Small (<0.5 mm), brownish-pink platy rosettes and yellow spherules, in cavities in nepheline syenite at the Diamond Jo quarry, Magnet Cove, Hot Spring County, Arkansas, have been identified as kassite, CaTi2O4(OH)2, a mineral previously known only from the Kola Peninsula, USSR. The Magnet Cove kassite is orthorhombic, in space group Ammm, A2mm, A222, or A2,22, with unit-cell parameters a = 12.10, b = 31.65, c = 4.95 Å, and Z = 16; dcalc = 3.28 g/cm3. Principal X-ray powder lines [d in Å, (I)] are 7.85(10), 3.26(7), 2.565(7), 1.910(8), 1.898(6). The X-ray powder and single-crystal data and density correspond to those reported by earlier workers for cafetite, (Ca,Mg)(Fe,Al)2Ti4O12·4H2O, from Kola, but the chemical and physical properties correspond to those given in their description of kassite. These earlier workers may have intermixed samples during their X-ray study of kassite and cafetite.
An inconvenience attending traditional use of associated Legendre functions in global modeling is that the functions are not separable with respect to the two indices (order and degree). In 1973 Merilees suggested a way to avoid the problem by showing that associated Legendre functions of order m and degree m+k can be expressed in terms of elementary functions as
Pmm+k(θ)=sinm(θ)∑ki=0amkicos(iθ)
where amki, the constants to be determined, are somewhat analogous to Fourier coefficients. Merilees noted that there are several advantages to using this form, but he also raises a question of precision for degree and order greater than 25. This note calls attention to some possible gains in time savings and accuracy in geomagnetic modeling based upon this form. For this purpose, expansions of associated Legendre polynomials in terms of sines and cosines of multiple angles are displayed up to degree and order 10. Examples are also given explaining how some surface spherical harmonics can be transformed into true Fourier series for selected polar great circle paths.
Dissolved organic matter and dissolved inorganic chemical species in anoxic pore water from Mangrove Lake, Bermuda sediments were studied to evaluate the role of pore water in the early diagenesis of organic matter. Dissolved sulphate, titration alkalinity, phosphate, and ammonia concentration versus depth profiles were typical of many nearshore clastic sediments and indicated sulphate reduction in the upper 100 cm of sediment. The dissolved organic matter in the pore water was made up predominantly of large molecules, was concentrated from large quantities of pore water by using ultrafiltration and was extensively tudied by using elemental and stable carbon isotope analysis and high-resolution, solid state 13C nuclear magnetic resonance and infrared spectroscopy. The results indicate that this material has a predominantly polysaccharide-like structure and in addition contains a large amount of oxygen-containing functional groups (e.g., carboxyl groups). The 13C nulcear magnetic resonance spectra of the high-molecular-weight dissolved organic matter resemble those of the organic matter in the surface sediments of Mangrove Lake. We propose that this high-molecular-weight organic matter in pore waters represents the partially degraded, labile organic components of the sedimentary organic matter and that pore waters serve as a conduit for removal of these labile organic components from the sediments. The more refractory components are, thus, selectively preserved in the sediments as humic substances (primarily humin).
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(86)90109-2","issn":"00167037","usgsCitation":"Orem, W., Hatcher, P.G., Spiker, E., Szeverenyi, N., and Maciel, G., 1986, Dissolved organic matter in anoxic pore waters from Mangrove Lake, Bermuda: Geochimica et Cosmochimica Acta, v. 50, no. 4, p. 609-618, https://doi.org/10.1016/0016-7037(86)90109-2.","productDescription":"10 p.","startPage":"609","endPage":"618","numberOfPages":"10","costCenters":[],"links":[{"id":226254,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"50","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0239e4b0c8380cd4ff5e","contributors":{"authors":[{"text":"Orem, W. H. 0000-0003-4990-0539","orcid":"https://orcid.org/0000-0003-4990-0539","contributorId":93084,"corporation":false,"usgs":true,"family":"Orem","given":"W. H.","affiliations":[],"preferred":false,"id":369545,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hatcher, Patrick G.","contributorId":93625,"corporation":false,"usgs":true,"family":"Hatcher","given":"Patrick","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":369546,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Spiker, E.C.","contributorId":103275,"corporation":false,"usgs":true,"family":"Spiker","given":"E.C.","affiliations":[],"preferred":false,"id":369547,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Szeverenyi, N.M.","contributorId":83663,"corporation":false,"usgs":true,"family":"Szeverenyi","given":"N.M.","email":"","affiliations":[],"preferred":false,"id":369544,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Maciel, G.E.","contributorId":43910,"corporation":false,"usgs":true,"family":"Maciel","given":"G.E.","email":"","affiliations":[],"preferred":false,"id":369543,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70014894,"text":"70014894 - 1986 - Regression approximations for transport model constraint sets in combined aquifer simulation-optimization studies","interactions":[],"lastModifiedDate":"2018-02-14T08:42:15","indexId":"70014894","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Regression approximations for transport model constraint sets in combined aquifer simulation-optimization studies","docAbstract":"Problems involving the combined use of contaminant transport models and nonlinear optimization schemes can be very expensive to solve. This paper explores the use of transport models with ordinary regression and regression on ranks to develop approximate response functions of concentrations at critical locations as a function of pumping and recharge at decision wells. These response functions combined with other constraints can often be solved very easily and may suggest reasonable starting points for combined simulation-management modeling or even relatively efficient operating schemes in themselves.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR022i004p00581","usgsCitation":"Alley, W.M., 1986, Regression approximations for transport model constraint sets in combined aquifer simulation-optimization studies: Water Resources Research, v. 22, no. 4, p. 581-586, https://doi.org/10.1029/WR022i004p00581.","productDescription":"6 p.","startPage":"581","endPage":"586","costCenters":[],"links":[{"id":225280,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"4","noUsgsAuthors":false,"publicationDate":"2010-07-09","publicationStatus":"PW","scienceBaseUri":"505a933fe4b0c8380cd80cdc","contributors":{"authors":[{"text":"Alley, William M. walley@usgs.gov","contributorId":1661,"corporation":false,"usgs":true,"family":"Alley","given":"William","email":"walley@usgs.gov","middleInitial":"M.","affiliations":[{"id":502,"text":"Office of Surface Water","active":true,"usgs":true}],"preferred":false,"id":369549,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014895,"text":"70014895 - 1986 - Air abrasion experiments in U-Pb dating of zircon","interactions":[],"lastModifiedDate":"2023-11-17T00:51:44.913158","indexId":"70014895","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Air abrasion experiments in U-Pb dating of zircon","docAbstract":"Air abrasion of zircon grains can remove metamict material that has lost radiogenic Pb and zircon overgrowths that were added during younger events and thereby improve the precision of the age measurements and permit closer estimates of the original age. Age discordance that resulted from a single disturbance of the UPb isotopic decay systems, as had been demonstrated by T.E. Krogh, can be considerably reduced, and, under favorable conditions, the ages brought into concordancy. Two or more events complicate the UPb systematics, but a series of abrasion experiments can be helpful in deciphering the geologic history and in arriving at a useful interpretation of the probable times of origin and disturbances. In east-central Minnesota, U.S.A., Penokean tonalite gneiss is dated at 1869 ± 5 Ma, and sheared granite gneiss is shown to have been a high-level granite intrusion at 1982 ± 5 Ma in the McGrath Gneiss precursor. Tonalite gneiss and a mafic granodiorite in the Rainy Lake area, Ontario, Canada, are dated at 2736 ± 16 and 2682 ± 4 Ma, respectively. The tonalitic phase of the Morton Gneiss, southwestern Minnesota, is dated at 3662 ± 42 Ma.
The chemical and isotopic compositions of hot springs in the San Marcos region of Guatemala are internally consistent with a hydrologic model in which a deep 240°C reservoir and one or more shallow 195–200°C reservoirs are present. Variations in hot-spring water compositions results from a combination of boiling, mixing with cold, dilute water, and chemical re-equilibration with decreasing temperature. The recharge water for the deep 240°C reservoir is isotopically heavier than the local meteoric water and probably comes from many kilometers to the west or southwest. The water in the shallow reservoir is a mixture of the 240°C water with about 20 ± 5% of cold, locally derived meteoric water. After mixing, the water in the shallow reservoir re-equilibrates with reservoir rock at 195–200°C. In some places additional mixing with cold water occurs after water leaves the shallow reservoir.
The Carter-Tracy calculation for water influx is adapted to groundwater flow simulation with additional clarifying explanation not present in the original papers. The Van Everdingen and Hurst aquifer-influence functions for radial flow from an outer aquifer region are employed. This technique, based on convolution of unit-step response functions, offers a simple but approximate method for embedding an inner region of groundwater flow simulation within a much larger aquifer region where flow can be treated in an approximate fashion. The use of aquifer-influence functions in groundwater flow modeling reduces the size of the computational grid with a corresponding reduction in computer storage and execution time. The Carter-Tracy approximation to the convolution integral enables the aquifer influence function calculation to be made with an additional storage requirement of only two times the number of boundary nodes more than that required for the inner region simulation. It is a good approximation for constant flow rates but is poor for time-varying flow rates where the variation is large relative to the mean. A variety of outer aquifer region geometries, exterior boundary conditions, and flow rate versus potentiometric head relations can be used. The radial, transient-flow case presented is representative. An analytical approximation to the functions of Van Everdingen and Hurst for the dimensionless potentiometric head versus dimensionless time is given.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR022i003p00423","usgsCitation":"Kipp, K.L., 1986, Adaptation of the Carter-Tracy water influx calculation to groundwater flow simulation: Water Resources Research, v. 22, no. 3, p. 423-428, https://doi.org/10.1029/WR022i003p00423.","productDescription":"6 p.","startPage":"423","endPage":"428","costCenters":[],"links":[{"id":225475,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"3","noUsgsAuthors":false,"publicationDate":"2010-07-09","publicationStatus":"PW","scienceBaseUri":"5059e625e4b0c8380cd471b9","contributors":{"authors":[{"text":"Kipp, Kenneth L. klkipp@usgs.gov","contributorId":1633,"corporation":false,"usgs":true,"family":"Kipp","given":"Kenneth","email":"klkipp@usgs.gov","middleInitial":"L.","affiliations":[],"preferred":true,"id":369584,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014909,"text":"70014909 - 1986 - Archaeological prospection: An introduction to the Special Issue","interactions":[],"lastModifiedDate":"2024-04-18T16:12:37.235212","indexId":"70014909","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1808,"text":"Geophysics","active":true,"publicationSubtype":{"id":10}},"title":"Archaeological prospection: An introduction to the Special Issue","docAbstract":"Archaeological prospection, as the use of geophysical methods in archaeology is known in Europe, is about four decades old (seven decades, if aerial photography of archaeological sites is included). Virtually the entire range of geophysical methods, perhaps excluding only borehole techniques, has found application in the search for archaeological sites unseen or partially known. Pressures by developers, and the public's growing sensitivity toward the preservation of historic and prehistoric cultural artifacts and sites, has led to an accelerating use of high-resolution geophysical methods in the archaeological sciences. The archaeogeophysical articles in this Special Issue are reasonably representative of the development of this specialty field of geophysics.
","language":"English","publisher":"Society of Exploration Geophysicists","doi":"10.1190/1.1442107","issn":"00168033","usgsCitation":"Wynn, J.C., 1986, Archaeological prospection: An introduction to the Special Issue: Geophysics, v. 51, no. 3, p. 533-537, https://doi.org/10.1190/1.1442107.","productDescription":"5 p.","startPage":"533","endPage":"537","numberOfPages":"5","costCenters":[],"links":[{"id":225476,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"51","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e634e4b0c8380cd47244","contributors":{"authors":[{"text":"Wynn, Jeffrey C.","contributorId":81081,"corporation":false,"usgs":true,"family":"Wynn","given":"Jeffrey","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":369585,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014910,"text":"70014910 - 1986 - Nature of phases synthesized along the join (Mg,Mn)2Si2O6.","interactions":[],"lastModifiedDate":"2012-03-12T17:19:36","indexId":"70014910","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":738,"text":"American Mineralogist","active":true,"publicationSubtype":{"id":10}},"title":"Nature of phases synthesized along the join (Mg,Mn)2Si2O6.","docAbstract":"Eight compositions were synthesized along this join. Orthopyroxene crystallized at X = Mn/(Mn + Mg) = 0.0-0.3, clinopyroxene at X 0.4-0.5, and pyroxmangite at X 0.65-1.0, consistent with the composition ranges that have been inferred by examination of metamorphic rock assemblages. Unit-cell dimensions for these phases and for rhodonite (X = 1.0) are presented, along with microprobe chemical analyses and phase diagrams.-J.A.Z.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"American Mineralogist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"0003004X","usgsCitation":"Huebner, J., 1986, Nature of phases synthesized along the join (Mg,Mn)2Si2O6.: American Mineralogist, v. 71, no. 1-2, p. 111-122.","startPage":"111","endPage":"122","numberOfPages":"12","costCenters":[],"links":[{"id":225477,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"71","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a639ce4b0c8380cd725cc","contributors":{"authors":[{"text":"Huebner, J.S.","contributorId":41422,"corporation":false,"usgs":true,"family":"Huebner","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":369586,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014921,"text":"70014921 - 1986 - Automated mapping of the ocean floor using the theory of intrinsic random functions of order k","interactions":[],"lastModifiedDate":"2012-03-12T17:19:00","indexId":"70014921","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2668,"text":"Marine Geophysical Research","active":true,"publicationSubtype":{"id":10}},"title":"Automated mapping of the ocean floor using the theory of intrinsic random functions of order k","docAbstract":"High-quality contour maps can be computer drawn from single track echo-sounding data by combining Universal Kriging and the theory of intrinsic random function of order K (IRFK). These methods interpolate values among the closely spaced points that lie along relatively widely spaced lines. The technique provides a variance which can be contoured as a quantitative measure of map precision. The technique can be used to evaluate alternative survey trackline configurations and data collection intervals, and can be applied to other types of oceanographic data. ?? 1986 D. Reidel Publishing Company.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Marine Geophysical Researches","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Kluwer Academic Publishers","doi":"10.1007/BF02424828","issn":"00253235","usgsCitation":"David, M., Crozel, D., and Robb, J.M., 1986, Automated mapping of the ocean floor using the theory of intrinsic random functions of order k: Marine Geophysical Research, v. 8, no. 1, p. 49-74, https://doi.org/10.1007/BF02424828.","startPage":"49","endPage":"74","numberOfPages":"26","costCenters":[],"links":[{"id":223956,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205432,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF02424828"}],"volume":"8","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059eef6e4b0c8380cd4a07d","contributors":{"authors":[{"text":"David, M.","contributorId":90438,"corporation":false,"usgs":true,"family":"David","given":"M.","email":"","affiliations":[],"preferred":false,"id":369613,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Crozel, D.","contributorId":90597,"corporation":false,"usgs":true,"family":"Crozel","given":"D.","email":"","affiliations":[],"preferred":false,"id":369614,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Robb, James M.","contributorId":73272,"corporation":false,"usgs":true,"family":"Robb","given":"James","email":"","middleInitial":"M.","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":false,"id":369612,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014923,"text":"70014923 - 1986 - The origin of fluids in the salt beds of the Delaware Basin, New Mexico and Texas","interactions":[],"lastModifiedDate":"2023-03-20T12:13:27.603327","indexId":"70014923","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":835,"text":"Applied Geochemistry","active":true,"publicationSubtype":{"id":10}},"title":"The origin of fluids in the salt beds of the Delaware Basin, New Mexico and Texas","docAbstract":"Oxygen and hydrogen isotope analyses have been made of (1) brines from several wells in the salt deposits of the Delaware Basin, (2) inclusion fluids in halite crystals from the ERDA No. 9 site, and (3) local ground waters of meteoric origin. The isotopic compositions indicate that the brines are genetically related and that they probably originated from the evaporation of paleo-ocean waters. Although highly variable in solute contents, the brines have rather uniform isotopic compositions. The stable isotope compositions of brine from the ERDA No. 6 site (826.3 m depth) and fluid inclusions from the ERDA No. 9 site are variable but remarkably regular and show that (1) mixing with old or modern meteoric waters has occurred, the extent of mixing apparently decreasing with depth, and (2) water in the ERDA No. 6 brine may have originated from the dehydration of gypsum. Alternatively, the data may reflect simple evaporation of meteoric water on a previously dry marine flat. Stable isotope compositions of all the waters analyzed indicate that there has been fairly extensive mixing with ground water throughout the area, but that no significant circulation has occurred. The conclusions bear importantly on the suitability of these salt beds and others as repositories for nuclear waste.
Samples of sedimentary organic matter from several geologic environments and ages which are enriched in uranium (56 ppm to 12%) have been characterized. The three analytical techniqyes used to study the samples were Rock-Eval pyrolysis, pyrolysis-gas chromatography-mass spectrometry, and solid-state C-13 nuclear magnetic resonance (NMR) spectroscopy. In samples with low uranium content, the pyrolysis-gas chromatography products contain oxygenated functional groups (as hydroxyl) and molecules with both aliphatic and aromatic carbon atoms. These samples with low uranium content give measurable Rock-Eval hydrocarbon and organic-CO2 yields, and C-13 NMR values of > 30% aliphatic carbon. In contrast, uranium-rich samples have few hydrocarbon pyrolysis products, increased Rock-Eval organic-CO2 contents and > 70% aromatic carbon contents from C-13 NMR. The increase in aromaticity and decrease in hydrocarbon pyrolysis yield are related to the amount of uranium and the age of the uranium minerals, which correspond to the degree of radiation damage. The three analytical techniques give complementary results. Increase in Rock-Eval organic-CO2 yield correlates with uranium content for samples from the Grants uranium region. Calculations show that the amount of organic-CO2 corresponds to the quantity of uranium chemically reduced by the organic matter for the Grants uranium region samples.
A fixed-size simplex has been used to determine the optimum conditions for the simultaneous determination of arsenic, selenium, and antimony by hydride generation and inductively coupled plasma emission spectrometry. The variables selected for the simplex were carrier gas flow rate, rf power, viewing height, and reagent conditions. The detection limit for selenium was comparable to the preoptimized case, but there were twofold and fourfold improvements in the detection limits for arsenic and antimony, respectively. Precision of the technique was assessed with the use of artificially prepared water samples.
","language":"English","publisher":"Sage Journals","doi":"10.1366/0003702864509376","usgsCitation":"Pyen, G.S., Long, S., and Browner, R.F., 1986, System optimization for the automatic simultaneous determination of arsenic, selenium, and antimony, using hydride generation introduction to an inductively coupled plasma: Applied Spectroscopy, v. 40, no. 2, p. 246-251, https://doi.org/10.1366/0003702864509376.","productDescription":"6 p.","startPage":"246","endPage":"251","numberOfPages":"6","costCenters":[],"links":[{"id":224393,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"40","issue":"2","noUsgsAuthors":false,"publicationDate":"1986-02-01","publicationStatus":"PW","scienceBaseUri":"505aafb3e4b0c8380cd87737","contributors":{"authors":[{"text":"Pyen, Grace S.","contributorId":73754,"corporation":false,"usgs":true,"family":"Pyen","given":"Grace","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":369683,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Long, Stephen","contributorId":34270,"corporation":false,"usgs":true,"family":"Long","given":"Stephen","email":"","affiliations":[],"preferred":false,"id":369682,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Browner, Richard F.","contributorId":19711,"corporation":false,"usgs":true,"family":"Browner","given":"Richard","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":369681,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014951,"text":"70014951 - 1986 - Estimation of distributional parameters for censored trace level water quality data: 1. Estimation techniques","interactions":[],"lastModifiedDate":"2018-02-14T08:40:00","indexId":"70014951","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Estimation of distributional parameters for censored trace level water quality data: 1. Estimation techniques","docAbstract":"A recurring difficulty encountered in investigations of many metals and organic contaminants in ambient waters is that a substantial portion of water sample concentrations are below limits of detection established by analytical laboratories. Several methods were evaluated for estimating distributional parameters for such censored data sets using only uncensored observations. Their reliabilities were evaluated by a Monte Carlo experiment in which small samples were generated from a wide range of parent distributions and censored at varying levels. Eight methods were used to estimate the mean, standard deviation, median, and interquartile range. Criteria were developed, based on the distribution of uncensored observations, for determining the best performing parameter estimation method for any particular data set. The most robust method for minimizing error in censored-sample estimates of the four distributional parameters over all simulation conditions was the log-probability regression method. With this method, censored observations are assumed to follow the zero-to-censoring level portion of a lognormal distribution obtained by a least squares regression between logarithms of uncensored concentration observations and their z scores. When method performance was separately evaluated for each distributional parameter over all simulation conditions, the log-probability regression method still had the smallest errors for the mean and standard deviation, but the lognormal maximum likelihood method had the smallest errors for the median and interquartile range. When data sets were classified prior to parameter estimation into groups reflecting their probable parent distributions, the ranking of estimation methods was similar, but the accuracy of error estimates was markedly improved over those without classification.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR022i002p00135","usgsCitation":"Gilliom, R.J., and Helsel, D., 1986, Estimation of distributional parameters for censored trace level water quality data: 1. Estimation techniques: Water Resources Research, v. 22, no. 2, p. 135-146, https://doi.org/10.1029/WR022i002p00135.","productDescription":"12 p.","startPage":"135","endPage":"146","costCenters":[],"links":[{"id":224396,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"2","noUsgsAuthors":false,"publicationDate":"2010-07-09","publicationStatus":"PW","scienceBaseUri":"505a0b83e4b0c8380cd52761","contributors":{"authors":[{"text":"Gilliom, Robert J. rgilliom@usgs.gov","contributorId":488,"corporation":false,"usgs":true,"family":"Gilliom","given":"Robert","email":"rgilliom@usgs.gov","middleInitial":"J.","affiliations":[{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true}],"preferred":true,"id":369689,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Helsel, Dennis R.","contributorId":85569,"corporation":false,"usgs":true,"family":"Helsel","given":"Dennis R.","affiliations":[],"preferred":false,"id":369688,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014966,"text":"70014966 - 1986 - Lateral blasts at Mount St. Helens and hazard zonation","interactions":[],"lastModifiedDate":"2012-03-12T17:18:54","indexId":"70014966","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1109,"text":"Bulletin of Volcanology","active":true,"publicationSubtype":{"id":10}},"title":"Lateral blasts at Mount St. Helens and hazard zonation","docAbstract":"Lateral blasts at andesitic and dacitic volcanoes can produce a variety of direct hazards, including ballistic projectiles which can be thrown to distances of at least 10 km and pyroclastic density flows which can travel at high speed to distances of more than 30 km. Indirect effect that may accompany such explosions include wind-borne ash, pyroclastic flows formed by the remobilization of rock debris thrown onto sloping ground, and lahars. Two lateral blasts occurred at a lava dome on the north flank of Mount St. Helens about 1200 years ago; the more energetic of these threw rock debris northeastward across a sector of about 30?? to a distance of at least 10 km. The ballistic debris fell onto an area estimated to be 50 km2, and wind-transported ash and lapilli derived from the lateral-blast cloud fell on an additional lobate area of at least 200 km2. In contrast, the vastly larger lateral blast of May 18, 1980, created a devastating pyroclastic density flow that covered a sector of as much as 180??, reached a maximum distance of 28 km, and within a few minutes directly affected an area of about 550 km2. The May 18 lateral blast resulted from the sudden, landslide-induced depressurization of a dacite cryptodome and the hydrothermal system that surrounded it within the volcano. We propose that lateral-blast hazard assessments for lava domes include an adjoining hazard zone with a radius of at least 10 km. Although a lateral blast can occur on any side of a dome, the sector directly affected by any one blast probably will be less than 180??. Nevertheless, a circular hazard zone centered on the dome is suggested because of the difficulty of predicting the direction of a lateral blast. For the purpose of long-term land-use planning, a hazard assessment for lateral blasts caused by explosions of magma bodies or pressurized hydrothermal systems within a symmetrical volcano could designate a circular potential hazard area with a radius of 35 km centered on the volcano. For short-term hazard assessments, if seismicity and deformation indicate that magma is moving toward the flank of a volcano, it should be recognized that a landslide could lead to the sudden unloading of a magmatic or hydrothermal system and thereby cause a catastrophic lateral blast. A hazard assessment should assume that a lateral blast could directly affect an area at least 180?? wide to a distance of 35 km from the site of the explosion, irrespective of topography. ?? 1986 Springer-Verlag.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Bulletin of Volcanology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF01073511","issn":"02588900","usgsCitation":"Crandell, D.R., and Hoblitt, R., 1986, Lateral blasts at Mount St. Helens and hazard zonation: Bulletin of Volcanology, v. 48, no. 1, p. 27-37, https://doi.org/10.1007/BF01073511.","startPage":"27","endPage":"37","numberOfPages":"11","costCenters":[],"links":[{"id":205411,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF01073511"},{"id":223740,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"48","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a456fe4b0c8380cd672f9","contributors":{"authors":[{"text":"Crandell, D. R.","contributorId":78385,"corporation":false,"usgs":true,"family":"Crandell","given":"D.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":369733,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hoblitt, R.","contributorId":89536,"corporation":false,"usgs":true,"family":"Hoblitt","given":"R.","affiliations":[],"preferred":false,"id":369734,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014967,"text":"70014967 - 1986 - Some Techniques for Reducing Landslide Hazards","interactions":[],"lastModifiedDate":"2023-11-03T00:48:56.278391","indexId":"70014967","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1115,"text":"Bulletin of the Association of Engineering Geologists","active":true,"publicationSubtype":{"id":10}},"title":"Some Techniques for Reducing Landslide Hazards","docAbstract":"Many techniques are available for reducing landslide hazards; 27 are described in this paper. Prerequisites for the successful use of these techniques are hazard information understandable to nongeologists and adequate communication of this information to those who will, or are required to, use it. It is concluded that certain factors needed to ensure the lasting effectiveness of these techniques are usually beyond the control of the public planner, engineer, and decisionmaker.","language":"English","publisher":"Association of Engineering Geologists","doi":"10.2113/gseegeosci.xxiii.1.29","issn":"00045691","usgsCitation":"Kockelman, W.J., 1986, Some Techniques for Reducing Landslide Hazards: Bulletin of the Association of Engineering Geologists, v. 23, no. 1, p. 29-52, https://doi.org/10.2113/gseegeosci.xxiii.1.29.","productDescription":"24 p.","startPage":"29","endPage":"52","numberOfPages":"24","costCenters":[],"links":[{"id":223741,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505aaf70e4b0c8380cd875b5","contributors":{"authors":[{"text":"Kockelman, William J.","contributorId":34510,"corporation":false,"usgs":true,"family":"Kockelman","given":"William","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":369735,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014969,"text":"70014969 - 1986 - Determination of total, commonality, and uniqueness of interpreted structural elements from remotely sensed data in Alaska","interactions":[],"lastModifiedDate":"2012-03-12T17:18:54","indexId":"70014969","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2700,"text":"Mathematical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Determination of total, commonality, and uniqueness of interpreted structural elements from remotely sensed data in Alaska","docAbstract":"Statistical analysis is conducted to determine the unique value of real- and synthetic-aperture side-looking airborne radar (SLAR) to detect interpreted structural elements. SLAR images were compared to standard and digitally enhanced Landsat multispectral scanner (MSS) images and to aerial photographs. After interpretation of the imagery, data were cumulated by total length in miles and by frequency of counts. Maximum uniqueness is obtained first from real-aperture SLAR, 58.3% of total, and, second, from digitally enhanced Landsat MSS images, 54.1% of total. ?? 1986 Plenum Publishing Corporation.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Mathematical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Kluwer Academic Publishers-Plenum Publishers","doi":"10.1007/BF00898281","issn":"08828121","usgsCitation":"Rosenfield, G., 1986, Determination of total, commonality, and uniqueness of interpreted structural elements from remotely sensed data in Alaska: Mathematical Geology, v. 18, no. 2, p. 161-179, https://doi.org/10.1007/BF00898281.","startPage":"161","endPage":"179","numberOfPages":"19","costCenters":[],"links":[{"id":205418,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00898281"},{"id":223792,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"18","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ffe0e4b0c8380cd4f44a","contributors":{"authors":[{"text":"Rosenfield, G.H.","contributorId":94670,"corporation":false,"usgs":true,"family":"Rosenfield","given":"G.H.","email":"","affiliations":[],"preferred":false,"id":369738,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014980,"text":"70014980 - 1986 - Summary of pre-1980 tephra-fall deposits erupted from Mount St. Helens, Washington State, USA","interactions":[],"lastModifiedDate":"2012-03-12T17:19:00","indexId":"70014980","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1109,"text":"Bulletin of Volcanology","active":true,"publicationSubtype":{"id":10}},"title":"Summary of pre-1980 tephra-fall deposits erupted from Mount St. Helens, Washington State, USA","docAbstract":"Mount St. Helens has been a prolific source of tephra-fall deposits for about 40 000 years. These tephra deposits (1) record numerous explosive eruptions, (2) form important regional time-stratigraphic marker beds, and (3) record repeated changes in composition within and between eruptive periods. Recognized tephra strata record more than 100 explosive eruptive events at Mount St. Helens; those tephra strata are classified as beds, layers, and sets. Tephra sets, each of which consists of a group of beds and layers, define in part the nine eruptive periods recognized at the volcano. Individual tephra sets are distinguished from stratigraphically adjacent sets by differences in composition or by evidence of clapsed time. Several tephra units from Mount St. Helens form important marker beds at distances of hundreds of kilometers downwind from the volcano. Cummingtonite phenocrysts, which are known in ejecta from only Mount St. Helens in the Pacific Northwest, characterize some marker beds and readily identify their source. The tephra sequence also records eruption of the mafic andesites that mark the appearance of the modern Mount St. Helens and numerous changes in composition among dacite, basalt, and andesite since that time. ?? 1986 Springer-Verlag.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Bulletin of Volcanology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF01073510","issn":"02588900","usgsCitation":"Mullineaux, D.R., 1986, Summary of pre-1980 tephra-fall deposits erupted from Mount St. Helens, Washington State, USA: Bulletin of Volcanology, v. 48, no. 1, p. 17-26, https://doi.org/10.1007/BF01073510.","startPage":"17","endPage":"26","numberOfPages":"10","costCenters":[],"links":[{"id":223958,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205433,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF01073510"}],"volume":"48","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9ea1e4b08c986b31e024","contributors":{"authors":[{"text":"Mullineaux, D. R.","contributorId":64248,"corporation":false,"usgs":true,"family":"Mullineaux","given":"D.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":369764,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014982,"text":"70014982 - 1986 - Predicting two-dimensional steady-state soil freezing fronts using the CVBEM","interactions":[],"lastModifiedDate":"2024-05-08T13:32:59.291979","indexId":"70014982","displayToPublicDate":"1986-01-01T00:00:00","publicationYear":"1986","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2332,"text":"Journal of Heat Transfer","active":true,"publicationSubtype":{"id":10}},"title":"Predicting two-dimensional steady-state soil freezing fronts using the CVBEM","docAbstract":"The complex variable boundary element method (CVBEM) is used instead of a real variable boundary element method due to the available modeling error evaluation techniques developed. The modeling accuracy is evaluated by the model-user in the determination of an approximative boundary upon which the CVBEM provides an exact solution. Although inhomogeneity (and anisotropy) can be included in the CVBEM model, the resulting fully populated matrix system quickly becomes large. Therefore in this paper, the domain is assumed homogeneous and isotropic except for differences in frozen and thawed conduction parameters on either side of the freezing front. The example problems presented were obtained by use of a popular 64K microcomputer (the current version of the program used in this study has the capacity to accommodate 30 nodal points).","language":"English","publisher":"ASME","doi":"10.1115/1.3246896","issn":"00221481","usgsCitation":"Hromadka, T., 1986, Predicting two-dimensional steady-state soil freezing fronts using the CVBEM: Journal of Heat Transfer, v. 108, no. 1, p. 235-237, https://doi.org/10.1115/1.3246896.","productDescription":"3 p.","startPage":"235","endPage":"237","numberOfPages":"3","costCenters":[],"links":[{"id":224009,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"108","issue":"1","noUsgsAuthors":false,"publicationDate":"1986-02-01","publicationStatus":"PW","scienceBaseUri":"505a7371e4b0c8380cd7702f","contributors":{"authors":[{"text":"Hromadka, T. V. II","contributorId":76464,"corporation":false,"usgs":true,"family":"Hromadka","given":"T. V.","suffix":"II","affiliations":[],"preferred":false,"id":369768,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}