Navon et al. (1996) demonstrated that the Navon and Stolper (1987) model can be formulated to reproduce a pattern of light-ion lithophile trace element (LIL) enrichments produced by a single, small-scale metasomatic process recorded in a composite xenolith from Dish Hill, California (Nielson et al. 1993). The Navon and Stolper model has failed repeatedly to reproduce the shape and lateral positions of LIL enrichment patterns for samples from peridotite massifs, which are of appropriate scale to test the assumption that LIL fractionation takes place in percolating melts over distances>100 m. The model results also produce unreasonably long times for solidification of thin dikes, which imply untenable thermal conditions for lithospheric mantle.
Using parameters drawn from sample compositions, Nielson et al. (1993) demonstrated, and the calculations of Navon et al. (1996) have shown again, that fractionated trace element patterns of a melt are imprinted upon relatively refractory peridotite matrix in zones closest to a melt source. The observed process sequentially extracts LIL into matrix, analogous to the ion-exchange chromatography of water-purification columns. We have never contended that this process is mathematically distinct from the percolation model of Navon and Stolper (1987), which assumes concentration ofLIL elements in melt. The choice of parameters defines the result, and one would notice a major difference in the taste of water from an ion-exchange column that traps target ions in matrix compared with one that concentrates those ions in the liquid.
The difference between the models is in the selection of parameters and values: The model ofNavon and Stolper (1987) assumes the reaction mechanism, uses theoretical melt compositions, and contains as many as nine unmeasurable parameters. We used the simplified model calculation to avoid reliance on theoretical parameters and to test our assumptions about the process. When the compositions of actual samples are taken as end-members of mantle reactions, the successful results imply that a fractionation-bypercolation process is not applicable to lithospheric mantle. Repetition of the observed small-scale reaction in refractory peridotite must extend the zone of reactions and relative enrichment, centimeter by centimeter, as long as melt aliquots percolate beyond peridotite matrix that had previously reacted to equilibrium with the melt composition. This process satisfactorily explains the wide variations ofLIL fractionation patterns over short distances that characterize mantle rocks in xenoliths and massifs, all of which contain complex systems of mafic intrusions with varied LIL fractionation patterns.
","language":"English","publisher":"Mineralogical Society of America","doi":"10.2138/am-1996-5-623","usgsCitation":"Nielson, J.E., and Wilshire, H.G., 1996, Magma transport and metasomatism in the mantle; a critical review of current geochemical models; reply: American Mineralogist, v. 81, no. 5-6, p. 760-765, https://doi.org/10.2138/am-1996-5-623.","productDescription":"6 p.","startPage":"760","endPage":"765","costCenters":[],"links":[{"id":419060,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"81","issue":"5-6","noUsgsAuthors":false,"publicationDate":"1996-06-01","publicationStatus":"PW","contributors":{"authors":[{"text":"Nielson, Jane E.","contributorId":9701,"corporation":false,"usgs":true,"family":"Nielson","given":"Jane","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":878178,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wilshire, Howard G.","contributorId":68346,"corporation":false,"usgs":true,"family":"Wilshire","given":"Howard","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":878179,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019000,"text":"70019000 - 1996 - Patterns of late Cenozoic volcanic and tectonic activity in the West Antarctic rift system revealed by aeromagnetic surveys","interactions":[],"lastModifiedDate":"2025-09-09T15:07:34.770002","indexId":"70019000","displayToPublicDate":"1996-06-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3524,"text":"Tectonics","active":true,"publicationSubtype":{"id":10}},"title":"Patterns of late Cenozoic volcanic and tectonic activity in the West Antarctic rift system revealed by aeromagnetic surveys","docAbstract":"Aeromagnetic surveys, spaced ≤5 km, over widely separated areas of the largely ice- and sea-covered West Antarctic rift system, reveal similar patterns of 100- to 1700-nT, shallow-source magnetic anomalies interpreted as evidence of extensive late Cenozoic volcanism. We use the aeromagnetic data to extend the volcanic rift interpretation over West Antarctica starting with anomalies over (1) exposures of highly magnetic, late Cenozoic volcanic rocks several kilometers thick in the McMurdo-Ross Island area and elsewhere; continuing through (2) volcanoes and subvolcanic intrusions directly beneath the Ross Sea continental shelf defined by marine magnetic and seismic reflection data and aeromagnetic data and (3) volcanic structures interpreted beneath the Ross Ice Shelf partly controlled by seismic reflection determinations of seafloor depth to (4) an area of similar magnetic pattern over the West Antarctic Ice Sheet (400 km from the nearest exposed volcanic rock), where interpretations of late Cenozoic volcanic rocks at the base of the ice are controlled in part by radar ice sounding. North trending magnetic rift fabric in the Ross Sea-Ross Ice Shelf and Corridor Aerogeophysics of the Southeast Ross Transect Zone (CASERTZ) areas, revealed by the aeromagnetic surveys, is probably a reactivation of older rift trends (late Mesozoic?) and is superimposed on still older crosscutting structural trends revealed by magnetic terrace maps calculated from horizontal gradient of pseudogravity. Long-wavelength (∼ 100-km wide) magnetic terraces from sources within the subvolcanic basement cross the detailed survey areas. One of these extends across the Ross Sea survey from the front of the Transantarctic Mountains with an east-southeast trend crossing the north trending rift fabric. The Ross Sea-Ross Ice Shelf survey area is characterized by highly magnetic northern and southern zones which are separated by magnetically defined faults from a more moderately magnetic central zone. Aeromagnetic data in the south delineate the Ross fault of unknown age. The extension of the southern Central Basin south of the Ross fault is associated with an 825-nT magnetic anomaly over the Ross Ice Shelf requiring inferred late Cenozoic volcanic rock essentially at the seafloor at its south end, as shown by magnetic models. Models show that the thickness of magnetic volcanic rocks beneath Hut Point Peninsula at McMurdo Station is probably <2 km. The detailed surveys, combined with data from > 100,000 km of widely spaced aeromagnetic profiles, led to the interpretation of the mostly subglacial West Antarctic flood basalts(?) or their subglacially erupted and intruded equivalent. The volume of the exposed volcanos is small in contrast to the much greater volume (> 106 km³) of late Cenozoic magmatic rock remaining at volcanic centers beneath the continental shelf, Ross Ice Shelf and West Antarctic Ice Sheet. We suggest as an alternative or supplemental explanation to the previously proposed mantle plume hypothesis for the late Cenozoic volcanism significantly greater lower lithosphere (mantle) stretching resulting in greater decompression melting than the limited Cenozoic crustal extension allows. However, this implies a space problem that is not obviously resolved, because the Antarctic Plate is essentially surrounded by spreading centers.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95TC03500","issn":"02787407","usgsCitation":"Behrendt, J.C., Saltus, R., Damaske, D., McCafferty, A., Finn, C., Blankenship, D., and Bell, R., 1996, Patterns of late Cenozoic volcanic and tectonic activity in the West Antarctic rift system revealed by aeromagnetic surveys: Tectonics, v. 15, no. 3, p. 660-676, https://doi.org/10.1029/95TC03500.","productDescription":"17 p.","startPage":"660","endPage":"676","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":226269,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"West Antarctic","volume":"15","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a75d9e4b0c8380cd77d9f","contributors":{"authors":[{"text":"Behrendt, John C. jbehrendt@usgs.gov","contributorId":25945,"corporation":false,"usgs":true,"family":"Behrendt","given":"John","email":"jbehrendt@usgs.gov","middleInitial":"C.","affiliations":[{"id":213,"text":"Crustal Imaging and Characterization Team","active":false,"usgs":true},{"id":218,"text":"Denver Federal Center","active":false,"usgs":true}],"preferred":false,"id":381350,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Saltus, R.","contributorId":107040,"corporation":false,"usgs":true,"family":"Saltus","given":"R.","email":"","affiliations":[],"preferred":false,"id":381355,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Damaske, D.","contributorId":66771,"corporation":false,"usgs":true,"family":"Damaske","given":"D.","affiliations":[],"preferred":false,"id":381351,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"McCafferty, A.","contributorId":83285,"corporation":false,"usgs":true,"family":"McCafferty","given":"A.","affiliations":[],"preferred":false,"id":381353,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Finn, C. A. 0000-0002-6178-0405","orcid":"https://orcid.org/0000-0002-6178-0405","contributorId":93917,"corporation":false,"usgs":true,"family":"Finn","given":"C. A.","affiliations":[],"preferred":false,"id":381354,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Blankenship, D.","contributorId":108260,"corporation":false,"usgs":true,"family":"Blankenship","given":"D.","affiliations":[],"preferred":false,"id":381356,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Bell, R.E.","contributorId":70010,"corporation":false,"usgs":true,"family":"Bell","given":"R.E.","email":"","affiliations":[],"preferred":false,"id":381352,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":70019059,"text":"70019059 - 1996 - Occurrence patterns of foreshocks to large earthquakes in the western United States","interactions":[],"lastModifiedDate":"2025-05-27T16:24:57.686182","indexId":"70019059","displayToPublicDate":"1996-05-23T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2840,"text":"Nature","active":true,"publicationSubtype":{"id":10}},"title":"Occurrence patterns of foreshocks to large earthquakes in the western United States","docAbstract":"Observations of foreshocks preceding large earthquakes provide one of the few well documented cases of premonitory events that are clearly related to a subsequent earthquake. Unfortunately, the apparent randomness of foreshock occurrence—they precede some events and not others—has severely hampered their use in reliable earthquake prediction. Understanding the factors that control foreshock occurrence is critical for determining how large earthquakes initiate and whether reliable short-term prediction will ever be possible1. Here we report the results of a comprehensive study of the occurrence patterns of foreshocks to large earthquakes in the western United States. The incidence of foreshocks decreases with increasing depth of the mainshock, and also depends on the mainshock slip orientation. This pattern of occurrence may be explained by a decrease in small-scale crustal heterogeneity with increasing depth, and suggests that increasing normal stress (both regional tectonic stress and lithostatic load) inhibits the occurrence of foreshocks. No relationship is observed between any aspect of foreshock occurrence and the magnitude of the subsequent mainshock, suggesting that the eventual size of the mainshock may be independent of the earthquake nucleation process, or that foreshocks are not part of this process.
","language":"English","publisher":"Springer Nature","doi":"10.1038/381303a0","issn":"00280836","usgsCitation":"Abercrombie, R., and Mori, J., 1996, Occurrence patterns of foreshocks to large earthquakes in the western United States: Nature, v. 381, no. 6580, p. 303-307, https://doi.org/10.1038/381303a0.","productDescription":"5 p.","startPage":"303","endPage":"307","costCenters":[],"links":[{"id":226536,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California, Nevada","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -125.41996898323475,\n 42.02198857745134\n ],\n [\n -123.74392816488624,\n 37.00917404315508\n ],\n [\n -119.20679562172873,\n 32.19218720248436\n ],\n [\n -114.50684900238613,\n 32.566731646414894\n ],\n [\n -113.8978877160888,\n 42.02198857745134\n ],\n [\n -125.41996898323475,\n 42.02198857745134\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"381","issue":"6580","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6c5fe4b0c8380cd74bb7","contributors":{"authors":[{"text":"Abercrombie, R.E.","contributorId":57611,"corporation":false,"usgs":true,"family":"Abercrombie","given":"R.E.","email":"","affiliations":[],"preferred":false,"id":381550,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mori, J.","contributorId":24923,"corporation":false,"usgs":true,"family":"Mori","given":"J.","email":"","affiliations":[],"preferred":false,"id":381549,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70170925,"text":"70170925 - 1996 - Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota","interactions":[],"lastModifiedDate":"2018-03-08T15:50:23","indexId":"70170925","displayToPublicDate":"1996-05-01T10:00:00","publicationYear":"1996","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":"Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota","docAbstract":"This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of δD values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate-poor, deep groundwater. Upwelling deep groundwater contained ammonium with a δ15N of 5‰ that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate δ15N values in shallow groundwater to decrease by as much as 19.5‰. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass-shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these sites. Water sources of riparian trees were identified by comparing δD values of sap water, soil water, groundwater, and stream water. Soil water was the main water source for trees in the outer 4 to 6 m of one part of the wooded riparian zone and outer 10 m of another part. Groundwater was a significant water source for trees closer to the streams where the water table was less than about 2.1 to 2.7 m below the surface. No evidence was found in the nitrate concentration profiles that trees close to the streams that took up groundwater through their roots also took up nitrate from groundwater. The lack of such evidence is attributed to the nitrate concentration profiles being insufficiently sensitive indicators of nitrate removal by trees.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03815","usgsCitation":"Komor, S., and Magner, J.A., 1996, Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota: Water Resources Research, v. 32, no. 4, p. 1039-1050, https://doi.org/10.1029/95WR03815.","productDescription":"12 p.","startPage":"1039","endPage":"1050","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":392,"text":"Minnesota Water Science Center","active":true,"usgs":true}],"links":[{"id":321107,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Minnesota","otherGeospatial":"Cobb River","volume":"32","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"573457c6e4b0dae0d5ddd39c","contributors":{"authors":[{"text":"Komor, Stephen C.","contributorId":12875,"corporation":false,"usgs":true,"family":"Komor","given":"Stephen C.","affiliations":[],"preferred":false,"id":629119,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Magner, Joseph A.","contributorId":172051,"corporation":false,"usgs":false,"family":"Magner","given":"Joseph","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":629120,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018598,"text":"70018598 - 1996 - Episodic acidification of small streams in the northeastern United states: Effects on fish populations","interactions":[],"lastModifiedDate":"2023-12-22T16:41:53.424785","indexId":"70018598","displayToPublicDate":"1996-05-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1450,"text":"Ecological Applications","active":true,"publicationSubtype":{"id":10}},"title":"Episodic acidification of small streams in the northeastern United states: Effects on fish populations","docAbstract":"As part of the Episodic Response Project (ERP), we studied the effects of episodic acidification on fish in 13 small streams in the northeastern United States: four streams in the Adirondack region of New York, four streams in the Catskills, New York, and five streams in the northern Appalachian Plateau, Pennsylvania. In situ bioassays with brook trout (Salvelinus fontinalis) and a forage fish species (blacknose dace (Rhinichthys atratulus), mottled sculpin (Cottus bairdi), or slimy sculpin (Cottus cognatus), depending on the region) measured direct toxicity. Movements of individual brook trout, in relation to stream chemistry, were monitored using radiotelemetry. Electrofishing surveys assessed fish community status and the density and biomass of brook trout in each stream. During low flow, all streams except one had chemical conditions considered suitable for the survival and reproduction of most fish species (median pH 6.0-7.2 during low flow; inorganic Al < 60 μg/L). ERP streams with suitable conditions during low flow, but moderate-to-severe episodic acidification during high flow, had higher fish mortality in bioassays, net down-stream movement of brook trout during events, and lower brook trout density and biomass compared to nonacidic streams, and lacked acid-sensitive fish species (blacknose dace and sculpin). Movement of trout into refugia (areas with higher pH and lower Al) during episodes partially mitigated the adverse effects of episodes. Recolonization from alkaline tributaries or microhabitats can maintain low densities of fish in streams that experience severe acidic episodes, but it is not sufficient to sustain fish densities and community composition at levels expected in the absence of these episodes. Fish responses to acid-base chemistry were fairly consistent across regions. In general, trout abundance was reduced and acid-sensitive fish species were absent from ERP streams with median pH < 5.0-5.2 during high flow and inorganic Al > 100-200 μg/L. We conclude that episodic acidification can have long-term effects on fish communities in small streams.
","language":"English","publisher":"Ecological Society of America","doi":"10.2307/2269380","issn":"10510761","usgsCitation":"Baker, J., Van Sickle, J., Gagen, C., DeWalle, D.R., Sharpe, W., Carline, R., Baldigo, B., Murdoch, P., Bath, D., Kretser, W., Simonin, H.A., and Wigington, P., 1996, Episodic acidification of small streams in the northeastern United states: Effects on fish populations: Ecological Applications, v. 6, no. 2, p. 422-437, https://doi.org/10.2307/2269380.","productDescription":"16 p.","startPage":"422","endPage":"437","numberOfPages":"16","costCenters":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"links":[{"id":227392,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"6","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0a0ee4b0c8380cd52198","contributors":{"authors":[{"text":"Baker, J.P.","contributorId":95418,"corporation":false,"usgs":true,"family":"Baker","given":"J.P.","email":"","affiliations":[],"preferred":false,"id":380180,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Van Sickle, J.","contributorId":79252,"corporation":false,"usgs":true,"family":"Van Sickle","given":"J.","email":"","affiliations":[],"preferred":false,"id":380177,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Gagen, C.J.","contributorId":51233,"corporation":false,"usgs":true,"family":"Gagen","given":"C.J.","email":"","affiliations":[],"preferred":false,"id":380175,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"DeWalle, David R.","contributorId":23291,"corporation":false,"usgs":true,"family":"DeWalle","given":"David","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":380173,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Sharpe, W.E.","contributorId":103016,"corporation":false,"usgs":true,"family":"Sharpe","given":"W.E.","email":"","affiliations":[],"preferred":false,"id":380183,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Carline, R.F.","contributorId":107444,"corporation":false,"usgs":true,"family":"Carline","given":"R.F.","affiliations":[],"preferred":false,"id":380184,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Baldigo, Barry P. 0000-0002-9862-9119","orcid":"https://orcid.org/0000-0002-9862-9119","contributorId":25174,"corporation":false,"usgs":true,"family":"Baldigo","given":"Barry P.","affiliations":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"preferred":true,"id":380174,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Murdoch, Peter S.","contributorId":73547,"corporation":false,"usgs":true,"family":"Murdoch","given":"Peter S.","affiliations":[],"preferred":false,"id":380176,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Bath, D.W.","contributorId":80436,"corporation":false,"usgs":true,"family":"Bath","given":"D.W.","email":"","affiliations":[],"preferred":false,"id":380178,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Kretser, W.A.","contributorId":102650,"corporation":false,"usgs":true,"family":"Kretser","given":"W.A.","email":"","affiliations":[],"preferred":false,"id":380182,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Simonin, H. A.","contributorId":85713,"corporation":false,"usgs":false,"family":"Simonin","given":"H.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":380179,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Wigington, P.J. Jr.","contributorId":96433,"corporation":false,"usgs":true,"family":"Wigington","given":"P.J.","suffix":"Jr.","email":"","affiliations":[],"preferred":false,"id":380181,"contributorType":{"id":1,"text":"Authors"},"rank":12}]}} ,{"id":70018560,"text":"70018560 - 1996 - Episodic acidification of small streams in the northeastern United States: Fish mortality in field bioassays","interactions":[],"lastModifiedDate":"2023-12-22T16:44:09.087786","indexId":"70018560","displayToPublicDate":"1996-05-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1450,"text":"Ecological Applications","active":true,"publicationSubtype":{"id":10}},"title":"Episodic acidification of small streams in the northeastern United States: Fish mortality in field bioassays","docAbstract":"In situ bioassays were performed as part of the Episodic Response Project, to evaluate the effects of episodic stream acidification on mortality of brook trout (Salvelinus fontinalis) and forage fish species. We report the results of 122 bioassays in 13 streams of the three study regions: the Adirondack mountains of New York, the Catskill mountains of New York, and the Northern Appalachian Plateau of Pennsylvania. Bioassays during acidic episodes had significantly higher mortality than did bioassays conducted under nonacidic conditions, but there was little difference in mortality rates in bioassays experiencing acidic episodes and those experiencing acidic conditions throughout the test period. Multiple logistic regression models were used to relate bioassay mortality rates to summary statistics of time-varying stream chemistry (inorganic monomeric aluminum, calcium, pH, and dissolved organic carbon) estimated for the 20-d bioassay periods. The large suite of candidate regressors also included biological, regional, and seasonal factors, as well as several statistics summarizing various features of aluminum exposure duration and magnitude. Regressor variable selection and model assessment were complicated by multicolinearity and overdispersion. For the target fish species, brook trout, bioassay mortality was most closely related to time-weighted median inorganic aluminum. Median Ca and minimum pH offered additional explanatory power, as did stream-specific aluminum responses. Due to high multicollinearity, the relative importance of different aluminum exposure duration and magnitude variables was difficult to assess, but these variables taken together added no significant explanatory power to models already containing median aluminum. Between 59 and 79% of the variation in brook trout mortality was explained by models employing between one and five regressors. Simpler models were developed for smaller sets of bioassays that tested slimy and mottled sculpin (Cottus cognatus and C. bairdi) as well as blacknose dace (Rhinichthys atratulus). For these forage species a single inorganic aluminum exposure variable successfully accounted for 86-98% of the observed mortality. Even though field bioassays showed evidence of multiple toxicity factors, models results suggest that adequate mortality predictions can be obtained from a single index of inorganic Al concentrations during exposure periods.
","language":"English","publisher":"Ecological Society of America","doi":"10.2307/2269379","issn":"10510761","usgsCitation":"Van Sickle, J., Baker, J., Simonin, H.A., Baldigo, B., Kretser, W., and Sharpe, W., 1996, Episodic acidification of small streams in the northeastern United States: Fish mortality in field bioassays: Ecological Applications, v. 6, no. 2, p. 408-421, https://doi.org/10.2307/2269379.","productDescription":"14 p.","startPage":"408","endPage":"421","numberOfPages":"14","costCenters":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"links":[{"id":227479,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"6","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0a0ee4b0c8380cd5219b","contributors":{"authors":[{"text":"Van Sickle, J.","contributorId":79252,"corporation":false,"usgs":true,"family":"Van Sickle","given":"J.","email":"","affiliations":[],"preferred":false,"id":380041,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Baker, J.P.","contributorId":95418,"corporation":false,"usgs":true,"family":"Baker","given":"J.P.","email":"","affiliations":[],"preferred":false,"id":380043,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Simonin, H. A.","contributorId":85713,"corporation":false,"usgs":false,"family":"Simonin","given":"H.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":380042,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Baldigo, Barry P. 0000-0002-9862-9119","orcid":"https://orcid.org/0000-0002-9862-9119","contributorId":25174,"corporation":false,"usgs":true,"family":"Baldigo","given":"Barry P.","affiliations":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"preferred":true,"id":380040,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Kretser, W.A.","contributorId":102650,"corporation":false,"usgs":true,"family":"Kretser","given":"W.A.","email":"","affiliations":[],"preferred":false,"id":380044,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Sharpe, W.E.","contributorId":103016,"corporation":false,"usgs":true,"family":"Sharpe","given":"W.E.","email":"","affiliations":[],"preferred":false,"id":380045,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70206237,"text":"70206237 - 1996 - Use of ground-penetrating radar and continuous seismic-reflection profiling on surface-water bodies in environmental and engineering studies","interactions":[],"lastModifiedDate":"2019-10-25T12:20:30","indexId":"70206237","displayToPublicDate":"1996-04-01T12:15:26","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3928,"text":"Journal of Environmental & Engineering Geophysics","printIssn":"1083-1363","active":true,"publicationSubtype":{"id":10}},"title":"Use of ground-penetrating radar and continuous seismic-reflection profiling on surface-water bodies in environmental and engineering studies","docAbstract":"Ground‐penetrating radar (GPR) and continuous seismic‐reflection profiling (CSP) on shallow rivers, lakes, and ponds are efficient and economical ways of obtaining subsurface hydrologic and geologic information for environmental and engineering studies. These methods are similar in that they produce continuous subsurface profiles, are easy to use in some applications, and the records can occasionally be straightforward to interpret. They are dissimilar in that GPR cannot penetrate electrically conductive water or subsurface sediments, and CSP usually cannot operate in water less than 5 feet (ft.) deep.
GPR records collected on a lake in New Hampshire have been interpreted to estimate the depth to bedrock and to evaluate the grain‐size characteristics of the underlying stratified drift at the lakeshore boundary. In a pond in Massachusetts, CSP and GPR were used to determine depth to bedrock and the grain‐size characteristics of the subbottom materials in part of the pond. Water‐column multiple reflections, depth and conductivity of water and subsurface materials, and diffractions degraded the quality of the GPR records. CSP records collected in the Connecticut River near Hartford, Connecticut were used to estimate the depth of till and bedrock interfaces and to evaluate grain‐size characteristics of subsurface materials. Interpreted CSP records also can indicate bedding planes within consolidated rock units. Water‐column multiple reflections and very shallow water degraded the quality of the CSP records. GPR and CSP methods have been used to delineate infilled scour holes near bridge piers. Scour holes that were filled with up to 8 ft. of loose sand were mapped during engineering scour studies near a bridge in Connecticut.
Because GPR and CSP operate on different physical principles, the two geophysical methods complement each other. Depending on the required depth of penetration and the degree of resolution needed, one or both of these methods can be used to acquire accurate and reliable subsurface hydrologic and geologic information critical to environmental and engineering studies.
","language":"English","publisher":"Environmental & Engineering Geophysical Society","doi":"10.4133/JEEG1.1.27","usgsCitation":"Haeni, F., 1996, Use of ground-penetrating radar and continuous seismic-reflection profiling on surface-water bodies in environmental and engineering studies: Journal of Environmental & Engineering Geophysics, v. 1, no. 1, p. 27-35, https://doi.org/10.4133/JEEG1.1.27.","productDescription":"9 p.","startPage":"27","endPage":"35","costCenters":[{"id":493,"text":"Office of Ground Water","active":true,"usgs":true}],"links":[{"id":368612,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"1","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Haeni, F.P.","contributorId":87105,"corporation":false,"usgs":true,"family":"Haeni","given":"F.P.","affiliations":[],"preferred":false,"id":773903,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018584,"text":"70018584 - 1996 - Influence of stretching and density contrasts on the chemical evolution of continental magmas: An example from the Ivrea-Verbano Zone","interactions":[],"lastModifiedDate":"2023-09-22T16:10:55.919698","indexId":"70018584","displayToPublicDate":"1996-04-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1336,"text":"Contributions to Mineralogy and Petrology","active":true,"publicationSubtype":{"id":10}},"title":"Influence of stretching and density contrasts on the chemical evolution of continental magmas: An example from the Ivrea-Verbano Zone","docAbstract":"The southern Ivrea-Verbano Zone of the Italian Western Alps contains a huge mafic complex that intruded high-grade metamorphic rocks while they were resident in the lower crust. Geologic mapping and chemical variations of the igneous body were used to study the evolution of underplated crust. Slivers of crustal rocks (septa) interlayered with igneous mafic rocks are concentrated in a narrow zone deep in the complex (Paragneiss-bearing Belt) and show evidence of advanced degrees of partial melting. Variations of rare-earth-element patterns and Sr isotope composition of the igneous rocks across the sequence are consistent with increasing crustal contamination approaching the septa. Therefore, the Paragneiss-bearing Belt is considered representative of an “assimilation region” where in-situ interaction between mantle- and crust-derived magmas resulted in production of hybrid melts. Buoyancy caused upwards migration of the hybrid melts that incorporated the last septa and were stored at higher levels, feeding the Upper Mafic Complex. Synmagmatic stretching of the assimilation region facilitated mixing and homogenization of melts. Chemical variations of granitoids extracted from the septa show that deep septa are more depleted than shallow ones. This suggests that the first incorporated septa were denser than the later ones, as required by the high density of the first-injected mafic magmas. It is inferred that density contrasts between mafic melts and crustal rocks play a crucial role for the processes of contamination of continental magmas. In thick under plated crust, the extraction of early felsic/hybrid melts from the lower crust may be required to increase the density of the lower crust and to allow the later mafic magmas to penetrate higher crustal levels.
","language":"English","publisher":"Springer Link","doi":"10.1007/s004100050153","usgsCitation":"Sinigoi, S., Quick, J.E., Mayer, A., and Budahn, J., 1996, Influence of stretching and density contrasts on the chemical evolution of continental magmas: An example from the Ivrea-Verbano Zone: Contributions to Mineralogy and Petrology, v. 123, no. 3, p. 238-250, https://doi.org/10.1007/s004100050153.","productDescription":"13 p.","startPage":"238","endPage":"250","numberOfPages":"13","costCenters":[],"links":[{"id":227169,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"123","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3b7fe4b0c8380cd625ad","contributors":{"authors":[{"text":"Sinigoi, S.","contributorId":77245,"corporation":false,"usgs":true,"family":"Sinigoi","given":"S.","affiliations":[],"preferred":false,"id":380114,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Quick, J. E.","contributorId":48563,"corporation":false,"usgs":true,"family":"Quick","given":"J.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":380113,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mayer, A.","contributorId":96780,"corporation":false,"usgs":true,"family":"Mayer","given":"A.","email":"","affiliations":[],"preferred":false,"id":380115,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Budahn, J. 0000-0001-9794-8882","orcid":"https://orcid.org/0000-0001-9794-8882","contributorId":33034,"corporation":false,"usgs":true,"family":"Budahn","given":"J.","affiliations":[],"preferred":false,"id":380112,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70211064,"text":"70211064 - 1996 - Controls on 222Rn variations in a fractured crystalline rock aquifer evaluated using aquifer tests and geophysical logging","interactions":[],"lastModifiedDate":"2021-02-01T14:56:28.157324","indexId":"70211064","displayToPublicDate":"1996-03-31T10:01:42","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3825,"text":"Groundwater","active":true,"publicationSubtype":{"id":10}},"displayTitle":"Controls on 222Rn variations in a fractured crystalline rock aquifer evaluated using aquifer tests and geophysical logging","title":"Controls on 222Rn variations in a fractured crystalline rock aquifer evaluated using aquifer tests and geophysical logging","docAbstract":"Concentrations of 222Rn in ground water may vary considerably within megascopically homogeneous rocks over relatively short distances. Calculations indicate that different hydraulic apertures of water‐bearing fractures may account for variations in dissolved 222Rn concentration measured in domestic water wells completed in fractured Pikes Peak Granite, assuming that all other factors influencing dissolved 222Rn concentrations are constant. Concentrations of dissolved 222Rn range from 124 to 840 kBq m‐3 [3,360 to 22,700 picocuries per liter (pCi L‐1)] within a 2.5 km2 well field. Aquifer tests show that transmissivities range from 0.072 to 160 m2 day‐1 within the well field. Acoustic televiewer and heat‐pulse flow meter logging of four wells reveals that, despite tens to hundreds of fractures that intersect each well, a single fracture supplies all the flow to three wells, and one fracture provides 65% of the flow to the fourth well. Aquifer tests indicate that two pairs of the four wells are hydraulically connected. Type‐curve interpretation of early‐time data from aquifer tests reveals classic half‐slope behavior on log‐log plots of drawdown versus time for two wells, suggesting linear flow to a single fracture. Drawdown versus time for the other two wells indicates radial or pseudo‐radial flow, which suggests a higher degree of fracture interconnectivity near those boreholes.
Hydraulic apertures calculated using the cubic law are 0.024 and 0.038 cm for producing fractures in the first hydraulically connected well pair and 0.011 and 0.020 cm for flowing fractures in the second well pair. Assuming uniform distribution of 226Ra along fracture walls and long residence time of water relative to 222Rn decay, the ratio of fracture apertures should equal the inverse ratio of 222Rn concentration in each well. Assuming 50% error in hydraulic aperture estimation and 10% analytical uncertainty in 222Rn measurement, differences in 222Rn concentration between wells in the hydraulically connected pairs can be attributed solely to differences in hydraulic aperture. Different hydraulic apertures, however, do not explain different 222Rn concentrations between well pairs. Allowing for measurement error, a cubic meter of rock transfers from 1.3 to 20 times more 222Rn to ground water in the first pair of wells than in the second pair. Nonuniform distribution of 226Ra along fracture walls, heterogeneous emanating power in the rock‐water system, or short ground‐water residence time along the transmissive fracture network may account for the difference between well pairs.
","language":"English","publisher":"National Groundwater Association","doi":"10.1111/j.1745-6584.1996.tb01885.x","usgsCitation":"Folger, P.F., Poeter, E., Wanty, R.B., Frishman, D., and Day, W., 1996, Controls on 222Rn variations in a fractured crystalline rock aquifer evaluated using aquifer tests and geophysical logging: Groundwater, v. 34, no. 2, p. 250-261, https://doi.org/10.1111/j.1745-6584.1996.tb01885.x.","productDescription":"12 p.","startPage":"250","endPage":"261","costCenters":[{"id":35995,"text":"Geology, Geophysics, and Geochemistry Science Center","active":true,"usgs":true}],"links":[{"id":376324,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Colorado","otherGeospatial":"Conifer, Elk Creek drainage basin, Pine Junction","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -105.39527893066406,\n 39.44520783247914\n ],\n [\n -105.28987884521484,\n 39.44520783247914\n ],\n [\n -105.28987884521484,\n 39.5712929506796\n ],\n [\n -105.39527893066406,\n 39.5712929506796\n ],\n [\n -105.39527893066406,\n 39.44520783247914\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"34","issue":"2","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","contributors":{"authors":[{"text":"Folger, P. F.","contributorId":57862,"corporation":false,"usgs":true,"family":"Folger","given":"P.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":792648,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Poeter, E.","contributorId":48708,"corporation":false,"usgs":true,"family":"Poeter","given":"E.","affiliations":[],"preferred":false,"id":792649,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wanty, Richard B. 0000-0002-2063-6423 rwanty@usgs.gov","orcid":"https://orcid.org/0000-0002-2063-6423","contributorId":443,"corporation":false,"usgs":true,"family":"Wanty","given":"Richard","email":"rwanty@usgs.gov","middleInitial":"B.","affiliations":[{"id":211,"text":"Crustal Geophysics and Geochemistry Science Center","active":true,"usgs":true}],"preferred":true,"id":792650,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Frishman, D.","contributorId":14959,"corporation":false,"usgs":true,"family":"Frishman","given":"D.","affiliations":[],"preferred":false,"id":792651,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Day, W. 0000-0002-9278-2120","orcid":"https://orcid.org/0000-0002-9278-2120","contributorId":72136,"corporation":false,"usgs":true,"family":"Day","given":"W.","affiliations":[],"preferred":false,"id":792652,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70177021,"text":"70177021 - 1996 - A model for field toxicity tests","interactions":[],"lastModifiedDate":"2016-10-14T13:44:30","indexId":"70177021","displayToPublicDate":"1996-03-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1577,"text":"Environmetrics","active":true,"publicationSubtype":{"id":10}},"title":"A model for field toxicity tests","docAbstract":"Toxicity tests conducted under field conditions present an interesting challenge for statistical modelling. In contrast to laboratory tests, the concentrations of potential toxicants are not held constant over the test. In addition, the number and identity of toxicants that belong in a model as explanatory factors are not known and must be determined through a model selection process. We present one model to deal with these needs. This model takes the record of mortalities to form a multinomial distribution in which parameters are modelled as products of conditional daily survival probabilities. These conditional probabilities are in turn modelled as logistic functions of the explanatory factors. The model incorporates lagged values of the explanatory factors to deal with changes in the pattern of mortalities over time. The issue of model selection and assessment is approached through the use of generalized information criteria and power divergence goodness-of-fit tests. These model selection criteria are applied in a cross-validation scheme designed to assess the ability of a model to both fit data used in estimation and predict data deleted from the estimation data set. The example presented demonstrates the need for inclusion of lagged values of the explanatory factors and suggests that penalized likelihood criteria may not provide adequate protection against overparameterized models in model selection.
","language":"English","publisher":"Wiley","doi":"10.1002/(SICI)1099-095X(199603)7:2<215::AID-ENV206>3.0.CO;2-B","usgsCitation":"Kaiser, M.S., and Finger, S.E., 1996, A model for field toxicity tests: Environmetrics, v. 7, no. 2, p. 215-229, https://doi.org/10.1002/(SICI)1099-095X(199603)7:2<215::AID-ENV206>3.0.CO;2-B.","productDescription":"15 p.","startPage":"215","endPage":"229","costCenters":[{"id":192,"text":"Columbia Environmental Research Center","active":true,"usgs":true}],"links":[{"id":329612,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"7","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5801eebfe4b0824b2d18c433","contributors":{"authors":[{"text":"Kaiser, Mark S.","contributorId":175398,"corporation":false,"usgs":false,"family":"Kaiser","given":"Mark","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":651015,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Finger, Susan E. sfinger@usgs.gov","contributorId":1317,"corporation":false,"usgs":true,"family":"Finger","given":"Susan","email":"sfinger@usgs.gov","middleInitial":"E.","affiliations":[],"preferred":true,"id":651016,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019390,"text":"70019390 - 1996 - Submarine landslides","interactions":[],"lastModifiedDate":"2025-07-17T22:55:31.188981","indexId":"70019390","displayToPublicDate":"1996-02-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3283,"text":"Reviews of Geophysics","active":true,"publicationSubtype":{"id":10}},"title":"Submarine landslides","docAbstract":"Landslides are common on inclined areas of the seafloor, particularly in environments where weak geologic materials such as rapidly deposited, finegrained sediment or fractured rock are subjected to strong environmental stresses such as earthquakes, large storm waves, and high internal pore pressures. Submarine landslides can involve huge amounts of material and can move great distances: slide volumes as large as 20,000 km3 and runout distances in excess of 140 km have been reported. They occur at locations where the downslope component of stress exceeds the resisting stress, causing movement along one or several concave to planar rupture surfaces. Some recent slides that originated nearshore and retrogressed back across the shoreline were conspicuous by their direct impact on human life and activities. Most known slides, however, occurred far from land in prehistoric time and were discovered by noting distinct to subtle characteristics, such as headwall scarps and displaced sediment or rock masses, on acoustic-reflection profiles and side-scan sonar images. Submarine landslides can be analyzed using the same mechanics principles as are used for occurrences on land. However, some loading mechanisms are unique, for example, storm waves, and some, such as earthquakes, can have greater impact. The potential for limited-deformation landslides to transform into sediment flows that can travel exceedingly long distances is related to the density of the slope-forming material and the amount of shear strength that is lost when the slope fails.","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95RG03287","issn":"87551209","usgsCitation":"Hampton, M.A., Lee, H., and Locat, J., 1996, Submarine landslides: Reviews of Geophysics, v. 34, no. 1, p. 33-59, https://doi.org/10.1029/95RG03287.","productDescription":"27 p.","startPage":"33","endPage":"59","costCenters":[],"links":[{"id":226922,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9d2ae4b08c986b31d6a2","contributors":{"authors":[{"text":"Hampton, M. A.","contributorId":103271,"corporation":false,"usgs":true,"family":"Hampton","given":"M.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":382570,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lee, H.J.","contributorId":96693,"corporation":false,"usgs":true,"family":"Lee","given":"H.J.","email":"","affiliations":[],"preferred":false,"id":382569,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Locat, J.","contributorId":56392,"corporation":false,"usgs":false,"family":"Locat","given":"J.","email":"","affiliations":[{"id":25484,"text":"Université Laval, Québec City, Canada","active":true,"usgs":false}],"preferred":false,"id":382568,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70006670,"text":"70006670 - 1996 - Mediterranean-type ecosystems: the influence of biodiversity on their functioning","interactions":[],"lastModifiedDate":"2014-06-30T13:41:51","indexId":"70006670","displayToPublicDate":"1996-01-01T13:22:33","publicationYear":"1996","noYear":false,"publicationType":{"id":5,"text":"Book chapter"},"publicationSubtype":{"id":24,"text":"Book Chapter"},"title":"Mediterranean-type ecosystems: the influence of biodiversity on their functioning","docAbstract":"Ecosystems in the Mediterranean-climate regions of the world have served as a unit for comparative ecological studies for over two decades. The cohesiveness of research in this set of widely distributed regions rests on the similarity of the climates where they occur, and the identifiable convergence in elements of their vegetation structure (Di Castri and Mooney 1973). In this chapter we review functional aspects of what have come to be known as Mediterranean-type ecosystems (METs) in the context of a concerned global interest in the sustainability of the human environment and its dependence on biological diversity. The approach we adopt here is to look for evidence that this biodiversity, for which some MTEs are renowned (Cowling, 1992; Hobbs, 1992), has an influence on processes which are important both for the maintenance of natural systems, and for providing \"ecosystem services\" with human utility.
\nAlmost a century ago, Schimper (1903) recognized the biological similarities between five widely separated regions characterized by Mediterranean-type climates, and much comparative work has been done on that basis since. These regions comprise the Mediterranean basin itself, a major portion of California, central Chile, the southwestern and southern extremities of South Africa, and parts of southwestern and southern Australia (Figure 7.1). The first attention paid to MTEs in terms of quantitative ecological research arose out of the International Biological Programme (IBP) of the 1960s and 1970s. Those efforts focused on comparisons between the Chilean and Californian systems (Mooney 1977), and dealt with parallel models of ecosystem processes, especially water flux (Fuentes et al 1995). Because of the already perceived similarities between vegetation in these and the other three regions, the project was soon extended to include all five regions. The first broad comparative overview was published as an anthology which considered the origins and the convergent evolution of MTE components (Di Castri and Mooney 1973). Although the currently accepted classifications of the MTEs is to some extent artificial, it does provide a basis for comparative work, as well as placing mild, temperate winter rainfall regions in perspective with other system types, such as forests, arid lands and even savannas.
\nIt is against this backdrop that the MTE research collegium has grown, giving rise to the organizational structure known as ISOMED (the International Society of Mediterranean Ecologists), which has convened regular conferences under the label MEDECOS, plus a number of extra meetings on specific topics (Table 7.1). One of the more recent in this series of MTE meetings was convened under the auspices of ICSU's Scientific Committee on Problems of the Environment (SCOPE) (see Table 7.1), and dealt with the questions about the functional value of biodiversity. This chapter is based on that meeting and its proceedings (Richardson and Cowling 1993); David and Richardson 1995), and is a distillation of input by teams of ecologists from each of the five regions.
","largerWorkType":{"id":4,"text":"Book"},"largerWorkTitle":"Functional Roles of Biodiversity: A Global Perspective","largerWorkSubtype":{"id":4,"text":"Other Government Series"},"language":"English","publisher":"John Wiley and Sons Ltd","publisherLocation":"Hoboken, NJ","usgsCitation":"Davis, G.W., Richardson, D.M., Keeley, J.E., and Hobbs, R., 1996, Mediterranean-type ecosystems: the influence of biodiversity on their functioning, chap. of Functional Roles of Biodiversity: A Global Perspective, v. Chapter 7, p. 151-183.","productDescription":"p. 151-183","startPage":"151","endPage":"183","numberOfPages":"33","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":289229,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"Chapter 7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"53b286f6e4b07b8813a554da","contributors":{"editors":[{"text":"Mooney, H. A.","contributorId":104219,"corporation":false,"usgs":false,"family":"Mooney","given":"H.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":508378,"contributorType":{"id":2,"text":"Editors"},"rank":1},{"text":"Cushman, J.H.","contributorId":113886,"corporation":false,"usgs":true,"family":"Cushman","given":"J.H.","email":"","affiliations":[],"preferred":false,"id":508381,"contributorType":{"id":2,"text":"Editors"},"rank":2},{"text":"Medina, E.","contributorId":111954,"corporation":false,"usgs":true,"family":"Medina","given":"E.","email":"","affiliations":[],"preferred":false,"id":508380,"contributorType":{"id":2,"text":"Editors"},"rank":3},{"text":"Sala, O.E.","contributorId":96638,"corporation":false,"usgs":true,"family":"Sala","given":"O.E.","email":"","affiliations":[],"preferred":false,"id":508377,"contributorType":{"id":2,"text":"Editors"},"rank":4},{"text":"Schulze, E. #NAME?","contributorId":111878,"corporation":false,"usgs":false,"family":"Schulze","given":"E.","email":"","middleInitial":"#NAME?","affiliations":[],"preferred":false,"id":508379,"contributorType":{"id":2,"text":"Editors"},"rank":5}],"authors":[{"text":"Davis, George W.","contributorId":12376,"corporation":false,"usgs":true,"family":"Davis","given":"George","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":354992,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Richardson, David M.","contributorId":14565,"corporation":false,"usgs":true,"family":"Richardson","given":"David","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":354993,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Keeley, Jon E. 0000-0002-4564-6521 jon_keeley@usgs.gov","orcid":"https://orcid.org/0000-0002-4564-6521","contributorId":1268,"corporation":false,"usgs":true,"family":"Keeley","given":"Jon","email":"jon_keeley@usgs.gov","middleInitial":"E.","affiliations":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"preferred":true,"id":354991,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hobbs, Richard J.","contributorId":59682,"corporation":false,"usgs":true,"family":"Hobbs","given":"Richard J.","affiliations":[],"preferred":false,"id":354994,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70017759,"text":"70017759 - 1996 - Using hydrogeochemical methods to evaluate complex quaternary subsurface stratigraphy Block Island, Rhode Island, USA","interactions":[],"lastModifiedDate":"2020-03-25T10:59:22","indexId":"70017759","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1923,"text":"Hydrogeology Journal","active":true,"publicationSubtype":{"id":10}},"title":"Using hydrogeochemical methods to evaluate complex quaternary subsurface stratigraphy Block Island, Rhode Island, USA","docAbstract":"One of the major problems in hydrogeologic investigations of glaciated regions is the determination of complex stratigraphic relationships in the subsurface where insufficient information is available from drilling and geophysical records. In this paper, chemical characteristics of groundwater were used to identify stratigraphic changes in glacial deposits that were previously inferred on Block Island, Rhode Island, USA, an emergent remnant of the late Wisconsinan terminal moraine, located approximately 16 km south of the Rhode Island mainland. Two chemically distinct water types are recognized on the island: 1) high-iron, characterized by dissolved silica levels in excess of 20 mg/L, bicarbonate greater than 30 mg/L and dissolved iron ranging from 1-20 mg/L; and 2) low-iron, characterized by dissolved silica levels below 16 mg/L, bicarbonate less than 30 mg/L, and less than 0.3 mg/L dissolved iron. The spatial distribution of iron-bearing minerals and organic matter and the resulting redox conditions are believed to control the occurrence of highiron groundwater. The high-iron waters occur almost exclusively in the eastern half of the island and appear to coincide with the presence of allochthonous blocks of Cretaceous-age coastal-plain sediments that were incorporated into Pleistocene-age deposits derived from the Narragansett Bay-Buzzard's Bay lobe of the Late Wisconsinan Laurentide ice sheet. The low-iron waters occur in the western half of the island, where the occurrence of these Cretaceous-age blocks is rare and the sediments are attributed to a sublobe of the Hudson-Champlain lobe of the Late Wisconsinan ice sheet.
","language":"English","publisher":"Springer","doi":"10.1007/s100400050093","usgsCitation":"Veeger, A., and Stone, B., 1996, Using hydrogeochemical methods to evaluate complex quaternary subsurface stratigraphy Block Island, Rhode Island, USA: Hydrogeology Journal, v. 4, no. 4, p. 69-82, https://doi.org/10.1007/s100400050093.","productDescription":"14 p.","startPage":"69","endPage":"82","numberOfPages":"14","costCenters":[{"id":40020,"text":"Florence Bascom Geoscience Center","active":true,"usgs":true}],"links":[{"id":488745,"rank":1,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://digitalcommons.uri.edu/geo_facpubs/178","text":"External Repository"},{"id":228484,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Rhode Island","otherGeospatial":"Block Island","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -71.61918640136719,\n 41.14531119462475\n ],\n [\n -71.54090881347656,\n 41.14531119462475\n ],\n [\n -71.54090881347656,\n 41.233800286547435\n ],\n [\n -71.61918640136719,\n 41.233800286547435\n ],\n [\n -71.61918640136719,\n 41.14531119462475\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"4","issue":"4","noUsgsAuthors":false,"publicationDate":"2012-11-20","publicationStatus":"PW","scienceBaseUri":"505bc05ee4b08c986b32a0ad","contributors":{"authors":[{"text":"Veeger, A.I.","contributorId":100031,"corporation":false,"usgs":true,"family":"Veeger","given":"A.I.","email":"","affiliations":[],"preferred":false,"id":377485,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stone, B. D. 0000-0001-6092-0798","orcid":"https://orcid.org/0000-0001-6092-0798","contributorId":50919,"corporation":false,"usgs":true,"family":"Stone","given":"B. D.","affiliations":[],"preferred":false,"id":377484,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019361,"text":"70019361 - 1996 - Stress/strain changes and triggered seismicity at The Geysers, California","interactions":[],"lastModifiedDate":"2024-11-13T17:44:17.558219","indexId":"70019361","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":"Stress/strain changes and triggered seismicity at The Geysers, California","docAbstract":"The principal results of this study of remotely triggered seismicity in The Geysers geothermal field are the demonstration that triggering (initiation of earthquake failure) depends on a critical strain threshold and that the threshold level increases with decreasing frequency, or, equivalently, depends on strain rate. This threshold function derives from (1) analyses of dynamic strains associated with surface waves of the triggering earthquakes, (2) statistically measured aftershock zone dimensions, and (3) analytic functional representations of strains associated with power production and tides. The threshold is also consistent with triggering by static strain changes and implies that both static and dynamic strains may cause aftershocks. The observation that triggered seismicity probably occurs in addition to background activity also provides an important constraint on the triggering process. Assuming the physical processes underlying earthquake nucleation to be the same, Gomberg [this issue] discusses seismicity triggered by the MW 7.3 Landers earthquake, its constraints on the variability of triggering thresholds with site, and the implications of time delays between triggering and triggered earthquakes. Our results enable us to reject the hypothesis that dynamic strains simply nudge prestressed faults over a Coulomb failure threshold sooner than they would have otherwise. We interpret the rate-dependent triggering threshold as evidence of several competing processes with different time constants, the faster one(s) facilitating failure and the other(s) inhibiting it. Such competition is a common feature of theories of slip instability. All these results, not surprisingly, imply that to understand earthquake triggering one must consider not only simple failure criteria requiring exceedence of some constant threshold but also the requirements for generating instabilities.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95JB03250","issn":"01480227","usgsCitation":"Gomberg, J., and Davis, S., 1996, Stress/strain changes and triggered seismicity at The Geysers, California: Journal of Geophysical Research B: Solid Earth, v. 101, no. 1, p. 733-749, https://doi.org/10.1029/95JB03250.","productDescription":"17 p.","startPage":"733","endPage":"749","numberOfPages":"17","costCenters":[],"links":[{"id":226377,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"1","noUsgsAuthors":false,"publicationDate":"1996-01-10","publicationStatus":"PW","scienceBaseUri":"505b9b6ee4b08c986b31cea4","contributors":{"authors":[{"text":"Gomberg, J.","contributorId":95994,"corporation":false,"usgs":true,"family":"Gomberg","given":"J.","email":"","affiliations":[],"preferred":false,"id":382476,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davis, S.","contributorId":43505,"corporation":false,"usgs":true,"family":"Davis","given":"S.","affiliations":[],"preferred":false,"id":382475,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019324,"text":"70019324 - 1996 - A one-pot procedure for the quantitative conversion of glycosides into acetylated glycosyl fluorides","interactions":[],"lastModifiedDate":"2012-03-12T17:19:11","indexId":"70019324","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1181,"text":"Carbohydrate Research","active":true,"publicationSubtype":{"id":10}},"title":"A one-pot procedure for the quantitative conversion of glycosides into acetylated glycosyl fluorides","docAbstract":"[No abstract available]","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Carbohydrate Research","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0008-6215(95)00328-2","issn":"00086215","usgsCitation":"Bergamaschi, B., and Hedges, J.I., 1996, A one-pot procedure for the quantitative conversion of glycosides into acetylated glycosyl fluorides: Carbohydrate Research, v. 280, no. 2, p. 345-350, https://doi.org/10.1016/0008-6215(95)00328-2.","startPage":"345","endPage":"350","numberOfPages":"6","costCenters":[],"links":[{"id":205721,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0008-6215(95)00328-2"},{"id":226424,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"280","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e4cee4b0c8380cd4693b","contributors":{"authors":[{"text":"Bergamaschi, B.A. 0000-0002-9610-5581","orcid":"https://orcid.org/0000-0002-9610-5581","contributorId":22401,"corporation":false,"usgs":true,"family":"Bergamaschi","given":"B.A.","affiliations":[],"preferred":false,"id":382353,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hedges, J. I.","contributorId":30757,"corporation":false,"usgs":true,"family":"Hedges","given":"J.","email":"","middleInitial":"I.","affiliations":[],"preferred":false,"id":382354,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018929,"text":"70018929 - 1996 - Outburst floods from glacier-dammed lakes: The effect of mode of lake drainage on flood magnitude","interactions":[],"lastModifiedDate":"2019-04-17T08:26:26","indexId":"70018929","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1425,"text":"Earth Surface Processes and Landforms","active":true,"publicationSubtype":{"id":10}},"title":"Outburst floods from glacier-dammed lakes: The effect of mode of lake drainage on flood magnitude","docAbstract":"Published accounts of outburst floods from glacier‐dammed lakes show that a significant number of such floods are associated not with drainage through a tunnel incised into the basal ice—the process generally assumed—but rather with ice‐marginal drainage, mechanical failure of part of the ice dam, or both. Non‐tunnel floods are strongly correlated with formation of an ice dam by a glacier advancing from a tributary drainage into either a main river valley or a pre‐existing body of water (lake or fiord). For a given lake volume, non‐tunnel floods tend to have significantly higher peak discharges than tunnel‐drainage floods. Statistical analysis of data for floods associated with subglacial tunnels yields the following empirical relation between lake volume V and peak discharge Qp : Qp = 46V0.66 (r2 = 0.70), when Qp is expressed in metres per second and V in millions of cubic metres. This updates the so‐called Clague–Mathews relation. For non‐tunnel floods, the analogous relation is Qp = 1100V0.44 (r2 = 0.58). The latter relation is close to one found by Costa (1988) for failure of constructed earthen dams. This closeness is probably not coincidental but rather reflects similarities in modes of dam failure and lake drainage. We develop a simple physical model of the breach‐widening process for non‐tunnel floods, assuming that (1) the rate of breach widening is controlled by melting of the ice, (2) outflow from the lake is regulated by the hydraulic condition of critical flow where water enters the breach, and (3) the effect of lake temperature may be dealt with as done by Clarke (1982). Calculations based on the model simulate quite well outbursts from Lake George, Alaska. Dimensional analysis leads to two approximations of the form Qp ∝ Vqf(hi, θ0), where q = 0.5 to 0.6, hi is initial lake depth, θ0 is lake temperature, and the form of f (hi, θ0) depends on the relative importance of viscous dissipation and the lake's thermal energy in determining the rate of breach opening. These expressions, along with the regression relations, should prove useful for assessing the probable magnitude of breach‐type outburst floods.
","language":"English","publisher":"Wiley","doi":"10.1002/(SICI)1096-9837(199608)21:8<701::AID-ESP615>3.0.CO;2-2","issn":"01979337","usgsCitation":"Walder, J.S., and Costa, J.E., 1996, Outburst floods from glacier-dammed lakes: The effect of mode of lake drainage on flood magnitude: Earth Surface Processes and Landforms, v. 21, no. 8, p. 701-723, https://doi.org/10.1002/(SICI)1096-9837(199608)21:8<701::AID-ESP615>3.0.CO;2-2.","productDescription":"23 p.","startPage":"701","endPage":"723","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":226529,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"21","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a71a6e4b0c8380cd766ca","contributors":{"authors":[{"text":"Walder, Joseph S. jswalder@usgs.gov","contributorId":2046,"corporation":false,"usgs":true,"family":"Walder","given":"Joseph","email":"jswalder@usgs.gov","middleInitial":"S.","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":381120,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Costa, John E.","contributorId":105743,"corporation":false,"usgs":true,"family":"Costa","given":"John","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":381119,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018809,"text":"70018809 - 1996 - The imaging node for the Planetary Data System","interactions":[],"lastModifiedDate":"2012-03-12T17:19:28","indexId":"70018809","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3083,"text":"Planetary and Space Science","active":true,"publicationSubtype":{"id":10}},"title":"The imaging node for the Planetary Data System","docAbstract":"The Planetary Data System Imaging Node maintains and distributes the archives of planetary image data acquired from NASA's flight projects with the primary goal of enabling the science community to perform image processing and analysis on the data. The Node provides direct and easy access to the digital image archives through wide distribution of the data on CD-ROM media and on-line remote-access tools by way of Internet services. The Node provides digital image processing tools and the expertise and guidance necessary to understand the image collections. The data collections, now approaching one terabyte in volume, provide a foundation for remote sensing studies for virtually all the planetary systems in our solar system (except for Pluto). The Node is responsible for restoring data sets from past missions in danger of being lost. The Node works with active flight projects to assist in the creation of their archive products and to ensure that their products and data catalogs become an integral part of the Node's data collections.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Planetary and Space Science","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0032-0633(95)00103-4","issn":"00320633","usgsCitation":"Eliason, E.M., LaVoie, S., and Soderblom, L., 1996, The imaging node for the Planetary Data System: Planetary and Space Science, v. 44, no. 1 SPEC. ISS., p. 23-32, https://doi.org/10.1016/0032-0633(95)00103-4.","startPage":"23","endPage":"32","numberOfPages":"10","costCenters":[],"links":[{"id":205848,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0032-0633(95)00103-4"},{"id":227091,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"44","issue":"1 SPEC. ISS.","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bacdae4b08c986b3237b4","contributors":{"authors":[{"text":"Eliason, E. M.","contributorId":93113,"corporation":false,"usgs":true,"family":"Eliason","given":"E.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":380821,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"LaVoie, S.K.","contributorId":47927,"corporation":false,"usgs":true,"family":"LaVoie","given":"S.K.","email":"","affiliations":[],"preferred":false,"id":380820,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Soderblom, L.A. 0000-0002-0917-853X","orcid":"https://orcid.org/0000-0002-0917-853X","contributorId":6139,"corporation":false,"usgs":true,"family":"Soderblom","given":"L.A.","affiliations":[],"preferred":false,"id":380819,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018782,"text":"70018782 - 1996 - Simulation of phosphate transport in sewage-contaminated groundwater, Cape Cod, Massachusetts","interactions":[],"lastModifiedDate":"2019-02-20T08:40:17","indexId":"70018782","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":835,"text":"Applied Geochemistry","active":true,"publicationSubtype":{"id":10}},"title":"Simulation of phosphate transport in sewage-contaminated groundwater, Cape Cod, Massachusetts","docAbstract":"Sewage-contaminated groundwater currently discharges to Ashumet Pond, located on Cape Cod, Massachusetts. Phosphate concentrations as high as 60 μmol l−1 have been measured in groundwater entering Ashumet Pond, and there is concern that the rate of eutrophication could increase. Phosphate in the sewage plume is sorbed by aquifer sediment; the amount is a function of phosphate concentration and pH. A nonelectrostatic surface-complexation model coupled with a one-dimensional solute-transport code was used to simulate sorption and desorption of phosphate in laboratory column experiments. The model simulated sorption of phosphate reasonably well, although the slow rate of approach to complete breakthrough indicated a nonequilibrium process that was not accounted for in the solute-transport model. The rate of phosphate desorption in the column experiments was relatively slow. Phosphate could still be measured in effluent after 160 pore volumes of uncontaminated groundwater had been flushed through the columns. Desorption was partly a function of the slowly decreasing pH in the columns and could be modeled quantitatively. Disposal of sewage at this site is scheduled to stop in 1995; however, a large reservoir of sorbed phosphate exists on aquifer sediment upgradient from Ashumet Pond. Computer simulations predict that desorption of phosphate could result in contamination of Ashumet Pond for decades.
Pesticides were detected in ground-water samples collected from 20 springs and nine wells in the Ozark Plateaus Province of Arkansas, Kansas, Missouri, and Oklahoma. From April through September 1993, water samples were collected from 50 shallow domestic wells and 50 springs in the Springfield Plateau and Ozark aquifers and analyzed for 47 pesticides and metabolites. Pesticides were detected in 17 water samples from the Springfield Plateau aquifer and 12 water samples from the Ozark aquifer. Fourteen pesticides were detected, with a maximum of four pesticides detected in any one sample. The most commonly detected pesticides were atrazine (14 detections), prometon (11 detections), and tebuthiuron (seven detections). P, P' DDE, a metabolite of DDT, was detected in water samples from three wells and one spring. The remaining pesticides were detected in three or less samples. The occurrence and distribution of pesticides probably are related to the local land use near a sampling site. Pesticide detections were significantly related to aquifer, site type, and discharge of springs.
Efflorescent crusts at the Eagle Borax spring in Death Valley, California, contain an array of rare Mg and K borate minerals, several of which are only known from one or two other localities. The Mg- and/or K-bearing borates include aristarainite, hydroboracite, kaliborite, mcallisterite, pinnoite, rivadavite, and santite. Ulexite and probertite also occur in the area, although their distribution is different from that of the Mg and K borates. Other evaporite minerals in the spring vicinity include halite, thenardite, eugsterite, gypsum-anhydrite, hexahydrite, and bloedite. Whereas the first five of these minerals are found throughout Death Valley, the last two Mg sulfates are more restricted in occurrence and are indicative of Mg-enriched ground water.Mineral associations observed at the Eagle Borax spring, and at many other borate deposits worldwide, can be explained by the chemical fractionation of borate-precipitating waters during the course of evaporative concentration. The Mg sulfate and Mg borate minerals in the Eagle Borax efflorescent crusts point to the fractionation of Ca by the operation of a chemical divide involving Ca carbonate and Na-Ca borate precipitation in the subsurface sediments. At many other borate mining localities, the occurrence of ulexite in both Na borate (borax-kernite) and Ca borate (ulexite-colemanite) deposits similarly reflects ulexite's coprecipitation with Ca carbonate at an early concentration stage. Such ulexite may perhaps be converted to colemanite by later reaction with the coexisting Ca carbonate--the latter providing the additional Ca (super 2+) ions needed for the conversion. Mg and Ca-Mg borates are the expected late-stage concentration products of waters forming ulexite-colemanite deposits and are therefore most likely to occur in the marginal zones or nearby mud facies of ulexite-colemanite orebodies. Under some circumstances, Mg and Ca-Mg borates might provide a useful prospecting guide for ulexite-colemanite deposits, although the high solubility of Mg borate minerals may prevent their formation in lacustrine settings and certainly inhibits their geologic preservation. The occurrence of Mg borates in borax-kernite deposits is also related to fractionation processes and points to the operation of an Mg borate chemical divide, characterized by Mg borate precipitation ahead of Mg carbonate. All of these considerations imply that Mg is a significant chemical component of many borate-depositing ground waters, even though Mg borate minerals may not be strongly evident in borate orebodies.The Eagle Borax spring borates and other evaporite minerals were studied using spectroscopic and X-ray powder diffraction methods, which were found to be highly complementary. Spectral reflectance measurements provide a sensitive means for detecting borates present in mixtures with other evaporites and can be used to screen samples rapidly for X-ray diffraction analysis. The apparently limited occurrence of Mg and K borate minerals compared to Ca and Na borates may stem partly from the inefficiency of X-ray diffraction methods for delineating the mineralogy of large and complex deposits. Spectral reflectance measurements can be made in the laboratory, in the field, on the mine face, and even remotely. Reflectance data should have an important role in studies of existing deposit mineralogy and related chemical fractionation processes, and perhaps in the discovery of new borate mineral resources.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.91.3.622","issn":"03610128","usgsCitation":"Crowley, J., 1996, Mg- and K-bearing borates and associated evaporites at Eagle Borax spring, Death Valley, California: A spectroscopic exploration: Economic Geology, v. 91, no. 3, p. 622-635, https://doi.org/10.2113/gsecongeo.91.3.622.","productDescription":"14 p.","startPage":"622","endPage":"635","numberOfPages":"14","costCenters":[],"links":[{"id":227003,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"91","issue":"3","noUsgsAuthors":false,"publicationDate":"1996-05-01","publicationStatus":"PW","scienceBaseUri":"505a5627e4b0c8380cd6d3ad","contributors":{"authors":[{"text":"Crowley, J.K.","contributorId":103690,"corporation":false,"usgs":true,"family":"Crowley","given":"J.K.","email":"","affiliations":[],"preferred":false,"id":380491,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018657,"text":"70018657 - 1996 - Low-velocity fault-zone guided waves: Numerical investigations of trapping efficiency","interactions":[],"lastModifiedDate":"2023-10-23T12:02:51.102592","indexId":"70018657","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":"Low-velocity fault-zone guided waves: Numerical investigations of trapping efficiency","docAbstract":"Recent observations have shown that shear waves trapped within low-velocity fault zones may be the most sensitive measure of fault-zone structure (Li et al., 1994a, 1994b). Finite-difference simulations demonstrate the effects of several types of complexity on observations of fault-zone trapped waves. Overlying sediments with a thickness more than one or two fault-zone widths and fault-zone step-overs more than one or two fault widths disrupt the wave guide. Fault kinks and changes in fault-zone width with depth leave readily observable trapped waves. We also demonstrate the effects of decreased trapped wave excitation with increasing hypocentral offset from the fault and the effects of varying the contrast between the velocity in the fault zone and surrounding hard rock. Careful field studies may provide dramatic improvements in our knowledge of fault-zone structure.
Continental North America's greatest earthquake sequence struck on the western frontier of the United States. The frontier was not then California but the valley of the continent's greatest river, the Mississippi, and the sequence was the New Madrid earthquakes of the winter of 1811–1812. Their described impacts on the land and the river were so dramatic as to produce widespread modern disbelief. However, geological, geophysical, and historical research, carried out mostly in the past two decades, has verified much in the historical accounts. The sequence included at least six (possibly nine) events of estimated moment magnitude M ≥ 7 and two of M ≃ 8. The faulting was in the intruded crust of a failed intracontinental rift, beneath the saturated alluvium of the river valley, and its violent shaking resulted in massive and extensive liquefaction. The largest earthquakes ruptured at least six (and possibly more than seven) intersecting fault segments, one of which broke the surface as a thrust fault that disrupted the bed of the Mississippi River in at least 2 (and possibly four) places.
","language":"English","publisher":"Annual Reviews","doi":"10.1146/annurev.earth.24.1.339","usgsCitation":"Johnston, A.C., and Schweig, E., 1996, The enigma of the New Madrid earthquakes of 1811-1812: Annual Review of Earth and Planetary Sciences, v. 24, p. 339-384, https://doi.org/10.1146/annurev.earth.24.1.339.","productDescription":"46 p.","startPage":"339","endPage":"384","numberOfPages":"46","costCenters":[],"links":[{"id":227619,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Arkansas, Kentucky, Missouri, Tennessee","otherGeospatial":"New Madrid seismic zone","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -91,\n 37\n ],\n [\n -91,\n 35\n ],\n [\n -89,\n 35\n ],\n [\n -89,\n 37\n ],\n [\n -91,\n 37\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"24","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505babcde4b08c986b3230a3","contributors":{"authors":[{"text":"Johnston, A. C.","contributorId":85574,"corporation":false,"usgs":true,"family":"Johnston","given":"A.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":380335,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schweig, E.S.","contributorId":34538,"corporation":false,"usgs":true,"family":"Schweig","given":"E.S.","email":"","affiliations":[],"preferred":false,"id":380334,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018618,"text":"70018618 - 1996 - Soil and soil solution chemistry under red spruce stands across the northeastern united states","interactions":[],"lastModifiedDate":"2012-03-12T17:19:26","indexId":"70018618","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3419,"text":"Soil Science","active":true,"publicationSubtype":{"id":10}},"title":"Soil and soil solution chemistry under red spruce stands across the northeastern united states","docAbstract":"Red spruce ecosystems in the northeastern United States are of interest because this species is undergoing regional decline. Their underlying soils have been examined closely at only a few sites, and information available on red spruce soils throughout this region is limited.This study was conducted to examine soil and soil solution chemistry at red spruce sites in the northeastern US that encompass the range of soil conditions in which red spruce grow. Soils and soil solutions from Oa and B horizons were obtained over a 2-year period from 12 undisturbed red spruce forests (elevations of 80-975 m) in New York, Vermont, New Hampshire, and Maine. All sites had extremely acid Spodosols (Oa soil pH range 2.56 to 3.11 in 0.01 M CaCl2), with generally low concentrations of base cations and high concentrations of Al on soil exchange sites. There was considerable range in exchange chemistry across the sites, however, with exchangeable Ca in Oa horizons ranging from 2.1 to 21.6 cmolckg-1 and exchangeable Al from 3.6 to 18.3 cmolckg-1. Solution chemistry had high concentrations of DOC in the Oa horizons (1160-15200 ??mol L-1), with higher concentrations in the fall than in the spring, which was probably a reflection of fresh litter inputs. Despite high concentrations of DOC in all solutions, inorganic Al was found in some Oa solutions at concentrations as high as 26 ??mol L-1. Ratios of Ca2+ to inorganic Al concentraturns were less than 1.0 in the Oa horizon of one site, and were well below 1.0 in B horizons of all sites. That soil chemistry was related to soil solution chemistry was demonstrated by solution Al concentrations in the forest floor having significant relationships with pyrophosphate extractable Al, although it was not related in the B horizon. Soil exchangeable Ca/Al ratios in the Oa horizon explained 75% of the variation in solution Ca2+/inorganic Al ratios when mean values were used for each site. Our studies have expanded the range of soil chemical conditions measured for red spruce soils. By characterizing the regional variability, these results will enable site intensive process studies to be better applied to regional problems such as spruce decline.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Soil Science","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"0038075X","usgsCitation":"David, M., and Lawrence, G., 1996, Soil and soil solution chemistry under red spruce stands across the northeastern united states: Soil Science, v. 161, no. 5, p. 314-328.","startPage":"314","endPage":"328","numberOfPages":"15","costCenters":[],"links":[{"id":227039,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"161","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b91eae4b08c986b319ba2","contributors":{"authors":[{"text":"David, M.B.","contributorId":20089,"corporation":false,"usgs":true,"family":"David","given":"M.B.","email":"","affiliations":[],"preferred":false,"id":380231,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lawrence, G.B. 0000-0002-8035-2350","orcid":"https://orcid.org/0000-0002-8035-2350","contributorId":76347,"corporation":false,"usgs":true,"family":"Lawrence","given":"G.B.","affiliations":[],"preferred":false,"id":380232,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018617,"text":"70018617 - 1996 - Factors affecting suspended-solids concentrations in South San Francisco Bay, California","interactions":[],"lastModifiedDate":"2024-04-30T16:30:32.812079","indexId":"70018617","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2315,"text":"Journal of Geophysical Research C: Oceans","active":true,"publicationSubtype":{"id":10}},"title":"Factors affecting suspended-solids concentrations in South San Francisco Bay, California","docAbstract":"Measurements of suspended-solids concentration (SSC) were made at two depths at three sites in South San Francisco Bay (South Bay) to determine the factors that affect SSC. Twenty-eight segments of reliable and continuous SSC time series data longer than 14 days were collected from late 1991 or 1992 through September 1993. Spectral analysis and singular spectrum analysis were used to relate these data segments to time series of several potential forcing factors, including diurnal and semidiurnal tides, the spring-neap tidal cycle, wind shear, freshwater runoff, and longitudinal density differences. SSC is greatest during summer, when a landward wind shear is applied to South Bay by the afternoon sea breeze. About one half the variance of SSC is caused by the spring-neap cycle, and SSC lags the spring-neap cycle by about 2 days. Relatively short duration of slack water limits the duration of deposition of suspended solids and consolidation of newly deposited bed sediment during the tidal cycle, so suspended solids accumulate in the water column as a spring tide is approached and slowly deposit as a neap tide is approached. Perturbations in SSC caused by wind and local runoff from winter storms during the study period were usually much smaller than SSC variations caused by the spring-neap cycle. Variations of SSC at the study sites at tidal timescales are tidally forced, and nonlinear physical processes are significant. Advective transport dominates during spring tides, when water with higher SSC due to wind wave resuspension is advected to the main channel from shallow water, but, during neap tides, advective transport is less significant. The findings of this and other studies indicate that the tidally averaged transport of suspended solids responds to seasonal variations of wind shear in South Bay.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JC00747","issn":"01480227","usgsCitation":"Schoellhamer, D., 1996, Factors affecting suspended-solids concentrations in South San Francisco Bay, California: Journal of Geophysical Research C: Oceans, v. 101, no. C5, p. 12087-12095, https://doi.org/10.1029/96JC00747.","productDescription":"9 p.","startPage":"12087","endPage":"12095","numberOfPages":"9","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":552,"text":"San Francisco Bay-Delta","active":false,"usgs":true},{"id":5079,"text":"Pacific Regional Director's Office","active":true,"usgs":true}],"links":[{"id":227038,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"C5","noUsgsAuthors":false,"publicationDate":"1996-05-15","publicationStatus":"PW","scienceBaseUri":"505a0ea8e4b0c8380cd5356c","contributors":{"authors":[{"text":"Schoellhamer, D. H. 0000-0001-9488-7340","orcid":"https://orcid.org/0000-0001-9488-7340","contributorId":85624,"corporation":false,"usgs":true,"family":"Schoellhamer","given":"D. H.","affiliations":[],"preferred":false,"id":380230,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}