We present an analysis of the coherence of seismic ground motion recorded on alluvial sediments in the San Fernando Valley, California. Using aftershocks of the 17 January 1994 Mw6.7 earthquake recorded at a quasi-dense array of portable stations, we analyze the coherence of three well-recorded magnitude 3.7 to 4.0 events over the frequency range 0.5 to 15 Hz and a distance range of 0.5 to 5.3 km. All stations are located at sites with broadly similar near-site geology, characterized by medium to fine-grain Quaternary alluvial sediments. On average, relatively high values of coherence are observed for distances up to 3 to 4 km and frequencies up to 2 to 3 Hz; coherence drops sharply at frequencies near and above 3 Hz. Although average coherence functions are described reasonably well by a log-linear relationship with frequency, the curves at all distances exhibit a flattening at low frequencies that is not consistent with previous observations of coherence at hardrock sites. The distance decay of coherence is also markedly less strong, with high coherence values observed over station separations corresponding to multiple wavelengths. This may reflect fundamental differences in shallow-wave propagation in the two environments, with high-frequency scattering relatively more dominant in regions of hard-rock near-surface geology. Within a sedimentary basin or valley, the site response itself generally reflects a resonance phenomenon that may tend to give rise to more uniform ground motions. However, previous studies have demonstrated the existence of pathological focusing and amplification effects within complex sedimentary basin environments such as the greater Los Angeles region; our results undoubtedly do not quantify the full range of ground-motion variability at all sites, but rather represent the level of that variability that can be expected, and quantified, for typical source/receiver paths.
The chloride mass-balance method, which integrates time and aerial distribution of ground water recharge, was applied to small alluvial aquifers in the wadi systems of the Asir and Hijaz mountains in western Saudi Arabia. This application is an extension of the method shown to be suitable for estimating recharge in regional aquifers in semi-arid areas. Because the method integrates recharge in time and space it appears to be, with certain assumptions, particularly well suited for and areas with large temporal and spatial variation in recharge. In general, recharge was found to be between 3 to 4% of precipitation - a range consistent with recharge rates found in other arid and semi-arid areas of the earth.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0022-1694(96)03028-4","issn":"00221694","usgsCitation":"Bazuhair, A., and Wood, W., 1996, Chloride mass-balance method for estimating ground water recharge in arid areas: Examples from western Saudi Arabia: Journal of Hydrology, v. 186, no. 1-4, p. 153-159, https://doi.org/10.1016/S0022-1694(96)03028-4.","productDescription":"7 p.","startPage":"153","endPage":"159","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":228697,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206142,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(96)03028-4"}],"country":"Saudi Arabia","otherGeospatial":"Asir mountains, Hijaz mountains","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n 42,\n 14\n ],\n [\n 36,\n 26\n ],\n [\n 45,\n 26\n ],\n [\n 45,\n 14\n ],\n [\n 42,\n 14\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"186","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f5c6e4b0c8380cd4c3f3","contributors":{"authors":[{"text":"Bazuhair, A.S.","contributorId":24119,"corporation":false,"usgs":true,"family":"Bazuhair","given":"A.S.","email":"","affiliations":[],"preferred":false,"id":378422,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wood, W.W.","contributorId":21974,"corporation":false,"usgs":true,"family":"Wood","given":"W.W.","email":"","affiliations":[],"preferred":false,"id":378421,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018072,"text":"70018072 - 1996 - A model of Precambrian geology of Kansas derived from gravity and magnetic data","interactions":[],"lastModifiedDate":"2012-03-12T17:19:58","indexId":"70018072","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1315,"text":"Computers & Geosciences","printIssn":"0098-3004","active":true,"publicationSubtype":{"id":10}},"title":"A model of Precambrian geology of Kansas derived from gravity and magnetic data","docAbstract":"The fabric of the Precambrian geology of Kansas is revealed through inversion of gravity and magnetic data to pseudo-lithology. There are five main steps in the inversion process: (1) reduction of potential-field data to a horizontal plane in the wavenumber domain; (2) separation of the residual anomaly of interest from the regional background, where an assumption is made that the regional anomaly could be represented by some order of polynomial; (3) subtraction of the signal due to the known topography on the Phanerozoic/Precambrian boundary from the residual anomaly (we assume what is left at this stage are the signals due to lateral variation in the Precambrian lithology); (4) inversion of the residual anomaly in the wavenumber domain to density and magnetization distribution in the top part of the Precambrian constrained by the known geologic information; (5) derivation of pseudo-lithology by characterization of density and magnetization. The boundary between the older Central Plains Province to the north and the Southern Granite-Rhyolite Province to the south is clearly delineated. The Midcontinent Rift System appears to widen in central Kansas and involve a considerable portion of southern Kansas. Lithologies in southwestern Kansas appear to change over fairly small areas and include mafic rocks which have not been encountered in drill holes. The texture of the potential field data from southwestern Kansas suggests a history of continental growth by broad extension. Copyright ?? 1996 Elsevier Science Ltd.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Computers and Geosciences","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0098-3004(96)00045-3","issn":"00983004","usgsCitation":"Xia, J., Sprowl, D., and Steeples, D., 1996, A model of Precambrian geology of Kansas derived from gravity and magnetic data: Computers & Geosciences, v. 22, no. 8, p. 883-895, https://doi.org/10.1016/S0098-3004(96)00045-3.","startPage":"883","endPage":"895","numberOfPages":"13","costCenters":[],"links":[{"id":206120,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0098-3004(96)00045-3"},{"id":228502,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e47ee4b0c8380cd46677","contributors":{"authors":[{"text":"Xia, J.","contributorId":63513,"corporation":false,"usgs":true,"family":"Xia","given":"J.","email":"","affiliations":[],"preferred":false,"id":378386,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sprowl, D.R.","contributorId":62775,"corporation":false,"usgs":true,"family":"Sprowl","given":"D.R.","email":"","affiliations":[],"preferred":false,"id":378385,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Steeples, D.W.","contributorId":45057,"corporation":false,"usgs":true,"family":"Steeples","given":"D.W.","email":"","affiliations":[],"preferred":false,"id":378384,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018070,"text":"70018070 - 1996 - Age of supergene oxidation and enrichment in the Chilean porphyry copper province","interactions":[],"lastModifiedDate":"2024-01-03T16:58:06.67885","indexId":"70018070","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1472,"text":"Economic Geology","active":true,"publicationSubtype":{"id":10}},"title":"Age of supergene oxidation and enrichment in the Chilean porphyry copper province","docAbstract":"Twenty-five samples of supergene alunite collected from deeply developed supergene profiles in porphyry copper deposits and prospects between latitudes 20 degrees and 27 degrees S in northern Chile yield K/Ar ages ranging from about 34 to 14 Ma. Therefore supergene oxidation and enrichment processes were active from the early Oligocene to the middle Miocene, a minimum of 20 m.y. Supergene activity at individual deposits lasted for at least 0.4 to 6.2 m.y. The early Oligocene supergene activity affected deposits in the Paleocene porphyry copper belt, whereas early and middle Miocene supergene processes are documented in the Early Cretaceous, Paleocene, and late Eocene to early Oligocene porphyry, copper belts. Middle Miocene oxidation also affected the oldest epithermal gold-silver deposits in the Maricunga belt farther east. Supergene activity commenced no less than 11 m.y. after generation of each porphyry copper deposit because of the time required to unroof the copper-bearing parts of the system. Supergene activity throughout northern Chile ceased at approximately 14 Ma. The geologic features of deposits and prospects and their morphotectonic positions, present latitudes, and present elevations display no obvious correlations with the supergene chronology. Exploration for major cumulative enrichment blankets should not be carried out either beneath thick sequences of piedmont gravels (+ or - ignimbrites) of Oligocene through middle Miocene age unless their accumulation is demonstrably late in the documented history of supergene activity, or in porphyry copper provinces, such as those of central Chile and northwestern Argentina, which formed after approximately 14 Ma. The uplift responsible for efficient cumulative copper enrichment is difficult to correlate convincingly with the brief pulses of compressive tectonism postulated for northern Chile and contiguous areas unless their effects were much more prolonged. Intensifying aridity is confirmed as the likely reason for the cessation of supergene activity in northern Chile, and tectonic uplift was its most probable cause. However, more fundamental global controls producing a period of chemical weathering followed by worldwide dessication also may have played a role.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.91.1.164","issn":"03610128","usgsCitation":"Sillitoe, R., and McKee, E., 1996, Age of supergene oxidation and enrichment in the Chilean porphyry copper province: Economic Geology, v. 91, no. 1, p. 164-179, https://doi.org/10.2113/gsecongeo.91.1.164.","productDescription":"16 p.","startPage":"164","endPage":"179","numberOfPages":"16","costCenters":[],"links":[{"id":228460,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"91","issue":"1","noUsgsAuthors":false,"publicationDate":"1996-02-01","publicationStatus":"PW","scienceBaseUri":"5059e8ede4b0c8380cd47fa8","contributors":{"authors":[{"text":"Sillitoe, R.H.","contributorId":76479,"corporation":false,"usgs":true,"family":"Sillitoe","given":"R.H.","email":"","affiliations":[],"preferred":false,"id":378380,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"McKee, E.H.","contributorId":20736,"corporation":false,"usgs":true,"family":"McKee","given":"E.H.","email":"","affiliations":[],"preferred":false,"id":378379,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019335,"text":"70019335 - 1996 - Porosity factors that control the hydraulic conductivity of soil-saprolite transitional zones","interactions":[],"lastModifiedDate":"2025-07-30T16:21:40.570331","indexId":"70019335","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3420,"text":"Soil Science Society of America Journal","active":true,"publicationSubtype":{"id":10}},"title":"Porosity factors that control the hydraulic conductivity of soil-saprolite transitional zones","docAbstract":"Slowly permeable transitional horizons separate soil and saprolite, but these horizons cannot be identified easily in the field. The objectives of this study were to determine why the soil-saprolite transitional zone (BC and CB horizons) is slowly permeable, and to evaluate ways for identifying it in the field. Two saprolite deposits were studied in the North Carolina Piedmont. At each site, saturated and unsaturated hydraulic conductivities (Ksat and Kunsat) were measured for major horizons. Volume fractions of water-conducting pores were also compared with the changes in hydraulic conductivity with depth. Horizon mean Ksat values at both sites ranged from virtually 0 to approximately 3 cm h-1. The lowest Ksat values (<0.3 cm h-1) occurred in or near the transitional horizons that were directly below the Bt horizons. Changes in the volume of pores within or between mineral grains (termed inter/intraparticle pores) with depth corresponded to changes in both Ksat and Kunsat. In the transitional horizons, the inter/intraparticle pores were plugged with clay and this caused the horizons to have low K values. In situ measurements of Ksat with depth were the most accurate technique to use for identifying transitional zones in the field. Examination of both the soil and rock structures in pits was also an acceptable technique. Texture and consistence were not considered reliable for pin-pointing transitional horizons.
","language":"English","publisher":"Wiley","doi":"10.2136/sssaj1996.03615995006000010031x","issn":"03615995","usgsCitation":"Vepraskas, M., Kleiss, H., Amoozegar, A., and Guertal, W., 1996, Porosity factors that control the hydraulic conductivity of soil-saprolite transitional zones: Soil Science Society of America Journal, v. 60, no. 1, p. 192-199, https://doi.org/10.2136/sssaj1996.03615995006000010031x.","productDescription":"8 p.","startPage":"192","endPage":"199","costCenters":[],"links":[{"id":226598,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"North Carolina","county":"Person County","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -79.11288378107477,\n 36.54010978670284\n ],\n [\n -79.11288378107477,\n 36.26588582450742\n ],\n [\n -78.82609448661837,\n 36.26588582450742\n ],\n [\n -78.82609448661837,\n 36.54010978670284\n ],\n [\n -79.11288378107477,\n 36.54010978670284\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"60","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7ddde4b0c8380cd7a1e5","contributors":{"authors":[{"text":"Vepraskas, M.J.","contributorId":37483,"corporation":false,"usgs":true,"family":"Vepraskas","given":"M.J.","email":"","affiliations":[],"preferred":false,"id":382382,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kleiss, H.J.","contributorId":27206,"corporation":false,"usgs":true,"family":"Kleiss","given":"H.J.","email":"","affiliations":[],"preferred":false,"id":382381,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Amoozegar, A.","contributorId":76077,"corporation":false,"usgs":true,"family":"Amoozegar","given":"A.","email":"","affiliations":[],"preferred":false,"id":382383,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Guertal, W.R.","contributorId":99311,"corporation":false,"usgs":true,"family":"Guertal","given":"W.R.","email":"","affiliations":[],"preferred":false,"id":382384,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018069,"text":"70018069 - 1996 - The Eocene Big Timber stock, south-central Montana: Development of extensive compositional variation in an arc-related intrusion by side-wall crystallization and cumulate glomerocryst remixing","interactions":[],"lastModifiedDate":"2023-12-23T15:09:36.133894","indexId":"70018069","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"The Eocene Big Timber stock, south-central Montana: Development of extensive compositional variation in an arc-related intrusion by side-wall crystallization and cumulate glomerocryst remixing","docAbstract":"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.
Interpretations of Pennsylvanian sedimentation and peat accumulation commonly use examples from the Appalachian basin because of the excellent outcrops and large reserve of coal (>100 billion metric tons) in the region. Particularly controversial is the origin of Lower and lower Middle Pennsylvanian quartzose sandstones; beach-barrier, marine-bar, tidal-strait, and fluvial models all have been applied to a series of sand bodies along the western outcrop margin of the basin. Interpretations of these sandstones and their inferred lateral relationships are critical for understanding the relative degree of eustatic, tectonic, and climatic controls on Early Pennsylvanian sedimentation.
Cross sections utilizing >1000 subsurface records and detailed sedimentological analysis of the Livingston Conglomerate, Rockcastle Sandstone, Corbin Sandstone, and Pine Creek sandstone (an informal member) of the Breathitt Group were used to show that each of the principal quartzose sandstones on the margin of the central Appalachian basin contains both fluvial and marginal marine facies.
The four sandstones are fluvially dominated and are inferred to represent successive bed-load trunk systems of the Appalachian foreland. Base-level rise and an associated decrease in extra-basinal sediment at the end of each fluvial episode led to the development of local estuaries and marine reworking of the tops of the sand belts. Each of the sand belts is capped locally by a coal, regardless of whether the upper surfaces of the sand belts are of fluvial or estuarine origin, suggesting allocyclic controls on deposition. Peats were controlled by a tropical ever-wet climate, which also influenced sandstone composition through weathering of stored sands in slowly aggrading braidplains.
Recurrent stacking of thick, coarse-grained, fluvial deposits with extra-basinal quartz pebbles; dominance of bed-load fluvial–lowstand deposits over mixed-load, estuarine-transgressive deposits; thinning of sand belts around tectonic highs and along faults; cratonward shift and amalgamation of successive sand belts on the margin of the basin; and truncation of successive sand belts toward the fault-bound margin of the basin are interpreted as regional responses to Alleghenian tectonism, inferred to have been the dominant control on accommodation space and sediment flux in the Early Pennsylvanian basin.
","language":"English","publisher":"Geological Society of America","doi":"10.1130/0016-7606(1996)108<0303:LALMPF>2.3.CO;2","issn":"00167606","usgsCitation":"Greb, S., and Chesnut, D., 1996, Lower and lower Middle Pennsylvanian fluvial to estuarine deposition, central Appalachian basin: Effects of eustasy, tectonics, and climate: Geological Society of America Bulletin, v. 108, no. 3, p. 303-317, https://doi.org/10.1130/0016-7606(1996)108<0303:LALMPF>2.3.CO;2.","productDescription":"15 p.","startPage":"303","endPage":"317","numberOfPages":"15","costCenters":[],"links":[{"id":227561,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"108","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4a7ae4b0c8380cd68dc7","contributors":{"authors":[{"text":"Greb, S.F.","contributorId":48294,"corporation":false,"usgs":true,"family":"Greb","given":"S.F.","email":"","affiliations":[],"preferred":false,"id":379608,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Chesnut, D.R. Jr.","contributorId":100548,"corporation":false,"usgs":true,"family":"Chesnut","given":"D.R.","suffix":"Jr.","email":"","affiliations":[],"preferred":false,"id":379609,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":96732,"text":"96732 - 1996 - The effects of off-road vehicles on animal populations and habitats: A review of the literature. For the U S Bureau of Land Management, Riverside","interactions":[],"lastModifiedDate":"2012-02-02T00:03:58","indexId":"96732","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":9,"text":"Other Report"},"title":"The effects of off-road vehicles on animal populations and habitats: A review of the literature. For the U S Bureau of Land Management, Riverside","docAbstract":"No abstract available at this time","language":"English","usgsCitation":"Berry, K., 1996, The effects of off-road vehicles on animal populations and habitats: A review of the literature. For the U S Bureau of Land Management, Riverside, 104 p.; appendices.","productDescription":"104 p.; appendices","costCenters":[],"links":[{"id":128321,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a9be4b07f02db65def9","contributors":{"authors":[{"text":"Berry, K.H.","contributorId":17934,"corporation":false,"usgs":true,"family":"Berry","given":"K.H.","email":"","affiliations":[],"preferred":false,"id":300148,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018638,"text":"70018638 - 1996 - Application of a feedforward neural network in the search for kuroko deposits in the Hokuroku District, Japan","interactions":[],"lastModifiedDate":"2018-05-24T16:18:27","indexId":"70018638","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Application of a feedforward neural network in the search for kuroko deposits in the Hokuroku District, Japan","docAbstract":"A feedforward neural network with one hidden layer and five neurons was trained to recognize the distance to kuroko mineral deposits. Average amounts per hole of pyrite, sericite, and gypsum plus anhydrite as measured by X-rays in 69 drillholes were used to train the net. Drillholes near and between the Fukazawa, Furutobe, and Shakanai mines were used. The training data were selected carefully to represent well-explored areas where some confidence of the distance to ore was assured. A logarithmic transform was applied to remove the skewness of distance and each variable was scaled and centered by subtracting the median and dividing by the interquartile range. The learning algorithm of annealing plus conjugate gradients was used to minimize the mean squared error of the scaled distance to ore. The trained network then was applied to all of the 152 drillholes that had measured gypsum, sericite, and pyrite. A contour plot of the neural net predicted distance to ore shows fairly wide areas of 1 km or less to ore; each of the known deposit groups is within the 1 km contour. The high and low distances on the margins of the contoured distance plot are in part the result of boundary effects of the contouring algorithm. For example, the short distances to ore predicted west of the Shakanai (Hanaoka) deposits are in basement. However, the short distances to ore predicted northeast of Furotobe, just off the figure, coincide with the location of the Nurukawa kuroko deposit and the Omaki deposit, south of the Shakanai-Hanaoka deposits, seems to be on an extension of short distance to ore contour, but is beyond the 3 km limit from drillholes. Also of interest are some areas only a few kilometers from the Fukazawa and Shakanai groups of deposits that are estimated to be many kilometers from ore, apparently reflecting the network's recognition of the extreme local variability of the geology near some deposits.
","language":"English","publisher":"Springer","doi":"10.1007/BF02068587","issn":"08828121","usgsCitation":"Singer, D.A., and Kouda, R., 1996, Application of a feedforward neural network in the search for kuroko deposits in the Hokuroku District, Japan: Mathematical Geology, v. 28, no. 8, p. 1017-1023, https://doi.org/10.1007/BF02068587.","productDescription":"7 p.","startPage":"1017","endPage":"1023","numberOfPages":"7","costCenters":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"links":[{"id":227351,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":268636,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF02068587"}],"country":"Japan","volume":"28","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ec8de4b0c8380cd4932e","contributors":{"authors":[{"text":"Singer, Donald A. dsinger@usgs.gov","contributorId":5601,"corporation":false,"usgs":true,"family":"Singer","given":"Donald","email":"dsinger@usgs.gov","middleInitial":"A.","affiliations":[],"preferred":true,"id":380290,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kouda, Ryoichi","contributorId":198036,"corporation":false,"usgs":false,"family":"Kouda","given":"Ryoichi","email":"","affiliations":[],"preferred":false,"id":380289,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":96750,"text":"96750 - 1996 - Assessments and scientific basis for management options. Ecology and management of giant sequoia groves","interactions":[],"lastModifiedDate":"2012-02-02T00:03:52","indexId":"96750","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":9,"text":"Other Report"},"title":"Assessments and scientific basis for management options. Ecology and management of giant sequoia groves","docAbstract":"No abstract available at this time","largerWorkType":{"id":18,"text":"Report"},"largerWorkTitle":"Sierra Nevada Ecosystem Project: Final report to Congress, Volume II","largerWorkSubtype":{"id":9,"text":"Other Report"},"language":"English","publisher":"University of California-Davis Centers for Water and Wildland Resources","publisherLocation":"Davis, CA","usgsCitation":"Stephenson, N., 1996, Assessments and scientific basis for management options. Ecology and management of giant sequoia groves, p. 1431-1467.","productDescription":"p. 1431-1467","startPage":"1,431","endPage":"1,467","numberOfPages":"37","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":127086,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4aafe4b07f02db66ce8d","contributors":{"authors":[{"text":"Stephenson, N.L.","contributorId":17559,"corporation":false,"usgs":true,"family":"Stephenson","given":"N.L.","email":"","affiliations":[],"preferred":false,"id":300194,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018483,"text":"70018483 - 1996 - Rupture distribution of the 1977 western Argentina earthquake","interactions":[],"lastModifiedDate":"2013-01-22T15:40:26","indexId":"70018483","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3071,"text":"Physics of the Earth and Planetary Interiors","active":true,"publicationSubtype":{"id":10}},"title":"Rupture distribution of the 1977 western Argentina earthquake","docAbstract":"Teleseismic P and SH body waves are used in a finite-fault, waveform inversion for the rupture history of the 23 November 1977 western Argentina earthquake. This double event consists of a smaller foreshock (M0 = 5.3 ?? 1026 dyn-cm) followed about 20 s later by a larger main shock (M0 = 1.5 ?? 1027 dyn-cm). Our analysis indicates that these two events occurred on different fault segments: with the foreshock having a strike, dip, and average rake of 345??, 45??E, and 50??, and the main shock 10??, 45??E, and 80??, respectively. The foreshock initiated at a depth of 17 km and propagated updip and to the north. The main shock initiated at the southern end of the foreshock zone at a depth of 25 to 30 km, and propagated updip and unilaterally to the south. The north-south separation of the centroids of the moment release for the foreshock and main shock is about 60 km. The apparent triggering of the main shock by the foreshock is similar to other earthquakes that have involved the failure of multiple fault segments, such as the 1992 Landers, California, earthquake. Such occurrences argue against the use of individual, mapped, surface fault or fault-segment lengths in the determination of the size and frequency of future earthquakes.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Physics of the Earth and Planetary Interiors","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/0031-9201(95)03080-8","issn":"00319201","usgsCitation":"Langer, C., and Hartzell, S., 1996, Rupture distribution of the 1977 western Argentina earthquake: Physics of the Earth and Planetary Interiors, v. 94, no. 1-2, p. 121-132, https://doi.org/10.1016/0031-9201(95)03080-8.","startPage":"121","endPage":"132","numberOfPages":"12","costCenters":[],"links":[{"id":227564,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":266263,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0031-9201(95)03080-8"}],"volume":"94","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505aaecde4b0c8380cd8721c","contributors":{"authors":[{"text":"Langer, C.J.","contributorId":31395,"corporation":false,"usgs":true,"family":"Langer","given":"C.J.","email":"","affiliations":[],"preferred":false,"id":379761,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hartzell, S.","contributorId":12603,"corporation":false,"usgs":true,"family":"Hartzell","given":"S.","email":"","affiliations":[],"preferred":false,"id":379760,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":96735,"text":"96735 - 1996 - Raven abundance at anthropogenic resources in the western Mojave Desert, California","interactions":[],"lastModifiedDate":"2012-02-02T00:03:59","indexId":"96735","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":9,"text":"Other Report"},"title":"Raven abundance at anthropogenic resources in the western Mojave Desert, California","docAbstract":"No abstract available at this time","language":"English","collaboration":"Report to Edwards Air Force Base.","usgsCitation":"Boarman, W.I., Camp, R., Hagan, M., and Deal, W., 1996, Raven abundance at anthropogenic resources in the western Mojave Desert, California, 21 p.","productDescription":"21 p.","startPage":"21","numberOfPages":"21","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":128438,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a7fe4b07f02db6486f7","contributors":{"authors":[{"text":"Boarman, William I.","contributorId":51683,"corporation":false,"usgs":true,"family":"Boarman","given":"William","email":"","middleInitial":"I.","affiliations":[],"preferred":false,"id":300156,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Camp, Richard J.","contributorId":27392,"corporation":false,"usgs":true,"family":"Camp","given":"Richard J.","affiliations":[],"preferred":false,"id":300154,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hagan, Mark","contributorId":45247,"corporation":false,"usgs":true,"family":"Hagan","given":"Mark","email":"","affiliations":[],"preferred":false,"id":300155,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Deal, Wanda","contributorId":19904,"corporation":false,"usgs":true,"family":"Deal","given":"Wanda","email":"","affiliations":[],"preferred":false,"id":300153,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":96734,"text":"96734 - 1996 - Summary of proposed endangered plant data collected on Santa Rosa Island by National Biological Survey staff and collaborators, 1994-1996","interactions":[],"lastModifiedDate":"2012-02-02T00:03:59","indexId":"96734","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":9,"text":"Other Report"},"title":"Summary of proposed endangered plant data collected on Santa Rosa Island by National Biological Survey staff and collaborators, 1994-1996","docAbstract":"No abstract available at this time","language":"English","publisher":"NBS-California Science Center; U.S. Geological Survey, Channel Islands Field Station","publisherLocation":"Ventura, CA","usgsCitation":"McEachern, A.K., 1996, Summary of proposed endangered plant data collected on Santa Rosa Island by National Biological Survey staff and collaborators, 1994-1996, 11 p.","productDescription":"11 p.","startPage":"11","numberOfPages":"11","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":128437,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b04e4b07f02db699094","contributors":{"authors":[{"text":"McEachern, A. Kathryn","contributorId":30165,"corporation":false,"usgs":true,"family":"McEachern","given":"A.","email":"","middleInitial":"Kathryn","affiliations":[],"preferred":false,"id":300152,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":96733,"text":"96733 - 1996 - Control of the European Green Crab in California: Detection of Natural Enemies. Final Report to Saltonstall-Kennedy. Grant Number: NA46FDO493","interactions":[],"lastModifiedDate":"2012-02-02T00:03:59","indexId":"96733","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":9,"text":"Other Report"},"title":"Control of the European Green Crab in California: Detection of Natural Enemies. Final Report to Saltonstall-Kennedy. Grant Number: NA46FDO493","docAbstract":"No abstract available at this time","language":"English","usgsCitation":"Kuris, A.M., Lafferty, K.D., and Torchin, M., 1996, Control of the European Green Crab in California: Detection of Natural Enemies. Final Report to Saltonstall-Kennedy. Grant Number: NA46FDO493.","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":128352,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4ae2e4b07f02db688c63","contributors":{"authors":[{"text":"Kuris, A. M.","contributorId":62164,"corporation":false,"usgs":true,"family":"Kuris","given":"A.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":300150,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lafferty, K. D.","contributorId":58213,"corporation":false,"usgs":false,"family":"Lafferty","given":"K.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":300149,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Torchin, M.E.","contributorId":90237,"corporation":false,"usgs":true,"family":"Torchin","given":"M.E.","affiliations":[],"preferred":false,"id":300151,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018484,"text":"70018484 - 1996 - Hydrogeology of the Hawaii Scientific Drilling Project borehole KP-1 1. Hydraulic conditions adjacent to the well bore","interactions":[],"lastModifiedDate":"2019-05-13T20:11:01","indexId":"70018484","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2314,"text":"Journal of Geophysical Research B: Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Hydrogeology of the Hawaii Scientific Drilling Project borehole KP-1 1. Hydraulic conditions adjacent to the well bore","docAbstract":"Temperature and formation resistivity logs obtained in borehole KP-1 of the Hawaii Scientific Drilling Project indicate that the adjacent formation is characterized by several zones of distinctly different average temperature and water salinity. A series of hydraulic analyses and water sampling programs were conducted to rule out the possibility of local hydraulic effects associated with the presence of the borehole in the generation of these apparent groundwater zones. Hydraulic tests and sampling with the borehole cased to a depth of 710 m and open below that depth indicate that the deep aquifer contains seawater at a temperature nearly identical to that of the open ocean at the same depth. Various analyses give estimates of aquifer transmissivity of about 10-3 m2/s in the vicinity of the borehole. Isolation of this deeper aquifer from the overlying groundwater zones was investigated by perforating the casing at six locations and then measuring the changes in water level in the borehole, in the salinity of the fluid column, in the temperature profile of the fluid column, and in the rate of flow in the fluid column induced by the perforations. These results positively confirm that the zones of distinctly different formation properties indicated on the temperature and resistivity logs are not caused by flow in or around casing. Flow and fluid column salinity induced by the perforations also confirm significant differences between the hydraulic heads and geochemistry of the different groundwater zones inferred from the well logs.","language":"English","publisher":"Wiley","doi":"10.1029/95JB03445","issn":"01480227","usgsCitation":"Paillet, F.L., and Thomas, D.M., 1996, Hydrogeology of the Hawaii Scientific Drilling Project borehole KP-1 1. Hydraulic conditions adjacent to the well bore: Journal of Geophysical Research B: Solid Earth, v. 101, no. 5, p. 11675-11682, https://doi.org/10.1029/95JB03445.","productDescription":"8 p.","startPage":"11675","endPage":"11682","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true},{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":227607,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"5","noUsgsAuthors":false,"publicationDate":"1996-05-10","publicationStatus":"PW","scienceBaseUri":"505a34a2e4b0c8380cd5f8fc","contributors":{"authors":[{"text":"Paillet, Frederick L.","contributorId":63820,"corporation":false,"usgs":true,"family":"Paillet","given":"Frederick","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":379763,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Thomas, D. M.","contributorId":8827,"corporation":false,"usgs":true,"family":"Thomas","given":"D.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":379762,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018487,"text":"70018487 - 1996 - Uranium-series dating of carbonate (tufa) deposits associated with quaternary fluctuations of Pyramid Lake, Nevada","interactions":[],"lastModifiedDate":"2012-03-12T17:19:23","indexId":"70018487","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3218,"text":"Quaternary Research","active":true,"publicationSubtype":{"id":10}},"title":"Uranium-series dating of carbonate (tufa) deposits associated with quaternary fluctuations of Pyramid Lake, Nevada","docAbstract":"Uranium-series dating of dense tufa deposited in a small cave, at former lake margins, and in large tufa mounds clarifies the timing of lake-level variation during the past 400,000 yr in the Pyramid Lake basin. A moderate-sized lake occasionally overflowed the Emerson Pass sill at elevation of ???1207 m between ca. 400,000 and 170,000 and from ca. 60,000 to 20,000 yr B.P., as shown by 230Th/234U ages of the cave samples, 230Th-excess ages of tubular tufas, and average isochron-plot ages of shoreline-deposited tufas. (By comparison, modern Pyramid Lake is ???50 m below this sill). There is a lack of tufa record during the intervening period from ca. 170,000 to 60,000 yr B.P. After ca. 20,000 yr, Pyramid Lake underwent abrupt changes in level and, based on previous 14C ages, reached its highest elevation (ca 1335 m) at ca. 14,000 yr B.P. The youngest uranium-series ages are comparable with previously reported 14C ages. ?? 1996 University of Washington.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Quaternary Research","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1006/qres.1996.0028","issn":"00335894","usgsCitation":"Szabo, B.J., Bush, C.A., and Benson, L.V., 1996, Uranium-series dating of carbonate (tufa) deposits associated with quaternary fluctuations of Pyramid Lake, Nevada: Quaternary Research, v. 45, no. 3, p. 271-281, https://doi.org/10.1006/qres.1996.0028.","startPage":"271","endPage":"281","numberOfPages":"11","costCenters":[],"links":[{"id":205961,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1006/qres.1996.0028"},{"id":227649,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"3","noUsgsAuthors":false,"publicationDate":"2017-01-20","publicationStatus":"PW","scienceBaseUri":"505bbdf7e4b08c986b329327","contributors":{"authors":[{"text":"Szabo, Barney J.","contributorId":6848,"corporation":false,"usgs":true,"family":"Szabo","given":"Barney","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":379775,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bush, C. A.","contributorId":43344,"corporation":false,"usgs":true,"family":"Bush","given":"C.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":379776,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Benson, L. V.","contributorId":50159,"corporation":false,"usgs":true,"family":"Benson","given":"L.","email":"","middleInitial":"V.","affiliations":[],"preferred":false,"id":379777,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018493,"text":"70018493 - 1996 - Waters associated with an active basaltic volcano, Kilauea, Hawaii: Variation in solute sources, 1973-1991","interactions":[],"lastModifiedDate":"2023-12-22T12:20:38.550959","indexId":"70018493","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Waters associated with an active basaltic volcano, Kilauea, Hawaii: Variation in solute sources, 1973-1991","docAbstract":"Chemical and isotopic analyses of samples collected from a December 1962-m-deep research borehole at the summit of Kilauea Volcano provide unique time-series data for composition of waters in the uppermost part of its hydrothermal system. These waters have a distinctive geochemical signature: a very low proportion of chloride relative to other anions compared with other Hawaiian waters—thermal (•30°C) or nonthermal (<30°C)—and with most thermal waters of the world. Isotope data demonstrate that the borehole waters are of essentially meteoric origin, with minimal magmatic input.
","language":"English","publisher":"Geological Society of America","doi":"10.1130/0016-7606(1996)108<0562:WAWAAB>2.3.CO;2","issn":"00167606","usgsCitation":"Tilling, R., and Jones, B., 1996, Waters associated with an active basaltic volcano, Kilauea, Hawaii: Variation in solute sources, 1973-1991: Geological Society of America Bulletin, v. 108, no. 5, p. 562-577, https://doi.org/10.1130/0016-7606(1996)108<0562:WAWAAB>2.3.CO;2.","productDescription":"16 p.","startPage":"562","endPage":"577","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":227073,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Hawaii","otherGeospatial":"Kilauea","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -155.5298831158459,\n 19.668190733857983\n ],\n [\n -155.5298831158459,\n 19.07662995285706\n ],\n [\n -154.9358196143554,\n 19.07662995285706\n ],\n [\n -154.9358196143554,\n 19.668190733857983\n ],\n [\n -155.5298831158459,\n 19.668190733857983\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"108","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bcf6be4b08c986b32e8b5","contributors":{"authors":[{"text":"Tilling, R.I. 0000-0003-4263-7221","orcid":"https://orcid.org/0000-0003-4263-7221","contributorId":98311,"corporation":false,"usgs":true,"family":"Tilling","given":"R.I.","affiliations":[],"preferred":false,"id":379805,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Jones, B.F.","contributorId":52156,"corporation":false,"usgs":true,"family":"Jones","given":"B.F.","email":"","affiliations":[],"preferred":false,"id":379804,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018495,"text":"70018495 - 1996 - Lithologic analysis from multispectral thermal infrared data of the alkalic rock complex at Iron Hill, Colorado","interactions":[],"lastModifiedDate":"2024-04-18T15:18:50.693012","indexId":"70018495","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1808,"text":"Geophysics","active":true,"publicationSubtype":{"id":10}},"title":"Lithologic analysis from multispectral thermal infrared data of the alkalic rock complex at Iron Hill, Colorado","docAbstract":"Airborne thermal-infrared multispectral scanner (TIMS) data of the Iron Hill carbonatite-alkalic igneous rock complex in south-central Colorado are analyzed using a new spectral emissivity ratio algorithm and confirmed by field examination using existing 1:24 000-scale geologic maps and petrographic studies. Color composite images show that the alkalic rocks could be clearly identified and that differences existed among alkalic rocks in several parts of the complex. An unsupervised classification algorithm defines four alkalic rock classes within the complex: biotitic pyroxenite, uncompahgrite, augitic pyroxenite, and fenite + nepheline syenite. Felsic rock classes defined in the surrounding country rock are an extensive class consisting of tuff, granite, and felsite, a less extensive class of granite and felsite, and quartzite. The general composition of the classes can be determined from comparisons of the TIMS spectra with laboratory spectra. Carbonatite rocks are not classified, and we attribute that to the fact that dolomite, the predominant carbonate mineral in the complex, has a spectral feature that falls between TIMS channels 5 and 6. Mineralogical variability in the fenitized granite contributed to the nonuniform pattern of the fenite-nepheline syenite class. The biotitic pyroxenite, which resulted from alteration of the pyroxenite, is spatially associated and appears to be related to narrow carbonatite dikes and sills. Results from a linear unmixing algorithm suggest that the detected spatial extent of the two mixed felsic rock classes was sensitive to the amount of vegetation cover. These results illustrate that spectral thermal infrared data can be processed to yield compositional information that can be a cost-effective tool to target mineral exploration, particularly in igneous terranes.
","language":"English","publisher":"Society of Exploration Geophysicists","doi":"10.1190/1.1443998","issn":"00168033","usgsCitation":"Watson, K., Rowan, L.C., Bowers, T.L., Anton-Pacheco, C., Gumiel, P., and Miller, S., 1996, Lithologic analysis from multispectral thermal infrared data of the alkalic rock complex at Iron Hill, Colorado: Geophysics, v. 61, no. 3, p. 706-721, https://doi.org/10.1190/1.1443998.","productDescription":"16 p.","startPage":"706","endPage":"721","numberOfPages":"16","costCenters":[],"links":[{"id":227118,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"61","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4841e4b0c8380cd67d27","contributors":{"authors":[{"text":"Watson, K.","contributorId":39123,"corporation":false,"usgs":true,"family":"Watson","given":"K.","email":"","affiliations":[],"preferred":false,"id":379815,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rowan, L. C.","contributorId":40584,"corporation":false,"usgs":true,"family":"Rowan","given":"L.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":379816,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bowers, T. 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Over the past few years, advances in the understanding of the physics of sediment transport in conjunction with rapidly increasing capabilities in computational fluid dynamics have yielded now approaches to problems in river mechanics. Techniques appropriate for length scales ranging from reaches to bars and bedforms are described here. Examples of the use of these computational approaches are discussed for three cases: (1) the design of diversion scenarios that maintain channel morphology in steep cobble-bedded channels in Colorado, (2) determination of channel maintenance flows for the preservation of channel islands in the Snake River in Idaho, and (3) prediction of the temporal evolution of deposits in lateral separation zones for future assessment of the impacts of various dam release scenarios on lateral separation deposits in the Colorado River in Grand Canyon. With continued development of their scientific and technical components, the methodologies described here can provide powerful tools for the management of river environments in the future.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Water, Air, and Soil Pollution","largerWorkSubtype":{"id":10,"text":"Journal Article"},"conferenceTitle":"Proceedings of the 1995 International Clean Water Conference on Clean Water: Factors that Influence its Availabilty, Quality and its Use","conferenceDate":"28 November 1995 through 30 November 1995","conferenceLocation":"La Jolla, CA, USA","language":"English","publisher":"Kluwer Academic Publishers","publisherLocation":"Dordrecht, Netherlands","doi":"10.1007/BF00619292","issn":"00496979","usgsCitation":"Nelson, J.M., 1996, Predictive techniques for river channel evolution and maintenance: Water, Air, & Soil Pollution, v. 90, no. 1-2, p. 321-333, https://doi.org/10.1007/BF00619292.","startPage":"321","endPage":"333","numberOfPages":"13","costCenters":[],"links":[{"id":205862,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00619292"},{"id":227165,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"90","issue":"1-2","noUsgsAuthors":false,"publicationDate":"1996-07-01","publicationStatus":"PW","scienceBaseUri":"505a8205e4b0c8380cd7b861","contributors":{"authors":[{"text":"Nelson, J. 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