestration from seawater by sorption, surface oxidation, substitution, and precipitation of discrete phases is discussed. Mechanisms of metal enrichment reflect modes of formation of the crusts and nodules, such as hydrogenetic (from seawater), diagenetic (from porewaters), and mixed diagenetic–hydrogenetic processes.

Book chapter↗

USGS2021

Ocean floor manganese deposits

Much of the dissolved Mn delivered to the oceans is slowly oxidized and precipitated alongside varying amounts of Fe into Mn and ferromanganese (FeMn) mineral deposits that occur extensively in the deep ocean wherever sediment accumulation is low and substrate is available. FeMn crusts grow as pavements on rock outcrops throughout the global ocean whereas nodules form as individual FeMn-encrusted particles on the sediment-covered abyssal plains. Both crusts and nodules are composed predominantly of Fe and Mn oxide minerals that precipitate from seawater and for some nodules also from porewaters of deep-sea sediment. In contrast, hydrothermal oxide deposits consist predominantly of Mn or Fe oxide. FeMn crusts and nodules exhibit very high specific surface areas that allow them to scavenge abundant metals and other elements, recording the history of the source waters. Crusts especially serve as an important record of paleoceanographic conditions over the past 70 + million years. Critical metals essential to many computer, military, and green technologies are enriched in crust and nodule deposits to concentrations high enough to compare with, or exceed, typical terrestrial deposits, and they can be considered as potential resources for mining in the near future. Twenty-three contracts pertaining to exploration for nodules and crusts have been signed with the International Seabed Authority, and resource/reserve, baseline, and environmental impact assessments are underway. Many challenges remain to be addressed before full-scale mining of marine FeMn deposits will occur. However, their unique genesis and the growing worldwide need for rare and critical metals keep these deep-ocean deposits relevant to industry, scientists, and governments.

Book chapter↗