A comparison of the aquifer parameter values obtained through the analysis of a local and a regional aquifer test involving the same area in southeast Georgia is made in order to evaluate the validity of extrapolating local aquifer-test results for use in large-scale flow simulations. Time-drawdown and time-recovery data were analyzed by using both graphical and least-squares fitting of the data to the Theis curve. Additionally, directional transmissivity, transmissivity tensor, and angle of anisotropy were computed for both tests.
","language":"English","publisher":"National Groundwater Association","issn":"0017467X","usgsCitation":"Randolph, R., Krause, R., and Maslia, M., 1985, Comparison of aquifer characteristics derived from local and regional aquifer tests: Groundwater, v. 23, no. 3, p. 309-316.","productDescription":"8 p.","startPage":"309","endPage":"316","numberOfPages":"8","costCenters":[],"links":[{"id":220566,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f850e4b0c8380cd4cffa","contributors":{"authors":[{"text":"Randolph, R.B.","contributorId":38606,"corporation":false,"usgs":true,"family":"Randolph","given":"R.B.","email":"","affiliations":[],"preferred":false,"id":365234,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Krause, R.E.","contributorId":73210,"corporation":false,"usgs":true,"family":"Krause","given":"R.E.","email":"","affiliations":[],"preferred":false,"id":365235,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Maslia, M.L.","contributorId":24090,"corporation":false,"usgs":true,"family":"Maslia","given":"M.L.","affiliations":[],"preferred":false,"id":365233,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70013078,"text":"70013078 - 1985 - Redescription of Bellerophon asiaticus Wirth (Early Triassic: Gastropoda) from China, and a survey of Triassic Bellerophontacea","interactions":[],"lastModifiedDate":"2024-06-21T11:09:22.482881","indexId":"70013078","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2412,"text":"Journal of Paleontology","active":true,"publicationSubtype":{"id":10}},"title":"Redescription of Bellerophon asiaticus Wirth (Early Triassic: Gastropoda) from China, and a survey of Triassic Bellerophontacea","docAbstract":"The bilaterally symmetrical gastropod Bellerophon asiaticus Wirth is redescribed from specimens collected in Guizhou Province, PRC. The species is reassigned to Retispira, a common late Paleozoic taxon. Retispira is another example of a Paleozoic gastropod genus that crossed the era boundary. Associated pelecypods that date these Guizhou occurrences as Early Triassic are well known species in PRC and are illustrated. Both Bellerophon and Euphemites probably occur in the Early Triassic, though the quality of illustrations leaves some uncertainty; the existence of Stachella in the Triassic is more problematic. There was no dramatic reduction of the Bellerophontacea from their abundance and diversity in the Permian. It may be a general phenomenon that most late Paleozoic family-level and many generic-level taxa of gastropods were unaffected by the late Permian 'crisis'.
","language":"English","publisher":"Paleontological Society","issn":"00223360","usgsCitation":"Yochelson, E., and Yin, H., 1985, Redescription of Bellerophon asiaticus Wirth (Early Triassic: Gastropoda) from China, and a survey of Triassic Bellerophontacea: Journal of Paleontology, v. 59, no. 5, p. 1305-1319.","productDescription":"15 p.","startPage":"1305","endPage":"1319","numberOfPages":"15","costCenters":[],"links":[{"id":430405,"rank":2,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.geoscienceworld.org/jpaleontol/article/59/5/1305/81946/Redescription-of-Bellerophon-asiaticus-Wirth-Early"},{"id":220515,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"59","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"50e4a3aae4b0e8fec6cdb90d","contributors":{"authors":[{"text":"Yochelson, E.Y.","contributorId":100531,"corporation":false,"usgs":true,"family":"Yochelson","given":"E.Y.","email":"","affiliations":[],"preferred":false,"id":365232,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Yin, Hongfu","contributorId":63530,"corporation":false,"usgs":true,"family":"Yin","given":"Hongfu","email":"","affiliations":[],"preferred":false,"id":365231,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013076,"text":"70013076 - 1985 - Origin of caves and other solution openings in the unsaturated (vadose) zone of carbonate rocks: A model for CO2 generation","interactions":[],"lastModifiedDate":"2020-03-09T19:28:50","indexId":"70013076","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Origin of caves and other solution openings in the unsaturated (vadose) zone of carbonate rocks: A model for CO2 generation","docAbstract":"The enigma that caves and other solution openings form in carbonate rocks at great depths below land surface rather than forming from the surface downward can be explained by the generation of CO2 within the aquifer system. In the proposed model, CO2 is generated by the oxidation of particulate and/or dissolved organic carbon that is transported from the land surface deep into the unsaturated zone by recharging ground water. The organic material is oxidized to CO2 by aerobic bacteria utilizing oxygen that diffuses in from the atmosphere. Because gas transport in the unsaturated zone is controlled largely by diffusion, steady-state generation of even minute amounts of CO2 deep in the unsaturated zone results in the creation of large concentrations of CO2 at depth as it establishes a concentration gradient to the surface or other sink.
","language":"English","publisher":"GSW","doi":"10.1130/0091-7613(1985)13<822:OOCAOS>2.0.CO;2","issn":"00917613","usgsCitation":"Wood, W., 1985, Origin of caves and other solution openings in the unsaturated (vadose) zone of carbonate rocks: A model for CO2 generation: Geology, v. 13, no. 11, p. 822-824, https://doi.org/10.1130/0091-7613(1985)13<822:OOCAOS>2.0.CO;2.","productDescription":"3 p.","startPage":"822","endPage":"824","numberOfPages":"3","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":220513,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"13","issue":"11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a70c7e4b0c8380cd76240","contributors":{"authors":[{"text":"Wood, W.W.","contributorId":21974,"corporation":false,"usgs":true,"family":"Wood","given":"W.W.","email":"","affiliations":[],"preferred":false,"id":365229,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013074,"text":"70013074 - 1985 - Global map of eolian features on Mars","interactions":[],"lastModifiedDate":"2024-06-27T15:37:07.083694","indexId":"70013074","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Global map of eolian features on Mars","docAbstract":"Ten basic categories of eolian features on Mars were identified from a survey of Mariner 9 and Viking orbiter images. The ten features mapped are (1) light streaks (including frost streaks), (2) dark streaks, (3) sand sheets or splotches, (4) barchari dunes, (5) transverse dunes, (6) crescentic dunes, (7) anomalous dunes, (8) yardangs, (9) wind grooves, and (10) deflation pits. The features were mapped in groups, not as individual landforms, and recorded according to their geographic positions and orientations on maps of 1:12.5 million or 1:25 million scale. In the north polar region, light and dark streaks indicate winds from the west and northwest. Frost streaks show northeast and northwest winds. Barchan dunes show southwest and west winds. Transverse dunes show east and west winds. Local erosional features show winds from the northwest or southeast and northeast or southwest. In the middle and low northern latitudes, streaks show northeast winds; yardangs and deflation pits show mostly easterly and northeasterly winds. In the low southern latitudes, light streaks and dunes record northwest and northeast winds; dark streaks record southeast winds. In high southern latitudes, most streaks and dunes record southeast and east winds. In the south polar region, light and frost streaks record southwest and northwest winds, whereas dark streaks and transverse dunes show southeast winds. The patterns recorded for ephemeral features conform to global conditions of strong southern spring and summer (northern fall and winter) wind circulation. Erosional features in bedrock indicate long-term and perhaps ancient wind trends, whereas depositional features may record relatively more recent winds. Wind directions indicated by yardangs, pits, and other erosional features seldom correspond to those shown by streaks. These erosional features indicating winds of different directions than those that formed the streaks may have been carved when the effective regional winds on Mars were different due to relative hemisphere insolation differences, which are related to obliquity variations. Alternatively, many yardangs and pits may be largely controlled by structure and carved along surface structural patterns or features that channeled both ancient and present-day winds. Deflation pits in the mantled terrain may contain the best record of ancient wind trends. These pits seem to have stratigraphically related orientations. Different stratigraphic units composing the mantle contain wind erosion pits that possibly record large-scale wind direction changes because of long-term changes in the obliquity of the Mars.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB090iB02p02038","issn":"01480227","usgsCitation":"Ward, A.W., Doyle, K., Helm, P.J., Weisman, M., and Witbeck, N., 1985, Global map of eolian features on Mars: Journal of Geophysical Research Solid Earth, v. 90, no. B2, p. 2038-2056, https://doi.org/10.1029/JB090iB02p02038.","productDescription":"19 p.","startPage":"2038","endPage":"2056","numberOfPages":"19","costCenters":[],"links":[{"id":220511,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"90","issue":"B2","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a294ce4b0c8380cd5a82d","contributors":{"authors":[{"text":"Ward, A. W.","contributorId":8129,"corporation":false,"usgs":true,"family":"Ward","given":"A.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":365220,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Doyle, K.B.","contributorId":103411,"corporation":false,"usgs":true,"family":"Doyle","given":"K.B.","email":"","affiliations":[],"preferred":false,"id":365224,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Helm, P. J.","contributorId":72813,"corporation":false,"usgs":true,"family":"Helm","given":"P.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":365223,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Weisman, M.K.","contributorId":39519,"corporation":false,"usgs":true,"family":"Weisman","given":"M.K.","email":"","affiliations":[],"preferred":false,"id":365222,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Witbeck, N.E.","contributorId":31473,"corporation":false,"usgs":true,"family":"Witbeck","given":"N.E.","email":"","affiliations":[],"preferred":false,"id":365221,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70013073,"text":"70013073 - 1985 - The Schwartzwalder uranium deposit, II: Age of uranium mineralization and lead isotope constraints on genesis","interactions":[],"lastModifiedDate":"2024-01-08T23:34:46.948528","indexId":"70013073","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1472,"text":"Economic Geology","active":true,"publicationSubtype":{"id":10}},"title":"The Schwartzwalder uranium deposit, II: Age of uranium mineralization and lead isotope constraints on genesis","docAbstract":"U-Pb isotope analyses of ores from the Schwartzwalder uranium mine, Colorado, show that these ores have high amounts of initial (common) Pb and that the initial Pb was both variable and relatively radiogenic in its Pb isotope ratios ( 206 Pb/ 204 Pb = 26-30). As a result, the only useful approach to dating these ores is with U-Pb isochrons, and even so, some means of dealing with the variable initial Pb isotope ratios is required. Because the common Pb in these ores was apparently derived from sources of similar age and Th/U, the observed 208 Pb/ 204 Pb of these Th-free ores can be used either to identify sample suites with similar initial Pb isotope ratios or to normalize for the variable initial Pb isotope ratios. The resulting U-Pb isochrons indicate an age of mineralization for both Illinois vein and Titan vein ores of 69.3 + or - 1.1 m.y., suggesting that the deposit was formed during the earliest stages of Laramide uplift and under at least 3 km of Phanerozoic cover. The initial Pb isotope systematics of the ores show that the metals in the Schwartzwalder ores were derived from source(s) of 1,730 + or - 130-m.y.-age, with a Th/U of 2.2 + or - 0.2 and 238 U/ 204 Pb of 30 to 60. These restrictions on the source(s) of the metals rule out the possibility that the deposit could have been formed by remobilization of a Proterozoic uranium deposit, and both the 69.3-m.y.-age of the ores and their initial Pb isotope ratios preclude any contribution of metals to the deposit by younger volcanics such as those in the Denver Formation.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.80.7.1858","issn":"03610128","usgsCitation":"Ludwig, K., Wallace, A.R., and Simmons, K.R., 1985, The Schwartzwalder uranium deposit, II: Age of uranium mineralization and lead isotope constraints on genesis: Economic Geology, v. 80, no. 7, p. 1858-1871, https://doi.org/10.2113/gsecongeo.80.7.1858.","productDescription":"14 p.","startPage":"1858","endPage":"1871","numberOfPages":"14","costCenters":[],"links":[{"id":220510,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"80","issue":"7","noUsgsAuthors":false,"publicationDate":"1985-11-01","publicationStatus":"PW","scienceBaseUri":"505ba8dbe4b08c986b321ecf","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":365219,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wallace, A. R.","contributorId":59445,"corporation":false,"usgs":true,"family":"Wallace","given":"A.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":365217,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Simmons, K. R.","contributorId":68771,"corporation":false,"usgs":true,"family":"Simmons","given":"K.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":365218,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70013072,"text":"70013072 - 1985 - Geophysical techniques for reconnaissance investigations of soils and surficial deposits in mountainous terrain","interactions":[],"lastModifiedDate":"2020-01-19T10:43:40","indexId":"70013072","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3420,"text":"Soil Science Society of America Journal","active":true,"publicationSubtype":{"id":10}},"title":"Geophysical techniques for reconnaissance investigations of soils and surficial deposits in mountainous terrain","docAbstract":"Two techniques were assessed for their capabilities in reconnaissance studies of soil characteristics: depth to the water table and depth to bedrock beneath surficial deposits in mountainous terrain. Ground-penetrating radar had the best near-surface resolution in the upper 2 m of the profile and provided continuous interpretable imagery of soil profiles and bedrock surfaces. Where thick colluvium blankets side slopes, the GPR could not consistently define the bedrock interface. In areas with clayey or shaley sediments, the GPR is also more limited in defining depth and is less reliable. Seismic refraction proved useful in determining the elevation of the water table and depth to bedrock, regardless of thickness of overlying material, but could not distinguish soil-profile characteristics.
","language":"English","publisher":"Soil Science Society of America","doi":"10.2136/sssaj1985.03615995004900060032x","issn":"03615995","usgsCitation":"Olson, C., and Doolittle, J., 1985, Geophysical techniques for reconnaissance investigations of soils and surficial deposits in mountainous terrain: Soil Science Society of America Journal, v. 49, no. 6, p. 1490-1498, https://doi.org/10.2136/sssaj1985.03615995004900060032x.","productDescription":"9 p.","startPage":"1490","endPage":"1498","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":220461,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"49","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a2878e4b0c8380cd5a147","contributors":{"authors":[{"text":"Olson, C.G.","contributorId":13743,"corporation":false,"usgs":true,"family":"Olson","given":"C.G.","email":"","affiliations":[],"preferred":false,"id":365215,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Doolittle, J.A.","contributorId":188185,"corporation":false,"usgs":false,"family":"Doolittle","given":"J.A.","email":"","affiliations":[],"preferred":false,"id":365216,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013071,"text":"70013071 - 1985 - Simulation of steady-state flow in three-dimensional fracture networks using the boundary-element method","interactions":[],"lastModifiedDate":"2020-01-19T10:35:26","indexId":"70013071","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":664,"text":"Advances in Water Resources","active":true,"publicationSubtype":{"id":10}},"title":"Simulation of steady-state flow in three-dimensional fracture networks using the boundary-element method","docAbstract":"An efficient method for simulating steady-state flow in three-dimensional fracture networks is formulated with the use of the boundary-element method. The host rock is considered to be impervious, and the fractures can be of any orientation and areal extent. The fractures are treated as surfaces where fluid movement is essentially two-dimensional. Fracture intersections are regarded as one-dimensional fluid conduits. Hence, the three-dimensional geometric characteristics of the fracture geometry is retained in solutions of coupled sets of one- and two-dimentional equations. Use of the boundary-element method to evaluate the fluid responses in the fractures precludes the need to internally discretize the areal extent of the fractures.
","language":"English","doi":"10.1016/0309-1708(85)90049-1","issn":"03091708","usgsCitation":"Shapiro, A., and Andersson, J., 1985, Simulation of steady-state flow in three-dimensional fracture networks using the boundary-element method: Advances in Water Resources, v. 8, no. 3, p. 106-110, https://doi.org/10.1016/0309-1708(85)90049-1.","productDescription":"5 p.","startPage":"106","endPage":"110","numberOfPages":"5","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":220460,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"8","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9088e4b08c986b31956e","contributors":{"authors":[{"text":"Shapiro, A.M. 0000-0002-6425-9607","orcid":"https://orcid.org/0000-0002-6425-9607","contributorId":88384,"corporation":false,"usgs":true,"family":"Shapiro","given":"A.M.","affiliations":[],"preferred":true,"id":365214,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Andersson, J.","contributorId":59558,"corporation":false,"usgs":true,"family":"Andersson","given":"J.","email":"","affiliations":[],"preferred":false,"id":365213,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013069,"text":"70013069 - 1985 - Assessment of long-term salinity changes in an irrigated stream-aquifer system","interactions":[],"lastModifiedDate":"2020-01-19T11:09:19","indexId":"70013069","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Assessment of long-term salinity changes in an irrigated stream-aquifer system","docAbstract":"Changes in salinity in groundwater and surface water in the Arkansas River valley of southeastern Colorado are primarily related to irrigation practices. A solute transport model was applied to an 11-mile reach of the valley to compute salinity changes in response to spatially and temporally varying stresses. The model was calibrated in 1973 using detailed field measurements made during 1971 and 1972. In 1973 the calibrated model was used to predict that a gradual long-term increase in groundwater salinity of about 2–3% per year would occur if the observed irrigation practices continued. The study area was resampled during the winter of 1982 to help evaluate if any long-term changes in salinity are actually occurring. Nonparametric and parametric statistical tests were used to help assess the significance of observed changes in groundwater salinity. These tests indicate that a statistically significant increase in salinity occurred between the winters of 1971 and 1972 (the model calibration period). However, a comparison of the winter 1972 and winter 1982 data indicates that no significant net change in salinity has occurred during this 10-year period. An analysis of the few available historical data (1895, 1923, 1959–1961, and 1964) supports the hypothesis that groundwater salinity in this irrigated area has reached a long-term dynamic equilibrium in response to irrigation practices. The model predictions of long-term salinity increases were invalid probably because the calibration period occurred during a short-term annual trend of increasing salinity in the river (and hence in leaky irrigation canals and in applied irrigation water), which was not representative of the long-term trend.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR021i011p01611","usgsCitation":"Konikow, L.F., and Person, M., 1985, Assessment of long-term salinity changes in an irrigated stream-aquifer system: Water Resources Research, v. 21, no. 11, p. 1611-1624, https://doi.org/10.1029/WR021i011p01611.","productDescription":"14 p.","startPage":"1611","endPage":"1624","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":220405,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Colorado","otherGeospatial":"Arkansas River valley","volume":"21","issue":"11","noUsgsAuthors":false,"publicationDate":"2008-01-08","publicationStatus":"PW","scienceBaseUri":"5059e637e4b0c8380cd47268","contributors":{"authors":[{"text":"Konikow, Leonard F. 0000-0002-0940-3856 lkonikow@usgs.gov","orcid":"https://orcid.org/0000-0002-0940-3856","contributorId":158,"corporation":false,"usgs":true,"family":"Konikow","given":"Leonard","email":"lkonikow@usgs.gov","middleInitial":"F.","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":365210,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Person, Mark","contributorId":55568,"corporation":false,"usgs":true,"family":"Person","given":"Mark","affiliations":[],"preferred":false,"id":365211,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013068,"text":"70013068 - 1985 - Geochemistry of groundwater in Cretaceous sediments of the southeastern coastal plain of eastern Mississippi and western Alabama","interactions":[],"lastModifiedDate":"2018-02-12T18:01:26","indexId":"70013068","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Geochemistry of groundwater in Cretaceous sediments of the southeastern coastal plain of eastern Mississippi and western Alabama","docAbstract":"Geochemical samples of waters along two hydrologic flow paths in four Upper Cretaceous aquifers of northeastern Mississippi and western Alabama indicate similar geochemical evolution of their respective waters. The waters of the Coker, Gordo, and Eutaw-McShan aquifers, noncalcareous sands, increase downgradient in dissolved solids and pH, and are dominated by sodium and bicarbonate ions, which generally result from a calcite dissolution-cation exchange process. Increases in dissolved iron from oxidation reduction reactions followed by decreases in total inorganic carbon from siderite precipitation occur along the flow paths. As the total inorganic carbon increases, carbon 13 (δ13C) generally is enriched in the moving waters, indicating the addition of a predominantly heavy source of carbon, most likely dissolving calcite. In the Coker aquifer δ13C values in the waters become more negative downgradient, resulting from lignite oxidation, followed by δ13C values becoming more positive, resulting from dissolving calcite and perhaps some mixing with brines. In northeastern Mississippi the Ripley aquifer, a calcareous sand, initially contains calcium-bicarbonate dominated water that evolves to a sodium- bicarbonate dominated water downgradient, primarily from the calcite dissolution-cation exchange process. Feldspar hydrolysis to kaolinite dominates aluminosilicate reactions in the upgradient parts of the aquifers. Authigenesis of smectite clay may be occurring in the deeper, downgradient parts of the aquifers.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/WR021i010p01545","usgsCitation":"Lee, R.W., 1985, Geochemistry of groundwater in Cretaceous sediments of the southeastern coastal plain of eastern Mississippi and western Alabama: Water Resources Research, v. 21, no. 10, p. 1545-1556, https://doi.org/10.1029/WR021i010p01545.","productDescription":"12 p.","startPage":"1545","endPage":"1556","costCenters":[],"links":[{"id":220404,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Alabama, Mississippi","otherGeospatial":"Southeastern Coastal Plain","volume":"21","issue":"10","noUsgsAuthors":false,"publicationDate":"2008-01-08","publicationStatus":"PW","scienceBaseUri":"505a16fbe4b0c8380cd55334","contributors":{"authors":[{"text":"Lee, Roger W.","contributorId":105273,"corporation":false,"usgs":true,"family":"Lee","given":"Roger","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":365209,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013066,"text":"70013066 - 1985 - Absolute calibration of Landsat instruments using the moon.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:38","indexId":"70013066","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3052,"text":"Photogrammetric Engineering and Remote Sensing","active":true,"publicationSubtype":{"id":10}},"title":"Absolute calibration of Landsat instruments using the moon.","docAbstract":"A lunar observation by Landsat could provide improved radiometric and geometric calibration of both the Thematic Mapper and the Multispectral Scanner in terms of absolute radiometry, determination of the modulation transfer function, and sensitivity to scattered light. A pitch of the spacecraft would be required. -Authors","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Photogrammetric Engineering and Remote Sensing","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","usgsCitation":"Kieffer, H.H., and Wildey, R., 1985, Absolute calibration of Landsat instruments using the moon.: Photogrammetric Engineering and Remote Sensing, v. 51, no. 9, p. 1391-1393.","startPage":"1391","endPage":"1393","numberOfPages":"3","costCenters":[],"links":[{"id":220349,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"51","issue":"9","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e64ae4b0c8380cd47308","contributors":{"authors":[{"text":"Kieffer, H. H.","contributorId":40725,"corporation":false,"usgs":false,"family":"Kieffer","given":"H.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":365206,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wildey, R.L.","contributorId":9700,"corporation":false,"usgs":true,"family":"Wildey","given":"R.L.","email":"","affiliations":[],"preferred":false,"id":365205,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013065,"text":"70013065 - 1985 - Drainage development of the Green River Basin in southwestern Wyoming and its bearing on fish biogeography, neotectonics, and paleoclimates.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:38","indexId":"70013065","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2789,"text":"Mountain Geologist","active":true,"publicationSubtype":{"id":10}},"title":"Drainage development of the Green River Basin in southwestern Wyoming and its bearing on fish biogeography, neotectonics, and paleoclimates.","docAbstract":"The Upper Green River flows southward out of the Green River Basin through a series of deep canyons across the Uinta Mountains in a course that post-dates the deposition of the Bishop Conglomerate (Oligocene). After the Eocene lakes disappeared, drainage was generally eastward across the present Continental Divide, until the Green River was captured near Green River, Wyo. by south-flowing drainage in middle Pleistocene time, ca., 600 kyr ago. Capture of the Upper Green River as recently as middle Pleistocene time, if a valid hypothesis, must take into account the marked differences between the endemic and indigenous fish fauna of the Green River and that of the North Platte. -from Author","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Mountain Geologist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"0027254X","usgsCitation":"Hansen, W.R., 1985, Drainage development of the Green River Basin in southwestern Wyoming and its bearing on fish biogeography, neotectonics, and paleoclimates.: Mountain Geologist, v. 22, no. 4, p. 192-204.","startPage":"192","endPage":"204","numberOfPages":"13","costCenters":[],"links":[{"id":220348,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a03cee4b0c8380cd50662","contributors":{"authors":[{"text":"Hansen, W. R.","contributorId":59378,"corporation":false,"usgs":true,"family":"Hansen","given":"W.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":365204,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013064,"text":"70013064 - 1985 - Lacustrine-humate model for primary uranium ore deposits, Grants uranium region, New Mexico","interactions":[],"lastModifiedDate":"2023-01-12T17:04:16.864261","indexId":"70013064","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":701,"text":"American Association of Petroleum Geologists Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Lacustrine-humate model for primary uranium ore deposits, Grants uranium region, New Mexico","docAbstract":"Two generations of uranium ore, primary and redistributed, occur in fluvial sandstones of the Upper Jurassic Morrison Formation in the San Juan basin; the two stages of ore formation can be related to the hydrologic history of the basin. Primary ore formed soon after Morrison deposition, in the Late Jurassic to Early Cretaceous, and a model, the lacustrine-humate model, is offered that views primary mineralization as a diagenetic event related to early pore fluid evolution. The basic premise is that the humate, a pore-filling organic material closely associated with primary ore, originated as humic acids dissolved in pore waters of greenish-gray lacustrine mudstones deposited in the mud-flat facies of the Brushy Basin Member and similar \"K\" shale beds in the Westwater Can on Member. During compaction associated with early burial, formation water expelled from lacustrine mudstone units carried these humic acids into adjacent sandstone beds where the organics precipitated, forming the humate deposits that concentrated uranium.
During the Tertiary, much later in the hydrologic history of the basin, when Jurassic sediments were largely compacted, oxygenated ground water flowed basinward from uplifted basin margins. This invasion of Morrison sandstone beds by oxidizing ground waters redistributed uranium from primary ores along redox boundaries, forming ore deposits that resemble roll-front-type uranium ores.
","language":"English","publisher":"American Association of Petroleum Geologists (AAPG)","doi":"10.1306/94885589-1704-11D7-8645000102C1865D","usgsCitation":"Turner-Peterson, C., 1985, Lacustrine-humate model for primary uranium ore deposits, Grants uranium region, New Mexico: American Association of Petroleum Geologists Bulletin, v. 69, no. 11, p. 1990-2020, https://doi.org/10.1306/94885589-1704-11D7-8645000102C1865D.","productDescription":"31 p.","startPage":"1990","endPage":"2020","numberOfPages":"31","costCenters":[],"links":[{"id":220347,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"New Mexico","otherGeospatial":"Grants uranium region","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -108.64038174995106,\n 36.04693775500846\n ],\n [\n -108.64038174995106,\n 34.70563438153877\n ],\n [\n -106.912022747075,\n 34.70563438153877\n ],\n [\n -106.912022747075,\n 36.04693775500846\n ],\n [\n -108.64038174995106,\n 36.04693775500846\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"69","issue":"11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4130e4b0c8380cd6537f","contributors":{"authors":[{"text":"Turner-Peterson, C. E.","contributorId":53958,"corporation":false,"usgs":true,"family":"Turner-Peterson","given":"C. E.","affiliations":[],"preferred":false,"id":365203,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013063,"text":"70013063 - 1985 - Saprolite formation beneath Coastal Plain sediments near Washington, D.C.","interactions":[],"lastModifiedDate":"2023-12-28T21:40:05.43964","indexId":"70013063","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Saprolite formation beneath Coastal Plain sediments near Washington, D.C.","docAbstract":"Crystalline rocks buried beneath Atlantic Coastal Plain sediments in the Washington, D.C., area commonly have weathering profiles that resemble exposed saprolite of the Piedmont. Cuts along the Washington Metropolitan Area Transit Authority (WMATA) route in northern Virginia show a bedrock weathering profile beneath Cretaceous and younger sediments.
Three lines of evidence indicate that this buried weathering profile (saprolite) has formed in the subsurface and is post-Miocene in age:
The thickness of the profile, ranging from 2 to 15 m, is thinner beneath clays and thicker beneath sands, apparently a function of the permeability of the overlying material.
The buried profile shows no evidence of soil formation at its upper surface and, therefore, no evidence of ever having been sub-aerially exposed.
Consolidation tests on the cohesive clayey silts in the samples of the weathering profile indicate mechanical equilibrium with the present overburden, whereas consolidation tests on superjacent Cretaceous clays indicate over-consolidation resulting from a thicker pre-upper Miocene overburden.
The post-Miocene age for the subsurface saprolite profile shows that not all saprolite beneath Cretaceous sediment is pre-Cretaceous in age. These observations have important implications for the interpretation of age of the exposed Piedmont saprolite.
","language":"English","publisher":"Geological Society of America","doi":"10.1130/0016-7606(1985)96<886:SFBCPS>2.0.CO;2","usgsCitation":"Pavich, M., and Obermeier, S., 1985, Saprolite formation beneath Coastal Plain sediments near Washington, D.C.: Geological Society of America Bulletin, v. 96, no. 7, p. 886-900, https://doi.org/10.1130/0016-7606(1985)96<886:SFBCPS>2.0.CO;2.","productDescription":"15 p.","startPage":"886","endPage":"900","numberOfPages":"15","costCenters":[],"links":[{"id":220346,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","otherGeospatial":"Washington, D.C.","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -77.81620998525524,\n 39.373216950063465\n ],\n [\n -77.81620998525524,\n 38.4155630828767\n ],\n [\n -76.37700100088063,\n 38.4155630828767\n ],\n [\n -76.37700100088063,\n 39.373216950063465\n ],\n [\n -77.81620998525524,\n 39.373216950063465\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"96","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b86bfe4b08c986b3160ee","contributors":{"authors":[{"text":"Pavich, M.J.","contributorId":70788,"corporation":false,"usgs":true,"family":"Pavich","given":"M.J.","email":"","affiliations":[],"preferred":false,"id":365202,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Obermeier, S. F.","contributorId":17602,"corporation":false,"usgs":true,"family":"Obermeier","given":"S. F.","affiliations":[],"preferred":false,"id":365201,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013062,"text":"70013062 - 1985 - Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece","interactions":[],"lastModifiedDate":"2024-04-26T16:44:32.08347","indexId":"70013062","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2309,"text":"Journal of Geology","active":true,"publicationSubtype":{"id":10}},"title":"Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece","docAbstract":"The 18,500 yr. b.p. Cape Riva (CR) eruption of Santorini vented several km3 or more of magma, generating four eruption units: a basal Plinian fall deposit (CR-A) and three pyroclastic flow deposits (CR-B to CR-D upwards). CR-B and CR-D are welded ignimbrites; CR-C consists predominantly of up to 25 m thick coarse, lithic-rich co-ignimbrite lag breccias resulting from a climactic phase of the eruption. The initial Plinian phase occurred from a localized vent in N Santorini, and subsequent column collapse resulted in emplacement of CR-B. Towards the end of CR-B, new conduits were activated and pyroclastic flows discharged from multiple vents to generate the lag breccias (CR-C). CR-D probably records a return to a localized vent as the eruption waned. The eruption sampled a zoned magma chamber containing rhyodacite overlying andesite, and leaks of these magmas were manifested as the Skaros-Therasia lavas preceding the CR eruption. Plinian and initial ignimbrite stages occurred while the magma chamber was overpressured; subsequent underpressuring, due to magma discharge, caused fracturing of the chamber roof, caldera collapse, and eruption of pyroclastic flows from multiple vents. Activation and widening of new conduits during collapse resulted in the rapid escalation of discharge rate favoring the formation of lag breccias by: (i) promoting erosion of lithic debris at the surface vent; and (ii) raising surface exit pressures, thereby resulting in a dramatic increase in the grain size of the ejecta.
","language":"English","publisher":"University of Chicago Press","doi":"10.1086/628965","issn":"00221376","usgsCitation":"Druitt, T.H., 1985, Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece: Journal of Geology, v. 93, no. 4, p. 439-454, https://doi.org/10.1086/628965.","productDescription":"16 p.","startPage":"439","endPage":"454","numberOfPages":"16","costCenters":[],"links":[{"id":220345,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bc201e4b08c986b32a89e","contributors":{"authors":[{"text":"Druitt, T. H.","contributorId":60662,"corporation":false,"usgs":true,"family":"Druitt","given":"T.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":365200,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013061,"text":"70013061 - 1985 - Electrical geophysical investigations of massive sulfide deposits and their host rocks, West Shasta copper-zinc district","interactions":[],"lastModifiedDate":"2024-01-08T18:28:43.380103","indexId":"70013061","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1472,"text":"Economic Geology","active":true,"publicationSubtype":{"id":10}},"title":"Electrical geophysical investigations of massive sulfide deposits and their host rocks, West Shasta copper-zinc district","docAbstract":"The West Shasta copper-zinc district, Shasta County, California, contains many volcanogenic sulfide deposits within Middle Devonian rhyolites that have not been highly metamorphosed. The district was selected by the U.S. Geological Survey for intensive geological, geochemical, and geophysical study under the Development of Assessment Techniques (DAT) project because accessible exposures have been created by erosion and mining. This report describes the geophysical methods applied to characterize the electrical properties of selected West Shasta massive sulfide deposits and their host rocks, at both small (less than 25 ft) and large (greater than 25 ft) scales. The electrical techniques used galvanic (spectral induced polarization--SIP) and induction (very low frequency--VLF, slingram, and time domain electro-magnetics--TDEM) methods.In situ spectral induced polarization measurements were carried out to determine whether or not conductive anomalies in the district could be differentiated by their polarization signatures. The sulfide, in situ, induced polarization-phase spectral signatures (the induced polarization effect as a function of frequency) have much less character and lack the distinctive shape reported for other massive sulfide deposits; however, they do have some identifiable massive sulfide traits, such as low resistivity and variable polarizability. The nondescript sulfide spectral signature is attributed to the poor development of polarization processes due to a high percentage of resistive, nonpolarizable gangue minerals, lack of pore space, and limited electrolytic fluids. Large-scale spectral induced polarization measurements over the Hornet orebody have a greater polarization than the in situ measurements. This observation, in addition to the fact that much of the Hornet sulfide body has been removed by previous mining activity, suggests that the dominant polarization processes occur at the ground-water-sulfide interface.Combined use of induction techniques, which have different depths of penetration, were used to locate conductive anomalies and determine their shape and depth. All the induction surveys over the Hornet orebody detected the conductive tabular-shaped massive pyritic sulfide deposit hosted in resistive rhyolite. Shallow penetrating induction methods near the Keystone mine detected a conductive fault zone where a block of shale has been downfaulted into volcanic rock. Integrated interpretation of deeper penetrating induction data over this conductive fault zone indicates that parts of the shale are also conductive, demonstrating that the integrated use of several induction methods provides better conductor definition than a single method.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.80.8.2213","issn":"03610128","usgsCitation":"Horton, R.J., Smith, B.D., and Washburne, J., 1985, Electrical geophysical investigations of massive sulfide deposits and their host rocks, West Shasta copper-zinc district: Economic Geology, v. 80, no. 8, p. 2213-2229, https://doi.org/10.2113/gsecongeo.80.8.2213.","productDescription":"17 p.","startPage":"2213","endPage":"2229","numberOfPages":"17","costCenters":[],"links":[{"id":220344,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"80","issue":"8","noUsgsAuthors":false,"publicationDate":"1985-12-01","publicationStatus":"PW","scienceBaseUri":"505a0890e4b0c8380cd51b8b","contributors":{"authors":[{"text":"Horton, R. J.","contributorId":19926,"corporation":false,"usgs":true,"family":"Horton","given":"R.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":365197,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Smith, B. D.","contributorId":71123,"corporation":false,"usgs":true,"family":"Smith","given":"B.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":365198,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Washburne, J.C.","contributorId":105431,"corporation":false,"usgs":true,"family":"Washburne","given":"J.C.","affiliations":[],"preferred":false,"id":365199,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70013060,"text":"70013060 - 1985 - Root zone of the late Proterozoic Salma caldera, northeastern Arabian Shield, Kingdom of Saudi Arabia","interactions":[],"lastModifiedDate":"2024-06-27T15:36:35.888731","indexId":"70013060","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Root zone of the late Proterozoic Salma caldera, northeastern Arabian Shield, Kingdom of Saudi Arabia","docAbstract":"The eroded root of the late Proterozoic Salma caldera crops out in a striking, roughly elliptical feature, about 27 km long and 22 km wide, near the northeastern edge of the Arabian Shield. The caldera is genetically part of an elongate alkalic granitic massif (Jabal Salma) that extends 35 km from the caldera to the southwest. Comenditic ash flow tuff and lava(?) of the caldera fill, probably more than 1 km thick, are the oldest recognized rocks of the caldera complex. These rocks were erupted during caldera collapse associated with the rapid evacuation of the upper, mildly peralkalic part of a zoned magma reservoir. Within the caldera fill, a massive, lithic-rich intracaldera rhyolite, probably a lava in excess of 1 km thick, is overlain by a layered ash flow sequence. Numerous megabreccia blocks, probably derived from the caldera wall, occur in the massive rhyolite. Open folds in the layered volcanic rocks may be due to high-temperature slumping of the rocks toward the center of the caldera following collapse. Later peralkalic granite that intruded the caldera ring fracture zone occurs in an arcuate pattern outside the area of exposed caldera fill. After caldera collapse, metaluminous to peraluminous magma rose beneath the caldera at approximately 580 Ma and solidified as biotite alkali granite, rim syenogranite, and late, high-level granophyre. Rare earth element abundances indicate that the layered rhyolite tuff, peralkalic granite, and granophyre are chemically more evolved than the biotite alkali granite and rim syenogranite. The granophyre intruded the caldera fill as a dome-shaped body composed of numerous sheetlike masses. Granophyric texture resulted from rapid pressure release and quenching accompanying the intrusion of each sheet. Maximum penetration of the granophyre into overlying rocks occurred in the central region and along the west side of the caldera, where the caldera fill volcanic rocks have been removed by erosion. No apparent structural doming of the exposed volcanic rocks along the east side of the caldera took place; the layered ash flows commonly dip steeply toward the center of the caldera. Postemplacement deformation and metamorphism of the caldera are minimal. Small-displacement strike-slip faults cut the complex, which is tilted to the northeast by no more than about 2°.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB090iB13p11253","issn":"01480227","usgsCitation":"Kellogg, K., 1985, Root zone of the late Proterozoic Salma caldera, northeastern Arabian Shield, Kingdom of Saudi Arabia: Journal of Geophysical Research Solid Earth, v. 90, no. B13, p. 11253-11262, https://doi.org/10.1029/JB090iB13p11253.","productDescription":"10 p.","startPage":"11253","endPage":"11262","costCenters":[],"links":[{"id":220289,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"90","issue":"B13","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505aae8ae4b0c8380cd8710c","contributors":{"authors":[{"text":"Kellogg, K.S.","contributorId":99145,"corporation":false,"usgs":true,"family":"Kellogg","given":"K.S.","email":"","affiliations":[],"preferred":false,"id":365196,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013059,"text":"70013059 - 1985 - Proximal bedded deposits related to pyroclastic flows of May 18, 1980, Mount St. Helens, Washington","interactions":[],"lastModifiedDate":"2023-12-28T21:43:45.357798","indexId":"70013059","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Proximal bedded deposits related to pyroclastic flows of May 18, 1980, Mount St. Helens, Washington","docAbstract":"Thin-bedded, dacitic, pumiceous pyroclastic-flow deposits partly cover the steep northern flank of Mount St. Helens volcano, Washington. They are termed proximal bedded pyroclastic-flow (PBPF) deposits and were formed during the eruption of May 18, 1980. These unconsolidated deposits, as much as 20 m thick, are characterized by well-defined, chiefly plane-parallel bedding sets separated by erosion surfaces. Most beds dip generally parallel to the slope of the underlying volcano flank, which averages 15° to the north but locally is as much as 30°. Individual beds range in thickness from 2 mm to >1 m. Cross-bedding, in which bedding sets dip gently to the north or locally to the south, is abundant. Cross-bedding is generally associated with large longitudinal dunes, apparently antidunes. Some cross-bedding sets, however, constitute small longitudinal anti-dunes (chute-and-pool structures) containing stoss-side beds that migrated south and dip steeply south toward the crater source.
","language":"English","publisher":"Geological Society of America","doi":"10.1130/0016-7606(1985)96<1373:PBDRTP>2.0.CO;2","usgsCitation":"Rowley, P.D., MacLeod, N.S., Kuntz, M.A., and Kaplan, A., 1985, Proximal bedded deposits related to pyroclastic flows of May 18, 1980, Mount St. Helens, Washington: Geological Society of America Bulletin, v. 96, no. 11, p. 1373-1383, https://doi.org/10.1130/0016-7606(1985)96<1373:PBDRTP>2.0.CO;2.","productDescription":"11 p.","startPage":"1373","endPage":"1383","numberOfPages":"11","costCenters":[],"links":[{"id":220288,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_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 \"coordinates\": [\n [\n [\n -122.45928961535084,\n 46.36694436062862\n ],\n [\n -122.45928961535084,\n 46.10477449114575\n ],\n [\n -121.95666510363209,\n 46.10477449114575\n ],\n [\n -121.95666510363209,\n 46.36694436062862\n ],\n [\n -122.45928961535084,\n 46.36694436062862\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"96","issue":"11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a8fb3e4b0c8380cd7f8f4","contributors":{"authors":[{"text":"Rowley, P. D.","contributorId":87551,"corporation":false,"usgs":true,"family":"Rowley","given":"P.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":365195,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"MacLeod, N. S.","contributorId":55816,"corporation":false,"usgs":true,"family":"MacLeod","given":"N.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":365193,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kuntz, M. A.","contributorId":33323,"corporation":false,"usgs":true,"family":"Kuntz","given":"M.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":365192,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kaplan, A.M.","contributorId":69234,"corporation":false,"usgs":true,"family":"Kaplan","given":"A.M.","email":"","affiliations":[],"preferred":false,"id":365194,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70013058,"text":"70013058 - 1985 - Streamflow variability in the United States: 1931-1978.","interactions":[],"lastModifiedDate":"2013-03-14T13:07:20","indexId":"70013058","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2217,"text":"Journal of Climate and Applied Meteorology","active":true,"publicationSubtype":{"id":10}},"title":"Streamflow variability in the United States: 1931-1978.","docAbstract":"Systematic modes of spatial and temporal variation in a 48-year record of streamflow are defined using principal components. The components were calculated from a matrix of annual streamflow departures for 106 grid cells covering the United States in the years 1931-78. Five statistically significant components are found to account for more than 56% of the total variance. A varimax orthogonal rotation of the original components describes regional anomaly cores located in the middle Mississippi Valley, Pacific Northwest, Far West, Northeast, and northern Great Plains. -from Author","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Climate and Applied Meteorology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1175/1520-0450(1985)024<0463:SVITUS>2.0.CO;2","usgsCitation":"Lins, H., 1985, Streamflow variability in the United States: 1931-1978.: Journal of Climate and Applied Meteorology, v. 24, no. 5, p. 463-471, https://doi.org/10.1175/1520-0450(1985)024<0463:SVITUS>2.0.CO;2.","startPage":"463","endPage":"471","numberOfPages":"9","costCenters":[],"links":[{"id":487166,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1175/1520-0450(1985)024<0463:svitus>2.0.co;2","text":"Publisher Index Page"},{"id":220287,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":269328,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1175/1520-0450(1985)024<0463:SVITUS>2.0.CO;2"}],"volume":"24","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9b26e4b08c986b31cceb","contributors":{"authors":[{"text":"Lins, H.F.","contributorId":81508,"corporation":false,"usgs":true,"family":"Lins","given":"H.F.","affiliations":[],"preferred":false,"id":365191,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013057,"text":"70013057 - 1985 - Saudi Arabian seismic-refraction profile: A traveltime interpretation of crustal and upper mantle structure","interactions":[],"lastModifiedDate":"2020-05-07T18:12:15.640576","indexId":"70013057","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3525,"text":"Tectonophysics","active":true,"publicationSubtype":{"id":10}},"title":"Saudi Arabian seismic-refraction profile: A traveltime interpretation of crustal and upper mantle structure","docAbstract":"The crustal and upper mantle compressional-wave velocity structure across the southwestern Arabian Shield has been investigated by a 1000-km-long seismic refraction profile. The profile begins in Mesozoic cover rocks near Riyadh on the Arabian Platform, trends southwesterly across three major Precambrian tectonic provinces, traverses Cenozoic rocks of the coastal plain near Jizan, and terminates at the outer edge of the Farasan Bank in the southern Red Sea. More than 500 surveyed recording sites were occupied, and six shot points were used, including one in the Red Sea.
Two-dimensional ray-tracing techniques, used to analyze amplitude-normalized record sections indicate that the Arabian Shield is composed, to first order, of two layers, each about 20 km thick, with average velocities of about 6.3 km/s and 7.0 km/s, respectively. West of the Shield-Red Sea margin, the crust thins to a total thickness of less than 20 km, beyond which the Red Sea shelf and coastal plain are interpreted to be underlain by oceanic crust.
A major crustal inhomogeneity at the northeast end of the profile probably represents the suture zone between two crustal blocks of different composition. Elsewhere along the profile, several high-velocity anomalies in the upper crust correlate with mapped gneiss domes, the most prominent of which is the Khamis Mushayt gneiss. Based on their velocities, these domes may constitute areas where lower crustal rocks have been raised some 20 km. Two intracrustal reflectors in the center of the Shield at 13 km depth probably represent the tops of mafic intrusives.
The Mohorovičić discontinuity beneath the Shield varies from a depth of 43 km and mantle velocity of 8.2 km/s in the northeast to a depth of 38 km and mantle velocity of 8.0 km/s depth in the southwest near the Shield-Red Sea transition. Two velocity discontinuities occur in the upper mantle, at 59 and 70 km depth.
The crustal and upper mantle velocity structure of the Arabian Shield is interpreted as revealing a complex crust derived from the suturing of island arcs in the Precarnbrian. The Shield is currently flanked by the active spreading boundary in the Red Sea.
","largerWorkTitle":"","language":"English","publisher":"Elsevier","doi":"10.1016/0040-1951(85)90287-2","issn":"00401951","usgsCitation":"Mooney, W.D., Gettings, M.E., Blank, H., and Healy, J.H., 1985, Saudi Arabian seismic-refraction profile: A traveltime interpretation of crustal and upper mantle structure: Tectonophysics, v. 111, no. 3-4, p. 173-246, https://doi.org/10.1016/0040-1951(85)90287-2.","productDescription":"55 p.","startPage":"173","endPage":"246","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":220286,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Saudi Arabia","geographicExtents":"{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"Polygon\",\"coordinates\":[[[42.77933,16.34789],[42.64957,16.77464],[42.34799,17.07581],[42.27089,17.47472],[41.75438,17.83305],[41.22139,18.6716],[40.93934,19.48649],[40.24765,20.17463],[39.80168,20.33886],[39.1394,21.2919],[39.0237,21.98688],[39.06633,22.57966],[38.49277,23.68845],[38.02386,24.07869],[37.48363,24.28549],[37.15482,24.85848],[37.20949,25.08454],[36.93163,25.60296],[36.6396,25.82623],[36.24914,26.57014],[35.64018,27.37652],[35.13019,28.06335],[34.63234,28.05855],[34.78778,28.60743],[34.83222,28.95748],[34.95604,29.35655],[36.06894,29.19749],[36.50121,29.50525],[36.74053,29.86528],[37.50358,30.00378],[37.66812,30.33867],[37.99885,30.5085],[37.00217,31.50841],[39.00489,32.01022],[39.19547,32.16101],[40.39999,31.88999],[41.88998,31.19001],[44.7095,29.17889],[46.56871,29.09903],[47.45982,29.00252],[47.70885,28.52606],[48.41609,28.552],[48.80759,27.68963],[49.29955,27.46122],[49.47091,27.11],[50.15242,26.68966],[50.21294,26.27703],[50.1133,25.94397],[50.23986,25.60805],[50.52739,25.32781],[50.66056,24.9999],[50.81011,24.75474],[51.11242,24.55633],[51.38961,24.62739],[51.57952,24.2455],[51.61771,24.01422],[52.00073,23.00115],[55.0068,22.49695],[55.20834,22.70833],[55.66666,22],[54.99998,19.99999],[52.00001,19],[49.11667,18.61667],[48.18334,18.16667],[47.46669,17.11668],[47,16.95],[46.74999,17.28334],[46.36666,17.23332],[45.4,17.33334],[45.21665,17.43333],[44.06261,17.41036],[43.79152,17.31998],[43.38079,17.57999],[43.1158,17.08844],[43.21838,16.66689],[42.77933,16.34789]]]},\"properties\":{\"name\":\"Saudi Arabia\"}}]}","volume":"111","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b86fce4b08c986b31623f","contributors":{"authors":[{"text":"Mooney, Walter D. 0000-0002-5310-3631 mooney@usgs.gov","orcid":"https://orcid.org/0000-0002-5310-3631","contributorId":3194,"corporation":false,"usgs":true,"family":"Mooney","given":"Walter","email":"mooney@usgs.gov","middleInitial":"D.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":365190,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gettings, M. E.","contributorId":25148,"corporation":false,"usgs":true,"family":"Gettings","given":"M.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":365187,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Blank, H. R.","contributorId":50516,"corporation":false,"usgs":true,"family":"Blank","given":"H. R.","affiliations":[],"preferred":false,"id":365189,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Healy, J. H.","contributorId":48968,"corporation":false,"usgs":true,"family":"Healy","given":"J.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":365188,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70013056,"text":"70013056 - 1985 - The National Cartographic Information Center: An information resource on mapping products for the nation","interactions":[],"lastModifiedDate":"2025-08-15T15:36:07.451625","indexId":"70013056","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3345,"text":"Science and Technology Libraries","active":true,"publicationSubtype":{"id":10}},"title":"The National Cartographic Information Center: An information resource on mapping products for the nation","docAbstract":"Since its inception in 1974 the National Cartographic Information Center (NCIC), U.S. Geological Survey, has rapidly developed to become a focial point for providing information on the availability of cartographic data, including maps/charts, aerial photographics, satellite imagery, geodetic control, digitial mapping data, map materials and related cartographic products. In early years NCIC concentrated its efforts on encoding and entering several major National Mapping Division record collections into its systems. NCIC is now stressing the acquisition of data from sources outside the National Mapping Division, including 37 Federal agencies and more than a thousand State and private insitutions. A critial review has recently been conducted by NCIC of its systems with the aim of improving its efficiency and levels of operation. Several activities which resulted include improving its existing networks, refinement of digital distribution, study of new storage media and related parts.
","language":"English","publisher":"Taylor & Francis","doi":"10.1300/J122v05n03_03","issn":"0194262X","usgsCitation":"Stevens, A.R., 1985, The National Cartographic Information Center: An information resource on mapping products for the nation: Science and Technology Libraries, v. 5, no. 3, p. 25-38, https://doi.org/10.1300/J122v05n03_03.","productDescription":"14 p.","startPage":"25","endPage":"38","numberOfPages":"14","costCenters":[],"links":[{"id":220230,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"5","issue":"3","noUsgsAuthors":false,"publicationDate":"2008-10-18","publicationStatus":"PW","scienceBaseUri":"505a6134e4b0c8380cd7183e","contributors":{"authors":[{"text":"Stevens, Alan R.","contributorId":82842,"corporation":false,"usgs":true,"family":"Stevens","given":"Alan","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":365186,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013055,"text":"70013055 - 1985 - Character and regional significance of Great Falls tectonic zone, east-central Idaho and west-central Montana","interactions":[],"lastModifiedDate":"2023-01-12T17:01:30.219496","indexId":"70013055","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":701,"text":"American Association of Petroleum Geologists Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Character and regional significance of Great Falls tectonic zone, east-central Idaho and west-central Montana","docAbstract":"The Great Falls tectonic zone, here named, is a belt of diverse northeast-trending geologic features that can be traced from the Idaho batholith in the Cordilleran miogeocline, across thrust-belt structures and basement rocks of west-central and southwestern Montana, through cratonic rocks of central Montana, and into southwesternmost Saskatchewan, Canada. Geologic mapping in east-central Idaho and west-central Montana has outlined a continuous zone of high-angle faults and shear zones. These structures (1) extend more than 150 km (93 mi) northeastward from near Salmon, Idaho, toward Anaconda, Montana, (2) had recurrent movement from middle Proterozoic to Holocene time, (3) controlled the intrusion and orientation of Late Cretaceous to early Tertiary dike swarms, and (4) ontrolled the uplift and orientation of the Anaconda-Pintlar Range. Recurrent fault movement in this zone and strong structural control over igneous intrusion suggest a fundamental tectonic feature that has influenced the tectonic development of the Idaho-Montana area from at least middle Proterozoic time to the present.
","language":"English","publisher":"American Association of Petroleum Geologists","doi":"10.1306/AD462506-16F7-11D7-8645000102C1865D","usgsCitation":"O’Neill, J.M., and Lopez, D.A., 1985, Character and regional significance of Great Falls tectonic zone, east-central Idaho and west-central Montana: American Association of Petroleum Geologists Bulletin, v. 69, no. 3, p. 437-447, https://doi.org/10.1306/AD462506-16F7-11D7-8645000102C1865D.","productDescription":"11 p.","startPage":"437","endPage":"447","numberOfPages":"11","costCenters":[],"links":[{"id":220229,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Idaho, Montana","otherGeospatial":"Great Falls tectonic zone","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -115.94970703125,\n 44.62175409623324\n ],\n [\n -111.20361328125,\n 44.62175409623324\n ],\n [\n -111.20361328125,\n 46.76996843356982\n ],\n [\n -115.94970703125,\n 46.76996843356982\n ],\n [\n -115.94970703125,\n 44.62175409623324\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"69","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f2cae4b0c8380cd4b38e","contributors":{"authors":[{"text":"O’Neill, J. Michael jmoneill@usgs.gov","contributorId":99522,"corporation":false,"usgs":true,"family":"O’Neill","given":"J.","email":"jmoneill@usgs.gov","middleInitial":"Michael","affiliations":[],"preferred":false,"id":365185,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lopez, David A.","contributorId":79445,"corporation":false,"usgs":true,"family":"Lopez","given":"David","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":365184,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013053,"text":"70013053 - 1985 - Degassing-induced crystallization of basaltic magma and effects on lava rheology","interactions":[],"lastModifiedDate":"2012-03-12T17:18:37","indexId":"70013053","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2840,"text":"Nature","active":true,"publicationSubtype":{"id":10}},"title":"Degassing-induced crystallization of basaltic magma and effects on lava rheology","docAbstract":"During the north-east rift eruption of Mauna Loa volcano, Hawaii, on 25 March-14 April 1984 (Fig. 1), microphenocryst contents of erupted lava increased from 0.5 to 30% without concurrent change in either bulk magma composition or eruption temperature (1,140 ?? 3 ??C). The crystallization of the microphenocrysts is interpreted here as being due to undercooling of the magma 20-30 ??C below its liquidas; the undercooling probably resulted from separation and release of volatiles as the magma migrated 12 km from the primary summit reservoir to the eruption site on the north-east rift zone. Such crystallization of magma during an eruption has not been documented previously. The undercooling and crystallization increased the effective viscosity of the magma, leading to decreased eruption rates and stagnation of the lava flow. ?? 1985 Nature Publishing Group.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Nature","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1038/317604a0","issn":"00280836","usgsCitation":"Lipman, P.W., Banks, N., and Rhodes, J., 1985, Degassing-induced crystallization of basaltic magma and effects on lava rheology: Nature, v. 317, no. 6038, p. 604-607, https://doi.org/10.1038/317604a0.","startPage":"604","endPage":"607","numberOfPages":"4","costCenters":[],"links":[{"id":205018,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1038/317604a0"},{"id":220227,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"317","issue":"6038","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fe50e4b0c8380cd4ec78","contributors":{"authors":[{"text":"Lipman, P. W.","contributorId":93470,"corporation":false,"usgs":true,"family":"Lipman","given":"P.","middleInitial":"W.","affiliations":[],"preferred":false,"id":365180,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Banks, N.G.","contributorId":60635,"corporation":false,"usgs":true,"family":"Banks","given":"N.G.","email":"","affiliations":[],"preferred":false,"id":365179,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rhodes, J.M.","contributorId":31110,"corporation":false,"usgs":true,"family":"Rhodes","given":"J.M.","affiliations":[],"preferred":false,"id":365178,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70013052,"text":"70013052 - 1985 - A nomogram for interpreting slope stability of fine-grained deposits in modern and ancient-marine environments.","interactions":[],"lastModifiedDate":"2024-05-21T11:17:03.144979","indexId":"70013052","displayToPublicDate":"1985-01-01T00:00:00","publicationYear":"1985","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2450,"text":"Journal of Sedimentary Petrology","active":true,"publicationSubtype":{"id":10}},"title":"A nomogram for interpreting slope stability of fine-grained deposits in modern and ancient-marine environments.","docAbstract":"Design of the nomogram is based on effective stress and combines consolidation theory as applicable to depositional environments with the infinite-slope model of slope-stability analysis. The link between the two combined theories is a term representing the effective overburden stress, which may be predicted from consolidation theory and a knowledge of sedimentation rate, time, and the coefficient of consolidation. In turn, if infinite-slope conditions are assumed to exist, the effective overburden stress can be used to derive a factor of safety against static slope failure by using the angle of internal friction and the slope angle. The nomogram applies to depostitional settings in which fine-grained sediment has accumulated at a relatively constant rate upon a base that is essentially impermeable. The model further assumes that the lateral extent of sediment affected by any mass movement will be great compared to its thickness and that no outside agents (e.g., cements, gas) are influencing the section. The nomogram is applicable to static conditions (inherent stability of the slope) and certain dynamic conditions (such as earthquakes). It may be used to investigate mass movements in the geologic past as well as those in modern environments.--Modified journal abstract.