Urban water-quality managers need load estimates of storm-runoff pollutants to design effective remedial programs. Estimates are commonly made using published models calibrated to large regions of the country. This paper presents statistical methods, termed model-adjustment procedures (MAPs), which use a combination of local data and published regional models to improve estimates of urban-runoff quality. Each MAP is a form of regression analysis that uses a local data base as a calibration data set to adjust the regional model, in effect increasing the size of the local data base without additional, expensive data collection. The adjusted regional model can then be used to estimate storm-runoff quality at unmonitored sites and storms in the locality. The four MAPs presented in this study are (1) single-factor regression against the regional model prediction, Pu; (2) least-squares regression against Pu; (3) least-squares regression against Pu and additional local variables; and (4) weighted combination of Pu and a local-regression prediction. Identification of the statistically most valid method among these four depends upon characteristics of the local data base. A MAP-selection scheme based on statistical analysis of the calibration data set is presented and tested.
A lumped-parameter model and least-squares method were used to simulate temporal variations of discharge from Big Spring, Iowa, USA, from 1983 to 1994. The simulated discharge rates poorly match the observed one when precipitation is taken as the sole input. The match is improved significantly when the processes of evapotranspiration and infiltration are considered. The best results are obtained when snowmelt is also included in the model. Potential evapotranspiration was estimated with Thornthwaite's formula, infiltration was calculated through a water-balance approach, and snowmelt was generated by a degree-day model. The results show that groundwater in the limestone aquifer is mainly recharged by snowmelt in early spring and by infiltration from rainfall in later spring and early summer. Simulated discharge was visually calibrated against measured discharge; the similarity between the two supports the validity of this approach. The model can be used to study the effects of climate change on groundwater resources and their quality.
Five methods of developing regional regression models to estimate flood characteristics at ungaged sites in Arkansas are examined. The methods differ in the manner in which the State is divided into subregions. Each successive method (A to E) is computationally more complex than the previous method. Method A makes no subdivision. Methods B and C define two and four geographic subregions, respectively. Method D uses cluster/discriminant analysis to define subregions on the basis of similarities in watershed characteristics. Method E, the new region of influence method, defines a unique subregion for each ungaged site. Split-sample results indicate that, in terms of root-mean-square error, method E (38 percent error) is best. Methods C and D (42 and 41 percent error) were in a virtual tie for second, and methods B (44 percent error) and A (49 percent error) were fourth and fifth best.
We have developed an observational scheme for the detection and discrimination of Mars atmospheric H2O and CO2 clouds using ground-based instruments in the near infrared. We report the results of our cloud detection and characterization study using Mars near IR images obtained during the 1990 and 1993 oppositions. We focused on specific wavelengths that have the potential, based on previous laboratory studies of H2O and CO2 ices, of yielding the greatest degree of cloud detectability and compositional discriminability. We have detected and mapped absorption features at some of these wavelengths in both the northern and southern polar regions of Mars. Compositional information on the nature of these absorption features was derived from comparisons with laboratory ice spectra and with a simplified radiative transfer model of a CO2 ice cloud overlying a bright surface. Our results indicate that both H2O and CO2 ices can be detected and distinguished in the polar hood clouds. The region near 3.00 μm is most useful for the detection of water ice clouds because there is a strong H2O ice absorption at this wavelength but only a weak CO2 ice band. The region near 3.33 μm is most useful for the detection of CO2 ice clouds because there is a strong, relatively narrow CO2 ice band at this wavelength but only broad “continuum” H2O ice absorption. Weaker features near 2.30 μm could arise from CO2 ice at coarse grain sizes, or surface/dust minerals. Narrow features near 2.00 μm, which could potentially be very diagnostic of CO2 ice clouds, suffer from contamination by Mars atmospheric CO2 absorptions and are difficult to interpret because of the rather poor knowledge of surface elevation at high latitudes. These results indicate that future ground-based, Earth-orbital, and spacecraft studies over a more extended span of the seasonal cycle should yield substantial information on the style and timing of volatile transport on Mars, as well as a more detailed understanding of the role of CO2 condensation in the polar heat budget.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JE00689","issn":"01480227","usgsCitation":"Bell, J., Calvin, W.M., Ockert-Bell, M.E., Crisp, D., Pollack, J.B., and Spencer, J., 1996, Detection and monitoring of H2O and CO2 ice clouds on Mars: Journal of Geophysical Research E: Planets, v. 101, no. E4, p. 9227-9237, https://doi.org/10.1029/96JE00689.","productDescription":"11 p.","startPage":"9227","endPage":"9237","numberOfPages":"11","costCenters":[],"links":[{"id":228723,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Mars","volume":"101","issue":"E4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ff67e4b0c8380cd4f184","contributors":{"authors":[{"text":"Bell, J.F. III","contributorId":97612,"corporation":false,"usgs":true,"family":"Bell","given":"J.F.","suffix":"III","email":"","affiliations":[],"preferred":false,"id":377527,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Calvin, W. M.","contributorId":17379,"corporation":false,"usgs":false,"family":"Calvin","given":"W.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":377523,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ockert-Bell, M. E.","contributorId":19317,"corporation":false,"usgs":true,"family":"Ockert-Bell","given":"M.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":377524,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Crisp, D.","contributorId":25718,"corporation":false,"usgs":true,"family":"Crisp","given":"D.","email":"","affiliations":[],"preferred":false,"id":377525,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Pollack, James B.","contributorId":12616,"corporation":false,"usgs":true,"family":"Pollack","given":"James","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":377522,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Spencer, J.","contributorId":92816,"corporation":false,"usgs":true,"family":"Spencer","given":"J.","affiliations":[],"preferred":false,"id":377526,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70017775,"text":"70017775 - 1996 - Extension across Tempe Terra, Mars, from measurements of fault scarp widths and deformed craters","interactions":[],"lastModifiedDate":"2024-08-01T13:28:57.358214","indexId":"70017775","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2317,"text":"Journal of Geophysical Research E: Planets","active":true,"publicationSubtype":{"id":10}},"title":"Extension across Tempe Terra, Mars, from measurements of fault scarp widths and deformed craters","docAbstract":"Two independent methods, with no common assumptions, have been used to estimate the extension across the heavily deformed Tempe Terra province of the Tharsis region of Mars. One method uses measurements of normal fault scarp width with average scarp slope data for simple grabens and rifts on Mars to estimate the fault throw, which, combined with sparse fault dip data, can be used to estimate extension. Formal uncertainties in this method are only slightly greater than those in other methods, given that the total uncertainty is dominated by the likely uncertainty in the fault dip (assumed to be 60° ± 15°). Measurement of normal fault scarp widths along two N25°–50°W directed traverses across Tempe Terra both yield about 22 ± 16 km of extension (or ∼2% strain across the northern traverse and nearly 3% across the southern one). About three quarters of the extension has occurred during the two main phases of Tharsis-related deformation from Middle/Late Noachian to Early Hesperian and from Late Hesperian to Early Amazonian, with more extension closer to the center of Tharsis during the first phase. Extension across the region was also determined by measuring the elongation and elongation direction of all ancient Noachian impact craters without ejecta blankets, which predate most of the deformation. Results have been corrected for initial non circularity of craters, established from similar measurements of young (post deformation) impact craters, yielding a statistically significant mean strain of 1.96 ± 0.35% in a N38° ± 10°W direction across Tempe Terra (extension of ∼20 ± 4, comparable in magnitude and direction to the average result from the scarp measurement method). Both methods indicate an average extension for single normal fault scarps (and shortening across wrinkle ridges for the crater method) of ∼100 m. The agreement between the results of the two independent methods in overall extension and average single normal fault extension argues that the average scarp slope and fault dip data in the fault scarp width method accurately represent the actual extension across the observed structures. This conclusion supports existing geometric and kinematic models for structural features on Mars. A preliminary estimate of the total circumferential extension around Tharsis (at a radius of ∼2500 km) is roughly 60 ± 42 km; total hoop strain is about 0.4% distributed heterogeneously (Tempe Terra is the most highly strained region on Mars).
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JE02709","issn":"01480227","usgsCitation":"Golombek, M., Tanaka, K.L., and Franklin, B., 1996, Extension across Tempe Terra, Mars, from measurements of fault scarp widths and deformed craters: Journal of Geophysical Research E: Planets, v. 101, no. E11, p. 26119-26130, https://doi.org/10.1029/96JE02709.","productDescription":"12 p.","startPage":"26119","endPage":"26130","numberOfPages":"12","costCenters":[],"links":[{"id":228772,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Mars","volume":"101","issue":"E11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0e41e4b0c8380cd53384","contributors":{"authors":[{"text":"Golombek, M.P.","contributorId":52696,"corporation":false,"usgs":true,"family":"Golombek","given":"M.P.","email":"","affiliations":[],"preferred":false,"id":377535,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Tanaka, K. L.","contributorId":31394,"corporation":false,"usgs":false,"family":"Tanaka","given":"K.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":377533,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Franklin, B.J.","contributorId":48358,"corporation":false,"usgs":true,"family":"Franklin","given":"B.J.","email":"","affiliations":[],"preferred":false,"id":377534,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70017783,"text":"70017783 - 1996 - Relationship between the present-day stress field and plate boundary forces in the Pacific Northwest","interactions":[],"lastModifiedDate":"2019-08-09T13:16:45","indexId":"70017783","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1807,"text":"Geophysical Research Letters","active":true,"publicationSubtype":{"id":10}},"title":"Relationship between the present-day stress field and plate boundary forces in the Pacific Northwest","docAbstract":"The relationship between plate boundary forces and the observed stress field in the Pacific Northwest is established using numerical models of continental deformation. Because the orientation of the greatest horizontal principal stress throughout the Pacific Northwest differs considerably from the direction of convergence between the Juan de Fuca and North American plates, the relationship between the stress field and forces acting along the subduction zone has been unclear. To address this relationship, a two‐dimensional finite element model developed by Bird [1989] is used that incorporates critical aspects of continental deformation such as a stratified rheology and interaction between thermal and mechanical components of deformation. Boundary conditions are specified in terms of either velocity or shear traction, depending on whether the computed shear stress at the plate boundary is less than or exceeds, respectively, a prescribed limit. Shear‐stress limits on the subduction and transform plate boundaries are independently varied to determine the relative effect of forces along these boundaries on intraplate deformation. Results from this study indicate that the shear stress limit of both subduction and transform boundaries is low, and that the intraplate stress field is attributed, in part, to the normal component of relative plate motion along the transform boundaries. However, the models also indicate that although the subduction zone fault is weak, a minimum shear strength (≥ 10 MPa) for the fault is necessary to explain the observed stress field. The balance among forces along the tectonic boundaries of North America results in a surprising degree of variation in the present‐day stress field.
","language":"English","publisher":"AGU","doi":"10.1029/96GL03157","issn":"00948276","usgsCitation":"Geist, E.L., 1996, Relationship between the present-day stress field and plate boundary forces in the Pacific Northwest: Geophysical Research Letters, v. 23, no. 23, p. 3381-3384, https://doi.org/10.1029/96GL03157.","productDescription":"4 p.","startPage":"3381","endPage":"3384","costCenters":[{"id":520,"text":"Pacific Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":228862,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"23","noUsgsAuthors":false,"publicationDate":"1996-11-15","publicationStatus":"PW","scienceBaseUri":"50e4a763e4b0e8fec6cdc436","contributors":{"authors":[{"text":"Geist, Eric L. 0000-0003-0611-1150 egeist@usgs.gov","orcid":"https://orcid.org/0000-0003-0611-1150","contributorId":1956,"corporation":false,"usgs":true,"family":"Geist","given":"Eric","email":"egeist@usgs.gov","middleInitial":"L.","affiliations":[{"id":186,"text":"Coastal and Marine Geology Program","active":true,"usgs":true},{"id":520,"text":"Pacific Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":377556,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70017799,"text":"70017799 - 1996 - Source and tectonic implications of tonalite-trondhjemite magmatism in the Klamath Mountains","interactions":[],"lastModifiedDate":"2023-09-22T16:15:29.997708","indexId":"70017799","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1336,"text":"Contributions to Mineralogy and Petrology","active":true,"publicationSubtype":{"id":10}},"title":"Source and tectonic implications of tonalite-trondhjemite magmatism in the Klamath Mountains","docAbstract":"In the Klamath Mountains, voluminous tonalite-trondhjemite magmatism was characteristic of a short period of time from about 144 to 136 Ma (Early Cretaceous). It occurred about 5 to 10 m.y. after the ∼165 to 159 Ma Josephine ophiolite was thrust beneath older parts of the province during the Nevadan orogeny (thrusting from ∼155 to 148 Ma). The magmatism also corresponds to a period of slow or no subduction. Most of the plutons crop out in the south-central Klamath Mountains in California, but one occurs in Oregon at the northern end of the province. Compositionally extended members of the suite consist of precursor gabbroic to dioritic rocks followed by later, more voluminous tonalitic and trondhjemitic intrusions. Most plutons consist almost entirely of tonalite and trondhjemite. Poorly-defined concentric zoning is common. Tonalitic rocks are typically of the low-Al type but trondhjemites are generally of the high-Al type, even those that occur in the same pluton as low-Al tonalite. The suite is characterized by low abundances of K2O, Rb, Zr, and heavy rare earth elements. Sr contents are generally moderate (∼450 ppm) by comparison with Sr-rich arc lavas interpreted to be slab melts (up to 2000 ppm). Initial 87Sr/86Sr, δ 18O, and ɛ Nd are typical of mantle-derived magmas or of crustally-derived magmas with a metabasic source. Compositional variation within plutons can be modeled by variable degrees of partial melting of a heterogeneous metabasaltic source (transitional mid-ocean ridge to island arc basalt), but not by fractional crystallyzation of a basaltic parent. Melting models require a residual assemblage of clinopyroxene+garnet±plagioclase±amphibole; residual plagioclase suggests a deep crustal origin rather than melting of a subducted slab. Such models are consistent with the metabasic part of the Josephine ophiolite as the source. Because the Josephine ophiolite was at low T during Nevadan thrusting, an external heat source was probably necessary to achieve significant degrees of melting; heat was probably extracted from mantle-derived basaltic melts, which were parental to the mafic precursors of the tonalite-trondhjemite suite. Thus, under appropriate tectonic and thermal conditions, heterogeneous mafic crustal rocks can melt to form both low- and high-Al tonalitic and trondhjemitic magmas; slab melting is not necessary.
","language":"English","publisher":"Springer Link","doi":"10.1007/s004100050142","usgsCitation":"Barnes, C., Petersen, S.W., Kistler, R.W., Murray, R., and Kays, M.A., 1996, Source and tectonic implications of tonalite-trondhjemite magmatism in the Klamath Mountains: Contributions to Mineralogy and Petrology, v. 123, no. 1, p. 40-60, https://doi.org/10.1007/s004100050142.","productDescription":"21 p.","startPage":"40","endPage":"60","numberOfPages":"21","costCenters":[],"links":[{"id":228350,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California, Oregon","otherGeospatial":"Klamath Mountains","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -124.58423057231622,\n 43.14760111393659\n ],\n [\n -124.58423057231622,\n 40.23260246232101\n ],\n [\n -120.96992289802705,\n 40.23260246232101\n ],\n [\n -120.96992289802705,\n 43.14760111393659\n ],\n [\n -124.58423057231622,\n 43.14760111393659\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"123","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9322e4b08c986b31a2ee","contributors":{"authors":[{"text":"Barnes, C. G.","contributorId":78819,"corporation":false,"usgs":false,"family":"Barnes","given":"C. G.","affiliations":[],"preferred":false,"id":377594,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Petersen, S. W.","contributorId":72946,"corporation":false,"usgs":false,"family":"Petersen","given":"S.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":377593,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kistler, R. W.","contributorId":36112,"corporation":false,"usgs":true,"family":"Kistler","given":"R.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":377591,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Murray, R.","contributorId":80440,"corporation":false,"usgs":true,"family":"Murray","given":"R.","affiliations":[],"preferred":false,"id":377595,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Kays, M. A.","contributorId":65925,"corporation":false,"usgs":false,"family":"Kays","given":"M.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":377592,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70017810,"text":"70017810 - 1996 - AMS radiocarbon analyses from Lake Baikal, Siberia: Challenges of dating sediments from a large, oligotrophic lake","interactions":[],"lastModifiedDate":"2017-08-16T09:08:37","indexId":"70017810","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3219,"text":"Quaternary Science Reviews","active":true,"publicationSubtype":{"id":10}},"title":"AMS radiocarbon analyses from Lake Baikal, Siberia: Challenges of dating sediments from a large, oligotrophic lake","docAbstract":"A suite of 146 new accelerator-mass spectrometer (AMS) radiocarbon ages provides the first reliable chronology for late Quaternary sediments in Lake Baikal. In this large, highly oligotrophic lake, biogenic and authigenic carbonate are absent, and plant macrofossils are extremely rare. Total organic carbon is therefore the primary material available for dating. Several problems are associated with the TOC ages. One is the mixture of carbon sources in TOC, not all of which are syndepositional in age. This problem manifests itself in apparent ages for the sediment surface that are greater than zero. However, because most of the organic carbon in Lake Baikal sediments is algal (autochthonous) in origin, this effect is limited to about 1000+500 years, which can be corrected, at least for young deposits. The other major problem with dating Lake Baikal sediments is the very low carbon contents of glacial-age deposits, which makes them extremely susceptible to contamination with modern carbon. This problem can be minimized by careful sampling and handling procedures. The ages show almost an order of magnitude difference in sediment-accumulation rates among different sedimentary environments in Lake Baikal, from about 0.04 mm/year on isolated banks such as Academician Ridge, to nearly 0.3 mm/year in the turbidite depositional areas beneath the deep basin floors, such as the Central Basin. The new AMS ages clearly indicate that the dramatic increase in diatom productivity in the lake, as evidenced by increases in biogenic silica and organic carbon, began about 13 ka, in contrast to previous estimates of 7 ka for the age of this transition. Holocene net sedimentation rates may be less than, equal to, or greater than those in the late Pleistocene, depending on the site. This variability reflects the balance between variable terrigenous sedimentation and increased biogenic sedimentation during interglaciations. The ages reported here, and the temporal and spatial variation in sedimentation rates that they imply, provide opportunities for paleoenvironmental reconstructions at different time scales and resolutions.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Quaternary Science Reviews","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0277-3791(96)00027-3","issn":"02773791","usgsCitation":"Colman, S.M., Jones, G.A., Rubin, M., King, J., Peck, J., and Orem, W., 1996, AMS radiocarbon analyses from Lake Baikal, Siberia: Challenges of dating sediments from a large, oligotrophic lake: Quaternary Science Reviews, v. 15, no. 7, p. 669-684, https://doi.org/10.1016/0277-3791(96)00027-3.","startPage":"669","endPage":"684","numberOfPages":"16","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":487268,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://digitalcommons.uri.edu/gsofacpubs/1758","text":"External Repository"},{"id":228487,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206118,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0277-3791(96)00027-3"}],"volume":"15","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e62ce4b0c8380cd471ee","contributors":{"authors":[{"text":"Colman, Steven M. 0000-0002-0564-9576","orcid":"https://orcid.org/0000-0002-0564-9576","contributorId":77482,"corporation":false,"usgs":true,"family":"Colman","given":"Steven","email":"","middleInitial":"M.","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":false,"id":377631,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Jones, Glenn A.","contributorId":17779,"corporation":false,"usgs":false,"family":"Jones","given":"Glenn","email":"","middleInitial":"A.","affiliations":[{"id":6706,"text":"Woods Hole Oceanographic Institution,","active":true,"usgs":false}],"preferred":false,"id":377628,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rubin, M.","contributorId":88079,"corporation":false,"usgs":true,"family":"Rubin","given":"M.","email":"","affiliations":[],"preferred":false,"id":377632,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"King, J.W.","contributorId":19265,"corporation":false,"usgs":true,"family":"King","given":"J.W.","email":"","affiliations":[],"preferred":false,"id":377629,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Peck, J.A.","contributorId":26398,"corporation":false,"usgs":true,"family":"Peck","given":"J.A.","email":"","affiliations":[],"preferred":false,"id":377630,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"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":377633,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70017811,"text":"70017811 - 1996 - Metasomatic tourmalinite formation along basement-cover decollements, Orobic Alps, Italy","interactions":[],"lastModifiedDate":"2015-05-21T14:19:48","indexId":"70017811","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3337,"text":"Schweizerische Mineralogische und Petrographische Mitteilungen","active":true,"publicationSubtype":{"id":10}},"title":"Metasomatic tourmalinite formation along basement-cover decollements, Orobic Alps, Italy","docAbstract":"Cryptocrystalline tourmalinites that occur discontinuously for ???30 km along basement-cover de??collements of the Orohic Alps (Italy) formed by the metasomatism of aluminous cataclasites derived from Permian conglomerates and/or feldspathic sandstones. Using Al as an immobile element monitor, calculations show that the majority of tourmalinites in the region formed through the addition of moderate to significant amounts of B, Mg, Na, Sr, and Be, and the loss of moderate to significant Mn, Ca, K, P, Rb, Ba, and Cr; minor Si, Ti, V, light REE, and Eu also were lost. Data tor relatively immobile Al, Zr, Th, Sc, Nb, and heavy REE indicate that, on average, these tourmalinites formed through ???12% net mass loss assuming an original conglomerate protolith, or through ???7% net mass loss assuming a sandstone protolith. The B and other introduced constituents in the tourmalinites were deposited by hydrothermal fluids focused along and near basement-cover de??collements. These fluids, believed to be associated with late Hercynian felsic magmatism, probably are related to fluids that formed the tourmaline-rich U-Mo-Zn deposits at the nearby Novazza mine and the U-Zn deposits at the nearby Val Vedello mine.","language":"English","issn":"00367699","usgsCitation":"Slack, J.F., Passchier, C., and Zhang, J., 1996, Metasomatic tourmalinite formation along basement-cover decollements, Orobic Alps, Italy: Schweizerische Mineralogische und Petrographische Mitteilungen, v. 76, no. 2, p. 193-207.","productDescription":"15 p.","startPage":"193","endPage":"207","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":228530,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"76","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a550ae4b0c8380cd6d0e6","contributors":{"authors":[{"text":"Slack, J. F.","contributorId":75917,"corporation":false,"usgs":true,"family":"Slack","given":"J.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":377634,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Passchier, C.W.","contributorId":77420,"corporation":false,"usgs":true,"family":"Passchier","given":"C.W.","email":"","affiliations":[],"preferred":false,"id":377635,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Zhang, J.S.","contributorId":82583,"corporation":false,"usgs":true,"family":"Zhang","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":377636,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70017833,"text":"70017833 - 1996 - Source parameters controlling the generation and propagation of potential local tsunamis along the cascadia margin","interactions":[],"lastModifiedDate":"2019-08-09T13:16:28","indexId":"70017833","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2822,"text":"Natural Hazards","active":true,"publicationSubtype":{"id":10}},"title":"Source parameters controlling the generation and propagation of potential local tsunamis along the cascadia margin","docAbstract":"The largest uncertainty in assessing hazards from local tsunamis along the Cascadia margin is estimating the possible earthquake source parameters. We investigate which source parameters exert the largest influence on tsunami generation and determine how each parameter affects the amplitude of the local tsunami. The following source parameters were analyzed: (1) type of faulting characteristic of the Cascadia subduction zone, (2) amount of slip during rupture, (3) slip orientation, (4) duration of rupture, (5) physical properties of the accretionary wedge, and (6) influence of secondary faulting. The effect of each of these source parameters on the quasi-static displacement of the ocean floor is determined by using elastic three-dimensional, finite-element models. The propagation of the resulting tsunami is modeled both near the coastline using the two-dimensional (x-t) Peregrine equations that includes the effects of dispersion and near the source using the three-dimensional (x-y-t) linear long-wave equations. The source parameters that have the largest influence on local tsunami excitation are the shallowness of rupture and the amount of slip. In addition, the orientation of slip has a large effect on the directivity of the tsunami, especially for shallow dipping faults, which consequently has a direct influence on the length of coastline inundated by the tsunami. Duration of rupture, physical properties of the accretionary wedge, and secondary faulting all affect the excitation of tsunamis but to a lesser extent than the shallowness of rupture and the amount and orientation of slip. Assessment of the severity of the local tsunami hazard should take into account that relatively large tsunamis can be generated from anomalous ‘tsunami earthquakes’ that rupture within the accretionary wedge in comparison to interplate thrust earthquakes of similar magnitude.
","language":"English","publisher":"Springer","doi":"10.1007/BF00138481","issn":"0921030X","usgsCitation":"Geist, E.L., and Yoshioka, S., 1996, Source parameters controlling the generation and propagation of potential local tsunamis along the cascadia margin: Natural Hazards, v. 13, no. 2, p. 151-177, https://doi.org/10.1007/BF00138481.","productDescription":"27 p.","startPage":"151","endPage":"177","costCenters":[{"id":520,"text":"Pacific Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":228819,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"13","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9335e4b08c986b31a37a","contributors":{"authors":[{"text":"Geist, Eric L. 0000-0003-0611-1150 egeist@usgs.gov","orcid":"https://orcid.org/0000-0003-0611-1150","contributorId":1956,"corporation":false,"usgs":true,"family":"Geist","given":"Eric","email":"egeist@usgs.gov","middleInitial":"L.","affiliations":[{"id":186,"text":"Coastal and Marine Geology Program","active":true,"usgs":true},{"id":520,"text":"Pacific Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":377686,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Yoshioka, Shoichi","contributorId":7358,"corporation":false,"usgs":true,"family":"Yoshioka","given":"Shoichi","email":"","affiliations":[],"preferred":false,"id":377687,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70017837,"text":"70017837 - 1996 - Relative sea-level changes during Middle Ordovician through Mississippian deposition in the Iowa area, North American craton","interactions":[],"lastModifiedDate":"2012-03-12T17:19:54","indexId":"70017837","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3005,"text":"Paleozoic sequence stratigraphy: views from the North American craton","active":true,"publicationSubtype":{"id":10}},"title":"Relative sea-level changes during Middle Ordovician through Mississippian deposition in the Iowa area, North American craton","docAbstract":"The Tippecanoe and Kaskaskia cratonic megasequences in the Iowa area are subdivided into a succession of third-order transgressive-regressive (T-R) depositional cycles of ~1 to 3 m.y. duration. Cratonic deposition in the Iowa area is categorized into two broad-scale facies groupings, each dominated by shallowing-upward patterns: 1) an inner shelf with shallow subtidal to peritidal facies, and 2) a middle shelf dominated by subtidal facies. Relative changes in sea level, as documented in the cycles, are considered primarily to reflect eustatic patterns, but local variations in subsidence history and sedimentation rates complicate interpretations of the eustatic signal. Minor modification of certain sequence stratigraphic paradigms that were developed originally for continental margin settings is suggested for application to the Iowa cratonic cycles.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Paleozoic sequence stratigraphy: views from the North American craton","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Geological Society of America; Special Paper","publisherLocation":"306","usgsCitation":"Witzke, B., and Bunker, B., 1996, Relative sea-level changes during Middle Ordovician through Mississippian deposition in the Iowa area, North American craton: Paleozoic sequence stratigraphy: views from the North American craton, p. 307-330.","startPage":"307","endPage":"330","numberOfPages":"24","costCenters":[],"links":[{"id":228864,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505aa692e4b0c8380cd84f1e","contributors":{"editors":[{"text":"Witzke B.J.","contributorId":128402,"corporation":true,"usgs":false,"organization":"Witzke B.J.","id":536381,"contributorType":{"id":2,"text":"Editors"},"rank":1}],"authors":[{"text":"Witzke, B.J.","contributorId":12976,"corporation":false,"usgs":true,"family":"Witzke","given":"B.J.","affiliations":[],"preferred":false,"id":377705,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bunker, B.J.","contributorId":15778,"corporation":false,"usgs":true,"family":"Bunker","given":"B.J.","email":"","affiliations":[],"preferred":false,"id":377706,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70017844,"text":"70017844 - 1996 - Modeling impact of small Kansas landfills on underlying aquifers","interactions":[],"lastModifiedDate":"2024-04-22T15:01:37.657099","indexId":"70017844","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2255,"text":"Journal of Environmental Engineering","active":true,"publicationSubtype":{"id":10}},"title":"Modeling impact of small Kansas landfills on underlying aquifers","docAbstract":"Small landfills are exempt from compliance with Resource Conservation and Recovery Act Subtitle D standards for liner and leachate collection. We investigate the ramifications of this exemption under western Kansas semiarid environments and explore the conditions under which naturally occurring geologic settings provide sufficient protection against ground-water contamination. The methodology we employed was to run water budget simulations using the Hydrologic Evaluation of Landfill Performance (HELP) model, and fate and transport simulations using the Multimedia Exposure Assessment Model (MULTIMED) for several western Kansas small landfill scenarios in combination with extensive sensitivity analyses. We demonstrate that requiring landfill cover, leachate collection system (LCS), and compacted soil liner will reduce leachate production by 56%, whereas requiring only a cover without LCS and liner will reduce leachate by half as much. The most vulnerable small landfills are shown to be the ones with no vegetative cover underlain by both a relatively thin vadose zone and aquifer and which overlie an aquifer characterized by cool temperatures and low hydraulic gradients. The aquifer-related physical and chemical parameters proved to be more important than vadose zone and biodegradation parameters in controlling leachate concentrations at the point of compliance.
","language":"English","publisher":"ASCE","doi":"10.1061/(ASCE)0733-9372(1996)122:12(1067)","issn":"07339372","usgsCitation":"Sophocleous, M., Stadnyk, N., and Stotts, M., 1996, Modeling impact of small Kansas landfills on underlying aquifers: Journal of Environmental Engineering, v. 122, no. 12, p. 1067-1077, https://doi.org/10.1061/(ASCE)0733-9372(1996)122:12(1067).","productDescription":"11 p.","startPage":"1067","endPage":"1077","numberOfPages":"11","costCenters":[],"links":[{"id":228952,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"122","issue":"12","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a5c04e4b0c8380cd6f987","contributors":{"authors":[{"text":"Sophocleous, M.","contributorId":13373,"corporation":false,"usgs":true,"family":"Sophocleous","given":"M.","email":"","affiliations":[],"preferred":false,"id":377721,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stadnyk, N.G.","contributorId":98484,"corporation":false,"usgs":true,"family":"Stadnyk","given":"N.G.","email":"","affiliations":[],"preferred":false,"id":377723,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Stotts, M.","contributorId":21306,"corporation":false,"usgs":true,"family":"Stotts","given":"M.","email":"","affiliations":[],"preferred":false,"id":377722,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70017849,"text":"70017849 - 1996 - Geomagnetic storms, the Dst ring-current myth and lognormal distributions","interactions":[],"lastModifiedDate":"2013-02-23T13:22:06","indexId":"70017849","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2188,"text":"Journal of Atmospheric and Terrestrial Physics","active":true,"publicationSubtype":{"id":10}},"title":"Geomagnetic storms, the Dst ring-current myth and lognormal distributions","docAbstract":"The definition of geomagnetic storms dates back to the turn of the century when researchers recognized the unique shape of the H-component field change upon averaging storms recorded at low latitude observatories. A generally accepted modeling of the storm field sources as a magnetospheric ring current was settled about 30 years ago at the start of space exploration and the discovery of the Van Allen belt of particles encircling the Earth. The Dst global 'ring-current' index of geomagnetic disturbances, formulated in that period, is still taken to be the definitive representation for geomagnetic storms. Dst indices, or data from many world observatories processed in a fashion paralleling the index, are used widely by researchers relying on the assumption of such a magnetospheric current-ring depiction. Recent in situ measurements by satellites passing through the ring-current region and computations with disturbed magnetosphere models show that the Dst storm is not solely a main-phase to decay-phase, growth to disintegration, of a massive current encircling the Earth. Although a ring current certainly exists during a storm, there are many other field contributions at the middle-and low-latitude observatories that are summed to show the 'storm' characteristic behavior in Dst at these observatories. One characteristic of the storm field form at middle and low latitudes is that Dst exhibits a lognormal distribution shape when plotted as the hourly value amplitude in each time range. Such distributions, common in nature, arise when there are many contributors to a measurement or when the measurement is a result of a connected series of statistical processes. The amplitude-time displays of Dst are thought to occur because the many time-series processes that are added to form Dst all have their own characteristic distribution in time. By transforming the Dst time display into the equivalent normal distribution, it is shown that a storm recovery can be predicted with remarkable accuracy from measurements made during the Dst growth phase. In the lognormal formulation, the mean, standard deviation and field count within standard deviation limits become definitive Dst storm parameters.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Atmospheric and Terrestrial Physics","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0021-9169(95)00103-4","issn":"00219169","usgsCitation":"Campbell, W., 1996, Geomagnetic storms, the Dst ring-current myth and lognormal distributions: Journal of Atmospheric and Terrestrial Physics, v. 58, no. 10, p. 1171-1187, https://doi.org/10.1016/0021-9169(95)00103-4.","startPage":"1171","endPage":"1187","numberOfPages":"17","costCenters":[],"links":[{"id":268032,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0021-9169(95)00103-4"},{"id":229003,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"58","issue":"10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a2762e4b0c8380cd59831","contributors":{"authors":[{"text":"Campbell, W.H.","contributorId":30749,"corporation":false,"usgs":true,"family":"Campbell","given":"W.H.","email":"","affiliations":[],"preferred":false,"id":377732,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70017853,"text":"70017853 - 1996 - Inelastic models of lithospheric stress - II. Implications for outer-rise seismicity and dynamics","interactions":[],"lastModifiedDate":"2024-02-08T12:08:05.077229","indexId":"70017853","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1803,"text":"Geophysical Journal International","active":true,"publicationSubtype":{"id":10}},"title":"Inelastic models of lithospheric stress - II. Implications for outer-rise seismicity and dynamics","docAbstract":"Concentrations of tourmaline in Early Proterozoic metasedimentary rocks of the Cuyuna iron range, east-central Minnesota, provide a basis for redefinition of the evolutionary history of the area. Manganiferous iron ore forms beds within the Early Proterozoic Trommald Formation, between thick-bedded granular iron-formation having shallow-water alepositional attributes and thin-bedded, nongranular iron-formation having deeper water attributes. These manganese-rich units were previously assumed to be sedimentary in origin. However, a reevaluation of drill core and mine samples from the Cuyuna North range has identified strata-bound tourmaline and tourmalinite, which has led to a rethinking of genetic models for the geology of the North range. We interpret the tourmaline-rich rocks of the area to be a product of submarine-hydrothermal solutions flowing along and beneath the sediment-seawater interface. This model for the depositional environment of the tourmaline is supported by previously reported mineral assemblages within the Trommald Formation that comprise aegirine; barium feldspar; manganese silicates, carbonates, and oxides; and Sr-rich barite veins.In many places, tourmaline-rich metasedimentary rocks and tourmalinites are associated locally with strata-bound sulfide deposits. At those localities, the tourmaline-rich strata are thought to be lateral equivalents of exhalative sulfide zones or genetically related subsea-floor replacements. On the basis of the occurrence of the tourmaline-rich rocks and tourmalinites, and on the associated minerals, we suggest that there is a previously unrecognized potential for sediment-hosted sulfide deposits in the Cuyuna North range.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.91.7.1282","issn":"03610128","usgsCitation":"Cleland, J., Morey, G.B., and McSwiggen, P., 1996, Significance of tourmaline-rich rocks in the North Range group of the Cuyuna iron range, east-central Minnesota: Economic Geology, v. 91, no. 7, p. 1282-1291, https://doi.org/10.2113/gsecongeo.91.7.1282.","productDescription":"10 p.","startPage":"1282","endPage":"1291","numberOfPages":"10","costCenters":[],"links":[{"id":228876,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"91","issue":"7","noUsgsAuthors":false,"publicationDate":"1996-11-01","publicationStatus":"PW","scienceBaseUri":"505b8f21e4b08c986b318d43","contributors":{"authors":[{"text":"Cleland, J.M.","contributorId":100559,"corporation":false,"usgs":true,"family":"Cleland","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":378322,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Morey, G. B.","contributorId":14406,"corporation":false,"usgs":true,"family":"Morey","given":"G.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":378320,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"McSwiggen, P.L.","contributorId":61970,"corporation":false,"usgs":true,"family":"McSwiggen","given":"P.L.","email":"","affiliations":[],"preferred":false,"id":378321,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018053,"text":"70018053 - 1996 - Using GIS and logistic regression to estimate agricultural chemical concentrations in rivers of the midwestern USA","interactions":[],"lastModifiedDate":"2012-03-12T17:19:56","indexId":"70018053","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1934,"text":"IAHS-AISH Publication","active":true,"publicationSubtype":{"id":10}},"title":"Using GIS and logistic regression to estimate agricultural chemical concentrations in rivers of the midwestern USA","docAbstract":"Agricultural chemicals (herbicides, insecticides, other pesticides and fertilizers) in surface water may constitute a human health risk. Recent research on unregulated rivers in the midwestern USA documents that elevated concentrations of herbicides occur for 1-4 months following application in spring and early summer. In contrast, nitrate concentrations in unregulated rivers are elevated during the fall, winter and spring. Natural and anthropogenic variables of river drainage basins, such as soil permeability, the amount of agricultural chemicals applied or percentage of land planted in corn, affect agricultural chemical concentrations in rivers. Logistic regression (LGR) models are used to investigate relations between various drainage basin variables and the concentration of selected agricultural chemicals in rivers. The method is successful in contributing to the understanding of agricultural chemical concentration in rivers. Overall accuracies of the best LGR models, defined as the number of correct classifications divided by the number of attempted classifications, averaged about 66%.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"IAHS-AISH Publication","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01447815","usgsCitation":"Battaglin, W., 1996, Using GIS and logistic regression to estimate agricultural chemical concentrations in rivers of the midwestern USA: IAHS-AISH Publication, no. 235, p. 253-260.","startPage":"253","endPage":"260","numberOfPages":"8","costCenters":[],"links":[{"id":228877,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"issue":"235","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bc00ee4b08c986b329ed7","contributors":{"authors":[{"text":"Battaglin, W.A.","contributorId":16376,"corporation":false,"usgs":true,"family":"Battaglin","given":"W.A.","email":"","affiliations":[],"preferred":false,"id":378323,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018056,"text":"70018056 - 1996 - Occurrence and significance of stalactites within the epithermal deposits at Creede, Colorado","interactions":[],"lastModifiedDate":"2012-03-12T17:19:56","indexId":"70018056","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1177,"text":"Canadian Mineralogist","active":true,"publicationSubtype":{"id":10}},"title":"Occurrence and significance of stalactites within the epithermal deposits at Creede, Colorado","docAbstract":"In addition to the common and abundant features in karst terranes, stalactites involving a wide variety of minerals have also been found in other settings, including epigenetic mineral deposits, but these are almost always associated with supergene stages. Here we describe a different mode of occurrence from the Creede epithermal ore deposits, in Colorado, wherein stalactites of silica, sphalerite, galena, or pyrite formed in a vapor-dominated setting, below the paleo-water table, and except possibly for pyrite, as part of the hypogene mineralization. Axial cavities may, or may not, be present. No stalagmites have been recognized. The stalactites are small, from a few millimeters to a few centimeters long and a few millimeters in outer diameter. They represent only a small fraction of one percent of the total mineralization, and are covered by later crystals. Their growth orientation usually is unobservable; however, the parallel arrangement of all stalactites in a given specimen, consistency with indicators of gravitational settling, and the common presence of axial structures make the stalactitic interpretation almost unavoidable. In contrast with common carbonate stalactites, the growth mechanism for the sulfide and silica stalactites requires extensive evaporation. Stalactitic forms have also been reported from other deposits, mostly epithermal or Mississippi-Valley-type occurrences, but we caution that stalactite-like features can form by alternative processes.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Canadian Mineralogist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00084476","usgsCitation":"Campbell, W.R., and Barton, P.B., 1996, Occurrence and significance of stalactites within the epithermal deposits at Creede, Colorado: Canadian Mineralogist, v. 34, no. 5, p. 905-930.","startPage":"905","endPage":"930","numberOfPages":"26","costCenters":[],"links":[{"id":228918,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6b7de4b0c8380cd7471b","contributors":{"authors":[{"text":"Campbell, W. R.","contributorId":20775,"corporation":false,"usgs":true,"family":"Campbell","given":"W.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":378332,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Barton, P. B. Jr.","contributorId":23683,"corporation":false,"usgs":true,"family":"Barton","given":"P.","suffix":"Jr.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":378333,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018058,"text":"70018058 - 1996 - Initial rupture of earthquakes in the 1995 Ridgecrest, California sequence","interactions":[],"lastModifiedDate":"2012-03-12T17:19:56","indexId":"70018058","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1807,"text":"Geophysical Research Letters","active":true,"publicationSubtype":{"id":10}},"title":"Initial rupture of earthquakes in the 1995 Ridgecrest, California sequence","docAbstract":"Close examination of the P waves from earthquakes ranging in size across several orders of magnitude shows that the shape of the initiation of the velocity waveforms is independent of the magnitude of the earthquake. A model in which earthquakes of all sizes have similar rupture initiation can explain the data. This suggests that it is difficult to estimate the eventual size of an earthquake from the initial portion of the waveform. Previously reported curvature seen in the beginning of some velocity waveforms can be largely explained as the effect of anelastic attenuation; thus there is little evidence for a departure from models of simple rupture initiation that grow dynamically from a small region. The results of this study indicate that any \"precursory\" radiation at seismic frequencies must emanate from a source region no larger than the equivalent of a M0.5 event (i.e. a characteristic length of ???10 m). The size of the nucleation region for magnitude 0 to 5 earthquakes thus is not resolvable with the standard seismic instrumentation deployed in California. Copyright 1996 by the American Geophysical Union.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Geophysical Research Letters","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00948276","usgsCitation":"Mori, J., and Kanamori, H., 1996, Initial rupture of earthquakes in the 1995 Ridgecrest, California sequence: Geophysical Research Letters, v. 23, no. 18, p. 2437-2440.","startPage":"2437","endPage":"2440","numberOfPages":"4","costCenters":[],"links":[{"id":228967,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"18","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3bebe4b0c8380cd6292d","contributors":{"authors":[{"text":"Mori, J.","contributorId":24923,"corporation":false,"usgs":true,"family":"Mori","given":"J.","email":"","affiliations":[],"preferred":false,"id":378337,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kanamori, H.","contributorId":55438,"corporation":false,"usgs":true,"family":"Kanamori","given":"H.","affiliations":[],"preferred":false,"id":378338,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018062,"text":"70018062 - 1996 - Simultaneous confidence intervals for a steady-state leaky aquifer groundwater flow model","interactions":[],"lastModifiedDate":"2012-03-12T17:19:56","indexId":"70018062","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1934,"text":"IAHS-AISH Publication","active":true,"publicationSubtype":{"id":10}},"title":"Simultaneous confidence intervals for a steady-state leaky aquifer groundwater flow model","docAbstract":"Using the optimization method of Vecchia & Cooley (1987), nonlinear Scheffe??-type confidence intervals were calculated tor the parameters and the simulated heads of a steady-state groundwater flow model covering 450 km2 of a leaky aquifer. The nonlinear confidence intervals are compared to corresponding linear intervals. As suggested by the significant nonlinearity of the regression model, linear confidence intervals are often not accurate. The commonly made assumption that widths of linear confidence intervals always underestimate the actual (nonlinear widths was not correct for the head intervals. Results show that nonlinear effects can cause the nonlinear intervals to be offset from, and either larger or smaller than, the linear approximations. Prior information on some transmissivities helps reduce and stabilize the confidence intervals, with the most notable effects occurring for the parameters on which there is prior information and for head values in parameter zones for which there is prior information on the parameters.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"IAHS-AISH Publication","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01447815","usgsCitation":"Christensen, S., and Cooley, R., 1996, Simultaneous confidence intervals for a steady-state leaky aquifer groundwater flow model: IAHS-AISH Publication, v. 237, p. 561-569.","startPage":"561","endPage":"569","numberOfPages":"9","costCenters":[],"links":[{"id":229015,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"237","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b90cfe4b08c986b31967c","contributors":{"authors":[{"text":"Christensen, S.","contributorId":30387,"corporation":false,"usgs":true,"family":"Christensen","given":"S.","email":"","affiliations":[],"preferred":false,"id":378344,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cooley, R.L.","contributorId":9272,"corporation":false,"usgs":true,"family":"Cooley","given":"R.L.","email":"","affiliations":[],"preferred":false,"id":378343,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018066,"text":"70018066 - 1996 - Erosional and depositional patterns associated with the 1993 Missouri River floods inferred from SIR-C and TOPSAR radar data","interactions":[],"lastModifiedDate":"2024-07-31T16:19:31.963329","indexId":"70018066","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2317,"text":"Journal of Geophysical Research E: Planets","active":true,"publicationSubtype":{"id":10}},"title":"Erosional and depositional patterns associated with the 1993 Missouri River floods inferred from SIR-C and TOPSAR radar data","docAbstract":"The Missouri River floods of 1993 caused significant and widespread damage to the floodplains between Kansas City and St. Louis. Immediately downstream of levee breaks, flood waters scoured the bottoms. As the floodwaters continued, they spread laterally and deposited massive amounts of sand as crevasse splays on top of agricultural fields. We explore the use of radar interferometry and backscatter data for quantitative estimation of scour and deposition for Jameson Island/Arrow Rock Bottoms and Lisbon Bottoms, two bottoms that were heavily damaged during the floods and subsequently abandoned. Shuttle imaging radar C (SIR-C) L band (24 cm) HH (horizontally transmitted and horizontally received) radar backscatter data acquired in October 1994 were used together with a distorted Born approximation canopy scattering model to determine that the abundance of natural leafy forbs controlled the magnitude of backscatter for former agricultural fields. Forb areal density was found to be inversely correlated with thickness of sand deposited during the floods, presumably because thick sands prevented roots from reaching nutrient rich, moist bottoms soils. Using the inverse relationship, a lower bound for the mass of sand added was found to be 6.3 million metric tons over the 17 km2 study area. Digital elevation data from topographic synthetic aperture radar (TOPSAR) C band (5.6 cm) interferometric observations acquired in August 1994 were compared to a series of elevation profiles collected on the ground. Vertical errors in TOPSAR were estimated to range from 1 to 2 m, providing enough accuracy to generate an estimate of total mass (4.7 million metric tons) removed during erosion of levees and scour of the bottoms terrains. Net accretion of material to the study areas is consistent with the geologic record of major floods where sediment-laden floodwaters crested over natural levees, initially scoured into the bottoms, and then deposited sands as crevasse splays as the flows spread out and slowed by frictional dissipation. The addition of artificial levees to the Missouri River system has undoubtedly enhanced flood damage, although quantitative estimation of the degree of enhancement will require additional work.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JE01975","issn":"01480227","usgsCitation":"Izenberg, N., Arvidson, R., Brackett, R., Saatchi, S., Osburn, G., and Dohrenwend, J., 1996, Erosional and depositional patterns associated with the 1993 Missouri River floods inferred from SIR-C and TOPSAR radar data: Journal of Geophysical Research E: Planets, v. 101, no. E10, p. 23149-23167, https://doi.org/10.1029/96JE01975.","productDescription":"19 p.","startPage":"23149","endPage":"23167","numberOfPages":"19","costCenters":[],"links":[{"id":228364,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"E10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0a41e4b0c8380cd52288","contributors":{"authors":[{"text":"Izenberg, N.R.","contributorId":35083,"corporation":false,"usgs":true,"family":"Izenberg","given":"N.R.","email":"","affiliations":[],"preferred":false,"id":378361,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Arvidson, R. E.","contributorId":46666,"corporation":false,"usgs":true,"family":"Arvidson","given":"R. E.","affiliations":[],"preferred":false,"id":378363,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Brackett, R.A.","contributorId":38725,"corporation":false,"usgs":true,"family":"Brackett","given":"R.A.","email":"","affiliations":[],"preferred":false,"id":378362,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Saatchi, S.S.","contributorId":88897,"corporation":false,"usgs":true,"family":"Saatchi","given":"S.S.","email":"","affiliations":[],"preferred":false,"id":378364,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Osburn, G.R.","contributorId":16592,"corporation":false,"usgs":true,"family":"Osburn","given":"G.R.","email":"","affiliations":[],"preferred":false,"id":378360,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Dohrenwend, J.","contributorId":108269,"corporation":false,"usgs":true,"family":"Dohrenwend","given":"J.","affiliations":[],"preferred":false,"id":378365,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70018068,"text":"70018068 - 1996 - A depositional model for the Taylor coal bed, Martin and Johnson counties, eastern Kentucky","interactions":[],"lastModifiedDate":"2024-02-21T13:01:14.473432","indexId":"70018068","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2033,"text":"International Journal of Coal Geology","active":true,"publicationSubtype":{"id":10}},"title":"A depositional model for the Taylor coal bed, Martin and Johnson counties, eastern Kentucky","docAbstract":"This study investigated the Taylor coal bed in Johnson and Martin counties, eastern Kentucky, using field and petrographic techniques to develop a depositional model of the coal bed. Petrography and chemistry of the coal bed were examined. Multiple benches of the Taylor coal bed were correlated over a 10 km distance. Three sites were studied in detail. The coal at the western and eastern sites were relatively thin and split by thick clastic partings. The coal at the central site was the thickest and unsplit. Two major clastic partings are included in the coal bed. Each represents a separate and distinct fluvial splay.
The Taylor is interpreted to have developed on a coastal plain with periodic flooding from nearby, structurally-controlled fluvial systems. Doming is unlikely due to the petrographic and chemical trends, which are inconsistent with modern Indonesian models. The depositional history and structural and stratigraphic setting suggest contemporaneous structural influence on thickness and quality of the Taylor coal bed in this area.
The Eocene Big Timber stock in the Crazy Mountains of south-central Montana is an elliptical, 8 by 13 km, compositionally and texturally diverse composite intrusion with a well-developed radial dike swarm. A sharp intrusive contact separates its two phases: the core of the intrusion is fine-grained quartz monzodiorite, and the volumetrically dominant remainder is composed of medium-grained diorite and gabbro.
Differentiation-related major oxide variation within the stock is extensive and spatially nonsystematic. However, abundances of most trace elements were not strongly influenced by differentiation; late zircon and apatite fractionation caused moderate heavy and slight light rare earth element abundance depletions, respectively. Mineral compositions and assemblages indicate crystallization between ≈950 and 700 °C at a pressure of ≈0.8 kbar (3 km). Mixing models indicate that fractionation of varying amounts of plagioclase, orthopyroxene, clinopyroxene, magnesio-hastingsite, hornblende, biotite, titanite, apatite, and magnetite (the stock's principal constituents, with quartz and potassium feldspar) and remixing of these minerals and residual liquids controlled compositional evolution in the reservoir. Crystals apparently nucleated at the reservoir wall while residual silicate liquid was displaced inward and remixed. Some crystals were plucked from the solidification front, as indicated by glomerocrysts present throughout the stock, and also remixed with residual liquid. Solidification of the reservoir represented by the stock involved heat loss to enclosing wall rock, side-wall crystallization, and subsequent, variably effective, crystal-liquid remixing. This process is an important variant of conventionally invoked models pertaining to solidification of intrusions and explains extensive, relatively nonsystematic compositional variation. The genesis of compositional evolution in other intrusions characterized by extensive, spatially nonsystematic variation may result from the important process documented herein.
Compositional and geologic relationships are consistent with magma genesis related to subduction and magmatic-arc processes inboard from the western edge of the early Cenozoic North American plate. Arc magmatism in south-central Montana during Eocene time is consistent with models pertaining to early Cenozoic southward sweep and westward retreat of magmatism. Magmatism represented by the Big Timber stock provides significant new support for steepening subduction, westward retreat of the subduction hinge line, and development of an asthenospheric mantle wedge that fueled renewed magmatism beneath the western edge of the North American continent following early Cenozoic shallow subduction.