In 1954, four earthquakes of M > 6.0 occurred within a 30 km radius in a period of six months. The Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes are among the largest to have been recorded geodetically in the Basin and Range province. The Fairview Peak earthquake (M = 7.2, December 12, 1954) followed two events in the Rainbow Mountains (M = 6.2, July 6, and M = 6.5, August 24, 1954) by 6 months. Four minutes later the Dixie Valley fault ruptured (M = 6.7, December 12, 1954). The changes in static stresses caused by the events are calculated using the Coulomb-Navier failure criterion and assuming uniform slip on rectangular dislocations embedded in an elastic half-space. Coulomb stress changes are resolved on optimally oriented faults and on each of the faults that ruptured in the chain of events. These calculations show that each earthquake in the Rainbow Mountain-Fairview Peak-Dixie Valley sequence was preceded by a static stress change that encouraged failure. The magnitude of the stress increases transferred from one earthquake to another ranged from 0.01 MPa (0.1 bar) to over 0.1 MPa (1 bar). Stresses were reduced by up to 0.1 MPa over most of the Rainbow Mountain-Fairview Peak area as a result of the earthquake sequence.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JB01302","issn":"01480227","usgsCitation":"Hodgkinson, K., Stein, R., and King, G., 1996, The 1954 Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes: A triggered normal faulting sequence: Journal of Geophysical Research B: Solid Earth, v. 101, no. B11, p. 25459-25471, https://doi.org/10.1029/96JB01302.","productDescription":"13 p.","startPage":"25459","endPage":"25471","numberOfPages":"13","costCenters":[],"links":[{"id":226999,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"B11","noUsgsAuthors":false,"publicationDate":"1996-11-10","publicationStatus":"PW","scienceBaseUri":"505ba61be4b08c986b320eca","contributors":{"authors":[{"text":"Hodgkinson, K.M.","contributorId":99314,"corporation":false,"usgs":true,"family":"Hodgkinson","given":"K.M.","affiliations":[],"preferred":false,"id":380353,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stein, R.S.","contributorId":8875,"corporation":false,"usgs":true,"family":"Stein","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":380351,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"King, G.C.P.","contributorId":18510,"corporation":false,"usgs":true,"family":"King","given":"G.C.P.","email":"","affiliations":[],"preferred":false,"id":380352,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018990,"text":"70018990 - 1996 - Mineral intergrowths replaced by \"elbow-twinned\" rutile in altered rocks","interactions":[],"lastModifiedDate":"2017-09-13T12:59:10","indexId":"70018990","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1177,"text":"Canadian Mineralogist","active":true,"publicationSubtype":{"id":10}},"title":"Mineral intergrowths replaced by \"elbow-twinned\" rutile in altered rocks","docAbstract":"Some aggregates of rutile, classically considered to be \"elbow\" twinned, instead are topotactic replacements of ilmenite or other hexagonal titaniferous precursors. Twinned rutile can be differentiated from the reticulated rutile of topotactic replacements by the angle of prism intersections, junction morphology, and the overall form of the aggregate. In a special case of topotactic replacement of ilmenite, rutile forms pseudomorphs of \"trellis\"-textured ilmenite lamellae in {111} of precursor magnetite. We trace the progress of rutile formation through the alteration of fine-grained magnetite-bearing host rocks. The sequential two-step topotaxy from magnetite through ilmenite to rutile requires rutile prisms to parallel the intersections of {111} planes in precursor magnetite. Some coarse reticulated rutile may result from the same paragenetic sequence.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Canadian Mineralogist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00084476","usgsCitation":"Force, E.R., Richards, R.P., Scott, K.M., Valentine, P.C., and Fishman, N., 1996, Mineral intergrowths replaced by \"elbow-twinned\" rutile in altered rocks: Canadian Mineralogist, v. 34, no. 3, p. 605-614.","productDescription":"10 p.","startPage":"605","endPage":"614","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":226764,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":345696,"rank":2,"type":{"id":15,"text":"Index Page"},"url":"https://canmin.geoscienceworld.org/content/34/3/605/article-info"}],"volume":"34","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a5792e4b0c8380cd6dd63","contributors":{"authors":[{"text":"Force, E. R.","contributorId":28235,"corporation":false,"usgs":true,"family":"Force","given":"E.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":381318,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Richards, R. P.","contributorId":60792,"corporation":false,"usgs":true,"family":"Richards","given":"R.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":381321,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Scott, K. M.","contributorId":8119,"corporation":false,"usgs":true,"family":"Scott","given":"K.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":381317,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Valentine, P. C.","contributorId":46505,"corporation":false,"usgs":true,"family":"Valentine","given":"P.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":381319,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Fishman, N.S.","contributorId":59441,"corporation":false,"usgs":true,"family":"Fishman","given":"N.S.","email":"","affiliations":[],"preferred":false,"id":381320,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70019025,"text":"70019025 - 1996 - Feruvite from the Sullivan Pb-Zn-Ag deposit, British Columbia","interactions":[],"lastModifiedDate":"2012-03-12T17:19:15","indexId":"70019025","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1177,"text":"Canadian Mineralogist","active":true,"publicationSubtype":{"id":10}},"title":"Feruvite from the Sullivan Pb-Zn-Ag deposit, British Columbia","docAbstract":"Feruvite, an uncommon Ca- and Fe2+-rich tourmaline species, has been discovered in the footwall of the Sullivan Pb-Zn-Ag deposit (British Columbia) near gabbro sills and dikes. Its chemical composition varies according to occurrence: feruvite from the shallow footwall has lower Ca, higher Al, and higher X-site vacancies than that from the deep footwall. The major chemical substitution involved in the feruvite is the exchange vector CaMgO???-1Al-1(OH)-1. The most important factor controlling feruvite formation at Sullivan is likely the reaction of Fe-rich hydrothermal fluids with Ca-rich minerals in gabbro and host rocks. This reaction led to the breakdown of Ca-rich minerals (plagioclase and hornblende), with release of Ca to solution and its incorporation into feruvite. This process probably postdated the main stages of formation of fine-grained, intermediate schorl-dravite in the tourmalinite pipe in the footwall, and is attributed to postore intrusion of gabbro and associated albite-chlorite-pyrite alteration.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Canadian Mineralogist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00084476","usgsCitation":"Jiang, S., Palmer, M.R., McDonald, A., Slack, J.F., and Leitch, C., 1996, Feruvite from the Sullivan Pb-Zn-Ag deposit, British Columbia: Canadian Mineralogist, v. 34, no. 4, p. 733-740.","startPage":"733","endPage":"740","numberOfPages":"8","costCenters":[],"links":[{"id":226674,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0f97e4b0c8380cd53944","contributors":{"authors":[{"text":"Jiang, S.-Y.","contributorId":79248,"corporation":false,"usgs":true,"family":"Jiang","given":"S.-Y.","email":"","affiliations":[],"preferred":false,"id":381434,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Palmer, M. R.","contributorId":81256,"corporation":false,"usgs":true,"family":"Palmer","given":"M.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":381435,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"McDonald, A.M.","contributorId":59578,"corporation":false,"usgs":true,"family":"McDonald","given":"A.M.","email":"","affiliations":[],"preferred":false,"id":381432,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Slack, J. F.","contributorId":75917,"corporation":false,"usgs":true,"family":"Slack","given":"J.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":381433,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Leitch, C.H.B.","contributorId":42841,"corporation":false,"usgs":true,"family":"Leitch","given":"C.H.B.","email":"","affiliations":[],"preferred":false,"id":381431,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70018871,"text":"70018871 - 1996 - Geochemistry of autochthonous and hypautochthonous siderite-dolomite coal-balls (Foord Seam, Bolsovian, Upper Carboniferous), Nova Scotia, Canada","interactions":[],"lastModifiedDate":"2024-02-21T00:48:15.282934","indexId":"70018871","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2033,"text":"International Journal of Coal Geology","active":true,"publicationSubtype":{"id":10}},"title":"Geochemistry of autochthonous and hypautochthonous siderite-dolomite coal-balls (Foord Seam, Bolsovian, Upper Carboniferous), Nova Scotia, Canada","docAbstract":"The 11–13 m thick Foord Seam in the fault-bounded Stellarton Basin, Nova Scotia, is the thickest seam from the Euramerican floral province known to contain coal-balls. In addition to the first discovery of autochthonous coal-balls in the Foord Seam, Nova Scotia, its shale parting also contains hypautochthonous coal-balls with histologically preserved plant structures. The coal-ball discovery helps fill a stratigraphic gap in coal-ball occurrences in the upper Carboniferous (Bolsovian) of Euramerica. The autochthonous and hypautochthonous coal-balls have a similar mineralogical composition and are composed of siderite (81–100%), dolomite-ankerite (0–19%), minor quartz and illite, and trace amounts of `calcite'. Similar is also their permineralizing mineralogy, which consists of dolomite-ankerite and siderite. Their low pyrite content and carbonate mineralogy, and nonmarine origin, differentiates the Foord Seam coal-balls from other Euramerican coal-ball occurrences.
A preliminary geochemical model, which is based on oxygen and carbon isotopic data, indicates that siderite in both the autochthonous and hypautochthonous coal-balls is of very early diagenetic (nonmarine) origin from 13C-enriched bicarbonate derived from bacterial methanogenesis of organic matter.
Wide angle X-ray scattering (WAXS) measurements have been made on a suite of “two-line” ferrihydrite (FHY2) samples containing varying amounts of coprecipitated arsenate. Samples prepared at pH 8 with counter ions chloride, nitrate, and a mixture of both also were examined. The raw WAXS scattering functions show that “two-line” ferrihydrite actually has a large number of non-Bragg (i.e., diffuse scattering) maxima up to our observation limit of 16 Å−1. The type of counter ion used during synthesis produces no significant change in this function. In unarsenated samples, Radial Distribution Functions (RDFs) produced from the scattering functions show a well-defined Fe-O peak at 2.02 Å in excellent agreement with the mean distance of 2.01 Å from extended X-ray absorption fine structure (EXAFS) analysis. The area under the Fe-O peak is consistent with only octahedral oxygen coordination about iron, and an iron coordination about oxygen of 2.2, in agreement with the EXAFS results, the sample composition, and XANES measurements. The second peak observed in the RDFs is clearly divided into two populations of correlations, at 3.07 and 3.52 Å, respectively. These distances are close to the EXAFS-derived Fe-Fe subshell distances of 3.02–3.05 and 3.43–3.46 Å, respectively, though this is misleading as the RDF peaks also include contributions from O-Fe and O-O correlations. Simulated RDFs of the FeOOH polymorphs indicate how the observed RDF structure relates to the EXAFS pair-correlation function, and allow comparisons with an ordered ferrihydrite structure.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(96)89830-9","issn":"00167037","usgsCitation":"Waychunas, G., Fuller, C.C., Rea, B., and Davis, J., 1996, Wide angle X-ray scattering (WAXS) study of \"two-line\" ferrihydrite structure: Effect of arsenate sorption and counterion variation and comparison with EXAFS results: Geochimica et Cosmochimica Acta, v. 60, no. 10, p. 1765-1781, https://doi.org/10.1016/0016-7037(96)89830-9.","productDescription":"17 p.","startPage":"1765","endPage":"1781","numberOfPages":"17","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479167,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1016/0016-7037(96)89830-9","text":"Publisher Index Page"},{"id":227349,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"60","issue":"10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bd0a8e4b08c986b32efb5","contributors":{"authors":[{"text":"Waychunas, G.A.","contributorId":90888,"corporation":false,"usgs":true,"family":"Waychunas","given":"G.A.","email":"","affiliations":[],"preferred":false,"id":380172,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fuller, C. C.","contributorId":29858,"corporation":false,"usgs":true,"family":"Fuller","given":"C.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":380169,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rea, B.A.","contributorId":39008,"corporation":false,"usgs":true,"family":"Rea","given":"B.A.","email":"","affiliations":[],"preferred":false,"id":380170,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Davis, J.A.","contributorId":71694,"corporation":false,"usgs":true,"family":"Davis","given":"J.A.","email":"","affiliations":[],"preferred":false,"id":380171,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70019024,"text":"70019024 - 1996 - Mud cracks and dedolomitization in the Wittenoom Dolomite, Hamersley Group, Western Australia","interactions":[],"lastModifiedDate":"2012-03-12T17:19:15","indexId":"70019024","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1844,"text":"Global and Planetary Change","active":true,"publicationSubtype":{"id":10}},"title":"Mud cracks and dedolomitization in the Wittenoom Dolomite, Hamersley Group, Western Australia","docAbstract":"Several impure dolomitic limestone beds in an outcrop of the latest Archean Wittenoom Dolomite (Hamersley Group, Western Australia) are polygonally cracked. The cracks appear to be sub-aerial desiccation features, suggesting that the known area of shallow water and locally emergent conditions extended from the far eastern part of the basin (the Carawine Dolomite) over 270 km farther west. This finding places shallow- water or emergent conditions either (1) near the middle of what Trendall (1983) defined as the probable original limits of the Hamersley Basin (Trendall's 'Pilbara Egg') or (2) near the southern edge of what Morris (1993) thought to be a broad carbonate platform which fed a deeper water sequence to the south. In any case, the Hamersley Basin in the area of Bee Gorge and eastward to the Carawine Dolomite may have been a carbonate mudflat in part with restricted circulation of sea water. The Carawine Dolomite and the Wittenoom Dolomite near Bee Gorge may have been affected by carbonate buildups along a shelf edge. Regardless of whether shallow water was widespread or local in the Hamersley basin, shallow water verging on emergence is supported by evidence of diagenetic dedolomitization under conditions of low atmospheric and hydrospheric P(O2) and precipitation of strontianite in the mud-cracked sample. Evidence of shallow water at Bee Gorge is consistent with Trendall's broad evaporite-basin model and with Morris' barred-platform model for the origin of Hamersley carbonates and banded iron-formations.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Global and Planetary Change","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0921-8181(95)00055-0","issn":"09218181","usgsCitation":"Kargel, J., Schreiber, J., and Sonett, C., 1996, Mud cracks and dedolomitization in the Wittenoom Dolomite, Hamersley Group, Western Australia: Global and Planetary Change, v. 14, no. 1-2, p. 73-96, https://doi.org/10.1016/0921-8181(95)00055-0.","startPage":"73","endPage":"96","numberOfPages":"24","costCenters":[],"links":[{"id":205770,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0921-8181(95)00055-0"},{"id":226673,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"14","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a5f83e4b0c8380cd70fcf","contributors":{"authors":[{"text":"Kargel, J.S.","contributorId":88096,"corporation":false,"usgs":true,"family":"Kargel","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":381429,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schreiber, J.F. Jr.","contributorId":93211,"corporation":false,"usgs":true,"family":"Schreiber","given":"J.F.","suffix":"Jr.","email":"","affiliations":[],"preferred":false,"id":381430,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Sonett, C.P.","contributorId":19309,"corporation":false,"usgs":true,"family":"Sonett","given":"C.P.","email":"","affiliations":[],"preferred":false,"id":381428,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018964,"text":"70018964 - 1996 - Self-healing slip pulses in dynamic rupture models due to velocity-dependent strength","interactions":[],"lastModifiedDate":"2023-10-23T11:54:12.417695","indexId":"70018964","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1135,"text":"Bulletin of the Seismological Society of America","onlineIssn":"1943-3573","printIssn":"0037-1106","active":true,"publicationSubtype":{"id":10}},"title":"Self-healing slip pulses in dynamic rupture models due to velocity-dependent strength","docAbstract":"Seismological observations of short slip duration on faults (short rise time on seismograms) during earthquakes are not consistent with conventional crack models of dynamic rupture and fault slip. In these models, the leading edge of rupture stops only when a strong region is encountered, and slip at an interior point ceases only when waves from the stopped edge of slip propagate back to that point. In contrast, some seismological evidence suggests that the duration of slip is too short for waves to propagate from the nearest edge of the ruptured surface, perhaps even if the distance used is an asperity size instead of the entire rupture dimension. What controls slip duration, if not dimensions of the fault or of asperities?
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA0860041130","issn":"00371106","usgsCitation":"Beeler, N., and Tullis, T., 1996, Self-healing slip pulses in dynamic rupture models due to velocity-dependent strength: Bulletin of the Seismological Society of America, v. 86, no. 4, p. 1130-1148, https://doi.org/10.1785/BSSA0860041130.","productDescription":"19 p.","startPage":"1130","endPage":"1148","numberOfPages":"19","costCenters":[],"links":[{"id":226353,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"4","noUsgsAuthors":false,"publicationDate":"1996-08-01","publicationStatus":"PW","scienceBaseUri":"505b8d01e4b08c986b318217","contributors":{"authors":[{"text":"Beeler, N.M. 0000-0002-3397-8481","orcid":"https://orcid.org/0000-0002-3397-8481","contributorId":68894,"corporation":false,"usgs":true,"family":"Beeler","given":"N.M.","affiliations":[],"preferred":false,"id":381226,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Tullis, T.E.","contributorId":91252,"corporation":false,"usgs":true,"family":"Tullis","given":"T.E.","email":"","affiliations":[],"preferred":false,"id":381227,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018848,"text":"70018848 - 1996 - Isotopic evidence for shifts in atmospheric circulation patterns during the late Quaternary in mid-North America","interactions":[],"lastModifiedDate":"2024-01-20T01:15:13.516957","indexId":"70018848","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Isotopic evidence for shifts in atmospheric circulation patterns during the late Quaternary in mid-North America","docAbstract":"Wyoming is now at the eastern margin of westerlies originating in the Pacific, but in the Pleistocene appears to have received moisture from elsewhere, possibly the Gulf of Mexico. Oxygen isotope ratios of pedogenic carbonate in postglacial terraces correspond to ratios in equilibrium with present meteoric waters, which show a strong relation to precipitation seasonality and storm sources. In contrast, the oxygen isotope ratios of all pre-Holocene soils are significantly more positive, even though the carbon isotope composition of coexisting organic matter suggests that the carbonate formed in temperatures cooler than today. The oxygen isotope ratios of paleowaters in mid–North America appear to be more useful for identifying past storm sources than for estimating paleotemperatures.
Stabilized eolian deposits, mostly parabolic dunes and sand sheets, cover much of the landscape of northeastern Colorado and adjacent parts of southwestern Nebraska in four geographically distinct dune fields. Stratigraphic and soil-geomorphic relations and accelerator radiocarbon dating indicate that at least three episodes of eolian sand movement occurred between 27 ka and 11 ka, possibly between 11 ka and 4 ka, and within the past 1.5 ka. Thus, eolian sand deposition took place under both glacial and interglacial climatic conditions. In the youngest episodes of eolian sand movement, Holocene parabolic dunes partially buried Pleistocene sand sheet deposits.
Late Holocene sands in the Fort Morgan and Wray dune fields, to the south of the South Platte River, have trace element ratios that are indistinguishable from modern South Platte River sands, but different from Ogallala Formation bedrock, which has previously been cited as the main source of dune sand on the Great Plains. Sands in the Greeley dune field, to the north of the South Platte River, have trace element concentrations that indicate a probable Laramie Formation source. Measurements of parabolic dunes indicate paleowinds from the northwest in all dune fields, in good agreement with resultant drift directions calculated for nearby weather stations. Thus, paleowinds were probably not significantly different from present-day winds, and are consistent with a South Platte River source for the Fort Morgan and Wray dune fields, and a Laramie Formation source for the Greeley dune field. Sand accumulated downwind of the South Platte River to form the Fort Morgan duen field. In addition, sand was also transported farther downwind over the upland formed by the calcrete caprock of the Ogallala Formation, and deposited in the lee of the upland on the southeast side. Because of high wind energy, the upland itself served as a zone of sand transport, but little or no sand accumulation took place on this surface.
These studies, which demonstrate the importance of fluvial-source sediments for dune fields in Colorado, may be applicable to other dune fields in North America. Because modern drift potentials in northeastern Colorado are among the highest in the world, the present stability of dunes in the region may be in part a function of the dunes being supply-limited rather than solely transport-limited. Extensive (∼ 7700 km2) late Holocene dunes document that eolian sand in northeastern Colorado is very sensitive to small changes in climate or fluvial source conditions.
We deployed portable digital seismographs in the San Fernando Valley (SFV), the Los Angeles basin (LAB), and surrounding hills to record aftershocks of the 17 January 1994 Northridge California earthquake. The purpose of the deployment was to investigate factors relevant to seismic zonation in urban areas, such as site amplification, sedimentary basin effects, and the variability of ground motion over short baselines. We placed seismographs at 47 sites (not all concurrently) and recorded about 290 earthquakes with magnitudes up to 5.1 at five stations or more. We deployed widely spaced stations for profiles across the San Fernando Valley, as well as five dense arrays (apertures of 200 to 500 m) in areas of high damage, such as the collapsed Interstate 10 overpass, Sherman Oaks, and the collapsed parking garage at CalState Northridge. Aftershock data analysis indicates a correlation of site amplification with mainshock damage. We found several cases where the site amplification depended on the azimuth of the aftershock, possibly indicating focusing from basin structures. For the parking garage array, we found large ground-motion variabilities (a factor of 2) over 200-m distances for sites on the same mapped soil unit. Array analysis of the aftershock seismograms demonstrates that sizable arrivals after the direct S waves consist of surface waves traveling from the same azimuth as that of the epicenter. These surface waves increase the duration of motions and can have frequencies as high as about 4 Hz. For the events studied here, we do not observe large arrivals reflected from the southern edge of the San Fernando Valley.
No abstract available.
","language":"English","publisher":"Cambridge University Press","doi":"10.1180/minmag.1996.060.399.14","usgsCitation":"Foord, E.E., 1996, Clinobisvanite, eulytite, and namibite from the Pala pegmatite district, San Diego Co., California, USA: Mineralogical Magazine, v. 60, no. 2, p. 387-388, https://doi.org/10.1180/minmag.1996.060.399.14.","productDescription":"2 p.","startPage":"387","endPage":"388","costCenters":[],"links":[{"id":227516,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","county":"San Diego County","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -117.30397037374222,\n 32.84257262633122\n ],\n [\n -117.30397037374222,\n 32.67946846399572\n ],\n [\n -116.9404228020268,\n 32.67946846399572\n ],\n [\n -116.9404228020268,\n 32.84257262633122\n ],\n [\n -117.30397037374222,\n 32.84257262633122\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"60","issue":"2","noUsgsAuthors":false,"publicationDate":"2018-07-05","publicationStatus":"PW","scienceBaseUri":"5059f670e4b0c8380cd4c773","contributors":{"authors":[{"text":"Foord, Eugene E.","contributorId":96319,"corporation":false,"usgs":true,"family":"Foord","given":"Eugene","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":379602,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018996,"text":"70018996 - 1996 - Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer","interactions":[],"lastModifiedDate":"2012-03-12T17:19:14","indexId":"70018996","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1565,"text":"Environmental Science & Technology","onlineIssn":"1520-5851","printIssn":"0013-936X","active":true,"publicationSubtype":{"id":10}},"title":"Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer","docAbstract":"The pore structure of Salem limestone is investigated, and conclusions regarding the effect of the pore geometry on modeling moisture and contaminant transport are discussed based on thin section petrography, scanning electron microscopy, mercury intrusion porosimetry, and nitrogen adsorption analyses. These investigations are compared to and shown to compliment permeability and capillary pressure measurements for this common building stone. Salem limestone exhibits a bimodal pore size distribution in which the larger pores provide routes for convective mass transfer of contaminants into the material and the smaller pores lead to high surface area adsorption and reaction sites. Relative permeability and capillary pressure measurements of the air/water system indicate that Salem limestone exhibits high capillarity end low effective permeability to water. Based on stone characterization, aqueous diffusion and convection are believed to be the primary transport mechanisms for pollutants in this stone. The extent of contaminant accumulation in the stone depends on the mechanism of partitioning between the aqueous and solid phases. The described characterization techniques and modeling approach can be applied to many systems of interest such as acidic damage to limestone, mass transfer of contaminants in concrete and other porous building materials, and modeling pollutant transport in subsurface moisture zones.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Environmental Science and Technology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1021/es950583q","issn":"0013936X","usgsCitation":"Leith, S., Reddy, M., Irez, W., and Heymans, M., 1996, Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer: Environmental Science & Technology, v. 30, no. 7, p. 2202-2210, https://doi.org/10.1021/es950583q.","startPage":"2202","endPage":"2210","numberOfPages":"9","costCenters":[],"links":[{"id":205798,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1021/es950583q"},{"id":226855,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"30","issue":"7","noUsgsAuthors":false,"publicationDate":"1996-06-26","publicationStatus":"PW","scienceBaseUri":"505a4784e4b0c8380cd678a5","contributors":{"authors":[{"text":"Leith, S.D.","contributorId":12634,"corporation":false,"usgs":true,"family":"Leith","given":"S.D.","email":"","affiliations":[],"preferred":false,"id":381339,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Reddy, M.M.","contributorId":24363,"corporation":false,"usgs":true,"family":"Reddy","given":"M.M.","email":"","affiliations":[],"preferred":false,"id":381340,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Irez, W.F.","contributorId":9783,"corporation":false,"usgs":true,"family":"Irez","given":"W.F.","email":"","affiliations":[],"preferred":false,"id":381338,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Heymans, M.J.","contributorId":39140,"corporation":false,"usgs":true,"family":"Heymans","given":"M.J.","email":"","affiliations":[],"preferred":false,"id":381341,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018151,"text":"70018151 - 1996 - Agricultural chemicals at the outlet of a shallow carbonate aquifer","interactions":[],"lastModifiedDate":"2012-03-12T17:19:28","indexId":"70018151","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3626,"text":"Transactions of the American Society of Agricultural Engineers","active":true,"publicationSubtype":{"id":10}},"title":"Agricultural chemicals at the outlet of a shallow carbonate aquifer","docAbstract":"A groundwater catchment, located in Woodford and Jessamine Counties in the Inner Bluegrass of Kentucky, was instrumented to develop long- term flow and water quality data. The land uses on this 1 620-ha catchment consist of approximately 59% in grasses consisting of beef farms, horse farms, and a golf course; 16% row crops; 6% orchard: 13% forest; and 6% residential. Water samples were analyzed twice a week for, Ca++, Mg++, Na+, Cl-, HCO3-, O4=, NO3-, total solids, suspended solids, fecal coliforms, fecal streptococci, and triazines. Flow rate and average ambient temperature were also recorded. No strong linear relationship was developed between chemical concentrations and other parameters. The transient nature of the system was emphasized by one event that drastically deviated from others. Pesticide data were summarized and the 'flushing' phenomena accredited to karst systems was discussed. The total solids content in the spring was consistent at approximately 2.06 mg/L. Fecal bacteria contamination was well above drinking water limits (fecal coliform and fetal streptococci averages were I 700 and 4 300 colony-forming-units/100 mL, respectively) and the temporal variation in bacterial contamination was not linked to any other variable.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Transactions of the American Society of Agricultural Engineers","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00012351","usgsCitation":"Felton, G., 1996, Agricultural chemicals at the outlet of a shallow carbonate aquifer: Transactions of the American Society of Agricultural Engineers, v. 39, no. 3, p. 873-882.","startPage":"873","endPage":"882","numberOfPages":"10","costCenters":[],"links":[{"id":227276,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e911e4b0c8380cd4808e","contributors":{"authors":[{"text":"Felton, G.K.","contributorId":75706,"corporation":false,"usgs":true,"family":"Felton","given":"G.K.","email":"","affiliations":[],"preferred":false,"id":378699,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018152,"text":"70018152 - 1996 - The 1994 Northridge, California, earthquake: Investigation of rupture velocity, risetime, and high-frequency radiation","interactions":[],"lastModifiedDate":"2024-11-12T17:44:46.281796","indexId":"70018152","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":"The 1994 Northridge, California, earthquake: Investigation of rupture velocity, risetime, and high-frequency radiation","docAbstract":"A hybrid global search algorithm is used to solve the nonlinear problem of calculating slip amplitude, rake, risetime, and rupture time on a finite fault. Thirty-five strong motion velocity records are inverted by this method over the frequency band from 0.1 to 1.0 Hz for the Northridge earthquake. Four regions of larger-amplitude slip are identified: one near the hypocenter at a depth of 17 km, a second west of the hypocenter at about the same depth, a third updip from the hypocenter at a depth of 10 km, and a fourth updip from the hypocenter and to the northwest. The results further show an initial fast rupture with a velocity of 2.8 to 3.0 km/s followed by a slow termination of the rupture with velocities of 2.0 to 2.5 km/s. The initial energetic rupture phase lasts for 3 s, extending out 10 km from the hypocenter. Slip near the hypocenter has a short risetime of 0.5 s, which increases to 1.5 s for the major slip areas removed from the hypocentral region. The energetic rupture phase is also shown to be the primary source of high-frequency radiation (1–15 Hz) by an inversion of acceleration envelopes. The same global search algorithm is used in the envelope inversion to calculate high-frequency radiation intensity on the fault and rupture time. The rupture timing from the low- and high-frequency inversions is similar, indicating that the high frequencies are produced primarily at the mainshock rupture front. Two major sources of high-frequency radiation are identified within the energetic rupture phase, one at the hypocenter and another deep source to the west of the hypocenter. The source at the hypocenter is associated with the initiation of rupture and the breaking of a high-stress-drop asperity and the second is associated with stopping of the rupture in a westerly direction.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JB01883","issn":"01480227","usgsCitation":"Hartzell, S., Liu, P., and Mendoza, C., 1996, The 1994 Northridge, California, earthquake: Investigation of rupture velocity, risetime, and high-frequency radiation: Journal of Geophysical Research B: Solid Earth, v. 101, no. 9, p. 20091-20108, https://doi.org/10.1029/96JB01883.","productDescription":"18 p.","startPage":"20091","endPage":"20108","numberOfPages":"18","costCenters":[],"links":[{"id":227277,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"9","noUsgsAuthors":false,"publicationDate":"1996-09-10","publicationStatus":"PW","scienceBaseUri":"505ba634e4b08c986b320f76","contributors":{"authors":[{"text":"Hartzell, S.","contributorId":12603,"corporation":false,"usgs":true,"family":"Hartzell","given":"S.","email":"","affiliations":[],"preferred":false,"id":378700,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Liu, P.","contributorId":98443,"corporation":false,"usgs":true,"family":"Liu","given":"P.","email":"","affiliations":[],"preferred":false,"id":378702,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mendoza, C.","contributorId":82059,"corporation":false,"usgs":true,"family":"Mendoza","given":"C.","email":"","affiliations":[],"preferred":false,"id":378701,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018959,"text":"70018959 - 1996 - Hot dry rock and the U.S. geological survey: a question of priorities","interactions":[],"lastModifiedDate":"2019-05-14T08:51:51","indexId":"70018959","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Hot dry rock and the U.S. geological survey: a question of priorities","docAbstract":"The enactment of the Energy Policy Act of 1992 saw the assignment of definite responsibilities relating to hot dry rock (HDR) to the US Geological Survey (USGS). This mandate provided some explicit guidelines and individual tasks in areas in which the USGS already had close ties to the Department of Energy and a number of its national laboratories. This paper discusses various tasks in terms of priorities being conducted by USGS as response to the Act.","language":"English","publisher":"Geothermal Resources Council","issn":"01607782","usgsCitation":"Sass, J.H., 1996, Hot dry rock and the U.S. geological survey: a question of priorities: Bulletin. Geothermal Resources Council, v. 25, no. 8, p. 313-315.","productDescription":"3 p. ","startPage":"313","endPage":"315","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":226267,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"25","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3238e4b0c8380cd5e601","contributors":{"authors":[{"text":"Sass, John H.","contributorId":69596,"corporation":false,"usgs":true,"family":"Sass","given":"John","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":381208,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018872,"text":"70018872 - 1996 - Relations of fish community composition to environmental variables in streams of central Nebraska, USA","interactions":[],"lastModifiedDate":"2023-12-17T15:44:27.301335","indexId":"70018872","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1547,"text":"Environmental Management","active":true,"publicationSubtype":{"id":10}},"title":"Relations of fish community composition to environmental variables in streams of central Nebraska, USA","docAbstract":"Nine sites on streams in the Platte River Basin in central Nebraska were sampled as part of the US Geological Survey's National Water Quality Assessment Program during 1993-1994. A combination of canonical correspondence analysis and an index of biotic integrity determined from fish community data produced complementary evaluations of water quality conditions. Results of the canonical correspondence analysis were useful in showing which environmental variables were significant in differentiating fish communities at the nine sites. Five environmental variables were statistically significant in the analysis. Median specific conductance of water samples collected at a site accounted for the largest amount of variability in the species data. Although the percentage of the basin as cropland was not the first variable chosen in a forward selection process, it was the most strongly correlated with the first ordination axis. A rangeland- dominated site was distinguished from all others along that axis. Median orthophosphate concentration of samples collected in the year up to the time of fish sampling was most strongly correlated with the second ordination axis. The index of biotic integrity produced results that could be interpreted in terms of the relative water quality between sites. Sites draining nearly 100% cropland had the lowest scores for two individual metrics of the index of biotic integrity that were related to species tolerance. Effective monitoring of water quality could be achieved by coupling methods that address both the ecological components of fish communities and their statistical relationships to environmental factors.","language":"English","publisher":"Springer","doi":"10.1007/BF01204140","issn":"0364152X","usgsCitation":"Frenzel, S., and Swanson, R.B., 1996, Relations of fish community composition to environmental variables in streams of central Nebraska, USA: Environmental Management, v. 20, no. 5, p. 689-705, https://doi.org/10.1007/BF01204140.","productDescription":"17 p.","startPage":"689","endPage":"705","numberOfPages":"17","costCenters":[],"links":[{"id":226481,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"20","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"50e4a714e4b0e8fec6cdc37f","contributors":{"authors":[{"text":"Frenzel, S.A.","contributorId":9246,"corporation":false,"usgs":true,"family":"Frenzel","given":"S.A.","email":"","affiliations":[],"preferred":false,"id":380986,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Swanson, R. B.","contributorId":10032,"corporation":false,"usgs":true,"family":"Swanson","given":"R.","middleInitial":"B.","affiliations":[],"preferred":false,"id":380987,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019030,"text":"70019030 - 1996 - Cryptic trace-element alteration of Anorthosite, Stillwater complex, Montana","interactions":[],"lastModifiedDate":"2012-03-12T17:19:15","indexId":"70019030","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1177,"text":"Canadian Mineralogist","active":true,"publicationSubtype":{"id":10}},"title":"Cryptic trace-element alteration of Anorthosite, Stillwater complex, Montana","docAbstract":"Evidence of cryptic alteration and correlations among K, Ba, and LREE concentrations indicate that a post-cumulus, low-density aqueous fluid phase significantly modified the trace-element contents of samples from Anorthosite zones I and II of the Stillwater Complex, Montana. Concentrations of Ba, Ca, Co, Cr, Cu, Fe, Hf, K, Li, Mg, Mn, Na, Ni, Sc, Sr, Th, Zn, and the rare-earth elements (REE) were measured in whole rocks and plagioclase separates from five traverses across the two main plagioclase cumulate (anorthosite) zones and the contiguous cumulates of the Stillwater Complex in an attempt to better understand the origin and solidification of the anorthosites. However, nearly the entire observed compositional range for many trace elements can be duplicated at a single locality by discriminating between samples rich in oikocrystic pyroxene and those which are composed almost entirely of plagioclase and show anhedral-granular texture. Plagioclase separates with high trace-element contents were obtained from the pyroxene-poor samples, for which maps of K concentration show plagioclase grains to contain numerous fractures hosting a fine-grained, K-rich phase, presumed to be sericite. Secondary processes in layered intrusions have the potential to cause cryptic disturbance, and the utmost care must be taken to ensure that samples provide information about primary processes. Although plagioclase from Anorthosite zones I and II shows significant compositional variation, there are no systematic changes in the major- or trace-element compositions of plagioclase over as much as 630 m of anorthosite thickness or 18 km of strike length. Plagioclase in the two major anorthosite zones shows little distinction in trace-element concentrations from plagioclase in the cumulates immediately below, between, and above these zones.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Canadian Mineralogist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00084476","usgsCitation":"Czamanske, G., and Loferski, P., 1996, Cryptic trace-element alteration of Anorthosite, Stillwater complex, Montana: Canadian Mineralogist, v. 34, no. 3, p. 559-576.","startPage":"559","endPage":"576","numberOfPages":"18","costCenters":[],"links":[{"id":226768,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fcf6e4b0c8380cd4e54b","contributors":{"authors":[{"text":"Czamanske, G.K.","contributorId":26300,"corporation":false,"usgs":true,"family":"Czamanske","given":"G.K.","email":"","affiliations":[],"preferred":false,"id":381456,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Loferski, P. J.","contributorId":12841,"corporation":false,"usgs":true,"family":"Loferski","given":"P. J.","affiliations":[],"preferred":false,"id":381455,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018979,"text":"70018979 - 1996 - Global distribution of beryllium isotopes in deep ocean water as derived from Fe-Mn crusts","interactions":[],"lastModifiedDate":"2023-12-09T00:40:16.997231","indexId":"70018979","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Global distribution of beryllium isotopes in deep ocean water as derived from Fe-Mn crusts","docAbstract":"The direct measurement of the ratio of cosmogenic 10Be (
If the residence time of 10Be (τ10Be) in deep water is constant globally, then the observed variations in
Mass balance considerations indicate that hydrothermal additions of 9Be to the oceans are negligible and that the dissolved riverine source is also small. Furthermore, aeolian dust input of 9Be appears insufficient to provide the dissolved 9Be inventory. The dissolution of only a small proportion (2%) of river-derived particulates could in principle supply the observed seawater 9Be content. If true, ocean margins would be the sites for 9Be addition. Due to the particle-reactive nature of Be, these would also be the primary sites of Be removal. A possible net result of horizontal water masses passing through these marginal areas might be a decrease in seawater
As τ10Be (∼ 600 a) is less than the apparent age of deep water in the Pacific (∼ 1500 a), the Pacific record of
In this paper the numerical model presented in the companion paper is tested and applied. Assessment of model accuracy was based on two approaches. First, predictions of evolution of a 13.5 km reach of the South Fork of the Forked Deer River, in west Tennessee, were compared to observations over a 24-yr period. Results suggest that although the model was able to qualitatively predict trends of widening and deepening, quantitative predictions were not reliable. Simulated widths and depths were within 15% of the corresponding observed values, but observed change in these parameters at the study sites were also close to these values. Simulated rates of depth adjustment were within 15% of observed rates, but observed rates of channel widening at the study sites were approximately three times those simulated by the model. In the second approach, the model was used to generate relationships between stable channel width and bank-full discharge. The model was able to successfully replicate the form of empirically derived regime-width equations. Simulations were used to demonstrate the model's ability to obtain more realistic predictions of bed evolution in widening channels.
","language":"English","publisher":"ASCE","doi":"10.1061/(ASCE)0733-9429(1996)122:4(194)","issn":"07339429","usgsCitation":"Darby, S., Thorne, C., and Simon, A., 1996, Numerical simulation of widening and bed deformation of straight sand-bed rivers. II: Model evaluation: Journal of Hydraulic Engineering, v. 122, no. 4, p. 194-202, https://doi.org/10.1061/(ASCE)0733-9429(1996)122:4(194).","productDescription":"9 p.","startPage":"194","endPage":"202","numberOfPages":"9","costCenters":[],"links":[{"id":227254,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"122","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a692ee4b0c8380cd73be2","contributors":{"authors":[{"text":"Darby, S.E.","contributorId":9012,"corporation":false,"usgs":true,"family":"Darby","given":"S.E.","email":"","affiliations":[],"preferred":false,"id":379844,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Thorne, Colin R.","contributorId":78886,"corporation":false,"usgs":true,"family":"Thorne","given":"Colin R.","affiliations":[],"preferred":false,"id":379846,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Simon, A.","contributorId":43501,"corporation":false,"usgs":true,"family":"Simon","given":"A.","email":"","affiliations":[],"preferred":false,"id":379845,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018718,"text":"70018718 - 1996 - Distribution of nitrate and orthophosphate in selected streams in Central Nebraska","interactions":[],"lastModifiedDate":"2013-02-19T10:41:49","indexId":"70018718","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3718,"text":"Water Resources Bulletin","printIssn":"0043-1370","active":true,"publicationSubtype":{"id":10}},"title":"Distribution of nitrate and orthophosphate in selected streams in Central Nebraska","docAbstract":"The Central Nebraska Basins is one of 60 study units in the National Water-Quality Assessment Program of the U.S. Geological Survey. The study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Agriculture is the predominant land use in the study unit, with only eight urbanized communities exceeding a population of 10,000. Water samples were collected from selected streams in the study unit during 1993- 1995. The data were used to assess the distribution of nitrogen compounds and phosphorus in the streams and to relate the concentrations of these constituents to environmental settings. This article focuses on dissolved nitrate and orthophosphate. Dissolved nitrate concentrations were highest (90th percentiles were less than 7.0 milligrams per liter as nitrogen) in areas with extensive cropland and pasture, where chemical fertilizers are intensively applied. Synoptic measurements conducted in March and August 1994 indicate that relatively little residual fertilizer, as nitrate, applied during a single crop-growing season enters streams. Dissolved nitrate concentrations showed a seasonal pattern, being highest during winter months and lowest during the late spring and summer. Dissolved orthophosphate concentrations tended to be low across the study unit, 90 percent of all analyses did not exceed 1.7 milligrams per liter as phosphorus.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Water Resources Bulletin","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Wiley","doi":"10.1111/j.1752-1688.1996.tb03494.x","issn":"00431370","usgsCitation":"Boyd, R., 1996, Distribution of nitrate and orthophosphate in selected streams in Central Nebraska: Water Resources Bulletin, v. 32, no. 6, p. 1247-1257, https://doi.org/10.1111/j.1752-1688.1996.tb03494.x.","startPage":"1247","endPage":"1257","numberOfPages":"11","costCenters":[],"links":[{"id":227267,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":267668,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1111/j.1752-1688.1996.tb03494.x"}],"volume":"32","issue":"6","noUsgsAuthors":false,"publicationDate":"2007-06-08","publicationStatus":"PW","scienceBaseUri":"505a02e8e4b0c8380cd5025e","contributors":{"authors":[{"text":"Boyd, R.A.","contributorId":19590,"corporation":false,"usgs":true,"family":"Boyd","given":"R.A.","email":"","affiliations":[],"preferred":false,"id":380544,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018565,"text":"70018565 - 1996 - Growth of the Tongariro volcanic complex: New evidence from K-Ar age determinations","interactions":[],"lastModifiedDate":"2019-06-06T13:16:54","indexId":"70018565","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2869,"text":"New Zealand Journal of Geology and Geophysics","active":true,"publicationSubtype":{"id":10}},"title":"Growth of the Tongariro volcanic complex: New evidence from K-Ar age determinations","docAbstract":"New K-Ar age determinations indicate that the exposed portion of the Tongariro volcanic complex has grown steadily since at least 275 ka, with intervals of vigorous cone growth at 210-200.130-70. and 25 ka to the present day.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"New Zealand Journal of Geology and Geophysics","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Taylor and Francis","doi":"10.1080/00288306.1996.9514701","issn":"00288306","usgsCitation":"Hobden, B., Houghton, B.F., Lanphere, M.A., and Nairn, I., 1996, Growth of the Tongariro volcanic complex: New evidence from K-Ar age determinations: New Zealand Journal of Geology and Geophysics, v. 39, no. 1, p. 151-154, https://doi.org/10.1080/00288306.1996.9514701.","productDescription":"4 p.","startPage":"151","endPage":"154","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":479130,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1080/00288306.1996.9514701","text":"Publisher Index Page"},{"id":227568,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":268059,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1080/00288306.1996.9514701"}],"volume":"39","issue":"1","noUsgsAuthors":false,"publicationDate":"2010-03-23","publicationStatus":"PW","scienceBaseUri":"505a2dfbe4b0c8380cd5c1d6","contributors":{"authors":[{"text":"Hobden, B.J.","contributorId":67677,"corporation":false,"usgs":true,"family":"Hobden","given":"B.J.","email":"","affiliations":[],"preferred":false,"id":380056,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Houghton, Bruce F. 0000-0002-7532-9770","orcid":"https://orcid.org/0000-0002-7532-9770","contributorId":140077,"corporation":false,"usgs":false,"family":"Houghton","given":"Bruce","email":"","middleInitial":"F.","affiliations":[{"id":6977,"text":"University of Hawai`i at Hilo","active":true,"usgs":false},{"id":13351,"text":"University of Hawaii Cooperative Studies Unit","active":true,"usgs":false}],"preferred":false,"id":380055,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lanphere, M. A.","contributorId":35298,"corporation":false,"usgs":true,"family":"Lanphere","given":"M.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":380054,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Nairn, I.A.","contributorId":92812,"corporation":false,"usgs":true,"family":"Nairn","given":"I.A.","email":"","affiliations":[],"preferred":false,"id":380057,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018502,"text":"70018502 - 1996 - A geochemical study of macerals from a Miocene lignite and an Eocene bituminous coal, Indonesia","interactions":[],"lastModifiedDate":"2012-03-12T17:19:25","indexId":"70018502","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2958,"text":"Organic Geochemistry","active":true,"publicationSubtype":{"id":10}},"title":"A geochemical study of macerals from a Miocene lignite and an Eocene bituminous coal, Indonesia","docAbstract":"Optical and chemical studies of maceral concentrates from a Miocene lignite and an Eocene high-volatile bituminous C coal from southeastern Kalimantan, Indonesia were undertaken using pyro-Lysis, optical, electron microprobe and FTIR techniques Pyrolysis products of vitrinite from bituminous coal were dominated by straight-chain aliphatics and phenols. The huminite of the Miocene lignite produced mostly phenolic compounds upon pyrolysis. Differences in the pyrolysis products between the huminite and vitrinite samples reflect both maturation related and paleobotanical differences. An undefined aliphatic source and/or bacterial biomass were the likely contributors of n-alkyl moieties to the vitrinite. The resinite fraction in the lignite yielded dammar-derived pyrolysis products, as well as aliphatics and phenols as the products of admixed huminite and other liptinites. The optically defined resinite-rich fraction of the bituminous coal from Kalimantan produced abundant n-aliphatic moieties upon pyrolysis, but only two major resin markers (cadalene and 1,6-dimethylnaphthalene). This phenomenon is likely due to the fact that Eocene resins were not dammar-related. Data from the electron microprobe and Fourier transform infrared spectrometry strongly support the results obtained by Py GC MS and microscopy.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Organic Geochemistry","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0146-6380(96)00038-1","issn":"01466380","usgsCitation":"Stankiewicz, B., Kruge, M., and Mastalerz, M., 1996, A geochemical study of macerals from a Miocene lignite and an Eocene bituminous coal, Indonesia: Organic Geochemistry, v. 24, no. 5, p. 531-545, https://doi.org/10.1016/0146-6380(96)00038-1.","startPage":"531","endPage":"545","numberOfPages":"15","costCenters":[],"links":[{"id":205879,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0146-6380(96)00038-1"},{"id":227253,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"24","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e3f7e4b0c8380cd46317","contributors":{"authors":[{"text":"Stankiewicz, B.A.","contributorId":83676,"corporation":false,"usgs":true,"family":"Stankiewicz","given":"B.A.","email":"","affiliations":[],"preferred":false,"id":379843,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kruge, M.A.","contributorId":55579,"corporation":false,"usgs":true,"family":"Kruge","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":379841,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mastalerz, Maria","contributorId":78065,"corporation":false,"usgs":true,"family":"Mastalerz","given":"Maria","affiliations":[],"preferred":false,"id":379842,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ]}