Journal of Research of the U. S. Geological Survey, 1978, volume 6, issue 6
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Geological Survey research 1972
This collection of 30 short papers is the third published chapter of "Geological Survey Research 1972." The papers report on scientific and economic results of current work by members of the Geologic and Water Resources Divisions of the U.S. Geological Survey. Chapter A, to be published later in the year, will present a summary of significant results of work done in fiscal year 1972, together with lists of investigations in progress, cooperating agencies, and Geological Survey offices. "Geological Survey Research 1972" is the thirteenth and last volume of the annual series Geological Survey Research. The short-papers chapters (B, C, and D) will be replaced in 197 3 by the "Journal of Research of the U.S. Geological Survey," and the summary chapter (A) will be published as a separate professional paper. The twelve volumes already published are listed below, with their series designations.
Professional Paper↗
Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects
Light-absorbing particles in atmospheric dust deposited on snow cover (dust-on-snow, DOS) diminish albedo and accelerate the timing and rate of snow melt. Identification of these particles and their effects are relevant to snow-radiation modeling and thus water-resource management. Laboratory-measured reflectance of DOS samples from the San Juan Mountains (USA) were compared with DOS mass loading, particle sizes, iron mineralogy, carbonaceous matter type and content, and chemical compositions. Samples were collected each spring for water years 2011-2016, when individual dust layers had merged into one (all layers merged) at the snow surface. Average reflectance values of the six samples were 0.2153 (sd, 0.0331) across the visible wavelength region (0.4-0.7 µm) and 0.3570 (sd, 0.0498) over the full-measurement range (0.4-2.50 µm). Reflectance values correlated inversely to concentrations of ferric oxide, organic carbon (1.4-10 wt. %), magnetite (0.05-0.13 wt. %), and silt (PM63-3.9; median grain sizes averaged 21.4 µm) but lacked correspondence to total iron and PM10 contents. Measurements of reflectance and Mössbauer spectra and magnetic properties indicated that microcrystalline hematite and nano-size goethite were primarily responsible for diminished visible reflectance. Positive correlations between organic carbon and metals attributed to fossil-fuel combustion, with observations from electron microscopy, indicated that some carbonaceous matter occurred as black carbon. Magnetite was a surrogate for related light-absorbing minerals, dark rock particles, and contaminants. Similar analyses of DOS from other areas would help evaluate the influences of varied dust sources, wind-storm patterns, and anthropogenic inputs on snow melt and water resources in and beyond the Colorado River basin.
Colorado↗
Spectrochemical computer analysis - instrumentation
A microphotometer is described for making magnetic tape recordings of spectra 480 mm long from 102- by 508-mm photographic plates. Transmission readings are recorded at a rate exceeding 1,300 per second for every 5.08 um of length of the spectrum, A two-line cadmium fiducial line system and a developing tank for 102- by 508-mm plates also are described as equipment ancillary to a system of computer spectral analysis applied to the spectrochemical analysis of geologic materials.
Journal of Research of the U.S. Geological Survey↗
An evaluation of errors in mapping land use changes for the Central Atlantic Regional Ecological Test Site
Land use change maps prepared from high-resolution, high-altitude aerial photographs for the period 1970 to 1972 of the CARETS (Central Atlantic Regional Ecological Test Site) project were analyzed for accuracy. To test for errors of commission, all outlined areas (polygons) of land use change on five l:100000-scale maps were examined for accuracy. An estimate of the errors of omission was obtained by comparing the land use change polygons mapped for the Norfolk SMSA (Norfolk and Virginia Beach Standard Metropolitan Statistical Area) with the changes mapped in a more detailed study of the same area. The results of these studies showed that the largest number of errors was caused by misregistration of the land use change map to the 1970 land use map; however, only a very small percentage of the total land area of the land use change was affected by misregistration. In the Norfolk SMSA, which is an area of rapid urban growth, many of the land use changes had not been mapped. The conclusion is that quality control checks are necessary both during and after map compilation. The experience of the CARETS and other land use mapping experiments conducted in the early 1970's has resulted in the development of carefully designed quality-control procedures implemented in the nationwide mapping of land use and land cover currently being carried out by the U.S. Geological Survey.
Maryland, Virginia↗
Crude-oil spill research project near Bemidji, Minnesota - Bibliography, 1984-1994
The U.S. Geological Survey began a research project at the site of a crude-oil spill near Bemidji, Minnesota in 1983. The project is part of the U.S. Geological Survey's Toxic Substances Hydrology Program. The objectives of research at the site are to obtain an understanding of the mobilization, transport, and fate of petroleum derivatives in the shallow subsurface and to use this understanding to develop predictive models of contaminant behavior. This report presents a bibliography of scientific papers that have been published from 1984 to early 1994. Research results have been published in scientific journals, conference proceedings, U.S. Geological Survey Reports, and academic theses.
Open-File Report↗
Use of a hybrid computer in engineering-seismology research
A hybrid computer is an important tool in the seismological research conducted by the U.S. Geological Survey in support of the Energy Research and Development Administration nuclear explosion testing program at the Nevada Test Site and the U.S. Geological Survey Earthquake Hazard Reduction Program. The hybrid computer system, which employs both digital and analog computational techniques, facilitates efficient seismic data processing. Standard data processing operations include: (1) preview of dubbed magnetic tapes of data; (2) correction of data for instrument response; (3) derivation of displacement and acceleration time histories from velocity recordings; (4) extraction of peak-amplitude data; (5) digitization of time histories; (6) rotation of instrumental axes; (7) derivation of response spectra; and (8) derivation of relative transfer functions between recording sites. Catalog of time histories and response spectra of ground motion from nuclear explosions and earthquakes that have been processed by the hybrid computer are used in the Earthquake Hazard Research Program to evaluate the effects of source, propagation path, and site effects on recorded ground motion; to assess seismic risk; to predict system response; and to solve system design problems.
Journal of Research of the U.S. Geological Survey↗
Lithium in sediments and brines--how, why and where to search
The possibility of using lithium in batteries to power electric vehicles and as fuel for thermonuclear power has focused attention on the limited resources of lithium other than in pegmatite minerals. The Clayton Valley, Nev., subsurface lithium brine has been the major source of lithium carbonate since about 1967, but the life of this brine field is probably limited to several more decades at the present rate of production. Lithium is so highly soluble during weathering and in sedimentary environments that no lithium-rich sedimentary minerals other than clays have been identified to date. The known deposits of lithium, such as the clay mineral hectorite and the lithium-rich brines, occur in closed desert basins of the Southwest in association with nonmarine evaporites. However, the ultimate source for the lithium in these deposits may be from hydrothermal solutions. The search for previously unreported deposits of nonpegmatitic lithium should consider its probable association, not only with nonmarine evaporite minerals, but also with recent volcanic and tectonic activity, as well as with deposits of boron, beryllium, fluorine, manganese, and possibly phosphate.
Journal of Research of the U.S. Geological Survey↗
Analyses and economic potential of monazite in Liberia
Eleven monazite samples from Liberia, including seven from beach sands, were analyzed by the X-ray fluorescence method. The monazite samples, containing only one-half percent impurities, were obtained by use of a hot Clerici-solution procedure for purification which was devised by the author. The percentage of the rare-earth elements in Liberian monazite concentrates does not differ greatly from that of monazite sands elsewhere in the world. The average of the 11 samples shows less praseodymium and neodymium than Russian and American monazites, but more cerium. Liberian coastal sands apparently contain sufficient reserves of monazite (and other heavy minerals of commerce) to encourage mining. A feasibility study of production and marketing of monazite from Liberian beach sands is recommended.
Journal of Research of the U.S. Geological Survey↗
Textural distribution of sea-floor sediments, south Texas Outer Continental Shelf
The general texture of sea-floor sediments along the south Texas Outer Continental Shelf was evaluated in terms of gravel, sand, silt, and clay components. The gravel component is quantitatively minor and is concentrated mainly in the southern sector; it consists, for the most part, of relict biogenic detritus dominated by molluscan shells. The sand component consists of terrigenous and biogenic detritus. Modern sand is localized along the shoreface sector, whereas palimpsest and relict sands characterize the northern and southern sectors, which are the respective locations of the ancestral Brazos-Colorado 'and Rio Grande deltas. The central sector contains an extensive modern mud blanket that appears to be migrating southward over relict deposits of the ancestral Rio Grande delta. The silt fraction is the highly dominant component of the mud blanket; silt appears to be hydraulically trapped within the shelf environment and constitutes the most abundant detrital component within the Outer Continental Shelf region. The subordinate clay component of the mud blanket is concentrated toward the shelf break and may be largely escaping into deeper water environments.
Texas↗
A model for earthquakes near Palisades Reservoir, southeast Idaho
The Palisades Reservoir seems to be triggering earthquakes: epicenters are concentrated near the reservoir, and quakes are concentrated in spring, when the reservoir level is highest or is rising most rapidly, and in fall, when the level is lowest. Both spring and fall quakes appear to be triggered by minor local stresses superposed on regional tectonic stresses; faulting is postulated to occur when the effective normal stress across a fault is decreased by a local increase in pore-fluid pressure. The spring quakes tend to occur when the reservoir level suddenly rises: increased pore pressure pushes apart the walls of the graben flooded by the reservoir, thus decreasing the effective normal stress across faults in the graben. The fall quakes tend to occur when the reservoir level is lowest: water that gradually infiltrated poorly permeable (fault-gouge?) zones during high reservoir stands is then under anomalously high pressure, which decreases the effective normal stress across faults in the poorly permeable zones.
Idaho↗
A portable helium sniffer
A portable helium sniffer has been developed for field use. The instrument is mounted in a four-wheel-drive pickup truck and can detect 50 parts per billion of helium in soil gas. The usefulness of helium sniffing in soil is being investigated as a prospecting tool in gas, oil, uranium, and geothermal prospecting as well as in earthquake prediction.
Journal of Research of the U.S. Geological Survey↗
Rise of a variable-viscosity fluid in a steadily spreading wedge-shaped conduit with accreting walls
Relatively rigid plates making up the outer 50 to 100 km of the Earth are steadily separating from one another along narrow globe-circling zones of submarine volcanism, the oceanic spreading centers. Continuity requires that the viscous underlying material rise beneath spreading centers and accrete onto the steadily diverging plates. It is likely that during the rise the viscosity changes systematically and that the viscous tractions exerted on the plates contribute to the unique pattern of submarine mountains and earthquake faults observed at spreading centers. The process is modeled by viscous creep in a wedge-shaped conduit (with apex at the sea floor) in which the viscosity varies as r m where r is distance from the apex and m is a parameter. For these conditions, the governing differential equations take a simple form. The solution for the velocity is independent of r and of the sign of m . As viscous stresses vary as r m-1 , the pattern of stress on the conduit wall is sensitive to viscosity variation. For negative m , the viscous pressure along the base of the conduit is quite uniform; for positive m , it falls toward zero in the axial region as the conduit base widens. For small opening angles, viscous forces push the plates apart, and for large ones, they oppose plate separation. Though highly idealized, the solution provides a tool for investigating tectonic processes at spreading centers.
Journal of Research of the U.S. Geological Survey↗
Possible extension of mineral belts, northern part of Coeur d'Alene district, Idaho
The ore deposits in the northern part of the Coeur d'Alene district are located within rocks of the Belt Supergroup that have been intruded by Cretaceous quartz monzonites. Lead-zinc-silver replacement veins constitute most of the deposits. The geometry of the district has been modified by post-ore faulting along the Osburn, Dobson Pass, and other faults. The original position of the Gem stocks, before their separation from the Diego Peak stocks by the Dobson Pass fault, can be approximately reconstructed by moving the truncated stocks and associated geochemical dispersion patterns back into matching positions. The known mineral belts are defined by dispersion patterns of both lead and the Pb:Zn ratio. Similar dispersion patterns of lead and the Pb:Zn ration northwest of the original position of the Gem stocks suggest that the mineral belts extend into that area.
Idaho↗
Natural radioactivity in geothermal waters, Alhambra Hot Springs and nearby areas, Jefferson County, Montana
Radioactive hot springs issue from a fault zone in crystalline rock of the Boulder batholith at Alhambra, Jefferson County, in southwestern Montana. The discharge contains high concentrations of radon, and the gross alpha activity and the concentration of adium-226 exceed maximum levels recommended by the Environmental Protection Agency for drinking water. Part of the discharge is diverted for space heating, bathing, and domestic use. The radioactive thermal waters at measured temperatures of about 60°C are of the sodium bicarbonate type and saturated with respect to calcium carbonate. Radium-226 in the rock and on fractured surfaces or coprecipitated with calcium carbonate probably is the principal source of radon that is dissolved in the thermal water and discharged with other gases from some wells and springs. Local surface water and shallow ground water are of the calcium bicarbonate type and exhibit low background activity. The temperature, percent sodium, and radioactivity of mixed waters adjacent to the fault zone increase with depth. Samples from most of the major hot springs in southwestern Montana have been analyzed for gross alpha and beta activity. The high level of radioactivity at Alhambra appears to be related to leaching of radioactive material from siliceous veins by ascending thermal waters and is not a normal characteristic of hot springs issuing from fractured crystalline rock in Montana.
Montana↗
Porphyry-type metallization and alteration at La Florida de Nacozari, Sonora, Mexico
Pervasive secondary biotite-rich mineral assemblages, characteristic of potassic alteration found in the cores of most commercial porphyry copper systems, are associated spatially with a conspicuous color and a geochemical anomaly at La Florida de Nacozari, Sonora. These composite biotite-magnetite assemblages, with or without actinolite, quartz, rutile, sphene, chalcopyrite, and pyrite assemblages, are primarily the result of early dispersed biotitic (EDB) alteration of andesite. The bulk of the near-surface copper in the area, however, was introduced later by the veins that cut the EDB-altered andesite. These late veins are distinguished by a quartz-calcite-chlorite±laumontite±chalcopyrite assemblage, and the chalcopyrite in these veins may reflect upward remobilization of deep EDB copper by fluids associated with the emplacement of nearby coarse-grained granite. Fluid-inclusion relations in the late veins suggest that their fluids were nonboiling and relatively dilute.
Sonora↗
High-resolution gamma-ray spectrometry in uranium exploration
Sedimentary-type uranium deposits accumulate at favorable sites along a migration path which may be kilometers in length. Their source is a large volume of rock from which the uranium has been leached. The geochemical mobilities and half lives of uranium and its daughter products vary widely so that they are transported from the source rocks, at different rates, along the migration path to their ultimate site. The radioactive disequilibrium resulting from this process has been well documented in the immediate vicinity of ore deposits, and disequilibrium is commonly recorded on gamma-ray logs up the hydraulic gradient from uranium ore. Little is known about the state of secular equilibrium in the leached host rocks, which often represent the only part of the migration path that is at or near the surface and is thus most accessible to the exploration geophysicist. High-resolution gamma-ray spectrometry provides a means of investigating the disequilibrium associated with uranium leaching and migration. Direct measurement of uranium can be made by this method, and the equivalent weight percents can be determined for six of the seven daughter-product decay groups that characterize the state of radioactive equilibrium. The technique has been used quantitatively in laboratory studies, where the results compare favorably with radiochemical analyses; field experiments suggest that semi-quantitative data may be obtained at the outcrop.
Journal of Research of the U.S. Geological Survey↗
Morphology of chasma walls, Mars
The landforms developed on the walls of the Valles Marineris system of chasmas are of three major types, which are locally transitional. The most common type is composed of steep spurs and gullies. The dominant process in the formation or modification of this type appears to be the downslope movement of. material under the influence of gravity, resulting in the accumulation of extensive talus deposits. The type is morphologically similar to high, steep terrestrial scarps in desert or alpine environments. The second morphologic type consists of walls dissected by tributary canyons with characteristic V-shaped cross profiles and blunt canyon heads that locally contain lobate deposits. The tributary canyons may be relict features of the time, when the existence of running water was possible on the surface of Mars. The third morphologic type consists of landslide scars forming broad curved or straight recessed sections of chasma wall. This type is accompanied by landslide deposits that form hummocky floors at the base of the recessed sections. The landslides developed at the expense of other wall morphologies. Chains of rimless depressions and craters that parallel the main structural trends of the chasmas are best interpreted as collapse holes. The origin of the chasmas on Mars is conjectural and may have been structural (grabens), but, on the basis of morphologic studies of their walls, it is suggested that most of the present wall configuration is the result of erosional scarp retreat, where erosion follows preestablished structural planes of weakness.
Journal of Research of the U.S. Geological Survey↗