Anomalous vertical magnetic field (tipper) profiles acquired using natural or very low-frequency (VLF) radio transmitter sources can be interpreted simply and rapidly for a number of geologic settings. The relations between computed numerical models, and outcropping dipping and buried vertical contacts are presented here in a series of interpretation charts. Use of the tipper phase in the analysis minimizes the effect of transmitter azimuth in the VLF case.Two examples illustrate the application to field data. An audiofrequency natural-field tipper profile over a conductive bed in a north-central Washington State metasedimentary sequence demonstrates the interpretation procedure for a dipping contact. VLF profiles over covered basement faults in Ontario demonstrate the application for a buried vertical contact. In both cases the quick results are in agreement with the much more laborious trial-and-error matching to two-dimensional models.
","language":"English","publisher":"Society of Exploration Geophysicists","doi":"10.1190/1.1442286","issn":"00168033","usgsCitation":"Labson, V.F., and Becker, A., 1987, Natural-field and very low-frequency tipper profile interpretation of contacts: Geophysics, v. 52, no. 12, p. 1697-1707, https://doi.org/10.1190/1.1442286.","productDescription":"11 p.","startPage":"1697","endPage":"1707","numberOfPages":"11","costCenters":[],"links":[{"id":225404,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"52","issue":"12","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6137e4b0c8380cd7184d","contributors":{"authors":[{"text":"Labson, Victor F. 0000-0003-1905-1820 vlabson@usgs.gov","orcid":"https://orcid.org/0000-0003-1905-1820","contributorId":326,"corporation":false,"usgs":true,"family":"Labson","given":"Victor","email":"vlabson@usgs.gov","middleInitial":"F.","affiliations":[{"id":349,"text":"International Water Resources Branch","active":true,"usgs":true}],"preferred":true,"id":369396,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Becker, Alex","contributorId":59567,"corporation":false,"usgs":true,"family":"Becker","given":"Alex","email":"","affiliations":[],"preferred":false,"id":369397,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014824,"text":"70014824 - 1987 - Computer simulations of large asteroid impacts into oceanic and continental sites--Preliminary results on atmospheric, cratering and ejecta dynamics","interactions":[],"lastModifiedDate":"2024-02-14T14:57:15.073617","indexId":"70014824","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2054,"text":"International Journal of Impact Engineering","active":true,"publicationSubtype":{"id":10}},"title":"Computer simulations of large asteroid impacts into oceanic and continental sites--Preliminary results on atmospheric, cratering and ejecta dynamics","docAbstract":"Computer simulations have been completed that describe passage of a 10-km-diameter asteroid through the Earth's atmosphere and the subsequent cratering and ejecta dynamics caused by impact of the asteroid into both oceanic and continental sites. The asteroid was modeled as a spherical body moving vertically at 20 km/s with a kinetic energy of 2.6 × 1030 ergs (6.2 × 107 Mt ). Detailed material modeling of the asteroid, ocean, crustal units, sedimentary unit, and mantle included effects of strength and fracturing, generic asteroid and rock properties, porosity, saturation, lithostatic stresses, and geothermal contributions, each selected to simulate impact and geologic conditions that were as realistic as possible. Calculation of the passage of the asteroid through a U.S. Standard Atmosphere showed development of a strong bow shock wave followed by a highly shock compressed and heated air mass. Rapid expansion of this shocked air created a large low-density region that also expanded away from the impact area. Shock temperatures in air reached ∼20, 000K near the surface of the uplifting crater rim and were as high as ∼2000K at more than 30 km range and 10 km altitude. Calculations to 30 s showed that the shock fronts in the air and in most of the expanding shocked air mass preceded the formation of the crater, ejecta, and rim uplift and did not interact with them. As cratering developed, uplifted rim and target material were ejected into the very low density, shock-heated air immediately above the forming crater, and complex interactions could be expected. Calculations of the impact events showed equally dramatic effects on the oceanic and continental targets through an interval of 120 s. Despite geologic differences in the targets, both cratering events developed comparable dynamic flow fields and by ∼29s had formed similar-sized transient craters ∼39km deep and ∼62km across. Transient-rim uplift of ocean and crust reached a maximum altitude of nearly 40 km at ∼30s and began to decay at velocities of 500 m/s to develop large-tsunami conditions. After ∼30s, strong gravitational rebound drove both craters toward broad flat-floored shapes. At 120 s, transient crater diameters were ∼80km (continental) and ∼105km (oceanic) and transient depths were ∼27km; crater floors consisting of melted and fragmented hot rock were rebounding rapidly upward. By 60 s, the continental crater had ejected ∼2 × 1014t, about twice the mass ejected from the oceanic crater. By 120 s, ∼70, 000km3 (continental) and ∼90, 000km3 (oceanic) target material were excavated (no mantle) and massive ejecta blankets were formed around the craters. We estimate that in excess of ∼70% of the ejecta would finally lie within ∼3 crater diameters of the impact, and the remaining ejecta (∼1013t), including the vaporized asteroid, would be ejected into the atmosphere to altitudes as high as the ionosphere. Effects of secondary volcanism and return of the ocean over hot oceanic crater floor could also be expected to contribute substantial material to the atmosphere.
Stable isotope compositions have been determined for modern mullusks and fossil mollusks collected from uplifted marine terraces at three localities in southern California. By using a paleoclimatic model that decouples the temperature and ice-volume signals in ocean water, ocean-water temperatures off southern California are estimated to have been −3.8 °C at ∼85 ka, −3.0 °C at ∼107 ka, and −2.2 °C at ∼125 ka relative to present temperature. These results indicate rather cool conditions during the peak of the last interglacial stage at 125 ka and conflict with results from terrace faunal studies that suggest water temperatures were warm or warmer than at present.
Large crescentic dunes that resemble barchans have been discovered within elongate scour depressions on the northern California inner continental shelf by using side-scan sonar. These dunes appear to be migrating obliquely to the regional shelf gradient; a preferred offshore direction of transport is indicated by the extended southern wings of many dunes. The isolated dunes and the scour depressions that contain them are located seaward of sea-floor outcrops off rocky capes and sea stacks. Repeated side-scan sonar records spanning four years (1981–1985) indicate that the dunes and bounding sidewalls of the scour depressions were somewhat modified, but the overall alteration to the bottom morphology during this period was only moderate to undetectable. The apparent low height of the dunes is consistent with a low migration speed. Over longer time periods (decades), the seaward transport of fine to medium sand in the crescentic dunes is probably an important way by which sand escapes the shallow part of the continental shelf in this region and mixes with the muddy deposits of the central shelf.
The diffusion model of degradation of topographic features is a promising means by which vertical offsets on Holocene faults might be dated. In order to calibrate the method, we have examined present-day profiles of wave-cut shoreline scarps of late Pleistocene lakes Bonneville and Lahontan. It may be assumed that these scarps were initially at least as steep as the angle of repose. Offsets range from 1 to 12 m, and present slope angles range from 9° to 29°. A parameter called apparent diffusion age, defined as half the mean square horizontal extent of the slope function of each profile, is plotted as a function of scarp offset. The points show a clear trend of apparent age increasing nearly linearly with offset. If linear diffusion held and scarps were initially vertical, apparent diffusion age would be the same for all the shoreline profiles. The increasing trend can only partly be explained by nonvertical initial scarp slope, and therefore the rate of transport of material downslope must increase significantly faster than a linear law in the range of slopes spanned by the data. The transport law must become linear at small slope to reduce scatter between profiles with varying ambient slopes. The transport law adopted for the purpose of dating is k0(1 + 5s2), where s is local slope. The transport coefficient k0 is correlated inversely with fan slope, suggesting that there is a dependence on the particle size distribution. A table is included that allows easy application of the model to scarps with simple initial shape.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB092iB12p12857","issn":"01480227","usgsCitation":"Andrews, D., and Bucknam, R.C., 1987, Fitting degradation of shoreline scarps by a nonlinear diffusion model: Journal of Geophysical Research Solid Earth, v. 92, no. B12, p. 12857-12867, https://doi.org/10.1029/JB092iB12p12857.","productDescription":"11 p.","startPage":"12857","endPage":"12867","numberOfPages":"11","costCenters":[],"links":[{"id":225596,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"92","issue":"B12","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a10c7e4b0c8380cd53dda","contributors":{"authors":[{"text":"Andrews, D.J.","contributorId":7416,"corporation":false,"usgs":true,"family":"Andrews","given":"D.J.","email":"","affiliations":[],"preferred":false,"id":369270,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bucknam, Robert C.","contributorId":104490,"corporation":false,"usgs":true,"family":"Bucknam","given":"Robert","email":"","middleInitial":"C.","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":369271,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014753,"text":"70014753 - 1987 - Integration of channel and floodplain suites. I. Developmental sequence and lateral relations of alluvial paleosols.","interactions":[],"lastModifiedDate":"2024-05-20T23:17:44.363198","indexId":"70014753","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2450,"text":"Journal of Sedimentary Petrology","active":true,"publicationSubtype":{"id":10}},"title":"Integration of channel and floodplain suites. I. Developmental sequence and lateral relations of alluvial paleosols.","docAbstract":"The lower Eocene Willwood Formation of the Bighorn Basin, northwest Wyoming, consists of about 770 m of alluvial rocks that exhibit extensive mechanical and geochemical modifications resulting from Eocene pedogenesis. Willwood paleosols vary considerably in their relative degrees of maturity; maturity is defined as stage of development as a function of the amount of time required to form. Five arbitrary stages are proposed to distinguish these soils of different maturities in the Willwood Formation. Stage 1 soils, the least mature, are entisols; stage 2 and stage 3 soils are intermediate in maturity and are probably alfisols; and stage 4 and stage 5 soils, the most mature, are spodosols. These stages are not only time-progressive elements of an in situ maturation sequence for Willwood soil formation, but, in the lateral dimension, they are also usually distributed sequentially. Study of Willwood paleosols indicates that an inverse relationship exists between soil maturity and short-term sediment accumulation rate. The least mature Willwood paleosols formed in areas of relatively high net rates of sediment accumulation on 1) channel, levee, and crevasse-splay sediments of the proximal alluvial ridge, and 2) deposits filling large and small paleovalleys formed by major episodes of gullying (lowered baselevels). In contrast, the fine-grained sediments of the distal floodplain, where net sediment accumulation rates were relatively low, experienced development of much more mature soils. Soils of intermediate maturities occur in the order of their stage on intervening proximal floodplain and distal alluvial ridge sediments. Adjacent bodies of sedimentary rock that differ in their ancient soil properties because of distance from areas of relatively high sediment accumulation are denoted by the new term pedofacies . The remarkable sequence of paleosols in the Willwood Formation clearly illustrates several important principles of soil-sediment interrelationships in aggrading alluvial systems that have broad application to other deposits. This is especially true in view of the widespread distribution of paleosols in nearly all ancient fluvial rocks. Further study of Willwood paleosols will not only enable precise lateral correlation of coeval alluvial sediments, and thereby fluvial sedimentary events, from the distal to the proximal realms of the floodplain but will also contribute to increasingly informative evaluations of the nature, tempo, and mode of alluvial succession.
Exceptional bundled slaty cleavage (defined herein) has been found in drill cores of laminated, folded, weakly metamorphosed argillite at several localities in the early Proterozoic Animikie basin of north-central Minnesota. The cleavage domains are more closely spaced within the cleavage bundles than outside them, the mean tectosilicate grain size of siltstone layers, measured normal to cleavage, is less in the cleavage bundles than outside them, and the cleavage bundles are enriched in opaque phases and phyllosilicates relative to extra-bundle segments. These facts suggest that pressure solution was a major factor in bundle development. If it is assumed that opaque phases have been conserved during pressure solution, the modal differences in composition between intra-bundle and extra-bundle segments of beds provide a means for estimating bulk material shortening normal to cleavage. Argillite samples from the central part of the Animikie basin have been shortened a minimum of about 22%, as estimated by this method. These estimates are similar to the shortening values derived from other strain markers in other rock types interbedded with the argillite, and are also consistent with the regional pattern of deformation.
Five stratiform Zn-Pb-Ag deposits are known in Early Cambrian metapelitic rocks along a curvilinear trend in the Anvil Range, central Yukon. The Anvil Range deposits occur along the southwestern boundary of the Selwyn basin in the stratigraphic transition zone between metapelites of the Mt. Mye unit and calcareous phyllites of the overlying Vangorda unit. The massive sulfides are associated closely with anomalously thick graphitic phyllites, apparently related to a second-order basin. A typical Anvil cycle of mineralization begins with a ribbon-banded graphitic-quartzitic-pyritic unit. This grades upward into sulfide-bearing quartzite, quartzitic massive sulfide, massive sulfide, and finally a baritic massive sulfide horizon. Sericitic alteration envelopes irregularly encompass each deposit and locally are developed best in footwall rocks. Detailed sulfur isotope studies have been carried out on the DY and Grum deposits and on one representative drill hole from the Faro deposit. The delta 34 S values of sulfide minerals generally range from 10 to 22 per mil and are similar in all three deposits. The delta 34 S values of pyrite in unmineralized samples from the district exhibit a wider range, from 6 to 34 per mil, and show distinct upward stratigraphic increase due to a stagnation cycle in the basin. The delta 34 S values of barite samples are strongly dependent on bottom-water conditions and mode of mixing during brine exhalation. They range from 22 to 26 per mil in the Faro deposit to 36 to 42 per mil in the DY deposit. These variations are due to mixing of isotopically light sulfate (18-20ppm) in Ba-bearing ore fluid and isotopically heavy residual sulfate (30-60ppm) in anoxic seawater. Thirty-eight samples of galena from the DY, Grum, Faro, SB, and Swim deposits have been analyzed for lead isotope ratios. In general, the lead isotope ratio data indicate an upper crustal lead source, with the Proterozoic Grit unit which is inferred to underlie the district being the most likely source rock. A small component of mantle leads from mafic igneous rocks or due to source rock inhomogeneity is also indicated. Graphitic host lithologies, lack of stratiform iron oxides, delta 34 S values of sedimentary pyrite, and sulfide sulfur-organic carbon variations in unmineralized cores indicate formation of the Anvil deposits in strongly reduced bottom water related to a previously unknown Early Cambrian anoxic event.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.82.3.600","issn":"03610128","usgsCitation":"Shanks, W.C., Woodruff, L.G., Jilson, G., Jennings, D., Modene, J., and Ryan, B., 1987, Sulfur and lead isotope studies of stratiform Zn-Pb-Ag deposits, Anvil Range, Yukon: Basinal brine exhalation and anoxic bottom-water mixing (Canada): Economic Geology, v. 82, no. 3, p. 600-634, https://doi.org/10.2113/gsecongeo.82.3.600.","productDescription":"35 p.","startPage":"600","endPage":"634","numberOfPages":"35","costCenters":[],"links":[{"id":226244,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"82","issue":"3","noUsgsAuthors":false,"publicationDate":"1987-05-01","publicationStatus":"PW","scienceBaseUri":"505b9dcee4b08c986b31daba","contributors":{"authors":[{"text":"Shanks, Wayne C. III","contributorId":100527,"corporation":false,"usgs":true,"family":"Shanks","given":"Wayne","suffix":"III","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":369193,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Woodruff, L. G.","contributorId":46999,"corporation":false,"usgs":true,"family":"Woodruff","given":"L.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":369190,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Jilson, G.A.","contributorId":78096,"corporation":false,"usgs":true,"family":"Jilson","given":"G.A.","email":"","affiliations":[],"preferred":false,"id":369191,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Jennings, D.S.","contributorId":24503,"corporation":false,"usgs":true,"family":"Jennings","given":"D.S.","email":"","affiliations":[],"preferred":false,"id":369189,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Modene, J.S.","contributorId":97642,"corporation":false,"usgs":true,"family":"Modene","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":369192,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Ryan, B.D.","contributorId":7017,"corporation":false,"usgs":true,"family":"Ryan","given":"B.D.","email":"","affiliations":[],"preferred":false,"id":369188,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70014736,"text":"70014736 - 1987 - Current loops fitted to geomagnetic model spherical harmonic coefficients.","interactions":[],"lastModifiedDate":"2024-04-25T00:08:49.782527","indexId":"70014736","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2310,"text":"Journal of Geomagnetism & Geoelectricity","active":true,"publicationSubtype":{"id":10}},"title":"Current loops fitted to geomagnetic model spherical harmonic coefficients.","docAbstract":"One hundred-sixty circular current loops with radial axes were fitted by least squares to the 899 spherical harmonic coefficients of a 29th degree model. In the first case, the parameters that were fitted for each loop were the normalized magnetic moment, the distance from the center of the Earth to the current element, the colatitude and E. longitude of the loop axis, and one-half of the central apex angle of the loop. For this case, two of the loops converged near the inner-core outer-core boundary. They accounted for most of the dipolar field. Twenty of the loops, all with much smaller magnetic moments than the two deep loops, converged in the distance range of 0.42 to 0.67 Earth's radius from the center of the Earth. The other 138 loops, after many iterations, were located at distances between 0.81 and 1.0 Earth's radius from the center of the Earth. The loops with radial distances between 0.21 and 0.67 Earth's radius from the center of the Earth are referred to as “core” loops and those at distances greater than 0.81 Earth's radius as “crustal” loops. The spherical harmonic coefficients from these 160 loops, when subtraced from the 899 coefficients of the original model, left a root-mean-square residual of only 0.2nT. A second case was tried which constrained the 138 “crustal” loops to be at 0.996 Earth's radius (25.5km depth). In this case, the root-mean-square residual of the spherical harmonic coefficients from the original model was 0.9nT.
Sidescan sonar has been used to delineate benthic feeding structures of the California gray whale ( Eschrichtius robustus ) and Pacific walrus ( Odobenus rosmarus divergens ) on the northeastern Bering Shelf. The gray whales (average mouth length, 2.0 m), when suction feeding on infaunal amphipods, create shallow pits in the sea floor, typically 2.5 m x 1.5 m x 10 cm deep, which are distinct and mappable on sidescan sonographs. Similarly, walrus, when foraging for shallow clams, create long, linear feeding furrows that average 47 x 0.4 x 0.1 m (length-width-depth). The distribution of the whale pits over 22,000 km 2 of the Bering Shelf closely matches 1) sightings of feeding whales identified by mud plumes; 2) the distribution of ampeliscid amphipods, the gray whale's main prey; and 3) the distribution of a transgressive inner-shelf fine sand that serves as a substrate for the amphipods. The walrus' furrows are recognized over 6,600 km 2 of variable muddier or coarser-grained substrate with clam-rich benthic communities that surround the fine sand substrate of whale feeding areas. The whale feeding pits are commonly enlarged and oriented by seasonal storm-related scour. Nonenlarged pits (less than 5.3 m 2 in area) form a discrete statistical population that we define as fresh . We estimate that a minimum of 5.6 percent (1,200 km 2 ) of the feeding area of the northeastern Bering Shelf (22,000 km 2 ) was covered by fresh pits made by whales during the 1980 feeding season. Assuming that the average pit depth is 10 cm, a minimum of 120 x 10 6 m 3 (172 x 10 6 metric tons) of sediment, equivalent to about three times the yearly sediment load of the Yukon River, is excavated and injected into the water column by as many as 16,000 gray whales feeding in northeastern Bering Sea each season. As a result of 1) sediment resuspension by whales, 2) average current speeds of 10.7 cm/s northward during the feeding season, and 3) enhanced post-feeding current scour because of bottom roughening, the following occur: the majority of the clay fraction (4.3 x 10 6 metric tons) of resuspended sediment is advected to the Chukchi Sea each year; sand gradually is transported northward and fills old feeding pits; modern mud does not accumulate in this region; and the whale-disturbed sand lacks physical sedimentary structures and matrix mud. Walrus feeding features are smaller, formed in higher-energy environments, and modified more rapidly than whale feeding pits. The amount of sediment reworking by walrus feeding may nearly equal that of whale feeding, but this cannot be quantified accurately.
Recent advances in spatial, spectral, and temporal resolution of civil land remote sensing satellite data are presenting new opportunities for image mapping applications. The U.S. Geological Survey's experimental satellite image mapping program is evolving toward larger scale image map products with increased information content as a result of improved image processing techniques and increased resolution. Thematic mapper data are being used to produce experimental image maps at 1:100,000 scale that meet established U.S. and European map accuracy standards. Availability of high quality, cloud-free, 30-meter ground resolution multispectral data from the Landsat thematic mapper sensor, along with 10-meter ground resolution panchromatic and 20-meter ground resolution multispectral data from the recently launched French SPOT satellite, present new cartographic and image processing challenges.
The need to fully exploit these higher resolution data increases the complexity of processing the images into large-scale image maps. The removal of radiometric artifacts and noise prior to geometric correction can be accomplished by using a variety of image processing filters and transforms. Sensor modeling and image restoration techniques allow maximum retention of spatial and radiometric information. An optimum combination of spectral information and spatial resolution can be obtained by merging different sensor types. These processing techniques are discussed and examples are presented.
","language":"English","publisher":"Elsevier","doi":"10.1016/0094-5765(87)90109-3","usgsCitation":"Watkins, A.H., and Thormodsgard, J.M., 1987, Higher resolution satellite remote sensing and the impact on image mapping: Acta Astronautica, v. 16, p. 221-232, https://doi.org/10.1016/0094-5765(87)90109-3.","productDescription":"12 p.","startPage":"221","endPage":"232","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":225851,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"16","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3143e4b0c8380cd5dd95","contributors":{"authors":[{"text":"Watkins, Allen H.","contributorId":10721,"corporation":false,"usgs":true,"family":"Watkins","given":"Allen","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":369133,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Thormodsgard, June M. thor@usgs.gov","contributorId":3035,"corporation":false,"usgs":true,"family":"Thormodsgard","given":"June","email":"thor@usgs.gov","middleInitial":"M.","affiliations":[],"preferred":true,"id":369132,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014721,"text":"70014721 - 1987 - Magmatic history of Red Sea rifting: Perspective from the central Saudi Arabian coastal plain","interactions":[],"lastModifiedDate":"2023-12-28T01:08:33.338673","indexId":"70014721","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","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":"Magmatic history of Red Sea rifting: Perspective from the central Saudi Arabian coastal plain","docAbstract":"A newly recognized Tertiary dike complex and comagmatic volcanic rocks exposed on the central Saudi Arabian coastal plain record early stages of magmatism related to Red Sea rifting. Intrusive and stratigraphic relationships and new potassium-argon dating indicate episodic magmatism from about 30 Ma to the present. Additional stratigraphic and radiometric evidence suggests that limited rift-related magmatism began as early as about 50 Ma. An early phase of crustal extension in the region was accompanied by faulting and graben formation and by dike-swarm intrusion. The style of extension and intrusion changed at ∼20 Ma. Localized volcanism and sheeted dike injection ceased and were replaced by the intrusion of thick gabbro dikes. This change may mark the onset of sea-floor spreading in the central Red Sea.
The dikes and volcanic rocks consist of a bimodal mafic-felsic suite with transitional subalkaline to alkaline chemistry. Although no unique petrogenetic model can be developed for the suite, the following observations and conclusions have been drawn from the available reconnaissance geochemistry: (1) strontium isotopic initial ratios overlap in the range 0.7031 to 0.7047 and are not clearly related to alkalinity or silica content. The bimodality and alkalinity of the suite are therefore not products of contamination by the radiogenic Precambrian upper-crustal granitic rocks exposed in the region. (2) Several of the evolved rocks (rhyolites and comendite) show large to extreme negative europium anomalies and heavy rare-earth–element (HREE) enrichment, features that cannot be explained by low-pressure crystal fractionation of potential parent magmas. An intriguing possibility is that HREE enrichments and large negative Eu anomalies of some peraluminous rhyolites (and granites) may result from the complete melting of garnet from middle or lower crustal rocks. (3) Most of the basalts are light rare-earth element (LREE) enriched, consistent with derivation from fertile mantle in a continental-rift setting; however, interaction of the mafic melts with lower continental crust cannot be ruled out.
A model of poly-baric mantle-melt derivation, producing several alkaline-subalkaline cycles, best explains magmatism in the Red Sea region. Differences in the depths and dynamics of mantle-melt extraction and transport brought about through changes in crust and mantle structure as the rift and paar developed may account for the transition from mixed alkaline-subalkaline bimodal magmatism of the pre-20 Ma rift basin to exclusively subalkaline (tholeiitic) magmatism at the Red Sea spreading axis and to predominantly alkali basalt volcanism inland (within the Arabian Shield).
","language":"English","publisher":"Geological Society of America","doi":"10.1130/0016-7606(1987)98<400:MHORSR>2.0.CO;2","usgsCitation":"Pallister, J., 1987, Magmatic history of Red Sea rifting: Perspective from the central Saudi Arabian coastal plain: Geological Society of America Bulletin, v. 98, no. 4, p. 400-417, https://doi.org/10.1130/0016-7606(1987)98<400:MHORSR>2.0.CO;2.","productDescription":"18 p.","startPage":"400","endPage":"417","numberOfPages":"18","costCenters":[],"links":[{"id":225848,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"98","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4b46e4b0c8380cd69407","contributors":{"authors":[{"text":"Pallister, J.S.","contributorId":46534,"corporation":false,"usgs":true,"family":"Pallister","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":369127,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014681,"text":"70014681 - 1987 - Tidal and tidally averaged circulation characteristics of Suisun Bay, California","interactions":[],"lastModifiedDate":"2018-02-21T11:07:16","indexId":"70014681","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Tidal and tidally averaged circulation characteristics of Suisun Bay, California","docAbstract":"Availability of extensive field data permitted realistic calibration and validation of a hydrodynamic model of tidal circulation and salt transport for Suisun Bay, California. Suisun Bay is a partially mixed embayment of northern San Francisco Bay located just seaward of the Sacramento-San Joaquin Delta. The model employs a variant of an alternating direction implicit finite-difference method to solve the hydrodynamic equations and an Eulerian-Lagrangian method to solve the salt transport equation. An upwind formulation of the advective acceleration terms of the momentum equations was employed to avoid oscillations in the tidally averaged velocity field produced by central spatial differencing of these terms. Simulation results of tidal circulation and salt transport demonstrate that tides and the complex bathymetry determine the patterns of tidal velocities and that net changes in the salinity distribution over a few tidal cycles are small despite large changes during each tidal cycle. Computations of tidally averaged circulation suggest that baroclinic and wind effects are important influences on tidally averaged circulation during low freshwater-inflow conditions. Exclusion of baroclinic effects would lead to overestimation of freshwater inflow by several hundred m3/s for a fixed set of model boundary conditions. Likewise, exclusion of wind would cause an underestimation of flux rates between shoals and channels by 70–100%.
In this paper we develop a numerical solution to equations developed in part 1 (M. Y. Corapcioglu and A. L. Baehr, this issue) to predict the fate of an immiscible organic contaminant such as gasoline in the unsaturated zone subsequent to plume establishment. This solution, obtained by using a finite difference scheme and a method of forward projection to evaluate nonlinear coefficients, provides estimates of the flux of solubilized hydrocarbon constituents to groundwater from the portion of a spill which remains trapped in a soil after routine remedial efforts to recover the product have ceased. The procedure was used to solve the one-dimensional (vertical) form of the system of nonlinear partial differential equations defining the transport for each constituent of the product. Additionally, a homogeneous, isothermal soil with constant water content was assumed. An equilibrium assumption partitions the constituents between air, water, adsorbed, and immiscible phases. Free oxygen transport in the soil was also simulated to provide an upper bound estimate of aerobic biodgradation rates. Results are presented for a hypothetical gasoline consisting of eight groups of hydrocarbon constituents. Rates at which hydrocarbon mass is removed from the soil, entering either the atmosphere or groundwater, or is biodegraded are presented. A significant sensitivity to model parameters, particularly the parameters characterizing diffusive vapor transport, was discovered. We conclude that hydrocarbon solute composition in groundwater beneath a gasoline contaminated soil would be heavily weighted toward aromatic constituents like benzene, toluene, and xylene.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR023i001p00201","usgsCitation":"Baehr, A.L., and Corapcioglu, M.Y., 1987, A compositional multiphase model for groundwater contamination by petroleum products: 2. Numerical solution: Water Resources Research, v. 23, no. 1, p. 201-213, https://doi.org/10.1029/WR023i001p00201.","productDescription":"13 p.","startPage":"201","endPage":"213","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":226037,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"1","noUsgsAuthors":false,"publicationDate":"2010-07-09","publicationStatus":"PW","scienceBaseUri":"5059e382e4b0c8380cd46096","contributors":{"authors":[{"text":"Baehr, Arthur L.","contributorId":104523,"corporation":false,"usgs":true,"family":"Baehr","given":"Arthur","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":368969,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Corapcioglu, M. Yavuz","contributorId":43114,"corporation":false,"usgs":false,"family":"Corapcioglu","given":"M.","email":"","middleInitial":"Yavuz","affiliations":[],"preferred":false,"id":368968,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014646,"text":"70014646 - 1987 - On the functional optimization of a certain class of nonstationary spatial functions","interactions":[],"lastModifiedDate":"2012-03-12T17:19:34","indexId":"70014646","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2407,"text":"Journal of Optimization Theory and Applications","active":true,"publicationSubtype":{"id":10}},"title":"On the functional optimization of a certain class of nonstationary spatial functions","docAbstract":"Procedures are developed in order to obtain optimal estimates of linear functionals for a wide class of nonstationary spatial functions. These procedures rely on well-established constrained minimum-norm criteria, and are applicable to multidimensional phenomena which are characterized by the so-called hypothesis of inherentity. The latter requires elimination of the polynomial, trend-related components of the spatial function leading to stationary quantities, and also it generates some interesting mathematics within the context of modelling and optimization in several dimensions. The arguments are illustrated using various examples, and a case study computed in detail. ?? 1987 Plenum Publishing Corporation.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Optimization Theory and Applications","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Kluwer Academic Publishers-Plenum Publishers","doi":"10.1007/BF00941280","issn":"00223239","usgsCitation":"Christakos, G., and Paraskevopoulos, P., 1987, On the functional optimization of a certain class of nonstationary spatial functions: Journal of Optimization Theory and Applications, v. 52, no. 2, p. 191-208, https://doi.org/10.1007/BF00941280.","startPage":"191","endPage":"208","numberOfPages":"18","costCenters":[],"links":[{"id":487230,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"http://doi.org/10.1007/BF00941280","text":"External Repository"},{"id":205635,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00941280"},{"id":225525,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"52","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6dd2e4b0c8380cd75345","contributors":{"authors":[{"text":"Christakos, G.","contributorId":87685,"corporation":false,"usgs":true,"family":"Christakos","given":"G.","email":"","affiliations":[],"preferred":false,"id":368905,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Paraskevopoulos, P.N.","contributorId":105062,"corporation":false,"usgs":true,"family":"Paraskevopoulos","given":"P.N.","email":"","affiliations":[],"preferred":false,"id":368906,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014470,"text":"70014470 - 1987 - Benthic foraminifers on the continental shelf and upper slope, Russian River area, northern California ( USA).","interactions":[],"lastModifiedDate":"2013-03-24T12:09:49","indexId":"70014470","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2294,"text":"Journal of Foraminiferal Research","active":true,"publicationSubtype":{"id":10}},"title":"Benthic foraminifers on the continental shelf and upper slope, Russian River area, northern California ( USA).","docAbstract":"We analyzed benthic foraminifers from 71 surface samples collected from the sea floor of the continental margin. One hundred and six different taxa were identified, and Q-mode factor analysis was used to identify assemblages. Six foraminiferal assemblage factors explain 94% of the variation in the data matrix. The Inner Shelf Assemblage is characterized by Trichohyalus ornatissima, Rotalia columbiensis, Cassidulina limbata, Cibicides fletcheri, Elphidiella hannai and Elphidium sp. 1 and occupies water depths less than 50 m. The Middle Shelf Assemblage is characterized by Nonionella basispinata, Elphidium excavatum and Florilus labradoricus and occupies water depths between 50 and 90 m. A Middle Shelf to Upper Bathyal Assemblage is characterized by Uvigerina juncea, Globobulimina spp. and Nonionella basispinata and occupies depths between about 90 and 450 m. Two overlapping assemblages make up the Upper Middle Bathyal Assemblage and are most abundant between water depths of 500 and 1300 m. They are associated with low- oxygen conditions. The Mid-Bathyal Assemblage is dominated by Uvigerina proboscidea and occurs on the slope at water depths ranging from 1200 to 2500 m. -from Authors","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Foraminiferal Research","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.2113/gsjfr.17.2.132","issn":"00961191","usgsCitation":"Quinterno, P., and Gardner, J., 1987, Benthic foraminifers on the continental shelf and upper slope, Russian River area, northern California ( USA).: Journal of Foraminiferal Research, v. 17, no. 2, p. 132-152, https://doi.org/10.2113/gsjfr.17.2.132.","startPage":"132","endPage":"152","numberOfPages":"21","costCenters":[],"links":[{"id":226087,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":269895,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.2113/gsjfr.17.2.132"}],"volume":"17","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f0b9e4b0c8380cd4a8a1","contributors":{"authors":[{"text":"Quinterno, P. J.","contributorId":65465,"corporation":false,"usgs":true,"family":"Quinterno","given":"P. J.","affiliations":[],"preferred":false,"id":368471,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gardner, J.V.","contributorId":76705,"corporation":false,"usgs":true,"family":"Gardner","given":"J.V.","affiliations":[],"preferred":false,"id":368472,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014471,"text":"70014471 - 1987 - GEOGRAPHIC ESTIMATION OF RUNOFF-MODEL PARAMETERS.","interactions":[],"lastModifiedDate":"2012-03-12T17:19:29","indexId":"70014471","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"GEOGRAPHIC ESTIMATION OF RUNOFF-MODEL PARAMETERS.","docAbstract":"The U. S. Geological Survey is developing techniques to estimate and evaluate unit-hydrograph and loss-rate parameter values for rainfall-runoff models using Geographic Information System (GIS) procedures. The data base includes basin, soil, and climatological characteristics that will be stored in a GIS, and unit-hydrograph and loss-rate parameters obtained from calibration of a commonly used flood-hydrograph rainfall-runoff model for 616 storms in 98 gaged drainage basins. Development of unit-hydrograph and loss-rate parameter-estimation techniques includes statistical methods (exploratory data analysis, regression analysis, and categorical data analysis) to relate the model parameters to hydrologic characteristics. The estimation techniques are evaluated by use of error analysis of simulated hydrograph characteristics (peak discharge, flood volume, and time to peak discharge). The hydrographs will be simulated with parameters estimated by the techniques for (1) 102 storms occurring at 36 gaged basins; and (2) a large storm system (one which produced floods with a 50-to 100-year recurrence interval).","conferenceTitle":"Engineering Hydrology, Proceedings of the Symposium. Held Jointly with the ASCE National Conference.","conferenceLocation":"Williamsburg, VA, USA","language":"English","publisher":"ASCE","publisherLocation":"New York, NY, USA","isbn":"0872626113","usgsCitation":"Schmidt, A.R., Weiss, L.S., and Oberg, K.A., 1987, GEOGRAPHIC ESTIMATION OF RUNOFF-MODEL PARAMETERS., Engineering Hydrology, Proceedings of the Symposium. Held Jointly with the ASCE National Conference., Williamsburg, VA, USA, p. 551-554.","startPage":"551","endPage":"554","numberOfPages":"4","costCenters":[],"links":[{"id":226088,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a144ce4b0c8380cd549b3","contributors":{"authors":[{"text":"Schmidt, Arthur R.","contributorId":105709,"corporation":false,"usgs":true,"family":"Schmidt","given":"Arthur","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":368475,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Weiss, Linda S. lsweiss@usgs.gov","contributorId":2955,"corporation":false,"usgs":true,"family":"Weiss","given":"Linda","email":"lsweiss@usgs.gov","middleInitial":"S.","affiliations":[],"preferred":true,"id":368474,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Oberg, Kevin A. kaoberg@usgs.gov","contributorId":928,"corporation":false,"usgs":true,"family":"Oberg","given":"Kevin","email":"kaoberg@usgs.gov","middleInitial":"A.","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":368473,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014643,"text":"70014643 - 1987 - Behavior of sensitivities in the one-dimensional advection-dispersion equation: Implications for parameter estimation and sampling design","interactions":[],"lastModifiedDate":"2018-02-21T11:09:03","indexId":"70014643","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Behavior of sensitivities in the one-dimensional advection-dispersion equation: Implications for parameter estimation and sampling design","docAbstract":"The spatial and temporal variability of sensitivities has a significant impact on parameter estimation and sampling design for studies of solute transport in porous media. Physical insight into the behavior of sensitivities is offered through an analysis of analytically derived sensitivities for the one-dimensional form of the advection-dispersion equation. When parameters are estimated in regression models of one-dimensional transport, the spatial and temporal variability in sensitivities influences variance and covariance of parameter estimates. Several principles account for the observed influence of sensitivities on parameter uncertainty. (1) Information about a physical parameter may be most accurately gained at points in space and time with a high sensitivity to the parameter. (2) As the distance of observation points from the upstream boundary increases, maximum sensitivity to velocity during passage of the solute front increases and the consequent estimate of velocity tends to have lower variance. (3) The frequency of sampling must be “in phase” with the S shape of the dispersion sensitivity curve to yield the most information on dispersion. (4) The sensitivity to the dispersion coefficient is usually at least an order of magnitude less than the sensitivity to velocity. (5) The assumed probability distribution of random error in observations of solute concentration determines the form of the sensitivities. (6) If variance in random error in observations is large, trends in sensitivities of observation points may be obscured by noise and thus have limited value in predicting variance in parameter estimates among designs. (7) Designs that minimize the variance of one parameter may not necessarily minimize the variance of other parameters. (8) The time and space interval over which an observation point is sensitive to a given parameter depends on the actual values of the parameters in the underlying physical system.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR023i002p00253","usgsCitation":"Knopman, D.S., and Voss, C.I., 1987, Behavior of sensitivities in the one-dimensional advection-dispersion equation: Implications for parameter estimation and sampling design: Water Resources Research, v. 23, no. 2, p. 253-272, https://doi.org/10.1029/WR023i002p00253.","productDescription":"20 p.","startPage":"253","endPage":"272","costCenters":[],"links":[{"id":225522,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"2","noUsgsAuthors":false,"publicationDate":"2010-07-09","publicationStatus":"PW","scienceBaseUri":"5059ef7de4b0c8380cd4a285","contributors":{"authors":[{"text":"Knopman, Debra S.","contributorId":51472,"corporation":false,"usgs":true,"family":"Knopman","given":"Debra","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":368896,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Voss, Clifford I. 0000-0001-5923-2752 cvoss@usgs.gov","orcid":"https://orcid.org/0000-0001-5923-2752","contributorId":1559,"corporation":false,"usgs":true,"family":"Voss","given":"Clifford","email":"cvoss@usgs.gov","middleInitial":"I.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":368895,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014633,"text":"70014633 - 1987 - CONCEPTUAL MODELS FOR THE LASSEN HYDROTHERMAL SYSTEM.","interactions":[],"lastModifiedDate":"2012-03-12T17:19:34","indexId":"70014633","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1141,"text":"Bulletin. Geothermal Resources Council","active":true,"publicationSubtype":{"id":10}},"title":"CONCEPTUAL MODELS FOR THE LASSEN HYDROTHERMAL SYSTEM.","docAbstract":"The Lassen hydrothermal system, like a number of other systems in regions of moderate to great topographic relief, includes steam-heated features at higher elevations and high-chloride springs at lower elevations, connected to and fed by a single circulation system at depth. Two conceptual models for such systems are presented. They are similar in several ways: however, there are basic differences in terms of the nature and extent of vapor-dominated conditions beneath the steam-heated features. For some Lassen-like systems, these differences could have environmental and economic implications. Available data do not make it possible to establish a single preferred model for the Lassen system, and the actual system is complex enough that both models may apply to different parts of the system.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Bulletin. Geothermal Resources Council","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01607782","usgsCitation":"Ingebritsen, S.E., and Sorey, M., 1987, CONCEPTUAL MODELS FOR THE LASSEN HYDROTHERMAL SYSTEM.: Bulletin. Geothermal Resources Council, v. 16, no. 2, p. 3-9.","startPage":"3","endPage":"9","numberOfPages":"7","costCenters":[],"links":[{"id":225326,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"16","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f2dee4b0c8380cd4b447","contributors":{"authors":[{"text":"Ingebritsen, S. E.","contributorId":8078,"corporation":false,"usgs":true,"family":"Ingebritsen","given":"S.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":368869,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sorey, M.L.","contributorId":73185,"corporation":false,"usgs":true,"family":"Sorey","given":"M.L.","affiliations":[],"preferred":false,"id":368870,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014631,"text":"70014631 - 1987 - Gravitational stresses in anisotropic rock masses","interactions":[],"lastModifiedDate":"2013-01-18T13:19:12","indexId":"70014631","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2071,"text":"International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts","active":true,"publicationSubtype":{"id":10}},"title":"Gravitational stresses in anisotropic rock masses","docAbstract":"This paper presents closed-form solutions for the stress field induced by gravity in anisotropic rock masses. These rocks are assumed to be laterally restrained and are modelled as a homogeneous, orthotropic or transversely isotropic, linearly elastic material. The analysis, constrained by the thermodynamic requirement that strain energy be positive definite, gives the following important result: inclusion of anisotropy broadens the range of permissible values of gravity-induced horizontal stresses. In fact, for some ranges of anisotropic rock properties, it is thermodynamically admissible for gravity-induced horizontal stresses to exceed the vertical stress component; this is not possible for the classical isotropic solution. Specific examples are presented to explore the nature of the gravity-induced stress field in anisotropic rocks and its dependence on the type, degree and orientation of anisotropy with respect to the horizontal ground surface. ?? 1987.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0148-9062(87)91227-7","issn":"01489062","usgsCitation":"Amadei, B., Savage, W.Z., and Swolfs, H., 1987, Gravitational stresses in anisotropic rock masses: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, v. 24, no. 1, p. 5-14, https://doi.org/10.1016/0148-9062(87)91227-7.","productDescription":"p.5-14","startPage":"5","endPage":"14","numberOfPages":"10","costCenters":[],"links":[{"id":265943,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0148-9062(87)91227-7"},{"id":225268,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"24","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a29f4e4b0c8380cd5ada0","contributors":{"authors":[{"text":"Amadei, B.","contributorId":86902,"corporation":false,"usgs":true,"family":"Amadei","given":"B.","affiliations":[],"preferred":false,"id":368865,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Savage, W. Z.","contributorId":106481,"corporation":false,"usgs":true,"family":"Savage","given":"W.","email":"","middleInitial":"Z.","affiliations":[],"preferred":false,"id":368866,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Swolfs, H.S.","contributorId":70759,"corporation":false,"usgs":true,"family":"Swolfs","given":"H.S.","affiliations":[],"preferred":false,"id":368864,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014497,"text":"70014497 - 1987 - EMBANKMENT-DAM BREACH PARAMETERS.","interactions":[],"lastModifiedDate":"2012-03-12T17:19:32","indexId":"70014497","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"EMBANKMENT-DAM BREACH PARAMETERS.","docAbstract":"The study used data from 43 embankment-dam failures to develop equations that predict breach formation model parameters. These data include the failure mode, embankment characteristics, reservoir conditions at the time of failure, geometry of the final breach, and the time taken to form the breach. Regression equations were developed to predict (1) the average width of a trapezoidal breach, (2) the average side-slope factor of a trapezoidal breach, and (3) the breach formation time.","conferenceTitle":"Hydraulic Engineering, Proceedings of the 1987 National Conference.","conferenceLocation":"Williamsburg, VA, USA","language":"English","publisher":"ASCE","publisherLocation":"New York, NY, USA","isbn":"0872626105","usgsCitation":"Froehlich, D.C., 1987, EMBANKMENT-DAM BREACH PARAMETERS., Hydraulic Engineering, Proceedings of the 1987 National Conference., Williamsburg, VA, USA, p. 570-575.","startPage":"570","endPage":"575","numberOfPages":"6","costCenters":[],"links":[{"id":225448,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a045ee4b0c8380cd50944","contributors":{"authors":[{"text":"Froehlich, David C.","contributorId":58617,"corporation":false,"usgs":true,"family":"Froehlich","given":"David","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":368525,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014500,"text":"70014500 - 1987 - Langrangian model of nitrogen kinetics in the Chattahoochee River","interactions":[],"lastModifiedDate":"2024-04-22T15:12:19.983383","indexId":"70014500","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","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":"Langrangian model of nitrogen kinetics in the Chattahoochee River","docAbstract":"A Lagrangian reference frame is used to solve the convection‐dispersion equation and interpret water‐quality data obtained from the Chattahoochee River. The model was calibrated using unsteady concentrations of organic nitrogen, ammonia, and nitrite plus nitrate obtained during June 1977 and verified using data obtained during August 1976. Reaction kinetics of the cascade type are shown to provide a reasonable description of the nitrogenspecies processes in the Chattahoochee River. The conceptual model is easy to visualize in the physical sense and the output includes information that is not easily determined from an Eulerian approach, but which is very helpful in model calibration and data interpretation. For example, the model output allows one to determine which data are of most value in model calibration or verification.
","language":"English","publisher":"ASCE","doi":"10.1061/(ASCE)0733-9372(1987)113:2(223)","issn":"07339372","usgsCitation":"Jobson, H., 1987, Langrangian model of nitrogen kinetics in the Chattahoochee River: Journal of Environmental Engineering, v. 113, no. 2, p. 223-242, https://doi.org/10.1061/(ASCE)0733-9372(1987)113:2(223).","productDescription":"20 p.","startPage":"223","endPage":"242","numberOfPages":"20","costCenters":[],"links":[{"id":225451,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"113","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a446ee4b0c8380cd66ad5","contributors":{"authors":[{"text":"Jobson, H.E.","contributorId":44952,"corporation":false,"usgs":true,"family":"Jobson","given":"H.E.","affiliations":[],"preferred":false,"id":368528,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70015325,"text":"70015325 - 1987 - 15N/14N variations in Cretaceous Atlantic sedimentary sequences: Implication for past changes in marine nitrogen biogeochemistry","interactions":[],"lastModifiedDate":"2023-12-09T15:58:03.148097","indexId":"70015325","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1427,"text":"Earth and Planetary Science Letters","active":true,"publicationSubtype":{"id":10}},"title":"15N/14N variations in Cretaceous Atlantic sedimentary sequences: Implication for past changes in marine nitrogen biogeochemistry","docAbstract":"At two locations in the Atlantic Ocean (DSDP Sites 367 and 530) early to middle Cretaceous organic-carbon-rich beds (“black shales”) were found to have significantly lower δ15N values (lower15N/14N ratios) than adjacent organic-carbon-poor beds (white limestones or green claystones). While these lithologies are of marine origin, the black strata in particular have °15N values that are significantly lower than those previously found in the marine sediment record and most contemporary marine nitrogen pools. In contrast, black, organic-carbon-rich beds at a third site (DSDP Site 603) contain predominantly terrestrial organic matter and have C- and N-isotopic compositions similar to organic matter of modern terrestrial origin.
The recurring15N depletion in the marine-derived Cretaceous sequences prove that the nitrogen they contain is the end result of an episodic and atypical biogeochemistry. Existing isotopic and other data indicate that the low15N relative abundance is the consequence of pelagic rather than post-depositional processes. Reduced ocean circulation, increased denitrification, and, hence, reduced euphotic zone nitrate availability may have led to Cretaceous phytoplankton assemblages that were periodically dominated by N2-fixing blue-green algae, a possible source of this sediment15N-depletion. Lack of parallel isotopic shifts in Cretaceous terrestrially-derived nitrogen (Site 603) argues that the above change in nitrogen cycling during this period did not extend beyond the marine environment.
","language":"English","publisher":"Elsevier","doi":"10.1016/0012-821X(87)90201-9","issn":"0012821X","usgsCitation":"Rau, G., Arthur, M., and Dean, W., 1987, 15N/14N variations in Cretaceous Atlantic sedimentary sequences: Implication for past changes in marine nitrogen biogeochemistry: Earth and Planetary Science Letters, v. 82, no. 3-4, p. 269-279, https://doi.org/10.1016/0012-821X(87)90201-9.","productDescription":"11 p.","startPage":"269","endPage":"279","numberOfPages":"11","costCenters":[],"links":[{"id":223870,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"82","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e228e4b0c8380cd459e1","contributors":{"authors":[{"text":"Rau, G.H.","contributorId":18112,"corporation":false,"usgs":true,"family":"Rau","given":"G.H.","email":"","affiliations":[],"preferred":false,"id":370649,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Arthur, M.A.","contributorId":24791,"corporation":false,"usgs":true,"family":"Arthur","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":370650,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Dean, W.E.","contributorId":97099,"corporation":false,"usgs":true,"family":"Dean","given":"W.E.","email":"","affiliations":[],"preferred":false,"id":370651,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ]}