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At least 1,531 records · Page 85Linked to original sources
USGS1989

Response of salmonid fish to artificial infection with chum salmon virus

In the fall of 1978, a reovirus was isolated from normal-appearing adult chum salmon (Oncorhynchus keta ) returning to the Tokushibetsu Hatchery in Hokkaido, Japan (Winton et al 1981). The chum salmon virus (CSW) was recovered in the chinook salmon ( Oncorhynchus tshawytscha ) embryo cell line (CHSE-214) where it replicated at 15-20 C, producing foci of syncytia in the monolayer. Electron microscopy revealed icosahedral particles, 75 nm in diameter, with a double capsid. The virus was not inactivated by chloroform or inhibited by fluorodeoxyuridine. It was unstable at 56 C, did not hemagglutinate human type 0 erythrocytes, and had a density of 1.33 g/ml in CsCl . The virus was not neutralized by antiserum against infectious pancreatic necrosis virus or mammalian reovirus serotypes 1, 2 or 3 (Winton 1981). Electrophoretic analysis showed the genome was composed of three large, three medium, and five small segments of double stranded RNA (dsRNA) that ranged from 0.37-2.5 x 10% molecular weight. The virions contained five major structural proteins and several minor proteins (Winton et al 1983).

Book chapter↗
USGS1976

Halogen contents of igneous minerals as indicators of magmatic evolution of rocks associated with the Ray porphyry copper deposit, Arizona

The contents of Cl, F, and H 2 O+ (calculated) in some hydrous igneous minerals in intrusive rocks of Laramide age (70-60 m.y.) near Ray, Ariz., appear to be related to the age and the chemistry of the whole-rock samples. Apatite and biotite in younger, more silicic rocks contain more F but less Cl and H 2 O+ than apatite and biotite in older, more mafic rock; the same relations hold for F and H 2 O+ in sphene. Correlations of the abundance of Cl, F, and H 2 O+ in hornblende with rock chemistry and age are not as strong as for apatite, biotite, and sphene; igneous (?) epidote does not contain Cl and F in amounts detectable by electron microprobe analysis. The contents of Cl, F, and H 2 O+ in whole-rock samples decrease with increasing differentiation index and decreasing age. Data for a single pluton of variable composition mirror the results for a suite of different plutons and dikes. The data are satisfactorily although not exclusively explained by postulating that the melts each contained progressively less Cl, F, and H 2 O and that the hydrons minerals consumed most of the Cl, F, and H 2 O in the magmas. The data may also be explained by postulating that (1) the stocks evolved Cl-bearing water during their ascent and crystallization, or that (2) Cl and H 2 O were concentrated during differentiation of the stocks but the minerals failed to record their buildup. Both alternative explanations find problems with and require special conditions to satisfy field, chemical, and experimental data. If many of the special conditions are not met, a nearby batholithic parent to the stocks is not a favorable source of the mineralized fluids at Ray. Propylitic alteration of biotite results in Cl-poor chlorites and may have provided some Cl to hydrothermal fluids; biotite may have also supplied some F to propylitizing fluids through alteration.

Arizona↗
USGS1992

Hazards of geomagnetic storms

Geomagnetic storms are large and sometimes rapid fluctuations in the Earth's magnetic field that are related to disturbances on the Sun's surface. Although it is not widely recognized, these transient magnetic disturbances can be a significant hazard to people and property. Many of us know that the intensity of the auroral lights increases during magnetic storms, but few people realize that these storms can also cause massive power outages, interrupt radio communications and satellite operations, increase corrosion in oil and gas pipelines, and lead to spuriously high rejection rates in the manufacture of sensitive electronic equipment.

Earthquakes & Volcanoes (USGS)↗
USGS1977

Feasibility and technology for making remote measurements of solutes in water

An indepth evaluation of the available technology in the field of laser-Raman spectroscopy indicates that a TV-type detector, a single monochromator with a holographic grating, an entrance slit filter blocking the Rayleigh light, and a pulsed laser coupled to signal averaging electronics is the best combination of commercial equipment that is presently available for building a remote water-quality sensor. The resultant sensor would be capable of measuring oxyanions in water at concentrations from 10 to 50 milligrams per liter at distances from ground level to 30 meters above the sample. The main interferences would be ambient light, bioluminescence, and natural fluorescence, all of which are minimized when taking advantage of the signal generating and readout capability contained in this equipment package.

Journal of Research of the U.S. Geological Survey↗
USGS1975

Experimental abrasion of detrital gold

The physical breakdown and abrasion rates of gold were studied using a tumbler to simulate natural high-energy environments. The gold fragments were tumbled for periods ranging from 30 to 240 h with different combinations of sand, cobbles, and water at velocities of 0.5 and 2.0 mi/h (0.85 and 3.22 km/h). With sand and gravel, the common bedload of the rivers that deposited the gold-bearing Tertiary sedimentary rocks of the Sierra Nevada, gold is abraded at rates of 0.015 to 0.007 percent (by weight) per hour of travel (at 0.5 mi/h or 0.845 km/h). Cobbles, rather than sand, are responsible for most of the physical changes and abrasion of the gold. Ten gold fragments tumbled for 120 h with cobbles and water (no sand) were broken down to 68 recoverable fragments and lost about 25 percent of their weight to particles smaller than could be recovered using conventional panning techniques. Gold tumbled for 120 h with sand and water lost less than 1 percent of its weight. Gold was abraded faster by wet sand than by dry sand. Velocity appears to be more important as a factor in abrasion of gold than travel distance a fourfold increase in velocity produced a tenfold increase in hourly abrasion rates of gold. Scanning electron microscope examination of the gold fragments after the tumbling experiments revealed differences in surface texture between fragments tumbled with (1) sand, (2) sand and cobbles, and (3) cobbles only.

Journal of Research of the U.S. Geological Survey↗
USGS1992

Small explosions interrupt 3-year quiescence at Mount St. Helens, Washington

On December 11, 1989, geologists working in the crater at Mount St. Helens discovered two thin layers of ash separated by fresh snow-clear evidence that at least two small explosions had occurred recently. The explosions were neither seen nor heard, but on December 7 scientists suspected that a small ash-producing explosion had occurred when seismometers near the volcano recorded a long explosion-like signal, and titlt and displacement meters showed minor deformation of the dome. There were no other large seismic signals to account for the second ash layer, which was most likely associated with one of several smaller signals in early December. The December ash-producing explosions were the first eruptive activity at Mount St. Helens since October 1986. There have been at least five more ash-producing explosions since December 1989, all without recognized seismic or other geophysical precursors. The ash from these explosions appears to be pulverized pieces of dacite dome. The absence of glass shards in the ash suggests that no new magmatic material was ejected. Several of the explosions were accompanied by snow and rock avalanches, pyroclastic flows, ballistic showers, and debris flows. These ash-producing explosions are part of a series of at least 28 explosion-like seismic events that began on August 24, 989. Seismic signals from these events resemble those associated with confirmed ash-producing explosions in April-May 1986. Yet not all of the 1989-1991 events produced ash plumes. Excellent visual observations during four of the events indicated that neither a steam nor ash plume was generated. There is little information about the other events because they occurred when the mountain was not visible, nor was there physical evidence of ashfall or surface changes when scientists visited the crater days to weeks alter. Considerable deformation of the north side of the dome occurred during the series of explosion-like seismic events. Sections of the dome slumped northward and two new vents were formed. However, monitoring the changes associated with individual events was often impossible because several key electronic-distance-meter (EDM) targets and tiltmeters were destroyed by the series of events.

Washington↗
USGS2016

Accretionary lapilli: what’s holding them together?

Accretionary lapilli from Tagus cone, Isla Isabela, Galápagos were analyzed using scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. Our main findings are (1) the lapilli formed and hardened in a few minutes while still aloft in the dispersing eruption column. (2) Palagonite rinds developed first on the basaltic glass clasts, and subsequently crystallized (3) The crystallization products contain submicron lamellar crystals of a clay (probably smectite) on the surfaces of basaltic glass clasts and (4) The interlocking of these lamellar clays from adjacent clasts binds and cements them together to form the accretionary lapillus. We argue that palagonite and possibly clay formation occur primarily in the presence of hot water vapor.

Conference Paper↗
USGS2016

Regional and local correlations of feldspar geochemistry of the Peach Spring Tuff, Alvord Mountain, California

The chemical composition of feldspar grains in an ignimbrite from the Spanish Canyon Formation in the Alvord Mountain area, California, have been used to confirm similarities in three measured sections locally, and they are similar to exposures of the Peach Spring Tuff (PST) regionally. Feldspar grains were identified on the basis of texture (zoning, as mantled feldspars, or in crystal clusters), whether the grains were attached to glass or were in pumice clasts, or were simply crystal fragments with no textural context. Chemistry was determined by electron microprobe analysis, and each analysis is calculated in terms of the percent endmember and plotted on orthoclase (Or) versus anorthite (An) plots. In general, the PST has sanidine and plagioclase compositions that are consistent with having formed in high-silica rhyolite and trachyte within a zoned magma chamber. Feldspars from the PST in Spanish Canyon area cluster along the rhyolitic trend with no grains along the trachytic trend. Similar clustering of feldspars along the rhyolitic trend with no grains along the trachytic trend also occur in the PST from Granite Spring and Providence Mountains to the east of the Alvord Mountain area, and the ranges in compositions are also similar in these locations. In contrast, the PST in the Kane Wash area of the Newberry Mountains has feldspars only from the rhyolitic trend in the basal deposits, but some grains from the trachytic trend are in the upper part of the deposit, and the range in compositions are greater than in the Spanish Canyon area. The variations in vertical compositional zoning and compositional range in these different deposits suggests there were probably different flow paths (or timing of the delivery) during the eruption and runout of the pyroclastic flow(s) generated from the climactic eruption of the PST magma chamber.

Arizon, California, Nevada↗
USGS2007

Interferometric synthetic-aperature radar (InSAR): Chapter 5

Geodesists are, for the most part, a patient and hardworking lot. A day spent hiking to a distant peak, hours spent waiting for clouds to clear a line-of-sight between observation points, weeks spent moving methodically along a level line – such is the normal pulse of the geodetic profession. The fruits of such labors are all the more precious because they are so scarce. A good day spent with an electronic distance meter (EDM) or level typically produces fewer than a dozen data points. A year of tiltmeter output sampled at ten-minute intervals constitutes less than half a megabyte of data. All of the leveling data ever collected at Yellowstone Caldera fit comfortably on a single PC diskette. These quantities are trivial by modern data-storage standards, in spite of the considerable efforts expended to produce them.

Book chapter↗
USGS2006

Applications of geophysical methods to volcano monitoring

The array of geophysical technologies used in volcano hazards studies - some developed originally only for volcano monitoring - ranges from satellite remote sensing including InSAR to leveling and EDM surveys, campaign and telemetered GPS networks, electronic tiltmeters and strainmeters, airborne magnetic and electromagnetic surveys, short-period and broadband seismic monitoring, even microphones tuned for infrasound. They include virtually every method used in resource exploration except large-scale seismic reflection. By “geophysical ” we include both active and passive methods as well as geodetic technologies. Volcano monitoring incorporates telemetry to handle high-bandwith cameras and broadband seismometers. Critical geophysical targets include the flux of magma in shallow reservoir and lava-tube systems, changes in active hydrothermal systems, volcanic edifice stability, and lahars. Since the eruption of Mount St. Helens in Washington State in 1980, and the eruption at Pu’u O’o in Hawai’i beginning in 1983 and still continuing, dramatic advances have occurred in monitoring technology such as “crisis GIS” and lahar modeling, InSAR interferograms, as well as gas emission geochemistry sampling, and hazards mapping and eruption predictions. The on-going eruption of Mount St. Helens has led to new monitoring technologies, including advances in broadband Wi-Fi and satellite telemetry as well as new instrumentation. Assessment of the gap between adequate monitoring and threat at the 169 potentially dangerous Holocene volcanoes shows where populations are dangerously exposed to volcanic catastrophes in the United States and its territories . This paper focuses primarily on Hawai’ian volcanoes and the northern Pacific and Cascades volcanoes. The US Geological Survey, the US National Park System, and the University of Utah cooperate in a program to monitor the huge Yellowstone volcanic system, and a separate observatory monitors the restive Long Valley caldera in collaboration with the US Forest Service.

Conference Paper↗
USGS2007

Mystery solved: White deposit on streambeds proves to be diatoms

In the late winter and early spring of 2006 an unusual white deposit was observed on rocks and margins of streambeds in a number of park streams. Inquiries were made to park staff and scientists studying water resources in the park as to what the deposit was and did it pose any type of risk. A number of explanations were proposed, but it was not until samples were collected and examined with a scanning electron microscope that the identity of the deposit was definitively determined.

Virginia↗
USGS2017

Extent and persistence of secondary water quality impacts after enhanced reductive bioremediation

Electron donor (ED) addition can be very effective in stimulating enhanced reductive bioremediation (ERB) of a wide variety of groundwater contaminants. However, ERB can result in Secondary Water Quality Impacts (SWQIs) including decreased levels of dissolved oxygen (O 2 ), nitrate (NO 3- ), and sulfate (SO 4 2- ), and elevated levels of dissolved manganese (Mn 2+ ), dissolved iron (Fe 2+ ), methane (CH 4 ), sulfide (S 2- ), organic carbon, and naturally occurring hazardous compounds (e.g., arsenic). Fortunately, this ‘plume’ of impacted groundwater is usually confined within the original contaminant plume and is unlikely to adversely impact potable water supplies. This report summarizes available information on processes controlling the production and natural attenuation of SWQI parameters and can be used as a guide in understanding the magnitude, areal extent, and duration of SWQIs in ERB treatment zones and the natural attenuation of SWQI parameters as the dissolved solutes migrate downgradient with ambient groundwater flow. This information was compiled from a wide variety of sources including a survey and statistical analysis of SWQIs from 47 ERB sites, geochemical model simulations, field studies at sites where organic-rich materials have entered the subsurface (e.g., wastewater, landfill leachate, and hydrocarbon plumes), and basic information on physical, chemical, and biological processes in the subsurface. This information is then integrated to provide a general conceptual model of the major processes controlling SWQI production and attenuation.

Technical Report↗
USGS1989

Performance and utility of satellite telemetry during field studies of free-ranging polar bears in Alaska

Satellite telemetry technology has been used during field studies of polar bears in Alaska since 1985. A total of 109 Platform Transmitter Terminals (PTT) have been deployed on free-ranging female polar bears that seasonally inhabit waters adjacent to the Alaskan coast. The PTTs transmitted locational and sensor data to TIROS-N polar-orbiting satellites during a duty cycle of 12 hours on/60 hours off in 1985, 1986, and 1987. Expected battery life was 13.8 months, and collars were normally removed and replaced with new or refurbished PTTs at 11-13 month intervals. Duty cycles were altered to 7-8 hours on/64-65 hours off in 1988 to prolong expected battery life to 19-21 months. Sensor data transmitted included PTT internal temperature, short term activity counts recorded at 60 second intervals, and long term activity counts for the preceding 24 or 72-hour period. Early failures of PTTs to fix location (less than 75% of expected battery life) were as high as 53% during 198501986. Subsequent improvements in battery design, including better shock insulation, improved electronic, and an improved battery system have reduced early failures to 27% in 1987-1988. The harsh environment and the degree of abuse observed in recovered collars indicate that an unavoidable failure rate of 8-10% is inherent within 60 days after deployment on polar bears. A total of 18,000 locations and 201,000 sensor messages were received from female polar bears between May 1985 and June 1988. Polar bears that were marked in Alaskan waters have been located as far south as 60°N 168°W, and as far east as 70°N 127°W in the Beaufort Sea. Polar bears in the Beaufort Sea are shared with Canada, while polar bears in the Chukchi and Bering seas are shared with the Soviet Union. The international ranges of the two hypothesized populations have been documented. Satellite telemetry has detailed the large movement patterns of polar bear over these vast areas that were previously not available using other techniques.

Alaska↗
USGS2017

Mineralogical characterization of weathered outcrops as a tool for constraining water chemistry predictions during project planning

Weathered samples from naturally exposed outcrops of troctolite associated with a magmatic Ni-Cu sulphide deposit were characterized by synchrotron-based micro-X-ray fluorescence mapping (µ-XRF) and X-ray absorption spectroscopy (XAS), as well as by lab-based X-ray diffraction, electron microscopy, Raman spectroscopy and wet chemical methods. Metal mobility in weathered samples was assessed using a sequential leach procedure. Results are interpreted in the context of predictions for future mine water chemistry and used to refine the conceptual model for metal mobility following weathering of waste rock at a potential future mine site.

Conference Paper↗
USGS2003

Determining temperature and thermal properties for heat-based studies of surface-water ground-water interactions: Appendix A of Heat as a tool for studying the movement of ground water near streams (Cir1260)

Advances in electronics leading to improved sensor technologies, large-scale circuit integration, and attendant miniaturization have created new opportunities to use heat as a tracer of subsurface flow. Because nature provides abundant thermal forcing at the land surface, heat is particularly useful in studying stream-groundwater interactions. This appendix describes methods for obtaining the thermal data needed in heat-based investigations of shallow subsurface flow.

Report↗
USGS1994

Tonsteins and clay-rich layers in coal-bearing intervals of the Eocene Manning formation, east-central Texas

Six samples from clay-rich intervals in the coal-bearing upper part of the Eocene Manning Formation were analyzed by scanning-electron microscopy and energy-dispersive X-ray fluorescence to determine the origin of minerals in the samples. Two samples were from surface-mine exposures of the 3500 coal bed near Bryan, Texas, and the remaining samples were from an exposure of a correlative interval at the Lake Somerville spillway about 60 km (37 mi) southwest of Bryan. Preliminary data suggest that both a 2-cm-thick (0.75-in) claystone from the upper part of the 3500 bed and the upper part of an 11-cm-thick (4.25-in) mudstone from the floor of the lower coal bed at the spillway were derived from volcanic ash falls. Both clay layers identified as possible tonsteins are composed of kaolinite and accessory quartz, euhedral to subhedral zircon, feldspars, and Ca-Al phosphates (crandallite?). Both alkali and plagioclase feldspars are observed in the two samples, but K-feldspar predominates in the upper clay layer of the 3500 bed, and plagioclase, with accessory Ti-bearing biotite, predominates in the sample from the floor of the spillway. These compositional differences suggest two separate volcanic ash falls. The other sampled clay layers contain rounded to subrounded zircons and feldspars in a mixed-layer clay groundmass, which suggests detrital rather than ash-fall origins.

Texas↗
USGS2019

Encylopedia of Caves

For many people, a visit to a cave is a wondrous event directing our minds to ponder the mysteries presented by these unique places and inspiring questions: How old is the cave? What was the role of water in forming the cave and where did the water come from? How is the cave connected to the surface environment? These are intriguing questions to ask, and karst scientists use isotope geochemistry to help solve these mysteries. Isotopes are atoms of the same chemical element that have the same number of protons but vary in their number of neutrons. As a result of their atomic mass difference, isotopes of a single element may exhibit slightly different chemical behavior. Radioisotopes are unstable and the nucleus of a parent isotope will spontaneously break apart (decay), releasing energy and changing into another element (daughter product) by loss or gain of protons, neutrons, or electrons. Stable isotopes, as implied by the name, are stable and do not spontaneously decay. These two types of isotopes are used widely by scientists to understand ancient and modern karst systems. Generally, radioisotopes are used for absolute dating karst water, cave sediments, cave formations (speleothems), and other material preserved in caves (such as bones). Stable isotopes can provide information about relative ages of cave water and speleothems. An absolute age provides a numeric date—such as 100,000 years old—whereas a relative age provides information that something is older or younger than something else—such as cave art is younger than a speleothem found in the same cave. Stable isotopes are used to study ancient karst systems because isotopic signals of past climate (paleoclimate) and environmental conditions (paleoenvironment) are preserved in speleothems and sediments. Stable isotopes are also used to understand modern systems, primarily through studies that distinguish sources of karst water, cave air, or contaminants, mixing of those sources, and biologic or chemical reactions that process compounds, such as breakdown of contaminants or organic matter. The variation in mass among isotopes is small, and isotope abundances are measured as a ratio of a common isotope to its less common isotopic counterparts (stable isotopes) or the abundance of a parent compared to daughter isotope (radioisotopes). As an example, hydrogen (H) has three naturally occurring isotopes. Most H comprises one proton (1H), but the rarer stable isotope (called deuterium) comprises one proton and one neutron (2H), and the radioisotope (called tritium) comprises one proton and two neutrons (3H). Because scientists use the minute differences in isotopes to test hypotheses, a scientist must understand the accuracy, precision, and error of the available methods, the assumptions about the chemical conditions of interest, and the limitations of the isotopic method being used. Many isotopic studies employ multiple isotopic tracers to better leverage the strengths and offset the limitations of using a single isotope. This article focuses on isotopes used to study the geology and hydrology of caves, but much additional isotopic work has been used to characterize the biology of caves.

Book chapter↗
USGS2019

Lithologies, ages, and provenance of clasts in the Ordovician Fincastle Conglomerate, Botetourt County, Virginia, USA

The Fincastle Conglomerate is an Ordovician polymictic, poorly sorted, matrix- and clast-supported cobble to boulder-rich conglomerate located just north of Fincastle, Botetourt County, VA. At least nine other cobble and boulder conglomerates are located in a similar stratigraphic position from Virginia to Georgia west of the Blue Ridge structural front. All except the Fincastle are dominated (~80%) by carbonate clasts; Fincastle clasts are much more varied and siliceous and it is this clast diversity that provides increased value for provenance and related studies. We have used a multidisciplinary approach that involves conodont analysis, sandstone petrography, in-situ outcrop clast characterization, optical petrography, electron-beam petrography and chemical analysis, and X-ray diffraction to provide data on lithologies, ages, and provenance. The size, roundness, and lithology of 1,656 clasts (> 1 cm) were measured in the field. Although, the clast lithology varies among the studied localities, the average lithology is sandstone and siltstone 12 %, vein quartz 17 %, limestone 31 %, low-grade quartzite/metasandstone 31 %, chert 6 %, and others 3 %. Dolomite, igneous, or high-grademetamorphic rock clastswere not identified in field study or in detailed laboratory analysis.Dolomite rhombs and authigenic albite feldsparwere observed in some limestone clasts. Quantitative petrographic data for the Fincastle sandstone clasts indicate tectonic environments from passive margin to transitional continental uplift, but the conglomeratematrixmodes have considerably less feldspar and plot in the foreland basin tectonic environment region. Proto-, para-, and euconodonts were identified from clast and matrix, but are long-ranging fauna indicating middle Cambrian toMiddle or Late Ordovician ages; color alteration index (CAI) for euconodonts varied from 3 to 3.5. The occurrence of well-rounded clasts including limestone suggests a nearby, high-energy environment, and that transport was rapid enough to preserve limestone before deposition into a foreland basin. The lack of igneous or high-grade metamorphic rocks clasts suggests that the erosional level sampled by the Fincastle Conglomerate did not include the underlying Grenville basement of igneous or high-grade metamorphic rocks.

Virginia↗