The Kellogg Shale of northern California has traditionally been considered to be late Eocene in age on the basis of benthic foraminifer, radiolarian, and diatom correlations. The 30-m-thick Kellogg section exposed west of Byron, California, however, contains middle Eocene planktonic foraminifers (Zone P12), coccoliths (Subzones CP13c and CP14a), silicoflagellates (Dictyocha hexacantha Zone), and diatoms. Quantitative studies of the silicoflagellates and diatoms show a general cooling trend through the section which is consistent with paleoclimatic trends for this part of the middle Eocene (ca. 42-45 Ma) from elsewhere in the world. Seven new silicoflagellate taxa (Corbisema angularis, C. exilis, C. hastata miranda, C. inermis ballantina, C. regina, Dictyocha byronalis, Naviculopsis americana) and one new coccolithophorid species (Helicosphaera neolophota) are described.
","language":"English","publisher":"The Micropaleontology Project., Inc.","doi":"10.2307/1485715","usgsCitation":"Barron, J.A., Bukry, D., and Poore, R.Z., 1984, Correlation of the middle eocene Kellogg Shale of northern California: Micropaleontology, v. 30, no. 2, p. 138-170, https://doi.org/10.2307/1485715.","productDescription":"33 p.","startPage":"138","endPage":"170","costCenters":[{"id":574,"text":"St. Petersburg Coastal and Marine Science Center","active":true,"usgs":true},{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"links":[{"id":372568,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","otherGeospatial":"Northern California","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -121.50329589843749,\n 37.74900069437069\n ],\n [\n -120.53649902343749,\n 37.74900069437069\n ],\n [\n -120.53649902343749,\n 38.53527591154413\n ],\n [\n -121.50329589843749,\n 38.53527591154413\n ],\n [\n -121.50329589843749,\n 37.74900069437069\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"30","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Barron, John A. 0000-0002-9309-1145 jbarron@usgs.gov","orcid":"https://orcid.org/0000-0002-9309-1145","contributorId":2222,"corporation":false,"usgs":true,"family":"Barron","given":"John","email":"jbarron@usgs.gov","middleInitial":"A.","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":782962,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bukry, David 0000-0003-4540-890X dbukry@usgs.gov","orcid":"https://orcid.org/0000-0003-4540-890X","contributorId":3550,"corporation":false,"usgs":true,"family":"Bukry","given":"David","email":"dbukry@usgs.gov","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":782963,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Poore, Richard Z. rpoore@usgs.gov","contributorId":147454,"corporation":false,"usgs":true,"family":"Poore","given":"Richard","email":"rpoore@usgs.gov","middleInitial":"Z.","affiliations":[{"id":574,"text":"St. Petersburg Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":782964,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70208675,"text":"70208675 - 1984 - Neogene silicoflagellates from Deep Sea Drilling Project Site 543, western tropical Atlantic Ocean","interactions":[],"lastModifiedDate":"2020-02-24T13:23:13","indexId":"70208675","displayToPublicDate":"1984-02-24T13:18:37","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1996,"text":"Initial Reports of the D.S.D.P.","active":true,"publicationSubtype":{"id":10}},"title":"Neogene silicoflagellates from Deep Sea Drilling Project Site 543, western tropical Atlantic Ocean","docAbstract":"The upper lower Miocene silicoflagellate assemblage in Core 19 from DSDP Hole 543 in the western Atlantic Ocean contains the greatest concentration (41%) of deflandroid Dictyochapulchella yet observed. The deflandroid morphology in Dictyocha persisted through the Eocene and Oligocene at middle and high latitude, but virtually disappeared in the late Oligocene, only to reappear as a short-lived variant of D. pulchella near the end of the early Miocene or the beginning of the middle Miocene at several low-latitude sites. Correlations with coeval tropical silicoflagellate and diatom assemblages from the tropical eastern Pacific and eastern Atlantic suggest that this deflandroid morphotype may be stratigraphically useful. A new diatom, Craspedodiscus barronii Bukry, found in Core 543-19, is described.
Eocene to Pliocene silicoflagellates from the Rockall Plateau are sparse to moderately abundant and include assem blages at the upper and lower boundaries of the Miocene Series. Relative paleotemperature values for silicoflagellates from the upper Miocene and lower Pliocene at DSDP Hole 552A based on quantitative data are cooler than are those from equatorial Pacific Sites 503 and 504, but show a matching warm peak at the Miocene/Pliocene boundary and a major cooling in the lower Pliocene.
Five new taxa of silicoflagellates are defined from Rockall Plateau assemblages: Corbisema panda Bukry, n. sp., Dictyochapulchella var. inflata Bukry, n. van, Distephanus xenus Bukry, n. sp., Mesocena apiculata evexa Bukry, n. subsp., and Naviculopsis pacifica pansa Bukry, n. subsp.
","language":"English","publisher":"Texas A&M","doi":"10.2973/dsdp.proc.81.112.1984","usgsCitation":"Bukry, D., 1984, Cenozoic silicoflagellates from Rockall Plateau, Deep Sea Drilling Project Leg 81: Initial Reports of the D.S.D.P., v. 81, p. 547-563, https://doi.org/10.2973/dsdp.proc.81.112.1984.","productDescription":"17 p.","startPage":"547","endPage":"563","numberOfPages":"17","costCenters":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"links":[{"id":488868,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.2973/dsdp.proc.81.112.1984","text":"Publisher Index Page"},{"id":372566,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Location of Deep Sea Drilling Project Leg 81 Sites 552 to 555 and Leg 48 Sites 403 to 406 at Rockall Plateau, west of Scotland","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -25.751953125,\n 51.83577752045248\n ],\n [\n -19.6875,\n 51.83577752045248\n ],\n [\n -19.6875,\n 57.89149735271034\n ],\n [\n -25.751953125,\n 57.89149735271034\n ],\n [\n -25.751953125,\n 51.83577752045248\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"81","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Bukry, David 0000-0003-4540-890X dbukry@usgs.gov","orcid":"https://orcid.org/0000-0003-4540-890X","contributorId":3550,"corporation":false,"usgs":true,"family":"Bukry","given":"David","email":"dbukry@usgs.gov","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":782957,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70208672,"text":"70208672 - 1984 - Paleogene paleoceanography of the Arctic Ocean is constrained by the middle or late Eocene age of USGS Core Fl-422: Evidence from silicoflagellates","interactions":[],"lastModifiedDate":"2020-02-24T12:57:58","indexId":"70208672","displayToPublicDate":"1984-02-24T12:55:22","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Paleogene paleoceanography of the Arctic Ocean is constrained by the middle or late Eocene age of USGS Core Fl-422: Evidence from silicoflagellates","docAbstract":"Arctic Ocean Core Fl-422 has been of central importance in Arctic tectonics and paleoceanography because it provides the sole evidence for early Cenozoic marine conditions in the Arctic. The presence of several Eocene and Eocene or Oligocene guide species of silicoflagellates in samples from this core shows that it is no older than middle Eocene, and is not Paleocene as previously reported. There is no evidence of any Paleocene (54 to 65 Ma) siliceous microfossils from Core Fl-422. Paleoceanographic inferences conerning the Cretaceous-Tertiary boundary and the timing of silica deposition in the Arctic have been erroneous because of unsupported biostratigraphic correlations.
","language":"English","publisher":"GSA","doi":"10.1130/0091-7613(1984)12<199:PPOTAO>2.0.CO;2","usgsCitation":"Bukry, D., 1984, Paleogene paleoceanography of the Arctic Ocean is constrained by the middle or late Eocene age of USGS Core Fl-422: Evidence from silicoflagellates: Geology, v. 12, no. 4, p. 199-201, https://doi.org/10.1130/0091-7613(1984)12<199:PPOTAO>2.0.CO;2.","productDescription":"3 p.","startPage":"199","endPage":"201","costCenters":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"links":[{"id":372565,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"12","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Bukry, David 0000-0003-4540-890X dbukry@usgs.gov","orcid":"https://orcid.org/0000-0003-4540-890X","contributorId":3550,"corporation":false,"usgs":true,"family":"Bukry","given":"David","email":"dbukry@usgs.gov","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":782956,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70209998,"text":"70209998 - 1984 - A seismic refraction survey of the Imperial Valley Region, California","interactions":[],"lastModifiedDate":"2020-05-08T14:33:17.65006","indexId":"70209998","displayToPublicDate":"1984-02-10T09:24:57","publicationYear":"1984","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":"A seismic refraction survey of the Imperial Valley Region, California","docAbstract":"The U.S. Geological Survey conducted an extensive seismic refraction survey in the Imperial Valley region of California in 1979. The Imperial Valley is located in the Salton Trough, an active rift between the Pacific and North American plates. Forty shots fired at seven shot points were recorded by 100 portable seismic instruments at typical spacing of 0.5–1 km. More than 1300 recording locations were occupied, and more than 3000 usable seismograms were obtained. We analyzed five profiles using a standard ray‐tracing program, constructed a contour map of reduced travel times from our most widely recorded shot point, and modeled an existing gravity profile across the Salton Trough. Results are itemized: (1) All models have in common a sedimentary layer (Vp = 1.8–5.0 km/s), a “transition zone” (Vp = 5.0–5.65 km/s), a basement (Vp = 5.65 km/s in the Imperial Valley, 5.9 km/s on the bordering mesas), and subbasement (Vp = 7.2 km/s). (2) The sedimentary layer ranges in thickness along the axis of the Salton Trough from 3.7 km (Salton Sea) to 4.8 km (U.S.‐Mexican border). On the bordering mesas it is quite variable in thickness. (3) The “transition” zone is about 1 km thick in most places. In the Imperial Valley there are no marked velocity discontinuities in this zone between the sedimentary layer and basement. On the bordering mesas, however, there is a discontinuity at the top of this zone. (4) There are apparently two types of basement. On the bordering mesas, basement is crystalline igneous and metamorphic rocks. In the Imperial Valley, basement is mostly lower‐greenshist‐facies sedimentary rocks, based primarily on the smooth transition in character from sediment to basement arrivals, the low value of basement velocity, and the fact that deep (4 km) wells in the valley penetrate only the upper part of the known Cenozoic stratigraphic column for the Salton Trough. (5) The subbasement, or intermediate crustal layer, ranges in depth along the axis of the Salton Trough from 16 km (Salton Sea) to 10 km (U.S.‐Mexican border). Gravity modeling requires that this layer deepen and/or pinch out beneath the bordering mesas and mountain ranges. Based on its high velocity and the presence of intrusive basaltic rocks in the sedimentary section in the Imperial Valley, the subbasement is thought to be a mafic intrusive complex similar to oceanic middle crust. (6) Several structures are seen that affect basement, transition zone, and deeper parts of the sedimentary layer. They include a scarp along the Imperial fault, as much as 1 km down to the northeast, and a scarp passing roughly along the topographic boundary between the Imperial Valley and the bordering mesa to the west, as much as 3½ km down to the east. We interpret the latter scarp to be the suture, or rift boundary, between the older crystalline basement on the mesa and the younger metasedimentary basement in the Imperial Valley. (7) On a contour map of reduced travel time from our most widely recorded shot point, subtle patches of early arrivals among otherwise late arrivals in the central Imperial Valley correlate well with known geothermal resource areas having reservoir temperatures of more than 150°C. Apparently the Salton Trough is a location where new crust is being generated. As the rift opens, mafic intrusive rocks fill it from below as sedimentary rocks fill it from above. Rifting and intrusion produce high heat flow that metamorphoses the sedimentary rocks to shallow depth (metasedimentary basement in the Imperial Valley) and thus consolidates the new crust.
Injections of NO3 and PO4 were made during September 1975 into Little Lost Man Creek, a small pristine stream in Redwood National Park, California. Chloride, a conservative constituent, was added in a known ratio to the nutrients. Nutrient loss at a downstream point was calculated using concentration of added Cl as a reference. Nitrate nitrogen (NO3‐N), added for 4 h, reached 920 μg/1 (above 5 μg/1 background) just below the injection point, but increased only to 405 μg/1 at 310 m downstream. The concentration decrease was attributed to dispersion and to uptake by stream biota. Percent of NO3‐N lost decreased with increasing concentration of NO3‐N. Phosphate phosphorus (PO4‐P) was added a week after the NO3‐N for 3 h, causing a concentration increase of 296 μg/1 (above 13 μg/1 background) just below the injection point, of 161 μg/1 at 90 m downstream, and of 98 μg/1 at 310 m. Percent loss of PO4‐P at downstream sites increased with increasing PO4‐P concentration and also for a short period after peak concentration occurred, but then decreased as PO4‐P concentration continued decreasing. Differences in stream response to added NO3‐N and PO4‐P are attributed to differing rates of reaction with biota and differing degrees of interaction with abiotic stream solids.
","language":"English","publisher":"American Water Resources Association","doi":"10.1111/j.1752-1688.1984.tb04646.x","usgsCitation":"Sebetich, M.J., Kennedy, V.C., Zand, S.M., Avanzino, R.J., and Zellweger, G.W., 1984, Dynamics of added nitrate and phosphate compared in a northern California woodland stream : Journal of the American Water Resources Association, v. 20, no. 1, p. 93-101, https://doi.org/10.1111/j.1752-1688.1984.tb04646.x.","productDescription":"9 p.","startPage":"93","endPage":"101","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":357775,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United states","state":"California","otherGeospatial":"Little Lost Man Creek, Redwood National Park","volume":"20","issue":"1","noUsgsAuthors":false,"publicationDate":"2007-06-08","publicationStatus":"PW","contributors":{"authors":[{"text":"Sebetich, Michael J.","contributorId":208200,"corporation":false,"usgs":false,"family":"Sebetich","given":"Michael","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":746342,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kennedy, Vance C.","contributorId":102063,"corporation":false,"usgs":true,"family":"Kennedy","given":"Vance","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":746343,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Zand, S. Marc","contributorId":104923,"corporation":false,"usgs":true,"family":"Zand","given":"S.","email":"","middleInitial":"Marc","affiliations":[],"preferred":false,"id":746344,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Avanzino, Ronald J.","contributorId":24355,"corporation":false,"usgs":true,"family":"Avanzino","given":"Ronald","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":746345,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Zellweger, Gary W.","contributorId":71171,"corporation":false,"usgs":true,"family":"Zellweger","given":"Gary","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":746346,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70120870,"text":"70120870 - 1984 - Tests of compensatory vs. additive hypotheses of mortality in mallards","interactions":[],"lastModifiedDate":"2014-08-18T10:37:32","indexId":"70120870","displayToPublicDate":"1984-02-01T10:31:37","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1465,"text":"Ecology","active":true,"publicationSubtype":{"id":10}},"title":"Tests of compensatory vs. additive hypotheses of mortality in mallards","docAbstract":"Band recovery data from over 410 000 adult Mallards (Anas platyrhynchos) banded in North America between 1950 and 1979 were analyzed to examine the effect of exploitation on annual survival rate. Two extreme hypotheses were defined: completely compensatory, and totally additive, and an explicit mathematical model was presented to represent each hypothesis. Comparison of the values of the log-likelihood functions at their maxima allowed discrimination between the two models (hypotheses). Extensive Monte Carlo studies were made on the performance of the discriminant test and the power of the test under the two extreme hypotheses and a range of intermediate hypotheses. The results of the discriminant tests on the data agreed closely with the expected performance of the test if the true underlying process was compensatory. We rejected the hypothesis of total additivity (P=.001). Instead, it appears that hunting mortalities are largely compensated for by other forms of mortality.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Ecology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Brooklyn Botanic Garden","publisherLocation":"Brooklyn, NY","doi":"10.2307/1939463","usgsCitation":"Burnham, K.P., and Anderson, D.R., 1984, Tests of compensatory vs. additive hypotheses of mortality in mallards: Ecology, v. 65, no. 1, p. 105-112, https://doi.org/10.2307/1939463.","productDescription":"8 p.","startPage":"105","endPage":"112","numberOfPages":"8","costCenters":[],"links":[{"id":292393,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":292391,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.2307/1939463"}],"volume":"65","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"53f25ff2e4b033341871896e","contributors":{"authors":[{"text":"Burnham, Kenneth P.","contributorId":95025,"corporation":false,"usgs":true,"family":"Burnham","given":"Kenneth","email":"","middleInitial":"P.","affiliations":[{"id":189,"text":"Colorado Cooperative Fish and Wildlife Research Unit","active":false,"usgs":true}],"preferred":false,"id":498519,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Anderson, David R.","contributorId":92722,"corporation":false,"usgs":true,"family":"Anderson","given":"David","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":498518,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013529,"text":"70013529 - 1984 - Lead retention in zircons","interactions":[],"lastModifiedDate":"2025-11-25T14:58:50.188092","indexId":"70013529","displayToPublicDate":"1984-02-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3338,"text":"Science","active":true,"publicationSubtype":{"id":10}},"title":"Lead retention in zircons","docAbstract":"No abstract available.
","language":"English","publisher":"American Association for the Advancement of Science","doi":"10.1126/science.223.4638.835.a","issn":"00368075","usgsCitation":"Ludwig, K., Zartman, R., and Goldich, S., 1984, Lead retention in zircons: Science, v. 223, no. 4638, p. 835-835, https://doi.org/10.1126/science.223.4638.835.a.","productDescription":"1 p.","startPage":"835","endPage":"835","costCenters":[],"links":[{"id":219858,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"223","issue":"4638","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a45d6e4b0c8380cd674e4","contributors":{"authors":[{"text":"Ludwig, K.R.","contributorId":97112,"corporation":false,"usgs":true,"family":"Ludwig","given":"K.R.","email":"","affiliations":[{"id":218,"text":"Denver Federal Center","active":false,"usgs":true}],"preferred":false,"id":366280,"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":366277,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Goldich, S. S.","contributorId":65536,"corporation":false,"usgs":true,"family":"Goldich","given":"S. S.","affiliations":[],"preferred":false,"id":366279,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70210056,"text":"70210056 - 1984 - Evaluation of the potential hazard to barn owls of talon (brodifacoum bait) used to control rats and house mice","interactions":[],"lastModifiedDate":"2020-05-12T18:09:41.85406","indexId":"70210056","displayToPublicDate":"1984-01-31T13:04:04","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1571,"text":"Environmental Toxicology and Chemistry","active":true,"publicationSubtype":{"id":10}},"title":"Evaluation of the potential hazard to barn owls of talon (brodifacoum bait) used to control rats and house mice","docAbstract":"During 1980, a radiotelemetry study on barn owls (Tyto alba) was conducted to evaluate the secondary hazards of the anticoagulant rodenticide TALON® (containing 0.005% brodifacoum) when it was used for controlling rats (Rattus spp.) and house mice (Mus musculus) on farms. Thirty‐five active nests were located in about 1,100 km2 (430 mi2) in southwestern New Jersey. Starting on June 9, 1980, radio transmitters with tail clips were attached to 26 adult nesting barn owls and 8 fledged young of the year. In one 20‐km2 (about 8 mi2) area, which was the most intensively searched, 12 active barn owl nests were located. Of all 35 active nests, 66% were in trees, 11% in barns, 8.5% in silos, 8.5% in chimneys and 6% in miscellaneous locations. Analysis of regurgitated pellets showed that meadow voles (Microtus pennsylvanicus) were the most common prey at all sites. Although Norway rats (Rattus norvegicus) and house mice occurred in some pellet collections, they made up only a small part of the diet (3.9% rats and 2% mice) of barn owls in the study area. Baiting at farms with TALON was begun on July 24, and ended on September 29, 1980. TALON was not observed to cause or implicated in barn owl mortality during the study. However, trace residues (< 0.05 ppm, the limit of determination) of brodifacoum were found in one electrocuted barn owl. Young barn owls were fledged from at least eight sites where poisoned rodents were available on the farms for at least part of the nesting and feeding period (including pre‐ and postfledging). Furthermore, radiotelemetry confirmed that at least 9, and possibly 12, of the radio‐equipped owls were present on sites posttreatment, when census evaluations showed commensal rodents were present and consuming TALON bait.
","language":"English","publisher":"Society of Environmental Toxicology and Chemistry","doi":"10.1002/etc.5620030119","usgsCitation":"Hegdal, P.L., and Blaskiewicz, R.W., 1984, Evaluation of the potential hazard to barn owls of talon (brodifacoum bait) used to control rats and house mice: Environmental Toxicology and Chemistry, v. 3, no. 1, p. 167-179, https://doi.org/10.1002/etc.5620030119.","productDescription":"13 p.","startPage":"167","endPage":"179","costCenters":[{"id":218,"text":"Denver Federal Center","active":false,"usgs":true}],"links":[{"id":374702,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"New Jersey","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -75.1080322265625,\n 39.18969082109678\n ],\n [\n -74.783935546875,\n 39.2407625100131\n ],\n [\n -74.970703125,\n 39.930800820752765\n ],\n [\n -75.322265625,\n 39.85915479295669\n ],\n [\n -75.531005859375,\n 39.64799732373418\n ],\n [\n -75.531005859375,\n 39.47436547486121\n ],\n [\n -75.1080322265625,\n 39.18969082109678\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"3","issue":"1","noUsgsAuthors":false,"publicationDate":"1984-01-01","publicationStatus":"PW","contributors":{"authors":[{"text":"Hegdal, Paul L.","contributorId":223410,"corporation":false,"usgs":false,"family":"Hegdal","given":"Paul","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":788939,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Blaskiewicz, Raymond W.","contributorId":224647,"corporation":false,"usgs":false,"family":"Blaskiewicz","given":"Raymond","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":788940,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70207304,"text":"70207304 - 1984 - Potential of cobalt and other metals in ferromanganese crusts on seamounts of the Central Pacific Basin","interactions":[],"lastModifiedDate":"2019-12-16T13:59:34","indexId":"70207304","displayToPublicDate":"1984-01-22T13:50:59","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2674,"text":"Marine Mining","active":true,"publicationSubtype":{"id":10}},"title":"Potential of cobalt and other metals in ferromanganese crusts on seamounts of the Central Pacific Basin","docAbstract":"No abstract available.
","language":"English","publisher":"Taylor & Francis","usgsCitation":"Halbach, P., and Manheim, F.T., 1984, Potential of cobalt and other metals in ferromanganese crusts on seamounts of the Central Pacific Basin: Marine Mining, v. 4, no. 4, p. 319-336.","productDescription":"18 p.","startPage":"319","endPage":"336","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":370315,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Pacific Ocean","volume":"4","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Halbach, P.E.","contributorId":104286,"corporation":false,"usgs":true,"family":"Halbach","given":"P.E.","email":"","affiliations":[],"preferred":false,"id":777635,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Manheim, Frank T. 0000-0003-4005-4524","orcid":"https://orcid.org/0000-0003-4005-4524","contributorId":20770,"corporation":false,"usgs":true,"family":"Manheim","given":"Frank","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":777636,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014058,"text":"70014058 - 1984 - Late Leonardian plants from West Texas: The youngest Paleozoic plant megafossils in North America","interactions":[],"lastModifiedDate":"2025-11-25T15:04:46.745348","indexId":"70014058","displayToPublicDate":"1984-01-20T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3338,"text":"Science","active":true,"publicationSubtype":{"id":10}},"title":"Late Leonardian plants from West Texas: The youngest Paleozoic plant megafossils in North America","docAbstract":"Abundant Permian plant megafossils were discovered in the Del Norte Mountains of Brewster County, Trans-Pecos Texas. The flora is dominated by a new and distinctive type of gigantopteroid leaves. Marine invertebrates are closely associated, and this admixture of continental and marine fossils indicates a deltaic depositional setting, probably on the southern margin of the Permian Basin. Conodonts indicate correlation with the uppermost Leonardian Road Canyon Formation in the Glass Mountains. These are the youngest Paleozoic plant megafossils known in North America; they add an important paleontological element to the classic Permian area of this Continent.
","language":"English","publisher":"American Association for the Advancement of Science","doi":"10.1126/science.223.4633.279","issn":"00368075","usgsCitation":"Mamay, S., Miller, J., and Rohr, D., 1984, Late Leonardian plants from West Texas: The youngest Paleozoic plant megafossils in North America: Science, v. 223, no. 4633, p. 279-281, https://doi.org/10.1126/science.223.4633.279.","productDescription":"3 p.","startPage":"279","endPage":"281","costCenters":[],"links":[{"id":225294,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"223","issue":"4633","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a44efe4b0c8380cd66ede","contributors":{"authors":[{"text":"Mamay, S.H.","contributorId":49422,"corporation":false,"usgs":true,"family":"Mamay","given":"S.H.","affiliations":[],"preferred":false,"id":367469,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Miller, J.M.","contributorId":88219,"corporation":false,"usgs":true,"family":"Miller","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":367470,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rohr, D.M.","contributorId":6276,"corporation":false,"usgs":true,"family":"Rohr","given":"D.M.","email":"","affiliations":[],"preferred":false,"id":367468,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70120700,"text":"70120700 - 1984 - Accessioning and cataloguing","interactions":[],"lastModifiedDate":"2014-08-15T14:32:42","indexId":"70120700","displayToPublicDate":"1984-01-19T14:31:00","publicationYear":"1984","noYear":false,"publicationType":{"id":4,"text":"Book"},"publicationSubtype":{"id":12,"text":"Conference publication"},"title":"Accessioning and cataloguing","docAbstract":"No abstract available.","largerWorkTitle":"Management of mammal collection in tropical environment: proceedings of the Workshop on Management of Mammal Collection in Tropical Environment","conferenceTitle":"Management of mammal collection in tropical environment","conferenceDate":"1984-01-19T00:00:00","conferenceLocation":"Calcutta","language":"English","publisher":"Zoological Survey of India","publisherLocation":"Calcutta","usgsCitation":"Wilson, D., 1984, Accessioning and cataloguing, 2 p.","productDescription":"2 p.","numberOfPages":"2","costCenters":[],"links":[{"id":292321,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"53ef1ec1e4b0bfa1f993eed3","contributors":{"authors":[{"text":"Wilson, D.E.","contributorId":107232,"corporation":false,"usgs":true,"family":"Wilson","given":"D.E.","email":"","affiliations":[],"preferred":false,"id":498408,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70207908,"text":"70207908 - 1984 - Ultrathin lava layers exposed near San Luis Obispo Bay, California","interactions":[],"lastModifiedDate":"2020-01-17T14:33:25","indexId":"70207908","displayToPublicDate":"1984-01-17T14:24:58","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Ultrathin lava layers exposed near San Luis Obispo Bay, California","docAbstract":"Sequences of extraordinarily thin (1–5 cm thick) lava layers, resembling individual lava flows, are interbedded with Jurassic and Cretaceous pillowed lava flows near San Luis Obispo Bay on the California coast. Such layers are formed inside submarine pillowed lava pipes or flow lobes. As the lava surface in a pillow pipe falls to a lower level owing to diminished supply entering the pipe, water enters the upper compartment through cracks in the outer crust and chills a new crust on top of the lava stream. Repeated lowerings of the lava level in the pipe create a series of discrete lava shelves, each of which represents the upper crust of the lava stream flowing within the pipe. These crusts are supported at different levels on their edges at the side of the pipe. The weight of subsequent overlying lava flows collapses the partly hollow tube, creating a stacked sequence of ultrathin lava layers progressively younger downward.
","language":"English","publisher":"GSA","doi":"10.1130/0091-7613(1984)12<542:ULLENS>2.0.CO;2","usgsCitation":"Moore, J.G., and Charlton, D., 1984, Ultrathin lava layers exposed near San Luis Obispo Bay, California: Geology, v. 12, no. 9, p. 542-545, https://doi.org/10.1130/0091-7613(1984)12<542:ULLENS>2.0.CO;2.","productDescription":"4 p.","startPage":"542","endPage":"545","costCenters":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"links":[{"id":371363,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","otherGeospatial":"San Luis Obispo Bay","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -121.11053466796875,\n 35.068221159859256\n ],\n [\n -120.574951171875,\n 35.068221159859256\n ],\n [\n -120.574951171875,\n 35.48751102385376\n ],\n [\n -121.11053466796875,\n 35.48751102385376\n ],\n [\n -121.11053466796875,\n 35.068221159859256\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"12","issue":"9","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Moore, James G. 0000-0002-7543-2401 jmoore@usgs.gov","orcid":"https://orcid.org/0000-0002-7543-2401","contributorId":2892,"corporation":false,"usgs":true,"family":"Moore","given":"James","email":"jmoore@usgs.gov","middleInitial":"G.","affiliations":[{"id":114,"text":"Alaska Science Center","active":true,"usgs":true},{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":779708,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Charlton, D.W.","contributorId":221678,"corporation":false,"usgs":false,"family":"Charlton","given":"D.W.","email":"","affiliations":[],"preferred":false,"id":779709,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70207881,"text":"70207881 - 1984 - Introduction and digest to the Special Issue on Chemical Effects of Water on the Deformation and Strengths of Rocks","interactions":[],"lastModifiedDate":"2020-07-09T15:04:55.823218","indexId":"70207881","displayToPublicDate":"1984-01-16T12:59:57","publicationYear":"1984","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":"Introduction and digest to the Special Issue on Chemical Effects of Water on the Deformation and Strengths of Rocks","docAbstract":"The important role of pore pressure in promoting such brittle processes as cataclasis, hydraulic fracturing, large‐scale faulting, and earthquakes within the crust is widely accepted in geology and geophysics [, 1957; , 1959; , 1958; ., 1963; , 1968; ., 1968; ., 1976; , 1973, 1980; , 1981]. Provided that fluid pressure is fully communicated with rock pore space, the effective normal stresses that control crack growth, macroscopic fracture, and friction are reduced by the magnitude of the fluid pressui'e. Beyond this physical effect of pore fluids, there are chemical effects of water on the strength of rocks that are also important in governing differential stresseg and flow in the continental crust. Some of these chemical effects of water on rock deformation have long been recognized.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB089iB06p03991","usgsCitation":"Kirby, S.H., 1984, Introduction and digest to the Special Issue on Chemical Effects of Water on the Deformation and Strengths of Rocks: Journal of Geophysical Research B: Solid Earth, v. 89, no. B6, p. 3991-3995, https://doi.org/10.1029/JB089iB06p03991.","productDescription":"5 p.","startPage":"3991","endPage":"3995","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":371318,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"89","issue":"B6","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","contributors":{"authors":[{"text":"Kirby, Stephen H. 0000-0003-1636-4688 skirby@usgs.gov","orcid":"https://orcid.org/0000-0003-1636-4688","contributorId":2752,"corporation":false,"usgs":true,"family":"Kirby","given":"Stephen","email":"skirby@usgs.gov","middleInitial":"H.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":779626,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70207878,"text":"70207878 - 1984 - Experimental deformation of topaz crystals: Possible embrittlement by intracrystalline water","interactions":[],"lastModifiedDate":"2020-01-16T12:56:11","indexId":"70207878","displayToPublicDate":"1984-01-16T12:43:21","publicationYear":"1984","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":"Experimental deformation of topaz crystals: Possible embrittlement by intracrystalline water","docAbstract":"Crystallographically oriented single‐crystal prisms of gem quality topaz (composition AlSiO (OH− F) where x = 0.04 ± 0.01) were deformed at a confining pressure of 1.50 GPa, a temperature of 800°C, and a strain rate of 2×10 s. Under nearly identical conditions, all crystals of anhydrous rock‐forming minerals that have been tested to date, such as olivine, quartz, feldspars, pyroxenes, and refractory oxides, deform plastically; in contrast, our topaz crystals failed by brittle fracture regardless of the orientation of the compression direction. No optical evidence for plastic deformation was detected. Another suite of experiments with compression perpendicular to the (001) cleavage at = 100°–950°C and a strain rate of 2×10 s displayed two regimes of behavior: (1) at >400°C, fracture strength was independent of temperature, and fracture occurred on one or two surfaces parallel to {103}; (2) at <400°C, the fracture strength increased rapidly with decreasing temperature, no macroscopic stress drop was observed, and many closely spaced conjugate fractures formed on (103) and (103). The anomalous brittleness of topaz compared to anhydrous silicate and oxide crystals indicates that intracrystalline “water” plays a role in the embrittlement. We suggest that water within the topaz crystals promotes fracture in ways similar to the mechanisms of slow crack growth aided by environmental moisture.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB089iB06p04161","usgsCitation":"Lee, R.W., and Kirby, S.H., 1984, Experimental deformation of topaz crystals: Possible embrittlement by intracrystalline water: Journal of Geophysical Research B: Solid Earth, v. 89, no. B6, p. 4161-4166, https://doi.org/10.1029/JB089iB06p04161.","productDescription":"6 p.","startPage":"4161","endPage":"4166","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":371315,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"89","issue":"B6","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","contributors":{"authors":[{"text":"Lee, R. W.","contributorId":86757,"corporation":false,"usgs":true,"family":"Lee","given":"R.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":779615,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kirby, Stephen H. 0000-0003-1636-4688 skirby@usgs.gov","orcid":"https://orcid.org/0000-0003-1636-4688","contributorId":2752,"corporation":false,"usgs":true,"family":"Kirby","given":"Stephen","email":"skirby@usgs.gov","middleInitial":"H.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":779616,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70207875,"text":"70207875 - 1984 - Effects of compression direction on the plasticity and rheology of hydrolytically weakened synthetic quartz crystals at atmospheric pressure","interactions":[],"lastModifiedDate":"2020-07-09T15:11:35.419434","indexId":"70207875","displayToPublicDate":"1984-01-16T12:27:39","publicationYear":"1984","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":"Effects of compression direction on the plasticity and rheology of hydrolytically weakened synthetic quartz crystals at atmospheric pressure","docAbstract":"A hydrothermally grown synthetic quartz crystal with 370±60 ppm hydroxyl impurity was cut into right rectangular prisms in eight crystallographic orientations. We compressed the prisms under constant axial force corresponding to a uniaxial stress of 140.0±0.5 MPa, and temperatures of 510° and 750°C. All but one of the samples sustained permanent axial strains of 2–3%. We established the operating slip systems from specimen shape change, slip bands and dislocation etch pits on polished surfaces, crystallographic orientation changes, stress optical features in thin sections, and transmission electron microscopy. The observed creep behavior and plasticity divided the samples into three groups: (1) Crystals compressed at 45° to [0001] and [ ] and those compressed ⊥( ) and ⊥( ) deformed principally by slip parallel to [0001]. Creep rates were relatively high and were not strongly sensitive to test temperature. Dislocation arrays approximately parallel to ( ) are common. Dislocation loops are elongate parallel to [0001], indicating that the edge segments were more mobile than the screw segments. (2) The second group of samples were loaded normal to [0001] in three orientations: ⊥( ), ⊥( ), and at 45° to ( ). These samples deformed primarily by { } 〈a〉 slip with some evidence for secondary slip on the other systems. They were more creep resistant than the first group and displayed a much higher sensitivity of creep rate to test temperature. Dislocation loops are very elongate parallel to [0001], indicating that the screw dislocation segments were much more mobile than the edge segments. (3) A sample compressed parallel to [0001] at 750°C crept at a barely detectable rate (∼10 s) and no optical scale slip features were observed. These results confirm our earlier work on one orientation each from groups 1 and 2, which indicated a strong creep anisotropy for this same crystal. This creep anisotropy parallels a remarkably similar anisotropy in the diffusivity of impurities in quartz, suggesting a causal relationship between impurity diffusion and creep associated with hydrolytic weakening. Appendix Tables A1‐A5 are available with entire article on microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W., Washington, DC 20009. Document B84‐004; $2.50. Payment must accompany order.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB089iB06p04241","usgsCitation":"Linker, M.F., Kirby, S.H., Ord, A., and Christie, J., 1984, Effects of compression direction on the plasticity and rheology of hydrolytically weakened synthetic quartz crystals at atmospheric pressure: Journal of Geophysical Research B: Solid Earth, v. 89, no. B6, p. 4241-4255, https://doi.org/10.1029/JB089iB06p04241.","productDescription":"15 p.","startPage":"4241","endPage":"4255","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":371313,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"89","issue":"B6","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","contributors":{"authors":[{"text":"Linker, Mark F.","contributorId":36283,"corporation":false,"usgs":true,"family":"Linker","given":"Mark","middleInitial":"F.","affiliations":[],"preferred":false,"id":779608,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kirby, Stephen H. 0000-0003-1636-4688 skirby@usgs.gov","orcid":"https://orcid.org/0000-0003-1636-4688","contributorId":2752,"corporation":false,"usgs":true,"family":"Kirby","given":"Stephen","email":"skirby@usgs.gov","middleInitial":"H.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":779609,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ord, A.","contributorId":221671,"corporation":false,"usgs":false,"family":"Ord","given":"A.","email":"","affiliations":[],"preferred":false,"id":779610,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Christie, J.M.","contributorId":21672,"corporation":false,"usgs":true,"family":"Christie","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":779611,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70207800,"text":"70207800 - 1984 - Geologic evolution, sedimentation, and paleoenvironments of the Angola Basin and adjacent Walvis Ridge: Synthesis of results of Deep Sea Drilling Project Leg 75","interactions":[],"lastModifiedDate":"2020-06-24T14:52:23.573871","indexId":"70207800","displayToPublicDate":"1984-01-13T11:31:22","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1996,"text":"Initial Reports of the D.S.D.P.","active":true,"publicationSubtype":{"id":10}},"title":"Geologic evolution, sedimentation, and paleoenvironments of the Angola Basin and adjacent Walvis Ridge: Synthesis of results of Deep Sea Drilling Project Leg 75","docAbstract":"The section recovered at Site 530 (Holes 53OA and 530B) consists of eight sedimentary units and one basalt unit. The composition of the basalt recovered in Hole 53OA is distinct from typical mid-ocean ridge basalts (MORBs) but is similar to that of Hawaiian tholeiites and basalt from the central part of Walvis Ridge. Throughout most of its history, the southern Angola Basin received large volumes of redeposited material in the form of turbidites and, most recently, debris-flow deposits. Most of this material was derived from Walvis Ridge to the south, but thickness trends of acoustic units suggest that some of the sediment was derived from the African continental margin to the east.
The basal sedimentary unit (Albian to Santonian) at Site 530 contains 262 beds of black shale that are interbedded with green and red claystone. Black shale makes up less than 10% of the total section, but in two cores of early Turonian age, black shale beds compose about 50% of the section. The black shales contain up to 19% organic carbon (average of about 5%) that is mainly of autochthonous marine origin but with significant contributions from terrigenous organic matter. The origin of these more- and less-reduced interbedded lithologies with varying amounts and types of organic matter, and variable amounts of pelagic, hemipelagic, and turbiditic sediment is complex and cannot be explained by any one simple process. Many factors affecting the concentration of dissolved oxygen in the bottom waters of the Angola Basin varied throughout the middle Cretaceous to produce bottom-water conditions that fluctuated between mildly oxic and oxygen-deficient, but most of the time bottom-waters and sediment-interstitial waters were sufficiently oxic to permit the accumulation of red oxidized sediment.
A relatively complete sedimentary record of the Cretaceous/Tertiary boundary was recovered within a sequence of mudstone and marlstone turbidites in Hole 530A. There is a significant increase in the concentration of iridium above background levels at the boundary. High concentrations of many other elements also occur within the same stratigraphic interval as the iridium anomaly. Furthermore, there is a marked decrease in CaCO3 in the Tertiary strata above the iridium anomaly which suggests that the production of shallow-water carbonate also may have been affected by whatever caused elevated concentrations of iridium and other elements. These observations are consistent with the asteroid-impact theory proposed to explain the worldwide occurrence of an iridium anomaly at the Cretaceous/Tertiary boundary.
The Cenozoic history of the Angola Basin was controlled mainly by (1) restriction of bottom-water flow from the south by Walvis Ridge; (2) development of glaciation on Antarctica; (3) opening of circulation passages in the southern oceans; (4) rapid turnover of cold, nutrient-rich waters that resulted in high productivity of diatoms; (5) influx of terrigenous sediment mainly by turbidity currents; and (6) production and preservation of carbonate sediment. The most distinctive Cenozoic event recorded in the section at Site 530 is the beginning of extensive glaciation on Anarctica and concomitant initiation of modern thermohaline bottom-water circulation that is manifested as a middle Eocene to middle Oligocene unconformity or compressed section accompanied by a drastic decrease in accumulation of CaCO3. Diatom abundances in HPC cores from Walvis Ridge (Site 532) and Angola Basin (Hole 53OB) indicate that Benguela upwelling in these areas began in the late Miocene, reached a peak in the late Pliocene to early Pleistocene, and declined thereafter. Short-term variations in sediment composition at Site 532 are manifested as cyclic variations in concentrations of clay, CaCO3, and organic carbon with average periodicities of about 30-60 k.y. The main variability that produced the cycles probably was the influx of terrigenous clastic material which diluted the CaCO3. The sediment at Site 532 also contains several percent organic carbon that is dominantly of marine origin, but with significant terrigenous components.
Data from multichannel seismic, gravity, and magnetic surveys were used to define the regional stratigraphic and structural evolution of Walvis Ridge and adjacent Cape and Angola basins. Six structural provinces are recognized, four on Walvis Ridge and two additional provinces that correspond to the Cape and Angola basins. The two eastern structural provinces on Walvis Ridge are underlain by continental crust. The two western structural provinces are underlain by oceanic basement. Two main directions of faults are evident in seismic profiles, one trending N 10° and one trending N 60°. The N 60° trend corresponds to the general orientation of the northern and southern flanks of Walvis Ridge as well as to the dominant direction of fracture zones.
During the first phase of separation of Africa from South America (ca. 120-130 m.y. ago), a voluminous mass of volcanics was emplaced simultaneous with the emplacement of basalt in the Parana Basin of Brazil and the Kaokoveld Region of South Africa. This period of volcanism also formed the series of seaward-dipping internal basement reflectors that are characteristic of the two structural provinces of Walvis Ridge. A system of fault blocks developed in the brittle upper part of the newly formed crust. During the second phase of rifting, which ended before late Aptian, more tilted fault blocks were created in the upper brittle stratified continental crust. Magnetic lineations in basement rocks in the Angola and Cape basins in the vicinity of Walvis Ridge are not distinct but suggest that oceanic crust began to be emplaced between 120 and 112 m.y. ago (Barremian to early Aptian). At least part of the oceanic crust of the central plateau of eastern Walvis Ridge (structural province 3) may have been emplaced before any oceanic crust formed in the adjacent basins. A ridge jump occurred during the late Aptian to early Albian in the southern part of the Angola Basin which translated the previously formed oceanic crust and its overlying evaporite deposits on the South American side. Several ridge jumps occurred on both sides of Walvis Ridge during the Late Cretaceous and early Tertiary to produce a 500-km-long segment of mid-ocean ridge.
","language":"English","publisher":"Texas A&M University","doi":"10.2973/dsdp.proc.75.109.1984","usgsCitation":"Dean, W.E., Hay, W., and Sibuet, J., 1984, Geologic evolution, sedimentation, and paleoenvironments of the Angola Basin and adjacent Walvis Ridge: Synthesis of results of Deep Sea Drilling Project Leg 75: Initial Reports of the D.S.D.P., v. 75, p. 509-544, https://doi.org/10.2973/dsdp.proc.75.109.1984.","productDescription":"36 p.","startPage":"509","endPage":"544","costCenters":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"links":[{"id":488895,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.2973/dsdp.proc.75.109.1984","text":"Publisher Index Page"},{"id":371189,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Locations of dredge CH 18-DR06 and DSDP drill sites","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n 9.31640625,\n -24.986058021167594\n ],\n [\n 16.89697265625,\n -24.986058021167594\n ],\n [\n 16.89697265625,\n -17.035777250427184\n ],\n [\n 9.31640625,\n -17.035777250427184\n ],\n [\n 9.31640625,\n -24.986058021167594\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"75","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779373,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hay, W.W.","contributorId":221650,"corporation":false,"usgs":false,"family":"Hay","given":"W.W.","email":"","affiliations":[{"id":28140,"text":"UC Boulder","active":true,"usgs":false}],"preferred":false,"id":779374,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Sibuet, Jean-Claude","contributorId":221651,"corporation":false,"usgs":false,"family":"Sibuet","given":"Jean-Claude","email":"","affiliations":[],"preferred":false,"id":779375,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70207799,"text":"70207799 - 1984 - Origin and geochemistry of Cretaceous deep-sea black shales and multicolored claystones, with emphasis on Deep Sea Drilling Project Site 530, southern Angola Basin","interactions":[],"lastModifiedDate":"2020-01-14T06:48:14","indexId":"70207799","displayToPublicDate":"1984-01-13T11:03:23","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1996,"text":"Initial Reports of the D.S.D.P.","active":true,"publicationSubtype":{"id":10}},"title":"Origin and geochemistry of Cretaceous deep-sea black shales and multicolored claystones, with emphasis on Deep Sea Drilling Project Site 530, southern Angola Basin","docAbstract":"Deep-water sedimentary sequences of mid-Cretaceous age, rich in organic carbon, have been recovered at many DSDP sites in the Atlantic Ocean. Most of these sequences have a marked cyclicity in amount of organic carbon resulting in interbedded multicolored shale, marlstone, and (or) limestone that have cycle periods of 20,000 to 100,000 years and average 40,000 to 50,000 years. These cycles may be related to some climatic control on influx of terrigenous organic matter and sediment, rates of upwelling and sea-surface production of organic matter, and preservation of organic matter related to deeper-water dissolved oxygen concentration. These variations in supply of organic matter had pronounced effects on the potential of the sediment for subsequent diagenetic changes and geochemical partitioning in adjacent beds.
Many trace elements are enriched in organic-carbon-rich lithologies relative to interbedded organic-carbon-poor lithologies. Elements that are most commonly enriched are Cr, Ni, V, Cu, Zn, and Mo. The association of high traceelement concentrations with organic matter may be the result of concentration of these elements by organisms or by chemical sorption and precipitation processes under anoxic conditions. Detailed trace-element profiles from organiccarbon-rich strata at Site 530 suggest that there may be differential mobility of trace elements, with diffusion of some elements over distances of at least tens of meters. The sequence of trace-element mobility, from highest to lowest, is approximately Ba, Mn, Pb, Ni, Co, Cr, Cu, Zn, V, Cd, and Mo. Slowly deposited, oxidized clays directly overlying some black shale sequences are enriched in some metals, particularly Fe, Mn, Zn, and Cu, relative to normal pelagic clays, and this enrichment may be the result of upward migration of metals in pore waters during compaction or diffusion from the underlying black shale.
Most depositional models that have been used to explain the accumulation of the organic-carbon-rich strata imply that reducing conditions in the sediments (and therefore the increased degree of preservation of organic matter) were the result of anoxic or near-anoxic conditions in oceanic bottom waters, or in a midwater oxygen-minimum zone. Evidence from several DSDP sites in the Atlantic, however, indicate that some of these middle Cretaceous \"black shale\" beds may be the result of variations in rate of supply of organic matter that produced anoxia or near-anoxia within midwater oxygen-minimum zones and possibly, under extreme conditions, throughout much of the bottomwater mass. Although bottom-water anoxia may have occurred during periods of organic-carbon-rich strata, it was not necessarily the only cause for accumulation of these strata. The main reason for the accumulation of organic-carbonrich strata was an increase in the relative amount of organic debris being deposited. Some of this organic debris was derived from continental-margin areas of increased production, accumulation, and preservation of organic matter from marine, terrestrial, or mixed sources and transported to slope and basinal sites by turbidity currents.
","language":"English","publisher":"Texas A&M University","doi":"10.2973/dsdp.proc.75.121.1984","usgsCitation":"Dean, W.E., Arthur, M., and Stow, D., 1984, Origin and geochemistry of Cretaceous deep-sea black shales and multicolored claystones, with emphasis on Deep Sea Drilling Project Site 530, southern Angola Basin: Initial Reports of the D.S.D.P., v. 75, p. 819-844, https://doi.org/10.2973/dsdp.proc.75.121.1984.","productDescription":"26 p.","startPage":"819","endPage":"844","costCenters":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"links":[{"id":487257,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.2973/dsdp.proc.75.121.1984","text":"Publisher Index Page"},{"id":371188,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Site 530","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n 9.31640625,\n -24.986058021167594\n ],\n [\n 16.89697265625,\n -24.986058021167594\n ],\n [\n 16.89697265625,\n -17.035777250427184\n ],\n [\n 9.31640625,\n -17.035777250427184\n ],\n [\n 9.31640625,\n -24.986058021167594\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"75","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779370,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Arthur, M.A.","contributorId":24791,"corporation":false,"usgs":true,"family":"Arthur","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":779371,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Stow, D.A.V.","contributorId":35441,"corporation":false,"usgs":true,"family":"Stow","given":"D.A.V.","email":"","affiliations":[],"preferred":false,"id":779372,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70207798,"text":"70207798 - 1984 - Carbonate and organic-carbon cycles and the history of upwelling at Deep Sea Drilling Project Site 532, Walvis Ridge, South Atlantic Ocean","interactions":[],"lastModifiedDate":"2020-06-25T13:50:17.773448","indexId":"70207798","displayToPublicDate":"1984-01-13T10:47:59","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1996,"text":"Initial Reports of the D.S.D.P.","active":true,"publicationSubtype":{"id":10}},"title":"Carbonate and organic-carbon cycles and the history of upwelling at Deep Sea Drilling Project Site 532, Walvis Ridge, South Atlantic Ocean","docAbstract":"Detailed carbonate and organic-carbon stratigraphies were constructed from samples collected every 20 cm in a 250-m hydraulic piston core recovered at DSDP Site 532 on Walvis Ridge. This sampling interval represents about one sample every 5000 yr., based on sediment accumulation rates calculated from nannofossil biostratigraphic zones. All samples were analyzed for percent CaCO3, resulting in a detailed carbonate stratigraphy for the past 5.0 m.y. The samples for the top 110 m of section were also analyzed for organic carbon in order to construct a detailed organiccarbon stratigraphy for the last 2.5 m.y.
The recovered section has distinct dark-light color cycles with average periodicities of 55, 58, and 30 k.y. for the Quaternary, upper Pliocene, and lower Pliocene, respectively. Periodicities of carbonate cycles are similar to the color cycles; most carbonate minima correspond to the dark parts of color cycles. The average periodicity for carbonate cycles is about 36 k.y. Darker parts of color cycles usually contain higher concentrations of organic carbon, but the organic-carbon record does not follow the cyclicity of the color cycles in detail, at least for the last 2.5 m.y. Organic-carbon cycles have an average periodicity of about 34 k.y. for the Quaternary and upper Pliocene.
The cycles of CaCO3 and color have periodicities similar to those reported from carbonate stratigraphies from the northeast Atlantic, Caribbean, and eastern equatorial Pacific. The carbonate cycles at Site 532 are the result of external forcing, probably related to global climate, that affected fluctuations in both sediment supply from the African continental margin and productivity of siliceous organisms. The organic-carbon cycles have similar periodicities and similar changes in periodicities to those of the CaCO3 cycles.
Semiquantitative estimates of diatom abundance from smear slides and concentrations of biogenic SiO2 calculated from chemical analyses suggest that upwelling at Site 532 was minor until about 3 m.y. ago. The Benguela-Current upwelling system either began at that time or, more likely, migrated into the area of Site 532, where it prevailed until some time between about 1.2 and 0.5 m.y. ago. The increase and decline of upwelling in the area of Site 532, however, did not disturb the trend of cyclicities of carbonate and organic carbon. The latest change in conditions at Site 532 was an increase in intensity of bottom currents during the past 0.5 m.y. that winnowed nannofossils, diatoms, and clay and left a lag deposit represented by a foraminifer-rich fades
","language":"English","publisher":"Texas A&M University","doi":"10.2973/dsdp.proc.75.126.1984","usgsCitation":"Gardner, J., Dean, W.E., and Wilson, C., 1984, Carbonate and organic-carbon cycles and the history of upwelling at Deep Sea Drilling Project Site 532, Walvis Ridge, South Atlantic Ocean: Initial Reports of the D.S.D.P., v. 75, p. 905-921, https://doi.org/10.2973/dsdp.proc.75.126.1984.","productDescription":"17 p.","startPage":"905","endPage":"921","costCenters":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"links":[{"id":487264,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"http://doi.org/10.2973/dsdp.proc.75.126.1984","text":"Publisher Index Page"},{"id":371187,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Locations of DSDP Sites 362 and 532.","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n 9.3603515625,\n -21.043491216803528\n ],\n [\n 14.2822265625,\n -21.043491216803528\n ],\n [\n 14.2822265625,\n -16.678293098288503\n ],\n [\n 9.3603515625,\n -16.678293098288503\n ],\n [\n 9.3603515625,\n -21.043491216803528\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"75","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Gardner, J.","contributorId":18176,"corporation":false,"usgs":true,"family":"Gardner","given":"J.","affiliations":[],"preferred":false,"id":779367,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779368,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wilson, C.R.","contributorId":78353,"corporation":false,"usgs":true,"family":"Wilson","given":"C.R.","email":"","affiliations":[],"preferred":false,"id":779369,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70207797,"text":"70207797 - 1984 - Middle Cretaceous black shales at Site 530 in the southeastern Angola Basin","interactions":[],"lastModifiedDate":"2020-06-24T14:26:20.080547","indexId":"70207797","displayToPublicDate":"1984-01-13T10:36:31","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1996,"text":"Initial Reports of the D.S.D.P.","active":true,"publicationSubtype":{"id":10}},"title":"Middle Cretaceous black shales at Site 530 in the southeastern Angola Basin","docAbstract":"The middle Cretaceous black shale interval at Site 530 is 170 m thick and late Albian to Coniacian in age. The organic-carbon-rich sediments occur as 260 separate beds (average 4 cm, maximum 60 cm thick) and make up less than 10% of the recovered section. Associated lithologies are greenish, grayish, and reddish mudstones, marlstones, and rare limestones. Organic-carbon contents of the black shales average about 5% (maximum 16%), and of the interbedded sediments, less than 0.5%. Careful study of the sedimentary and biogenic structures and composition and review of paleoceanographic conditions in the Angola Basin indicate that a complex interplay of processes controlled black shale accumulation. Relatively low oxygen concentrations in sediment and bottom waters occurred periodically, and conditions locally may have been anoxic or near anoxic both in the basin and on the continental margin. Pelagic, hemipelagic, and turbiditic depositional processes all operated to varying degrees at different times.
","language":"English","publisher":"Texas A&M D.S.D.P.","doi":"10.2973/dsdp.proc.75.120.1984","usgsCitation":"Stow, D., and Dean, W.E., 1984, Middle Cretaceous black shales at Site 530 in the southeastern Angola Basin: Initial Reports of the D.S.D.P., v. 75, no. 2, p. 809-817, https://doi.org/10.2973/dsdp.proc.75.120.1984.","productDescription":"9 p.","startPage":"809","endPage":"817","costCenters":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"links":[{"id":488865,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.2973/dsdp.proc.75.120.1984","text":"Publisher Index Page"},{"id":371186,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Drilling Site 530, 531, 532","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n 1.2744140625,\n -22.87744046489713\n ],\n [\n 14.5458984375,\n -22.87744046489713\n ],\n [\n 14.5458984375,\n -10.660607953624762\n ],\n [\n 1.2744140625,\n -10.660607953624762\n ],\n [\n 1.2744140625,\n -22.87744046489713\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"75","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Stow, D.A.","contributorId":44336,"corporation":false,"usgs":true,"family":"Stow","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":779365,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779366,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70207758,"text":"70207758 - 1984 - Shimada Seamount: An example of recent mid-plate volcanism","interactions":[],"lastModifiedDate":"2020-06-24T14:29:39.079206","indexId":"70207758","displayToPublicDate":"1984-01-09T13:34:15","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1723,"text":"GSA Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Shimada Seamount: An example of recent mid-plate volcanism","docAbstract":"Shimada Seamount is an isolated volcanic feature located between the Clipperton and Clarion Fracture Zones ∼1,150 km west of the East Pacific Rise and ∼600 km west of the inactive spreading center represented by the Mathematician Seamounts. It rises ∼3,900 m above the surrounding sea floor to within 50 m of present-day sea level. The area of Shimada Seamount should be volcanically dormant, because it is far from an active spreading center and is located on oceanic crust of early Miocene age. Nevertheless, evidence was found that Shimada Seamount has formed geologically recently. For example, seismic-reflection profiles-indicate that virtually no sediment has accumulated on the summit or flanks of the seamount; television, still-camera, and dredge-haul data indicate that a platform near the summit at a water depth of ∼180 m is a carbonate build-up formed by coralline red algae attached to fresh pillow basalt. Glassy pillow basalt too young to date by the K/Ar method and showing little or no devitrification and lacking manganese encrustations was dredged from the seamount below the algal reefs (500–750 m). Several cores taken from the adjacent basin (∼3,900 m deep) contain fresh glassy basalt detritus, and one core sampled a thin flow of unaltered basaltic glass at the sediment surface.
The origin and history of Shimada Seamount differ importantly from volcanoes generally thought to form at spreading centers, along transform faults, or at hot spots. The existence of Shimada Seamount, therefore, has implications about tectonic processes that occur in interplate regions.
","language":"English","publisher":"GSA","doi":"10.1130/0016-7606(1984)95<855:SSAEOR>2.0.CO;2","usgsCitation":"Gardner, J.V., Dean, W.E., and Blakely, R.J., 1984, Shimada Seamount: An example of recent mid-plate volcanism: GSA Bulletin, v. 95, p. 855-862, https://doi.org/10.1130/0016-7606(1984)95<855:SSAEOR>2.0.CO;2.","productDescription":"8 p.","startPage":"855","endPage":"862","costCenters":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true},{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true},{"id":662,"text":"Western Mineral and Environmental Resources Science Center","active":true,"usgs":true}],"links":[{"id":371118,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Shimada Seamount","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -118.65234374999999,\n 14.859850400601037\n ],\n [\n -105.8203125,\n 14.859850400601037\n ],\n [\n -105.8203125,\n 21.861498734372567\n ],\n [\n -118.65234374999999,\n 21.861498734372567\n ],\n [\n -118.65234374999999,\n 14.859850400601037\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"95","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Gardner, J. V.","contributorId":114111,"corporation":false,"usgs":true,"family":"Gardner","given":"J.","email":"","middleInitial":"V.","affiliations":[],"preferred":false,"id":779206,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779207,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Blakely, Richard J. 0000-0003-1701-5236 blakely@usgs.gov","orcid":"https://orcid.org/0000-0003-1701-5236","contributorId":1540,"corporation":false,"usgs":true,"family":"Blakely","given":"Richard","email":"blakely@usgs.gov","middleInitial":"J.","affiliations":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true},{"id":662,"text":"Western Mineral and Environmental Resources Science Center","active":true,"usgs":true}],"preferred":true,"id":779208,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70207757,"text":"70207757 - 1984 - Models for the deposition of Mesozoic-Cenozoic fine-grained organic-carbon-rich sediment in the deep sea","interactions":[],"lastModifiedDate":"2020-01-10T06:34:05","indexId":"70207757","displayToPublicDate":"1984-01-09T13:13:29","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":5011,"text":"Geological Society of London Special Publications","active":true,"publicationSubtype":{"id":10}},"title":"Models for the deposition of Mesozoic-Cenozoic fine-grained organic-carbon-rich sediment in the deep sea","docAbstract":"The widespread occurrence of organic-carbon-rich strata (‘black shales’) in certain portions of Jurassic, Cretaceous and Cenozoic sequences has been well-documented from Deep Sea Drilling Project sites in the Atlantic and Pacific Oceans and from sequences, now exposed on land, originally deposited in the Tethyan ocean. These ancient black shales usually have been explained by analogy with examples of modern deep-sea sediments in which organic matter locally is preserved by (1) increasing the supply of organic matter, (2) increasing the rate of sedimentation, and/or (3) decreasing the oxygen content of the bottom water. However, detailed examination of many black shales reveals characteristics that cannot be explained by simple local models, including: their approximate coincidence in time globally; their occurrence in a variety of different environments, including open oxygenated oceans, restricted basins, deep and shallow water; their interbedding with organic-carbonpoor strata which often dominate a so-called black shale sequence; their deposition by pelagic, hemipelagic, turbiditic and other processes; and the variations in type and amount of organic matter that occur even within the same sequence.
A more complex model for the origin of black shales therefore appears most appropriate, in which the cyclic preservation of organic matter depends on the interplay of the three main variables, namely supply of organic matter, sedimentation rate, and deep-water oxygenation, each of which varies independently to some extent. The variation and relative importance of these parameters in individual basins and widespread black shale deposition in general are linked globally and temporally by changes in global sea-level, climate and related changes in oceanic circulation. An important and often overlooked factor for the supply of organic matter to deep-basin sediments is the frequency and magnitude of redepositional processes. The interplay of these variables is discussed in relation to the middle Cretaceous and Cenozoic organic-carbon-rich strata, in particular, which show marked differences in the relative importance of the different variables.
","language":"English","publisher":"The Geological Society","doi":"10.1144/GSL.SP.1984.015.01.34","usgsCitation":"Arthur, M., Dean, W.E., and Stow, D., 1984, Models for the deposition of Mesozoic-Cenozoic fine-grained organic-carbon-rich sediment in the deep sea: Geological Society of London Special Publications, v. 15, p. 527-560, https://doi.org/10.1144/GSL.SP.1984.015.01.34.","productDescription":"34 p.","startPage":"527","endPage":"560","costCenters":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"links":[{"id":371116,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"15","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Arthur, M.A.","contributorId":24791,"corporation":false,"usgs":true,"family":"Arthur","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":779203,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779204,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Stow, D.A.V.","contributorId":35441,"corporation":false,"usgs":true,"family":"Stow","given":"D.A.V.","email":"","affiliations":[],"preferred":false,"id":779205,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70208825,"text":"cir921 - 1984 - Between Mount St. Helens and the world: How the U.S. Geological Survey provided news-media information on the 1980 volcanic eruptions","interactions":[],"lastModifiedDate":"2020-03-02T15:06:13","indexId":"cir921","displayToPublicDate":"1984-01-01T16:04:40","publicationYear":"1984","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":307,"text":"Circular","code":"CIR","onlineIssn":"2330-5703","printIssn":"1067-084X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"921","title":"Between Mount St. Helens and the world: How the U.S. Geological Survey provided news-media information on the 1980 volcanic eruptions","docAbstract":"The eruptions of Mount St. Helens volcano, Wash., constituted one of the major national and international news stories of 1980 and involved the U.S. Geological Survey in more news coverage than any other event in its history. Much of the information about the volcano came from monitoring and research by geologists, geophysicists, hydrologists, and other scientists of the U.S. Geological Survey. This scientific information was distributed to the public, through news media, by U.S. Geological Survey personnel. Key members of this group were Mount St. Helens hazards assessment scientists, monitoring scientists, and research scientists; public affairs officers; and the Information Scientist for Mount St. Helens. The Information Scientist, a geologist or geophysicist, assumed the major role of on-site (Vancouver, Wash.) news spokesman about a week after the main eruption of May 18. The Geological Survey released information through news conferences, interviews, news pools of reporters and cameramen on trips to the volcano, special television and radio appearances, news releases, and informal contacts with reporters. Members of the U.S. Forest Service, Federal Emergency Management Agency, State of Washington, and other government agencies cooperated extensively with the Geological Survey. By providing assistance to news representatives, the Geological Survey and these other agencies helped effect rapid dissemination of the background information and daily events of a highly complex story while limiting disruption to the scientific working team and minimizing dangers to reporters and scientists.
","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/cir921","usgsCitation":"Peter D. Rowley, Hait, M.H., Finley, D.R., Kelly, D.B., Russell-Robinson, S.L., Buchanan-Banks, J.M., Cashman, K.V., and King, E.G., 1984, Between Mount St. Helens and the world: How the U.S. Geological Survey provided news-media information on the 1980 volcanic eruptions: U.S. Geological Survey Circular 921, iii, 10 p., https://doi.org/10.3133/cir921.","productDescription":"iii, 10 p.","costCenters":[],"links":[{"id":372811,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/circ/0921/report.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":372810,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/circ/0921/report-thumb.jpg"}],"country":"United States","state":"Washington","otherGeospatial":"Mount St. Helens","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -122.27439880371094,\n 46.14178273759234\n ],\n [\n -122.09381103515624,\n 46.14178273759234\n ],\n [\n -122.09381103515624,\n 46.262967961777214\n ],\n [\n -122.27439880371094,\n 46.262967961777214\n ],\n [\n -122.27439880371094,\n 46.14178273759234\n ]\n ]\n ]\n }\n }\n ]\n}","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Peter D. Rowley","contributorId":194406,"corporation":false,"usgs":false,"family":"Peter D. Rowley","affiliations":[],"preferred":false,"id":783530,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hait, M. H. Jr.","contributorId":53451,"corporation":false,"usgs":true,"family":"Hait","given":"M.","suffix":"Jr.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":783531,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Finley, Donald R.","contributorId":222922,"corporation":false,"usgs":true,"family":"Finley","given":"Donald","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":783532,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kelly, Donovan B.","contributorId":56205,"corporation":false,"usgs":true,"family":"Kelly","given":"Donovan","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":783533,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Russell-Robinson, Susan L.","contributorId":82002,"corporation":false,"usgs":true,"family":"Russell-Robinson","given":"Susan","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":783534,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Buchanan-Banks, Jane M.","contributorId":29421,"corporation":false,"usgs":true,"family":"Buchanan-Banks","given":"Jane","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":783535,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Cashman, Katherine V.","contributorId":127856,"corporation":false,"usgs":false,"family":"Cashman","given":"Katherine","email":"","middleInitial":"V.","affiliations":[{"id":7172,"text":"University of Bristol, U.K. and University of Oregon, Eugene","active":true,"usgs":false}],"preferred":false,"id":783536,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"King, Edna G.","contributorId":222923,"corporation":false,"usgs":true,"family":"King","given":"Edna","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":783537,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"id":70007004,"text":"70007004 - 1984 - Third report to the fish farmers : the status of warmwater fish farming and progress in fish farming research","interactions":[],"lastModifiedDate":"2014-06-27T15:43:46","indexId":"70007004","displayToPublicDate":"1984-01-01T15:21:33","publicationYear":"1984","noYear":false,"publicationType":{"id":4,"text":"Book"},"title":"Third report to the fish farmers : the status of warmwater fish farming and progress in fish farming research","docAbstract":"No abstract available.","largerWorkType":{"id":18,"text":"Report"},"largerWorkTitle":"Third Report to the Fish Farmers: The Status of Warmwater Fish Farming Research","largerWorkSubtype":{"id":9,"text":"Other Report"},"language":"English","publisher":"U.S. Fish and Wildlife Service","publisherLocation":"Washington, DC","collaboration":"None","usgsCitation":"Dupree H. K., H.J., 1984, Third report to the fish farmers : the status of warmwater fish farming and progress in fish farming research, vi, 270 p.","productDescription":"vi, 270 p.","numberOfPages":"272","costCenters":[{"id":365,"text":"Leetown Science Center","active":true,"usgs":true}],"links":[{"id":289147,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"53ae7873e4b0abf75cf2d5b8","contributors":{"authors":[{"text":"Dupree H. K., Huner Jay V.","contributorId":58567,"corporation":false,"usgs":true,"family":"Dupree H. K.","given":"Huner","email":"","middleInitial":"Jay V.","affiliations":[],"preferred":false,"id":355638,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70006428,"text":"70006428 - 1984 - Flow-through bioassay for measuring bioaccumulation of toxic substances from sediment","interactions":[],"lastModifiedDate":"2014-05-29T15:08:37","indexId":"70006428","displayToPublicDate":"1984-01-01T14:45:00","publicationYear":"1984","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":1,"text":"Federal Government Series"},"seriesNumber":"EPA-905/3-84-007","title":"Flow-through bioassay for measuring bioaccumulation of toxic substances from sediment","docAbstract":"Over 10 million cubic meters of sediment are dredged annually from Great Lakes waterways. Because much of this material is taken from harbors, connecting channels, and other nearshore areas that often are contaminated with toxic substances, the sediments proposed for dredging need to be evaluated for the presence of bioavailable contaminants and the potential for toxicity to the biota. Sound decisions on the appropriate disposal of the dredged material can be made only after such an evaluation. Presently, no standardized procedure exists for evaluating dredged material in freshwater systems although current criteria for discharge of dredged material into marine water have been developed (USEPA/CE 1977). In the ocean discharge guideline, it is recommended that bioassays be conducted on liquid, solid, and suspended particulate phases of dredged material. because it appears that the solid phase has the greatest potential for environmental damage and because measurement of bioaccumulation must be made to evaluate sediments for disposal (USEPA/CE 1977, Seeyle and Mac 1983), we developed a bioassay for testing the solid phase of dredged material that measures the survival of organisms and, perhaps more important, the bioaccumulation of toxic substances by aquatic organisms from naturally contaminated sediments (Peddicord et al. 1980; Rubinstein et al. 1980, 1983; Seeyle st al. 1982), several have used testing methods that result in unacceptable mortality to control organisms (Bahnick et al. 1981, Prater et al. 1983).
\nOur bioassay is intended to estimate the potential for bioaccumlation of contaminants from sediments that are not acutely toxic to test organisms, but are suspected of containing persistent contaminants. By using test organisms that are not highly susceptible to toxic compounds, the bioaccumulation test allows estimation of the potential food-chain accumulation of contaminants that may occur in local biota from surficial sediments. In practice, bioaccumulation observed in this bioassay by organisms exposed to test sediments (sediments to be dredged) would be compared to bioaccumulation observed from sediments collected from a reference site (e.g. a disposal site or open lake), and also from control sediments (relatively clean sediment). Decisions could then be based on a comparison of results between tests and reference sediments to determine if disposal would cause dehydration to the habitat, and between reference and control sediment to determine if even the reference material is seriously contaminated. Although the test is not intended to be a toxicity test per se, use of test, reference, and control sediments enables interpretation of any mortality of organisms that may occur during the bioassays. High mortality in bioassays with test or reference sediment would indicate acute toxicity of sediments in the project area. However if high mortality occurs in all three sediments, it can be assumed that the organisms were not in a healthy state at the time of testing.
\nWe describe the results of 10-day sediment bioassays in which both mortality and bioaccumulation were measured in four aquatic organisms. We exposed two infaunal organisms and two species of fish to test and control sediments in the laboratory.
","language":"English","publisher":"U.S. Environmental Protection Agency","publisherLocation":"Chicago, IL","usgsCitation":"Mac, M.J., Edsall, C., Hesselberg, R.J., and Sayers, R.E., 1984, Flow-through bioassay for measuring bioaccumulation of toxic substances from sediment, vi, 17 p.","productDescription":"vi, 17 p.","numberOfPages":"25","costCenters":[{"id":324,"text":"Great Lakes Science Center","active":true,"usgs":true}],"links":[{"id":287837,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":287836,"type":{"id":15,"text":"Index Page"},"url":"https://nepis.epa.gov/Exe/ZyNET.exe/200071QP.txt?ZyActionD=ZyDocument&Client=EPA&Index=1981%20Thru%201985&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZYFILES%5CINDEX%20DATA%5C81THRU85%5CTXT%5C00000002%5C200071QP.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=p%7Cf&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"538856fbe4b0318b93124a8c","contributors":{"authors":[{"text":"Mac, Michael J.","contributorId":16772,"corporation":false,"usgs":true,"family":"Mac","given":"Michael","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":354477,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Edsall, Carol C.","contributorId":39726,"corporation":false,"usgs":true,"family":"Edsall","given":"Carol C.","affiliations":[],"preferred":false,"id":354479,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hesselberg, Robert J.","contributorId":36074,"corporation":false,"usgs":true,"family":"Hesselberg","given":"Robert","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":354478,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Sayers, Richard E. Jr.","contributorId":58570,"corporation":false,"usgs":true,"family":"Sayers","given":"Richard","suffix":"Jr.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":354480,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ]}