The Ozark region of the U.S. midcontinent is host to a number of Mississippi Valley-type districts, including the world-class Viburnum Trend, Old Lead Belt, and Tri-State districts and the smaller Southeast Missouri barite, Northern Arkansas, and Central Missouri districts. There is increasing evidence that the Ozark Mississippi Valley-type districts formed locally within a large, interconnected hydrothermal system that also produced broad fringing areas of trace mineralization, extensive subtle hydrothermal alteration, broad thermal anomalies, and regional deposition of hydrothermal dolomite cement. The fluid drive was provided by gravity flow accompanying uplift of foreland thrust belts during the Late Pennsylvanian to Early Permian Ouaehita orogeny.In this study, we use chemical speciation and reaction path calculations, based on quantitative chemical analyses of fluid inclusions, to constrain likely hydrothermal brine compositions and to determine which precipitation mechanisms are consistent with the hydrothermal mineral assemblages observed regionally and locally within each Mississippi Valley-type district in the Ozark region. Deposition of the regional hydrothermal dolomite cement with trace sulfides likely occurred in response to near-isothermal effervescence of CO 2 from basinal brines as they migrated to shallower crustal levels and lower confining pressures. In contrast, our calculations indicate that no one depositional process can reproduce the mineral assemblages and proportions of minerals observed in each Ozark ore district; rather, individual districts require specific depositional mechanisms that reflect the local host-rock composition, structural setting, and hydrology.Both the Northern Arkansas and Tri-State districts are localized by normal faults that likely allowed brines to rise from deeper Cambrian-Ordovician dolostone aquifers into shallower carbonate sequences dominated by limestones. In the Northern Arkansas district, jasperoid preferentially replaced limestones in the mixed dolostone-limestone sedimentary packages. Modeling results indicate that the ore and alteration assemblages in the Tri-State and Northern Arkansas districts resulted from the flow of initially dolomite-saturated brines into cooler limestones. Adjacent to fluid conduits where water/rock ratios were the highest, the limestone was replaced by dolomite. As the fluids moved outward into cooler limestone, jasperoid and sulfide replaced limestone. Isothermal boiling of the ore fluids may have produced open-space filling of hydrothermal dolomite with minor sulfides in breccia and fault zones. Local mixing of the regional brine with locally derived sulfur undoubtedly played a role in the development of sulfide-rich ore runs.Sulfide ores of the Central Missouri district are largely open-space filling of sphalerite plus minor galena in dolostone karst features localized along a broad anticline. Hydrothermal solution collapse during ore deposition was a minor process, indicating dolomite was slightly undersaturated during ore deposition. No silicification and only minor hydrothermal dolomite is present in the ore deposits. The reaction path that best explains the features of the Central Missouri sulfide deposits is the near-isothermal mixing of two dolomite-saturated fluids with different H 2 S and metal contents. Paleokarst features may have allowed the regional brine to rise stratigraphically and mix with locally derived, H 2 S-rich fluids. The Viburnum Trend and Old Lead Belt ores are galena rich with lesser amounts of sphalerite; they replace the most permeable dolostone facies in the Bonneterre Dolomite. Hydrothermal dissolution of host dolostone was concurrent with sulfide deposition, but dolomite deposition occurred episodically between periods of sulfide deposition. The important ore controls in these districts are a variety of sedimentary and geologic features that allowed cross-stratigraphic fluid flow and provided opportunities for fluid mixing. The reaction path which best reproduces the broad features of the Viburnum Trend and Old Lead Belt ores is one in which a dolomite-saturated, lead-rich, zinc- and H 2 S-poor brine mixes with a less saline, H 2 S-rich fluid. The brine became enriched in K, Mg, and Pb and depleted in H 2 S as it flowed through sandstone and redbed aquifers prior to entering the district. This mixing model is consistent with the abundant fluid inclusion and stable isotope evidence for fluid mixing in the districts. Small amounts of cooling associated with the mixing may have contributed to sulfide deposition.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.89.6.1361","issn":"03610128","usgsCitation":"Plumlee, G., Leach, D.L., Hofstra, A., Landis, G.P., Rowan, E., and Viets, J., 1994, Chemical reaction path modeling of ore deposition in Mississippi Valley-type Pb-Zn deposits of the Ozark region, US midcontinent: Economic Geology, v. 89, no. 6, p. 1361-1383, https://doi.org/10.2113/gsecongeo.89.6.1361.","productDescription":"23 p.","startPage":"1361","endPage":"1383","costCenters":[],"links":[{"id":228512,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Alabama, Arkansas, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Oklahoma, Tennessee, Texas","otherGeospatial":"Ozarks","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -98.17169017092607,\n 39.06166617237287\n ],\n [\n -98.17169017092607,\n 31.661702492806285\n ],\n [\n -85.2462291629069,\n 31.661702492806285\n ],\n [\n -85.2462291629069,\n 39.06166617237287\n ],\n [\n -98.17169017092607,\n 39.06166617237287\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"89","issue":"6","noUsgsAuthors":false,"publicationDate":"1994-10-01","publicationStatus":"PW","scienceBaseUri":"5059f593e4b0c8380cd4c2c5","contributors":{"authors":[{"text":"Plumlee, G.S.","contributorId":80698,"corporation":false,"usgs":true,"family":"Plumlee","given":"G.S.","email":"","affiliations":[],"preferred":false,"id":376542,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Leach, D. L.","contributorId":18758,"corporation":false,"usgs":true,"family":"Leach","given":"D.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":376539,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hofstra, A. H. 0000-0002-2450-1593","orcid":"https://orcid.org/0000-0002-2450-1593","contributorId":41426,"corporation":false,"usgs":true,"family":"Hofstra","given":"A. H.","affiliations":[],"preferred":false,"id":376541,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Landis, G. P.","contributorId":102846,"corporation":false,"usgs":true,"family":"Landis","given":"G.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":376544,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Rowan, E. L. 0000-0001-5753-6189","orcid":"https://orcid.org/0000-0001-5753-6189","contributorId":34921,"corporation":false,"usgs":true,"family":"Rowan","given":"E. L.","affiliations":[],"preferred":false,"id":376540,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Viets, J.G.","contributorId":82300,"corporation":false,"usgs":true,"family":"Viets","given":"J.G.","affiliations":[],"preferred":false,"id":376543,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":1015809,"text":"1015809 - 1994 - Vertical distribution of a deep-water moss and associated epiphytes in Crater Lake, Oregon","interactions":[],"lastModifiedDate":"2012-02-02T00:04:58","indexId":"1015809","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2900,"text":"Northwest Science","onlineIssn":"2161-9859","printIssn":"0029-344X","active":true,"publicationSubtype":{"id":10}},"title":"Vertical distribution of a deep-water moss and associated epiphytes in Crater Lake, Oregon","docAbstract":"A one-person submersible was used to examine the vertical distribution of the deep-water moss\r\nDrepanocladus aduncus (Hedw.) Warnst in Crater Lake (Oregon). Living specimens were found\r\nattached to sediment and rocks at depths between 25 m and 140 m. Dense beds of the moss\r\nwere observed at depths between 30 m and 80 m, a region that corresponded roughly to the\r\nzone of maximum primary production by phytoplankton. The moss population supported a diverse\r\nassemblage of epiphytic algae, of which the most abundant genera included Cladophora,Oedogonium, Rhizoclonium, Tribonema, Vaucheria, and the diatoms Cocconeis,\r\nCymbella, Epithemia, Fragilaria, Gomphonema, Melosira, Navicula, and Synedra. Chemical and\r\nphysical data supported the hypothesis that the lower limit of distribution of the moss is\r\ndetermined by light limitation, whereas the upper limit is related to the availability of nutrients, particularly nitrate-nitrogen and trace elements. Deep-water videotapes of the moss population indicated that D. aduncus with its epiphytic algae was abundant enough in regions associated with the metalimnion and upper hypolimnion to have a potential influence on the nutrient dynamics of the Crater Lake ecosystem. Although the maximum depth at which living bryophytes occur in Crater Lake is similar to that found for Lake Tahoe, conditions in Lake Tahoe allow the growth and survival of a much more diverse assemblage of bryophytes and charophytes than is present in Crater Lake.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Northwest Science","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","usgsCitation":"McIntire, C.D., Phinney, H., Larson, G.L., and Buktenica, M., 1994, Vertical distribution of a deep-water moss and associated epiphytes in Crater Lake, Oregon: Northwest Science, v. 68, no. 1, p. 11-21.","productDescription":"p. 11-21","startPage":"11","endPage":"21","numberOfPages":"11","costCenters":[{"id":290,"text":"Forest and Rangeland Ecosystem Science Center","active":false,"usgs":true}],"links":[{"id":135774,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"68","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a13e4b07f02db6021c8","contributors":{"authors":[{"text":"McIntire, C. D.","contributorId":35274,"corporation":false,"usgs":false,"family":"McIntire","given":"C.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":323175,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Phinney, H.K.","contributorId":30961,"corporation":false,"usgs":true,"family":"Phinney","given":"H.K.","email":"","affiliations":[],"preferred":false,"id":323174,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Larson, Gary L. gary_l._larson@usgs.gov","contributorId":2990,"corporation":false,"usgs":true,"family":"Larson","given":"Gary","email":"gary_l._larson@usgs.gov","middleInitial":"L.","affiliations":[],"preferred":true,"id":323173,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Buktenica, M.W.","contributorId":68263,"corporation":false,"usgs":true,"family":"Buktenica","given":"M.W.","affiliations":[],"preferred":false,"id":323176,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70017500,"text":"70017500 - 1994 - Comparison of manual and automated pretreatment methods for AMS radiocarbon dating of plant fossils","interactions":[],"lastModifiedDate":"2025-07-16T15:41:41.737712","indexId":"70017500","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3225,"text":"Radiocarbon","active":true,"publicationSubtype":{"id":10}},"title":"Comparison of manual and automated pretreatment methods for AMS radiocarbon dating of plant fossils","docAbstract":"A new automated pretreatment system for the preparation of materials submitted for accelerator mass spectrometry (AMS) analysis is less time-consuming and results in a higher sample yield. The new procedure was tested using two groups of plant fossils: one group was pretreated using the traditional method, and the second, using the automated pretreatment apparatus. We compared the time it took to complete the procedure and the amount of sample material remaining. The automated pretreatment apparatus proved to be more than three times faster and, in most cases, produced a higher yield. We also observed a darker discoloration of the KOH solutions, indicating that the automated system is more thorough in removing humates from the specimen compared to the manual method.
","language":"English","publisher":"Cambridge University Press","doi":"10.1017/S0033822200014570","issn":"00338222","usgsCitation":"Bradley, L.A., and Stafford, T.W., 1994, Comparison of manual and automated pretreatment methods for AMS radiocarbon dating of plant fossils: Radiocarbon, v. 36, no. 3, p. 399-405, https://doi.org/10.1017/S0033822200014570.","productDescription":"7 p.","startPage":"399","endPage":"405","numberOfPages":"7","costCenters":[],"links":[{"id":492506,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1017/s0033822200014570","text":"Publisher Index Page"},{"id":228374,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"36","issue":"3","noUsgsAuthors":false,"publicationDate":"2016-07-18","publicationStatus":"PW","scienceBaseUri":"5059f871e4b0c8380cd4d0e6","contributors":{"authors":[{"text":"Bradley, L. A.","contributorId":35738,"corporation":false,"usgs":true,"family":"Bradley","given":"L.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":376668,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stafford, Thomas W. Jr.","contributorId":21283,"corporation":false,"usgs":true,"family":"Stafford","given":"Thomas","suffix":"Jr.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":376667,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70017540,"text":"70017540 - 1994 - Increased pressure from rising bubbles as a mechanism for remotely triggered seismicity","interactions":[],"lastModifiedDate":"2019-06-05T13:04:44","indexId":"70017540","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2840,"text":"Nature","active":true,"publicationSubtype":{"id":10}},"title":"Increased pressure from rising bubbles as a mechanism for remotely triggered seismicity","docAbstract":"Aftershocks of large earthquakes tend to occur close to the main rupture zone, and can be used to constrain its dimensions. But following the 1992 Landers earthquake (magnitude M(w) = 7.3) in southern California, many aftershocks were reported in areas remote from the mainshock. Intriguingly, this remote seismicity occurred in small clusters near active volcanic and geothermal systems. For one of these clusters (Long Valley, about 400 km from the Landers earthquake), crustal deformation associated with the seismic activity was also monitored. Here we argue that advective overpressure provides a viable mechanism for remote seismicity triggered by the Landers earthquake. Both the deformation and seismicity data are consistent with pressure increases owing to gas bubbles rising slowly within a volume of magma. These bubbles may have been shaken loose during the passage of seismic waves generated by the mainshock.","language":"English","publisher":"Springer","doi":"10.1038/371408a0","issn":"00280836","usgsCitation":"Linde, A.T., Sacks, I.S., Johnston, M., Hill, D., and Bilham, R., 1994, Increased pressure from rising bubbles as a mechanism for remotely triggered seismicity: Nature, v. 371, no. 6496, p. 408-410, https://doi.org/10.1038/371408a0.","productDescription":"3 p.","startPage":"408","endPage":"410","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":229029,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206179,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1038/371408a0"}],"volume":"371","issue":"6496","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a39fce4b0c8380cd61aed","contributors":{"authors":[{"text":"Linde, A. T.","contributorId":21700,"corporation":false,"usgs":true,"family":"Linde","given":"A.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":376799,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sacks, I. S.","contributorId":58038,"corporation":false,"usgs":true,"family":"Sacks","given":"I.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":376802,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Johnston, M.J.S. 0000-0003-4326-8368","orcid":"https://orcid.org/0000-0003-4326-8368","contributorId":104889,"corporation":false,"usgs":true,"family":"Johnston","given":"M.J.S.","affiliations":[],"preferred":false,"id":376803,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hill, D.P.","contributorId":27432,"corporation":false,"usgs":true,"family":"Hill","given":"D.P.","email":"","affiliations":[],"preferred":false,"id":376801,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Bilham, R.G.","contributorId":24120,"corporation":false,"usgs":true,"family":"Bilham","given":"R.G.","email":"","affiliations":[],"preferred":false,"id":376800,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70017548,"text":"70017548 - 1994 - Multicomponent-flow analyses by multimode method of characteristics","interactions":[],"lastModifiedDate":"2024-12-12T16:49:56.004158","indexId":"70017548","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2338,"text":"Journal of Hydraulic Engineering","active":true,"publicationSubtype":{"id":10}},"title":"Multicomponent-flow analyses by multimode method of characteristics","docAbstract":"For unsteady open-channel flows having N interacting unknown variables, a system of N mutually independent, partial differential equations can be used to describe the flow-field. The system generally belongs to marching-type problems and permits transformation into characteristic equations that are associated with N distinct characteristics directions. Because characteristics can be considered 'wave' or 'disturbance' propagation, a fluvial system so described can be viewed as adequately definable using these N component waves. A numerical algorithm to solve the N families of characteristics can then be introduced for formulation of an N-component flow-simulation model. The multimode method of characteristics (MMOC), a new numerical scheme that has a combined capacity of several specified-time-interval (STI) schemes of the method of characteristics, makes numerical modeling of such N-component riverine flows feasible and attainable. Merging different STI schemes yields different kinds of MMOC schemes, for which two kinds are displayed herein. With the MMOC, each characteristics is dynamically treated by an appropriate numerical mode, which should lead to an effective and suitable global simulation, covering various types of unsteady flow. The scheme is always linearly stable and its numerical accuracy can be systematically analyzed. By increasing the N value, one can develop a progressively sophisticated model that addresses increasingly complex river-mechanics problems.","language":"English","publisher":"ASCE","doi":"10.1061/(ASCE)0733-9429(1994)120:3(378)","issn":"07339429","usgsCitation":"Lai, C., 1994, Multicomponent-flow analyses by multimode method of characteristics: Journal of Hydraulic Engineering, v. 120, no. 3, p. 378-395, https://doi.org/10.1061/(ASCE)0733-9429(1994)120:3(378).","productDescription":"18 p.","startPage":"378","endPage":"395","numberOfPages":"18","costCenters":[],"links":[{"id":228379,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"120","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a601be4b0c8380cd712da","contributors":{"authors":[{"text":"Lai, Chintu","contributorId":16860,"corporation":false,"usgs":true,"family":"Lai","given":"Chintu","email":"","affiliations":[],"preferred":false,"id":376816,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70017600,"text":"70017600 - 1994 - Role of olivine cumulates in destabilizing the flanks of Hawaiian volcanoes","interactions":[],"lastModifiedDate":"2012-03-12T17:19:53","indexId":"70017600","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1109,"text":"Bulletin of Volcanology","active":true,"publicationSubtype":{"id":10}},"title":"Role of olivine cumulates in destabilizing the flanks of Hawaiian volcanoes","docAbstract":"The south flank of Kilauea Volcano is unstable and has the structure of a huge landslide; it is one of at least 17 enormous catastrophic landslides shed from the Hawaiian Islands. Mechanisms previously proposed for movement of the south flank invoke slip of the volcanic pile over seafloor sediments. Slip on a low friction de??collement alone cannot explain why the thickest and widest sector of the flank moves more rapidly than the rest, or why this section contains a 300 km3 aseismic volume above the seismically defined de??collement. It is proposed that this aseismic volume, adjacent to the caldera in the direction of flank slip, consists of olivine cumulates that creep outward, pushing the south flank seawards. Average primary Kilauea tholeiitic magma contains about 16.5 wt.% MgO compared with an average 10 wt.% MgO for erupted subaerial and submarine basalts. This difference requires fractionation of 17 wt.% (14 vol.%) olivine phenocrysts that accumulate near the base of the magma reservoir where they form cumulates. Submarine-erupted Kilauea lavas contain abundant deformed olivine xenocrysts derived from these cumulates. Deformed dunite formed during the tholeiitic shield stage is also erupted as xenoliths in subsequent alkalic lavas. The deformation structures in olivine xenocrysts suggest that the cumulus olivine was densely packed, probably with as little as 5-10 vol.% intercumulus liquid, before entrainment of the xenocrysts. The olivine cumulates were at magmatic temperatures (>1100??C) when the xenocrysts were entrained. Olivine at 1100??C has a rheology similar to ice, and the olivine cumulates should flow down and away from the summit of the volcano. Flow of the olivine cumulates places constant pressure on the unbuttressed seaward flank, leading to an extensional region that localizes deep intrusions behind the flank; these intrusions add to the seaward push. This mechanism ties the source of gravitational instability to the caldera complex and deep rift systems and, therefore, limits catastrophic sector failure of Hawaiian volcanoes to their active growth phase, when the core of olivine cumulates is still hot enough to flow. ?? 1994 Springer-Verlag.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Bulletin of Volcanology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF00302824","issn":"02588900","usgsCitation":"Clague, D., and Denlinger, R., 1994, Role of olivine cumulates in destabilizing the flanks of Hawaiian volcanoes: Bulletin of Volcanology, v. 56, no. 6-7, p. 425-434, https://doi.org/10.1007/BF00302824.","startPage":"425","endPage":"434","numberOfPages":"10","costCenters":[],"links":[{"id":228566,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206124,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00302824"}],"volume":"56","issue":"6-7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505aae62e4b0c8380cd870ad","contributors":{"authors":[{"text":"Clague, D.A.","contributorId":36129,"corporation":false,"usgs":true,"family":"Clague","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":376966,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Denlinger, R.P.","contributorId":49367,"corporation":false,"usgs":true,"family":"Denlinger","given":"R.P.","email":"","affiliations":[],"preferred":false,"id":376967,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70017602,"text":"70017602 - 1994 - Petrology of gabbroic xenoliths in 1960 Kilauea basalt: crystalline remnants of prior (1955) magmatism","interactions":[],"lastModifiedDate":"2012-03-12T17:19:53","indexId":"70017602","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1109,"text":"Bulletin of Volcanology","active":true,"publicationSubtype":{"id":10}},"title":"Petrology of gabbroic xenoliths in 1960 Kilauea basalt: crystalline remnants of prior (1955) magmatism","docAbstract":"The 1960 Kapoho lavas of Kilauea's east rift zone contain 1-10 cm xenoliths of olivine gabbro, olivine gabbro-norite, and gabbro norite. Textures are poikilitic (ol+sp+cpx in pl) and intergranular (cpx+pl??ol??opx). Poikilitic xenoliths, which we interpret as cumulates, have the most primitive mineral compositions, Fo82.5, cpx Mg# 86.5, and An80.5. Many granular xenoliths (ol and noritic gabbro) contain abundant vesicular glass that gives them intersertal, hyaloophitic, and overall 'open' textures to suggest that they represent 'mush' and 'crust' of a magma crystallization environment. Their phase compositions are more evolved (Fo80-70, cpx Mg# 82-75, and An73-63) than those of the poikilitic xenoliths. Associated glass is basaltic, but evolved (MgO 5 wt%; TiO2 3.7-5.8 wt%). The gabbroic xenolith mineral compositions fit existing fractional crystallization models that relate the origins of various Kilauea lavas to one another. FeO/MgO crystal-liquid partitioning is consistent with the poikilitic ol-gabbro assemblage forming as a crystallization product from Kilauea summit magma with ???8 wt% MgO that was parental to evolved lavas on the east rift zone. For example, least squares calculations link summit magmas to early 1955 rift-zone lavas (???5 wt% MgO) through ???28-34% crystallization of the ol+sp+cpx+pl that comprise the poikilitic ol-gabbros. The other ol-gabbro assemblages and the olivine gabbro-norite assemblages crystallized from evolved liquids, such as represented by the early 1955 and late 1955 lavas (???6.5 wt% MgO) of the east rift zone. The eruption of 1960 Kapoho magmas, then, scoured the rift-zone reservoir system to entrain portions of cumulate and solidification zones that had coated reservoir margins during crystallization of prior east rift-zone magmas. ?? 1994 Springer-Verlag.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Bulletin of Volcanology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF00279729","issn":"02588900","usgsCitation":"Fodor, R., and Moore, R.B., 1994, Petrology of gabbroic xenoliths in 1960 Kilauea basalt: crystalline remnants of prior (1955) magmatism: Bulletin of Volcanology, v. 56, no. 1, p. 62-74, https://doi.org/10.1007/BF00279729.","startPage":"62","endPage":"74","numberOfPages":"13","costCenters":[],"links":[{"id":228568,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206125,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00279729"}],"volume":"56","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7831e4b0c8380cd7866b","contributors":{"authors":[{"text":"Fodor, R.V.","contributorId":106638,"corporation":false,"usgs":true,"family":"Fodor","given":"R.V.","email":"","affiliations":[],"preferred":false,"id":376970,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Moore, R. B.","contributorId":98720,"corporation":false,"usgs":true,"family":"Moore","given":"R.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":376969,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70017633,"text":"70017633 - 1994 - Clastic metasediments of the Early Proterozoic Broken Hill Group, New South Wales, Australia: Geochemistry, provenance, and metallogenic significance","interactions":[],"lastModifiedDate":"2023-12-21T23:03:34.803491","indexId":"70017633","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Clastic metasediments of the Early Proterozoic Broken Hill Group, New South Wales, Australia: Geochemistry, provenance, and metallogenic significance","docAbstract":"Whole-rock analyses of samples of pelite, psammite, and psammopelite from the Early Proterozoic Broken Hill Group (Willyama Supergroup) in the Broken Hill Block, New South Wales, Australia, reveal distinctive geochemical signatures. Major-element data show high Al2O3 and K2O, low MgO and Na2O, and relatively high
The geochemical data indicate derivation of the metasedimentary rocks of the Broken Hill Group by the erosion mainly of felsic igneous (or meta-igneous) rocks. High concentrations of HFSE, Y, and REEs in the metasediments suggest a provenance dominanted by anorogenic granites and(or) rhyolites, including those with A-type chemistry. Likely sources of the metasediments were the rhyolitic to rhyodacitic protoliths of local quartz + feldspar ± biotite ± garnet gneisses (e.g., Potosi-type gneiss) that occur within the lower part of the Willyama Supergroup, or chemically similar basement rocks in the region; alternative sources may have included Early Proterozoic anorogenic granites and(or) rhyolites in the Mount Isa and(or) Pine Creek Blocks of northern Australia, or in the Gawler craton of South Australia.
Metallogenic considerations suggest that the metasediments of the Broken Hill Block formed enriched source rocks during the generation of pegmatite-hosted deposits and concentrations of La, Ce, Nb, Ta, Th, and Sn in the region. Li, Be, B, W, and U in pegmatite minerals of the district may have been acquired during granulite-facies metamorphism of the local metasediments.
The Spatial Data Transfer Standard (SDTS), or Federal Information Processing Standard (FIPS) 173, is designed to support all types of spatial data. Implementing all of the standard's options at one time is impractical. Therefore, implementation of the SDTS is being accomplished through the use of profiles. Profiles are clearly defined, limited subsets of the SDTS created for use with a specific type or model of data and designed with as few options as possible. When a profile is proposed, specific choices are made for encoding possibilities that were not addressed, left optional, or left with numerous choices within the SDTS. Profile development is coordinated by the U.S. Geological SUIVey's SDTS Task Force. When completed, profiles are submitted to the National Institute of Standards and Technology (NIST) for approval as official amendments to the SDTS. The first profile, the Topological Vector Profile (TVP), has been completed. A Raster Profile has been tested and is being finalized for submission to the NIST. Other vector profiles, such as those for network and nontopological data, are also being considered as future implementation options for the SDTS.
","language":"English","publisher":"Taylor & Francis","doi":"10.1559/152304094782602908","usgsCitation":"Szemraj, J.A., Fegeas, R.G., and Tolar, B.R., 1994, Profile development for the Spatial Data Transfer Standard: Cartography and Geographic Information Systems, v. 21, no. 3, p. 150-154, https://doi.org/10.1559/152304094782602908.","productDescription":"5 p.","startPage":"150","endPage":"154","numberOfPages":"5","costCenters":[],"links":[{"id":228522,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"21","issue":"3","noUsgsAuthors":false,"publicationDate":"2013-03-14","publicationStatus":"PW","scienceBaseUri":"505a8dffe4b0c8380cd7ef61","contributors":{"authors":[{"text":"Szemraj, John A.","contributorId":42735,"corporation":false,"usgs":true,"family":"Szemraj","given":"John","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":377100,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fegeas, Robin G.","contributorId":27033,"corporation":false,"usgs":true,"family":"Fegeas","given":"Robin","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":377098,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Tolar, Billy R.","contributorId":29974,"corporation":false,"usgs":true,"family":"Tolar","given":"Billy","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":377099,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70017668,"text":"70017668 - 1994 - Hornblende-melt trace-element partitioning measured by ion microprobe","interactions":[],"lastModifiedDate":"2019-05-07T18:38:07","indexId":"70017668","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Hornblende-melt trace-element partitioning measured by ion microprobe","docAbstract":"Trace-element abundances were measured in situ by ion microprobe in five samples of hornblende and melt ranging from basaltic andesite to high-silica rhyolite. Except for one sample, for which quench overgrowth or disequilibrium is suspected, the abundance ratios show systematic inter-element and inter-sample variations, and probably approach true partition coefficients. Apparent partition coefficients are reported for La, Ce, Nd, Sm, Dy, Er, Yb, Sc, Ti, V, Cr, Sr, Y and Zr. Rare-earth elements (REE) and Y form smooth convex-upward partitioning patterns that rise to higher D-values and become increasingly convex in more evolved samples. Apparent partition coefficients for REE, Y, Ti, V and Cr can be parameterized as functions of the distribution of Ca between hornblende and melt, giving expressions to predict hornblende-melt trace-element partitioning values. These expressions are used to show that heavy REE-enriched hornblende/whole-rock REE abundance patterns in granitoids may result from partial re-equilibration of hornblende and late-stage residual liquids rather than from anomalous partitioning values.
","language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(94)90135-X","issn":"00092541","usgsCitation":"Sisson, T.W., 1994, Hornblende-melt trace-element partitioning measured by ion microprobe: Chemical Geology, v. 117, no. 1-4, p. 331-344, https://doi.org/10.1016/0009-2541(94)90135-X.","productDescription":"14 p.","startPage":"331","endPage":"344","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":228477,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"117","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3225e4b0c8380cd5e567","contributors":{"authors":[{"text":"Sisson, T. W.","contributorId":108120,"corporation":false,"usgs":true,"family":"Sisson","given":"T.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":377193,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70017755,"text":"70017755 - 1994 - Studies of the Reactivity of the Ferrihydrite Surface by Iron Isotopic Exchange and Mössbauer Spectroscopy","interactions":[],"lastModifiedDate":"2023-06-02T13:43:05.166992","indexId":"70017755","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1245,"text":"Clays and Clay Minerals","onlineIssn":"1552-8367","printIssn":"0009-8604","active":true,"publicationSubtype":{"id":10}},"title":"Studies of the Reactivity of the Ferrihydrite Surface by Iron Isotopic Exchange and Mössbauer Spectroscopy","docAbstract":"Two-line ferrihydrite is an important adsorbent of many toxics in natural and anthropogenic systems; however, the specific structural sites responsible for the high adsorption capacity are not well understood. A combination of chemical and spectroscopic techniques have been employed in this study to gain further insight into the structural nature of sites at the ferrihydrite surface. The kinetics of iron isotopic exchange demonstrated that there are at least two types of iron sites in ferrihydrite. One population of sites, referred to as labile sites, approached iron isotopic equilibrium within 24 hr in 59Fe-NTA solutions, while the second population of sites, referred to as non-labile, exhibited a much slower rate of isotopic exchange. Adsorbed arsenate reduced the degree of exchange by labile sites, indicating that the anion blocked or greatly inhibited the rate of exchange of these sites. Mössbauer spectra were collected from a variety of samples including 56Fe-ferrihydrite samples with 57Fe in labile sites, samples containing 57Fe throughout the structure, and samples with 57Fe in non-labile sites. The spectra showed characteristic broad doublets signifying poor structural order. Refined fits of the spectra indicated that labile sites have larger quadrupole splitting, hence more local distortion, than non-labile sites. In all cases, the spectra demonstrated some degree of asymmetry, indicating a distribution of Fe environments in ferrihydrite. Overall spectral findings, combined with recent EXAFS results (Waychunas et al., 1993), indicate that labile sites likely are more reactive (with respect to iron isotopic exchange) because they have fewer neighboring Fe octahedra and are therefore bound less strongly to the ferrihydrite structure. The labile population of sites probably is composed of end sites of the dioctahedral chain structure of 2-line ferrihydrite, which is a subset of the entire population of surface sites. Mössbauer spectra of samples containing adsorbed arsenate indicated that the anion may slightly decrease the distortion of labile sites and stabilized the structure as a whole by bidentate bonding.
","language":"English","publisher":"Springer","doi":"10.1346/CCMN.1994.0420104","usgsCitation":"Rea, B.A., Davis, J., and Waychunas, G.A., 1994, Studies of the Reactivity of the Ferrihydrite Surface by Iron Isotopic Exchange and Mössbauer Spectroscopy: Clays and Clay Minerals, v. 42, no. 1, p. 23-34, https://doi.org/10.1346/CCMN.1994.0420104.","productDescription":"12 p.","startPage":"23","endPage":"34","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":228440,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"42","issue":"1","noUsgsAuthors":false,"publicationDate":"2024-02-28","publicationStatus":"PW","scienceBaseUri":"505b9cb1e4b08c986b31d488","contributors":{"authors":[{"text":"Rea, Brigid A.","contributorId":82282,"corporation":false,"usgs":true,"family":"Rea","given":"Brigid","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":377473,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davis, James A.","contributorId":69289,"corporation":false,"usgs":true,"family":"Davis","given":"James A.","affiliations":[],"preferred":false,"id":377474,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Waychunas, Glenn A.","contributorId":189615,"corporation":false,"usgs":false,"family":"Waychunas","given":"Glenn","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":377475,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70017819,"text":"70017819 - 1994 - Experimental studies of alunite: II. Rates of alunite-water alkali and isotope exchange","interactions":[],"lastModifiedDate":"2023-12-21T00:41:18.527333","indexId":"70017819","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Experimental studies of alunite: II. Rates of alunite-water alkali and isotope exchange","docAbstract":"Rates of alkali exchange between alunite and water have been measured in hydrothermal experiments of 1 hour to 259 days duration at 150 to 400°C. Examination of run products by scanning electron microscope indicates that the reaction takes place by dissolution-reprecipitation. This exchange is modeled with an empirical rate equation which assumes a linear decrease in mineral surface area with percent exchange (f) and a linear dependence of the rate on the square root of the affinity for the alkali exchange reaction. This equation provides a good fit of the experimental data for f = 17% to 90% and yields log rate constants which range from −6.25 moles alkali m−2s−1 at 400°C to − 11.7 moles alkali m−2s−1 at 200°C. The variation in these rates with temperature is given by the equation log
In the absence of coupled alkali exchange, oxygen isotope exchange between alunite and water also occurs by dissolution-reprecipitation but rates are one to three orders of magnitude lower than those for alkali exchange. In fine-grained alunites, significant D-H exchange occurs by hydrogen diffusion at temperatures as low as 100°C. Computed hydrogen diffusion coefficients range from −15.7 to −17.3 cm2s−1 and suggest that the activation energy for hydrogen diffusion may be as low as 6 kcal/mol.
These experiments indicate that rates of alkali exchange in the relatively coarse-grained alunites typical of hydrothermal ore deposits are insignificant, and support the reliability of K-Ar age data from such samples. However, the fine-grained alunites typical of low temperature settings may be susceptible to limited alkali exchange at surficial conditions which could cause alteration of their radiometric ages. Furthermore, the rapid rate of hydrogen diffusion observed at 100–150°C suggests that fine-grained alunites are susceptible to rapid D-H re-equilibration even at surficial conditions.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(94)90515-0","issn":"00167037","usgsCitation":"Stoffregen, R., Rye, R.O., and Wasserman, M., 1994, Experimental studies of alunite: II. Rates of alunite-water alkali and isotope exchange: Geochimica et Cosmochimica Acta, v. 58, no. 2, p. 917-929, https://doi.org/10.1016/0016-7037(94)90515-0.","productDescription":"13 p.","startPage":"917","endPage":"929","costCenters":[],"links":[{"id":228628,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"58","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0de1e4b0c8380cd53232","contributors":{"authors":[{"text":"Stoffregen, R.E.","contributorId":70417,"corporation":false,"usgs":true,"family":"Stoffregen","given":"R.E.","affiliations":[],"preferred":false,"id":377658,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rye, R. O.","contributorId":66208,"corporation":false,"usgs":true,"family":"Rye","given":"R.","email":"","middleInitial":"O.","affiliations":[],"preferred":false,"id":377657,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wasserman, M.D.","contributorId":77949,"corporation":false,"usgs":true,"family":"Wasserman","given":"M.D.","email":"","affiliations":[],"preferred":false,"id":377659,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70017563,"text":"70017563 - 1994 - Lead and barium sources in Cambrian siliciclastics and sediment provenance of a sector of the Taconic Orogen, Quebec: a mixing scenario based on Pb-isotopic evidence","interactions":[],"lastModifiedDate":"2023-08-04T15:24:57.713631","indexId":"70017563","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","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":"Lead and barium sources in Cambrian siliciclastics and sediment provenance of a sector of the Taconic Orogen, Quebec: a mixing scenario based on Pb-isotopic evidence","docAbstract":"To test the hypothesis that siliciclastic rocks constituted the major source of Pb and Ba in barite-galena deposits of the Taconic Orogen, we determined Pb-isotope ratios in galena, barren rocks and contained minerals, as well as concentrations of Pb, U, Th and Ba in the latter (detrital feldspars, sandstones, mudstones, rock clasts and carbonate cements and clasts). Ranges in206Pb/204Pb,207Pb/204Pb and208Pb/204Pb of 28 galena samples are 17.96–18.05, 15.56–15.59 and 37.75–37.93, respectively; ranges for 41 barren rocks and minerals are 16.17–23.31, 15.26–15.86 and 35.98–42.51, respectively. The lowest ratios are in feldspar, and the highest in carbonate and mudstone. Values of the mudstones samples overlap those of galena when corrected for in situ decay of U and Th since galena precipitation (∼450Ma). We thus propose that mudstones constituted a source of lead. Corrected ratios for anomalously Pb-rich mudstones are virtually identical to galena-Pb ratios and may be due to contamination by lead-bearing brines. Assuming that burial diagenesis did not disturb the Pb-isotope values of sandstones, these rocks contributed only a minor fraction of lead to the galena, estimated at∼20% for one deposit. The source of barite-Ba was probably perthite. Low Ba and Pb concentrations of sandstone adjacent to this deposit, compared to high concentrations remote from it, support leaching of barium (and minor lead) from feldspar penecontemporaneous with feldspar dissolution.
Geological data indicate that the provenance of the siliciclastic rocks was mainly from Grenville terrane. A comparison of our Pb-isotopic data for Taconic perthite with those of Grenville K-feldspar, as well as ratios of trace elements, support this provenance for both sandstones and mudstones.
The presence of carbonate platforms peripheral to the orogen, and the Middle Ordovician-Middle Devonian depositional range of the studied and Mississippi Valley type deposits north (Newfoundland) and south (U.S.A. Appalachians) of our study area suggest targets for exploration in these platforms.
","language":"English","publisher":"Elsevier","doi":"10.1016/0883-2927(94)90066-3","usgsCitation":"Schrijver, K., Zartman, R., and Williams-Jones, A.E., 1994, Lead and barium sources in Cambrian siliciclastics and sediment provenance of a sector of the Taconic Orogen, Quebec: a mixing scenario based on Pb-isotopic evidence: Applied Geochemistry, v. 9, no. 4, p. 455-476, https://doi.org/10.1016/0883-2927(94)90066-3.","productDescription":"22 p.","startPage":"455","endPage":"476","numberOfPages":"22","costCenters":[],"links":[{"id":228710,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"9","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a45a9e4b0c8380cd67468","contributors":{"authors":[{"text":"Schrijver, K.","contributorId":16595,"corporation":false,"usgs":true,"family":"Schrijver","given":"K.","email":"","affiliations":[],"preferred":false,"id":376875,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Zartman, R. E.","contributorId":15632,"corporation":false,"usgs":true,"family":"Zartman","given":"R. E.","affiliations":[],"preferred":false,"id":376874,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Williams-Jones, A. E.","contributorId":81266,"corporation":false,"usgs":true,"family":"Williams-Jones","given":"A.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":376876,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":1000704,"text":"1000704 - 1994 - Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)","interactions":[],"lastModifiedDate":"2016-04-21T12:55:44","indexId":"1000704","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1176,"text":"Canadian Journal of Zoology","active":true,"publicationSubtype":{"id":10}},"title":"Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)","docAbstract":"There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.
","language":"English","publisher":"NRC Research Press","doi":"10.1139/z94-057","usgsCitation":"Nichols, S.J., and Black, M., 1994, Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea): Canadian Journal of Zoology, v. 72, no. 3, p. 406-417, https://doi.org/10.1139/z94-057.","productDescription":"12 p.","startPage":"406","endPage":"417","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":324,"text":"Great Lakes Science Center","active":true,"usgs":true}],"links":[{"id":133160,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"72","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a09e4b07f02db5faa5f","contributors":{"authors":[{"text":"Nichols, S. Jerrine","contributorId":25887,"corporation":false,"usgs":true,"family":"Nichols","given":"S.","email":"","middleInitial":"Jerrine","affiliations":[],"preferred":false,"id":309169,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Black, M.G.","contributorId":21124,"corporation":false,"usgs":true,"family":"Black","given":"M.G.","email":"","affiliations":[],"preferred":false,"id":309168,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70135340,"text":"70135340 - 1994 - Acoustic mapping as an environmental management tool: I. detection of barrels of low-level radioactive waste, Gulf of the Farallones National Marine Sanctuary, California","interactions":[],"lastModifiedDate":"2017-08-16T08:59:56","indexId":"70135340","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2926,"text":"Ocean and Coastal Management","active":true,"publicationSubtype":{"id":10}},"title":"Acoustic mapping as an environmental management tool: I. detection of barrels of low-level radioactive waste, Gulf of the Farallones National Marine Sanctuary, California","docAbstract":"The oceans have been and will continue to be disposal sites for a wide variety of waste products. Often these wastes are not dumped at the designated sites or transport occurs during or after dumping, and, subsequent attempts to monitor the effects the waste products have on the environment are inadequate because the actual location of the waste is not known. Acoustic mapping of the seafloor with sidescan sonar is a very effective technique for locating and monitoring dredge-spoil material and other debris. Sidescan sonar provides an acoustic image or sonograph of the sea floor that is similar to a satellite image of the Earth's land surface. In effect sidescan sonar allows the water column to be stripped from the sea floor, thereby providing a clear, unobstructed view of the sea bed.
\n\n
An example of the potential of this technique is summarized herein for the Gulf of the Farallones region. More than 47 800 drums (55 gallon) and other containers of low-level radioactive waste were dumped on the continental margin offshore the San Francisco Bay between 1946 and 1970. These drums now litter a large area (1200 km2) of the sea floor within the Gulf of the Farallones National Marine Sanctuary (GFNMS). The exact location of the drums and the potential hazard the drums pose to the environment are unknown. To evaluate the risk, samples of the sediment, biota and water must be collected near and distant from the concentrations of barrels. To do this the exact location of the barrels must be known prior to sampling. The USGS, through a cooperative research agreement with GFNMS, used sidescan sonar to map two areas within the sanctuary. Total sea-floor coverage was obtained and computer-processed sonographic mosaics were constructed on board ship. Many small nongeologic targets were distributed throughout the survey areas that covered about 70 km2 on the shelf and 120 km2 on the slope. Analysis of the sidescan data suggests that the targets are 55-gallon drums. This interpretation was confirmed at one site with an underwater video and 35-mm camera system. Data were collected with both a 30-kHz and a 120-kHz sidescan system within a 15-km2 area on the shelf. We found that the barrels were more easily detected with the mid-range 30-kHz system than with the higher resolution 120-kHz system. Maps of barrel distribution derived from the sonographs are being used to design sampling schemes to evaluate the risk that the radioactivity may have on the biota and environment.
","language":"English","publisher":"Elsevier","doi":"10.1016/0964-5691(94)90032-9","usgsCitation":"Karl, H., Schwab, W.C., Wright, A.S., Drake, D.E., Chin, J., Danforth, W.W., and Ueber, E., 1994, Acoustic mapping as an environmental management tool: I. detection of barrels of low-level radioactive waste, Gulf of the Farallones National Marine Sanctuary, California: Ocean and Coastal Management, v. 22, no. 3, p. 201-227, https://doi.org/10.1016/0964-5691(94)90032-9.","productDescription":"27 p.","startPage":"201","endPage":"227","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":186,"text":"Coastal and Marine Geology Program","active":true,"usgs":true},{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":296640,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","otherGeospatial":"Gulf of the Farallones","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -122.904052734375,\n 38.039438891821746\n ],\n [\n -123.32702636718749,\n 37.883524980871336\n ],\n [\n -122.958984375,\n 37.38325280195101\n ],\n [\n -122.40966796874999,\n 37.60117623656667\n ],\n [\n -122.607421875,\n 38.013476231041935\n ],\n [\n -122.904052734375,\n 38.039438891821746\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"22","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"548c1fc4e4b0ca8c43c36954","contributors":{"authors":[{"text":"Karl, Herman A.","contributorId":55796,"corporation":false,"usgs":true,"family":"Karl","given":"Herman A.","affiliations":[],"preferred":false,"id":527067,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schwab, William C. 0000-0001-9274-5154 bschwab@usgs.gov","orcid":"https://orcid.org/0000-0001-9274-5154","contributorId":417,"corporation":false,"usgs":true,"family":"Schwab","given":"William","email":"bschwab@usgs.gov","middleInitial":"C.","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":527068,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wright, A. St. C.","contributorId":71784,"corporation":false,"usgs":false,"family":"Wright","given":"A.","email":"","middleInitial":"St. C.","affiliations":[],"preferred":false,"id":527069,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Drake, David E.","contributorId":74752,"corporation":false,"usgs":true,"family":"Drake","given":"David","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":527070,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Chin, John L.","contributorId":98291,"corporation":false,"usgs":true,"family":"Chin","given":"John L.","affiliations":[],"preferred":false,"id":527071,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Danforth, William W. 0000-0002-6382-9487 bdanforth@usgs.gov","orcid":"https://orcid.org/0000-0002-6382-9487","contributorId":3292,"corporation":false,"usgs":true,"family":"Danforth","given":"William","email":"bdanforth@usgs.gov","middleInitial":"W.","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":527072,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Ueber, Edward","contributorId":102925,"corporation":false,"usgs":false,"family":"Ueber","given":"Edward","email":"","affiliations":[{"id":6637,"text":"National Oceanic and Atmospheric Administration, Northwest Fisheries Science Center, 2725 Montlake Blvd E, Seattle, WA 98112","active":true,"usgs":false}],"preferred":false,"id":527073,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":1008135,"text":"1008135 - 1994 - Analysis of bank erosion on the Merced River, Yosemite Valley, Yosemite National Park, California, USA","interactions":[],"lastModifiedDate":"2023-12-17T15:51:16.837102","indexId":"1008135","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1547,"text":"Environmental Management","active":true,"publicationSubtype":{"id":10}},"title":"Analysis of bank erosion on the Merced River, Yosemite Valley, Yosemite National Park, California, USA","docAbstract":"Channel changes from 1919 to 1989 were documented in two study reaches of the Merced River in Yosemite National Park through a review of historical photographs and documents and a comparison of survey data. Bank erosion was prevalent and channel width increased an average of 27% in the upstream reach, where human use was concentrated. Here, trampling of the banks and riparian vegetation was common, and banks eroded on straight stretches as frequently as on meander bends. Six bridges in the upper reach constrict the channel by an average of 38% of the original width, causing severe erosion. In the downstream control reach, where human use was minimal, channel widths both decreased and increased, with a mean increase of only 4% since 1919. Bank erosion in the control reach occurred primarily on meander bends. The control reach also had denser stands of riparian vegetation and a higher frequency of large woody debris in channels. There is only one bridge in the lower reach, located at the downstream end. Since 1919, bank erosion in the impacted upstream reach contributed a significant amount of sediment (74,800 tonnes, equivalent to 2.0 t/km2/yr) to the river. An analysis of 75 years of precipitation and hydrologic records showed no trends responsible for bank erosion in the upper reach. Sediment input to the upper reach has not changed significantly during the study period. Floodplain soils are sandy, with low cohesion and are easily detached by lateral erosion. The degree of channel widening was positively correlated with the percentage of bare ground on the streambanks and low bank stability ratings. Low bank stability ratings were, in turn, strongly associated with high human use areas. Channel widening and bank erosion in the upper reach were due primarily to destruction of riparian vegetation by human trampling and the effect of bridge constrictions on high flow, and secondarily to poorly installed channel revetments. Several specific recommendations for river restoration were provided to park management.
From 1985 through 1990, I monitored the populations of two species of toads, Bufo quercicus and B. terrestris, at a temporary pond in the xeric uplands of north-central Florida. A drift fence with pitfall traps completely encircled the pond basin; the fence was monitored 5 days per week throughout the year. The 5-year study coincided with a severe regional drought that resulted in generally short hydroperiods at unpredictable times of the year. More than 800 toads were captured. Successful metamorphosis never occurred at the pond although toads continued to visit it throughout the study. The sex ratio was male biased in B. quercicus but not in B. terrestris, although significant variation was observed from one year to the next. Likewise, the size-class structure and length-weight patterns varied among species, sexes, and years. Although fewer toads entered the pond basin as the study progressed, toads may have gone elsewhere to breed or they may have remained in refugia. Thus, decreased capture does not necessarily indicate that a drought-related population decline occurred. Drought may have disrupted normal arrival patterns and length of stay within the pond basin. Drought also could be responsible for variation in annual size-class structure of captured toads. The uncertainty of the hydroperiod both spatially and temporally in adjacent breeding sites, the ability of toads to move long distances with the potential for migration between breeding sites, and the lack of specificity in the choice of breeding sites (i.e. permanent versus different types of temporary wetlands) may lead to the formation of metapopulations in the xeric upland habitats of north-central Florida. Long-term monitoring under a variety of climatic conditions is needed to assess the effects of drought and other types of environmental stresses on toad populations.
","language":"English","publisher":"Taylor & Francis","doi":"10.1080/08927014.1994.9522985","usgsCitation":"Dodd, C., 1994, The effects of drought on population structure, activity, and orientation of toads Bufo quercicus and B. terrestris at a temporary pond: Ethology Ecology and Evolution, v. 6, no. 3, p. 331-349, https://doi.org/10.1080/08927014.1994.9522985.","productDescription":"19 p.","startPage":"331","endPage":"349","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":131514,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"6","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a9be4b07f02db65df98","contributors":{"authors":[{"text":"Dodd, C.K. Jr.","contributorId":86286,"corporation":false,"usgs":true,"family":"Dodd","given":"C.K.","suffix":"Jr.","affiliations":[],"preferred":false,"id":317776,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018001,"text":"70018001 - 1994 - Cryovolcanism on the icy satellites","interactions":[],"lastModifiedDate":"2013-01-17T21:47:06","indexId":"70018001","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1429,"text":"Earth, Moon and Planets","active":true,"publicationSubtype":{"id":10}},"title":"Cryovolcanism on the icy satellites","docAbstract":"Evidence of past cryovolcanism is widespread and extremely varied on the icy satellites. Some cryovolcanic landscapes, notably on Triton, are similar to many silicate volcanic terrains, including what appear to be volcanic rifts, calderas and solidified lava lakes, flow fields, breached cinder cones or stratovolcanoes, viscous lava domes, and sinuous rilles. Most other satellites have terrains that are different in the important respect that no obvious volcanoes are present. The preserved record of cryovolcanism generally is believed to have formed by eruptions of aqueous solutions and slurries. Even Triton's volcanic crust, which is covered by nitrogen-rich frost, is probably dominated by water ice. Nonpolar and weakly polar molecular liquids (mainly N2, CH4, CO, CO2, and Ar), may originate by decomposition of gas-clathrate hydrates and may have been erupted on some icy satellites, but without water these substances do not form rigid solids that are stable against sublimation or melting over geologic time. Triton's plumes, active at the time of Voyager 2's flyby, may consist of multicomponent nonpolar gas mixtures. The plumes may be volcanogenic fumaroles or geyserlike emissions powered by deep internal heating, and, thus, the plumes may be indicating an interior that is still cryomagmatically active; or Triton's plumes may be powered by solar heating of translucent ices very near the surface. The Uranian and Neptunian satellites Miranda, Ariel, and Triton have flow deposits that are hundreds to thousands of meters thick (implying highly viscous lavas); by contrast, the Jovian and Saturnian satellites generally have plains-forming deposits composed of relatively thin flows whose thicknesses have not been resolved in Voyager images (thus implying relatively low-viscosity lavas). One possible explanation for this inferred rheological distinction involves a difference in volatile composition of the Uranian and Neptunian satellites on one hand and of the Jovian and Saturnian satellites on the other hand. Perhaps the Jovian and Saturnian satellites tend to have relatively \"clean\" compositions with water ice as the main volatile (ammonia and water-soluble salts may also be present). The Uranian and Neptunian satellites may possess large amounts of a chemically unequilibrated comet-like volatile assemblage, including methanol, formaldehyde, and a host of other highly water- and ammonia-water-soluble constituents and gas clathrate hydrates. These two volatile mixtures would produce melts that differ enormously in viscosity The geomorphologic similarity in the products of volcanism on Earth and Triton may arise partly from a rheological similarity of the ammonia-water-methanol series of liquids and the silicate series ranging from basalt to dacite. An abundance of gas clathrate hydrates hypothesized to be contained by the satellites of Uranus and Neptune could contribute to evidence of explosive volcanism on those objects. ?? 1995 Kluwer Academic Publishers.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Earth, Moon and Planets","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Kluwer Academic Publishers","doi":"10.1007/BF00613296","issn":"01679295","usgsCitation":"Kargel, J., 1994, Cryovolcanism on the icy satellites: Earth, Moon and Planets, v. 67, no. 1-3, p. 101-113, https://doi.org/10.1007/BF00613296.","startPage":"101","endPage":"113","numberOfPages":"13","costCenters":[],"links":[{"id":480267,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://doi.org/10.1007/bf00613296","text":"External Repository"},{"id":206165,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00613296"},{"id":228916,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"67","issue":"1-3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fcf5e4b0c8380cd4e543","contributors":{"authors":[{"text":"Kargel, J.S.","contributorId":88096,"corporation":false,"usgs":true,"family":"Kargel","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":378158,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70017964,"text":"70017964 - 1994 - Probability of one or more M ≥7 earthquakes in southern California in 30 years","interactions":[],"lastModifiedDate":"2020-05-28T13:30:58.363653","indexId":"70017964","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1807,"text":"Geophysical Research Letters","active":true,"publicationSubtype":{"id":10}},"title":"Probability of one or more M ≥7 earthquakes in southern California in 30 years","docAbstract":"Eight earthquakes of magnitude greater than or equal to seven have occurred in southern California in the past 200 years. If one assumes that such events are the product of a Poisson process, the probability of one or more earthquakes of magnitude seven or larger in southern California within any 30 year interval is 67% ± 23% (95% confidence interval). Because five of the eight M ≥ 7 earthquakes in southern California in the last 200 years occurred off of the San Andreas fault system, the probability of one or more M ≥ 7 earthquakes in southern California but not on the San Andreas fault system occurring within 30 years is 52% ± 27% (95% confidence interval).
Addition of hydrogen or formate significantly enhanced the rate of consumption of nitrate in slurried core samples obtained from an active zone of denitrification in a nitrate-contaminated sand and gravel aquifer (Cape Cod, Mass.). Hydrogen uptake by the core material was immediate and rapid, with an apparent Km of 0.45 to 0.60 μM and a Vmax of 18.7 nmol cm-3 h-1 at 30°C. Nine strains of hydrogen-oxidizing denitrifying bacteria were subsequently isolated from the aquifer. Eight of the strains grew autotrophically on hydrogen with either oxygen or nitrate as the electron acceptor. One strain grew mixotrophically. All of the isolates were capable of heterotrophic growth, but none were similar to Paracoccus denitrificans, a well-characterized hydrogen-oxidizing denitrifier. The kinetics for hydrogen uptake during denitrification were determined for each isolate with substrate depletion progress curves; the Kms ranged from 0.30 to 3.32 μM, with Vmaxs of 1.85 to 13.29 fmol cell-1 h-1. Because these organisms appear to be common constituents of the in situ population of the aquifer, produce innocuous end products, and could be manipulated to sequentially consume oxygen and then nitrate when both were present, these results suggest that these organisms may have significant potential for in situ bioremediation of nitrate contamination in groundwater.
A major goal of the Kenya Rift International Seismic Project (KRISP) 1990 experiment was the determination of deep lithospheric structure. In the refraction/wide-angle reflection part of the KRISP effort, the experiment was designed to obtain arrivals to distances in excess of 400 km. Phases from interfaces within the mantle were recorded from many shotpoints, and by design, the best data were obtained along the axial profile. Reflected arrivals from two thin (< 10 km), high-velocity layers were observed along this profile and a refracted arrival was observed from the upper high-velocity layer. These mantle phases were observed on record sections from four axial profile shotpoints so overlapping and reversed coverage was obtained. Both high-velocity layers are deepest beneath Lake Turkana and become more shallow southward as the apex of the Kenya dome is approached. The first layer has a velocity of 8.05-8.15 km/s, is at a depth of about 45 km beneath Lake Turkana, and is observed at depths of about 40 km to the south before it disappears near the base of the crust. The deeper layer has velocities ranging from 7.7 to 7.8 km/s in the south to about 8.3 km/s in the north, has a similar dip as the upper one, and is found at depths of 60-65 km. Mantle arrivals outside the rift valley appear to correlate with this layer. The large amounts of extrusive volcanics associated with the rift suggest compositional anomalies as an explanation for the observed velocity structure. However, the effects of the large heat anomaly associated with the rift indicate that composition alone cannot explain the high-velocity layers observed. These layers require some anisotropy probably due to the preferred orientation of olivine crystals. The seismic model is consistent with hot mantle material rising beneath the Kenya dome in the southern Kenya rift and north-dipping shearing along the rift axis near the base of the lithosphere beneath the northern Kenya rift. This implies lithosphere thickening towards the north and is consistent with a thermal thinning of the lithosphere from below in the south changing to thinning of the lithosphere due to stretching in the north.
","largerWorkTitle":"","language":"English","publisher":"Elsevier","doi":"10.1016/0040-1951(94)90177-5","issn":"00401951","usgsCitation":"Keller, G.R., Mechie, J., Braile, L., Mooney, W.D., and Prodehl, C., 1994, Seismic structure of the uppermost mantle beneath the Kenya rift: Tectonophysics, v. 236, no. 1-4, p. 201-216, https://doi.org/10.1016/0040-1951(94)90177-5.","productDescription":"16 p.","startPage":"201","endPage":"216","numberOfPages":"16","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":228853,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Kenya","geographicExtents":"{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"Polygon\",\"coordinates\":[[[40.993,-0.85829],[41.58513,-1.68325],[40.88477,-2.08255],[40.63785,-2.49979],[40.26304,-2.57309],[40.12119,-3.27768],[39.80006,-3.68116],[39.60489,-4.34653],[39.20222,-4.67677],[37.7669,-3.67712],[37.69869,-3.09699],[34.07262,-1.05982],[33.90371,-0.95],[33.89357,0.10981],[34.18,0.515],[34.6721,1.17694],[35.03599,1.90584],[34.59607,3.05374],[34.47913,3.5556],[34.005,4.24988],[34.6202,4.84712],[35.29801,5.506],[35.81745,5.33823],[35.81745,4.77697],[36.15908,4.44786],[36.85509,4.44786],[38.12091,3.59861],[38.43697,3.58851],[38.67114,3.61607],[38.89251,3.50074],[39.55938,3.42206],[39.85494,3.83879],[40.76848,4.25702],[41.1718,3.91909],[41.85508,3.91891],[40.98105,2.78452],[40.993,-0.85829]]]},\"properties\":{\"name\":\"Kenya\"}}]}","volume":"236","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b8b69e4b08c986b3177ec","contributors":{"authors":[{"text":"Keller, Gordon R.","contributorId":90280,"corporation":false,"usgs":true,"family":"Keller","given":"Gordon","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":377152,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mechie, J.","contributorId":37902,"corporation":false,"usgs":true,"family":"Mechie","given":"J.","email":"","affiliations":[],"preferred":false,"id":377149,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Braile, L.W.","contributorId":85332,"corporation":false,"usgs":true,"family":"Braile","given":"L.W.","email":"","affiliations":[],"preferred":false,"id":377151,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Mooney, Walter D. 0000-0002-5310-3631 mooney@usgs.gov","orcid":"https://orcid.org/0000-0002-5310-3631","contributorId":3194,"corporation":false,"usgs":true,"family":"Mooney","given":"Walter","email":"mooney@usgs.gov","middleInitial":"D.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":377150,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Prodehl, C.","contributorId":100376,"corporation":false,"usgs":true,"family":"Prodehl","given":"C.","affiliations":[],"preferred":false,"id":377153,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70017624,"text":"70017624 - 1994 - The KRISP 90 seismic experiment-a technical review","interactions":[],"lastModifiedDate":"2020-05-05T16:00:51.300433","indexId":"70017624","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3525,"text":"Tectonophysics","active":true,"publicationSubtype":{"id":10}},"title":"The KRISP 90 seismic experiment-a technical review","docAbstract":"On the basis of a preliminary experiment in 1985 (KRISP 85), a seismic refraction/wide-angle reflection survey and a teleseismic tomography experiment were jointly undertaken to study the lithospheric structure of the Kenya rift down to depths of greater than 200 km. This report serves as an introduction to a series of subsequent papers and will focus on the technical description of the seismic surveys of the main KRISP 90 effort. The seismic refraction/wide-angle reflection survey was carried out in a 4-week period in January and February 1990. It consisted of three profiles: one extending along the rift valley from Lake Turkana to Lake Magadi, one crossing the rift at Lake Baringo, and one located on the eastern flank of the rift proper. A total of 206 mobile vertical-component seismographs, with an average station interval of about 2 km, recorded the energy of underwater and borehole explosions to distances of up to about 550 km. During the teleseismic survey an array of 65 seismographs was deployed to record teleseismic, regional and local events for a period of about 7 months from October 1989 to April 1990. The elliptical array spanned the central portion of the rift, with Nakuru at its center, and covered an area about 300 × 200 km, with an average station spacing of 10–30 km.
","largerWorkTitle":"","language":"English","publisher":"Elevier","doi":"10.1016/0040-1951(94)90168-6","issn":"00401951","usgsCitation":"Prodehl, C., Mechie, J., Achauer, U., Keller, G.R., Khan, M., Mooney, W.D., Gaciri, S., and Obel, J., 1994, The KRISP 90 seismic experiment-a technical review: Tectonophysics, v. 236, no. 1-4, p. 33-60, https://doi.org/10.1016/0040-1951(94)90168-6.","productDescription":"28 p.","startPage":"33","endPage":"60","numberOfPages":"28","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":229034,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"236","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba795e4b08c986b321670","contributors":{"authors":[{"text":"Prodehl, C.","contributorId":100376,"corporation":false,"usgs":true,"family":"Prodehl","given":"C.","affiliations":[],"preferred":false,"id":377057,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mechie, J.","contributorId":37902,"corporation":false,"usgs":true,"family":"Mechie","given":"J.","email":"","affiliations":[],"preferred":false,"id":377051,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Achauer, U.","contributorId":91998,"corporation":false,"usgs":true,"family":"Achauer","given":"U.","affiliations":[],"preferred":false,"id":377056,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Keller, Gordon R.","contributorId":90280,"corporation":false,"usgs":true,"family":"Keller","given":"Gordon","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":377055,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Khan, M.A.","contributorId":81916,"corporation":false,"usgs":true,"family":"Khan","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":377054,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Mooney, Walter D. 0000-0002-5310-3631 mooney@usgs.gov","orcid":"https://orcid.org/0000-0002-5310-3631","contributorId":3194,"corporation":false,"usgs":true,"family":"Mooney","given":"Walter","email":"mooney@usgs.gov","middleInitial":"D.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":377053,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Gaciri, S.J.","contributorId":66870,"corporation":false,"usgs":true,"family":"Gaciri","given":"S.J.","email":"","affiliations":[],"preferred":false,"id":377052,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Obel, J.D.","contributorId":7438,"corporation":false,"usgs":true,"family":"Obel","given":"J.D.","email":"","affiliations":[],"preferred":false,"id":377050,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"id":70017623,"text":"70017623 - 1994 - The volcanic history of Volcán Alcedo, Galápagos Archipelago: a case study of rhyolitic oceanic volcanism","interactions":[],"lastModifiedDate":"2017-04-26T14:14:17","indexId":"70017623","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1994","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1109,"text":"Bulletin of Volcanology","active":true,"publicationSubtype":{"id":10}},"title":"The volcanic history of Volcán Alcedo, Galápagos Archipelago: a case study of rhyolitic oceanic volcanism","docAbstract":"Volcán Alcedo is one of the seven western Galápagos shields and is the only active Galápagos volcano known to have erupted rhyolite as well as basalt. The volcano stands 4 km above the sea floor and has a subaerial volume of 200 km3, nearly all of which is basalt. As Volcán Alcedo grew, it built an elongate domal shield, which was partly truncated during repeated caldera-collapse and partial-filling episodes. An outward-dipping sequence of basalt flows at least 250 m thick forms the steepest (to 33°) flanks of the volcano and is not tilted; thus a constructional origin for the steep upper flanks is favored. About 1 km3 of rhyolite erupted late in the volcano's history from at least three vents and in 2–5 episodes. The most explosive of these produced a tephra blanket that covers the eastern half of the volcano. Homogeneous rhyolitic pumice is overlain by dacite-rhyolite commingled pumice, with no stratigraphic break. The tephra is notable for its low density and coarse grain size. The calculated height of the eruption plume is 23–30 km, and the intensity is estimated to have been 1.2x108 kg/s. Rhyolitic lavas vented from the floor of the caldera and from fissures along the rim overlie the tephra of the plinian phase. The age of the rhyolitic eruptions is ≤120 ka, on the basis of K-Ar ages. Between ten and 20 basaltic lava flows are younger than the rhyolites. Recent faulting resulted in a moat around part of the caldera floor. Alcedo most resently erupted sometime between 1946 and 1960 from its southern flank. Alcedo maintains an active, transient hydrothermal system. Acoustic and seismic activity in 1991 is attributed to the disruption of the hydrothermal system by a regional-scale earthquake.
","language":"English","publisher":"Springer","doi":"10.1007/BF00302078","issn":"02588900","usgsCitation":"Geist, D.J., Howard, K.A., Jellinek, A.M., and Rayder, S., 1994, The volcanic history of Volcán Alcedo, Galápagos Archipelago: a case study of rhyolitic oceanic volcanism: Bulletin of Volcanology, v. 56, no. 4, p. 243-260, https://doi.org/10.1007/BF00302078.","productDescription":"18 p.","startPage":"243","endPage":"260","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":229033,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -91.36505126953125,\n -0.6674043402557768\n ],\n [\n -90.83221435546875,\n -0.6674043402557768\n ],\n [\n -90.83221435546875,\n -0.29113644247137116\n ],\n [\n -91.36505126953125,\n -0.29113644247137116\n ],\n [\n -91.36505126953125,\n -0.6674043402557768\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"56","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb1c0e4b08c986b3253d2","contributors":{"authors":[{"text":"Geist, Dennis J.","contributorId":47145,"corporation":false,"usgs":true,"family":"Geist","given":"Dennis","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":377047,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Howard, Keith A. 0000-0002-6462-2947 khoward@usgs.gov","orcid":"https://orcid.org/0000-0002-6462-2947","contributorId":3439,"corporation":false,"usgs":true,"family":"Howard","given":"Keith","email":"khoward@usgs.gov","middleInitial":"A.","affiliations":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"preferred":true,"id":377048,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Jellinek, A. Mark","contributorId":54364,"corporation":false,"usgs":true,"family":"Jellinek","given":"A.","email":"","middleInitial":"Mark","affiliations":[],"preferred":false,"id":377049,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Rayder, Scott","contributorId":12995,"corporation":false,"usgs":true,"family":"Rayder","given":"Scott","email":"","affiliations":[],"preferred":false,"id":377046,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ]}