A subsurface model for the Goddard pendant is constructed from a residual gravity high of about 7 mGal over the pendant. The model, which is the simplest and most geologically reasonable possibility, shows a metamorphic block that tapers with depth and extends about 3.5 km below the surface. The structures in the Goddard pendant are similar in style and orientation to those in other Sierra Nevada pendants, indicating that the country rock was neither deformed nor rotated during pluton emplacement. Consequently, emplacement must have been a passive rather than a forceful process. The pendant itself represents a piece of country rock trapped between plutons which are dome shaped in cross section.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB086iB10p09279","issn":"01480227","usgsCitation":"Bray, D., and Oliver, H.W., 1981, Gravity model and structural implications of the Goddard Pendant, Sierra Nevada, California: Journal of Geophysical Research Solid Earth, v. 86, no. B10, p. 9279-9286, https://doi.org/10.1029/JB086iB10p09279.","productDescription":"8 p.","startPage":"9279","endPage":"9286","numberOfPages":"8","costCenters":[],"links":[{"id":221553,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"B10","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a2a25e4b0c8380cd5af18","contributors":{"authors":[{"text":"Bray, du","contributorId":28749,"corporation":false,"usgs":true,"family":"Bray","given":"du","email":"","affiliations":[],"preferred":false,"id":362255,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Oliver, H. W.","contributorId":85570,"corporation":false,"usgs":true,"family":"Oliver","given":"H.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":362256,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70011915,"text":"70011915 - 1981 - Chemical modifications accompanying blueschist facies metamorphism of Franciscan conglomerates, Diablo Range, California","interactions":[],"lastModifiedDate":"2013-01-21T09:39:52","indexId":"70011915","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Chemical modifications accompanying blueschist facies metamorphism of Franciscan conglomerates, Diablo Range, California","docAbstract":"As part of an investigation of blueschist-facies mineral parageneses in pebbles and matrix of some Franciscan metaconglomerates of the Diablo Range, California, textural and major-element chemical analyses were conducted on a number of igneous pebbles that comprise a range of rock types from granite and dacite to gabbro and basalt. Compositions of the igneous pebbles differ significantly from common igneous rocks, particularly with respect to Ca, K, Na, Si and H2O. The SiO2 and H2O contents are characteristically high and the K2O contents low. The CaO and Na2O contents may be relatively enriched or reduced in different pebbles. The igneous pebbles show little evidence of alteration prior to their incorporation into the Franciscan conglomerates, and the chemical modifications are considered to have been produced during metamorphism of the conglomerates to (lawsonite + albite + aragonite ?? jadeite)-bearing assemblages. The observed variations in the pebbles are shown to be functions of: (1) bulk chemistry; (2) the igneous mineral assemblage; (3) the stable metamorphic mineral assemblage; and (4) the composition of pore fluids in the conglomerates. The relative proportions of Mg and Fe in most of the pebbles apparently have been unaffected by the metamorphism, and these parameters, along with other textural and chemical factors, were used to determine the petrogenetic affinities of the igneous pebbles. The plutonic and most of the volcanic pebbles correspond to calc-alkaline rock series, whereas a few volcanic pebbles show apparent Fe-enrichment characteristic of tholeiitic rocks. A continental margin arc-batholith complex would be the best source for these igneous detrital assemblages. Conglomerates in local areas differ in igneous lithologies from conglomerates in other areas and probably differ somewhat in age, perhaps reflecting varying degrees of unroofing of such a complex during deposition of Franciscan sediments. ?? 1981.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(81)90103-0","issn":"00092541","usgsCitation":"Moore, D., Liou, J.G., and King, B., 1981, Chemical modifications accompanying blueschist facies metamorphism of Franciscan conglomerates, Diablo Range, California: Chemical Geology, v. 33, no. 1-4, p. 237-263, https://doi.org/10.1016/0009-2541(81)90103-0.","startPage":"237","endPage":"263","numberOfPages":"27","costCenters":[],"links":[{"id":220726,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":266123,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0009-2541(81)90103-0"}],"volume":"33","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f580e4b0c8380cd4c276","contributors":{"authors":[{"text":"Moore, Diane E. 0000-0002-8641-1075","orcid":"https://orcid.org/0000-0002-8641-1075","contributorId":106496,"corporation":false,"usgs":true,"family":"Moore","given":"Diane E.","affiliations":[],"preferred":false,"id":362278,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Liou, J. G.","contributorId":87687,"corporation":false,"usgs":false,"family":"Liou","given":"J.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":362277,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"King, B.-S.","contributorId":54592,"corporation":false,"usgs":true,"family":"King","given":"B.-S.","email":"","affiliations":[],"preferred":false,"id":362276,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70011918,"text":"70011918 - 1981 - The Redskin granite: Evidence for thermogravitational diffusion in a Precambrian granite batholith","interactions":[],"lastModifiedDate":"2024-07-16T16:04:04.778321","indexId":"70011918","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","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":"The Redskin granite: Evidence for thermogravitational diffusion in a Precambrian granite batholith","docAbstract":"The 1000-Ma-old composite Pikes Peak batholith consists largely of medium- to coarse-grained biotite granite but is intruded by several smaller granite plutons. Two of these, the Tarryall Mountains batholith and the Redskin Granite (Hawley, 1969; Hawley and Wobus, 1977), are here interpreted as cupolas atop the main mass of the Pikes Peak batholith.
Chemical analysis for 38 elements in rocks from the Redskin Granite, the Tarryall Mountains batholith, and the biotite granite of the Pikes Peak batholith support the contention that the compositions of the smaller plutons are unlikely to have evolved from that of the main mass of the batholith by crystal fractionation. It is believed that these compositions arose through liquid-state fractionation processes, possibly the convection-aided thermogravitational model of Shaw et al. (1976).
It is important to recognize that the chemical signature of this fractionation process can be discerned in holocrystalline rocks as well as in their glassy equivalents because the process may be instrumental in the formation of some kinds of lithophile ore deposits.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB086iB11p10423","issn":"01480227","usgsCitation":"Ludington, S., 1981, The Redskin granite: Evidence for thermogravitational diffusion in a Precambrian granite batholith: Journal of Geophysical Research Solid Earth, v. 86, no. B11, p. 10423-10430, https://doi.org/10.1029/JB086iB11p10423.","productDescription":"8 p.","startPage":"10423","endPage":"10430","numberOfPages":"8","costCenters":[],"links":[{"id":220729,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"B11","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505ba8afe4b08c986b321da0","contributors":{"authors":[{"text":"Ludington, S.","contributorId":91987,"corporation":false,"usgs":true,"family":"Ludington","given":"S.","email":"","affiliations":[],"preferred":false,"id":362284,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70011923,"text":"70011923 - 1981 - The origin and isotopic composition of dissolved sulfide in groundwater from carbonate aquifers in Florida and Texas","interactions":[],"lastModifiedDate":"2019-12-06T07:05:00","indexId":"70011923","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"The origin and isotopic composition of dissolved sulfide in groundwater from carbonate aquifers in Florida and Texas","docAbstract":"The δ34S values of dissolved sulfide and the sulfur isotope fractionations between dissolved sulfide and sulfate species in Floridan ground water generally correlate with dissolved sulfate concentrations which are related to flow patterns and residence time within the aquifer. The dissolved sulfide derives from the slow in situ biogenic reduction of sulfate dissolved from sedimentary gypsum in the aquifer. In areas where the water is oldest, the dissolved sulfide has apparently attained isotopic equilibrium with the dissolved sulfate (Δ34S = 65 per mil) at the temperature (28°C) of the system. This approach to equilibrium reflects an extremely slow reduction rate of the dissolved sulfate by bacteria; this slow rate probably results from very low concentrations of organic matter in the aquifer.
In the reducing part of the Edwards aquifer, Texas, there is a general down-gradient increase in both dissolved sulfide and sulfate concentrations, but neither the δ34S values of sulfide nor the sulfide-sulfate isotope fractionation correlates with the ground-water flow pattern. The dissolved sulfide species appear to be derived primarily from biogenic reduction of sulfate ions whose source is gypsum dissolution although upgradient diffusion of H2S gas from deeper oil field brines may be important in places. The sulfur isotope fractionation for sulfide-sulfate (about 38 per mil) is similar to that observed for modern oceanic sediments and probably reflects moderate sulfate reduction in the reducing part of the aquifer owing to the higher temperature and significant amount of organic matter present; contributions of isotopically heavy H2S from oil field brines are also possible.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(81)90024-7","issn":"00167037","usgsCitation":"Rye, R.O., Back, W., Hanshaw, B., Rightmire, C., and Pearson, F.J., 1981, The origin and isotopic composition of dissolved sulfide in groundwater from carbonate aquifers in Florida and Texas: Geochimica et Cosmochimica Acta, v. 45, no. 10, p. 1941-1950, https://doi.org/10.1016/0016-7037(81)90024-7.","productDescription":"10 p. 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\"}}]}","volume":"45","issue":"10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bae63e4b08c986b32406d","contributors":{"authors":[{"text":"Rye, R. O.","contributorId":66208,"corporation":false,"usgs":true,"family":"Rye","given":"R.","email":"","middleInitial":"O.","affiliations":[],"preferred":false,"id":362301,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Back, W.","contributorId":33839,"corporation":false,"usgs":true,"family":"Back","given":"W.","email":"","affiliations":[],"preferred":false,"id":362299,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hanshaw, B.B.","contributorId":25928,"corporation":false,"usgs":true,"family":"Hanshaw","given":"B.B.","email":"","affiliations":[],"preferred":false,"id":362298,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Rightmire, C.T.","contributorId":63822,"corporation":false,"usgs":true,"family":"Rightmire","given":"C.T.","email":"","affiliations":[],"preferred":false,"id":362300,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Pearson, F. J. Jr.","contributorId":7696,"corporation":false,"usgs":true,"family":"Pearson","given":"F.","suffix":"Jr.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":362297,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70011927,"text":"70011927 - 1981 - First manned submersible dives on the East Pacific Rise at 21°N (project RITA): general results","interactions":[],"lastModifiedDate":"2015-06-10T13:27:10","indexId":"70011927","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2668,"text":"Marine Geophysical Research","active":true,"publicationSubtype":{"id":10}},"title":"First manned submersible dives on the East Pacific Rise at 21°N (project RITA): general results","docAbstract":"A submersible study has been conducted in February–March 1978 at the axis of the East Pacific Rise near 21°N. The expedition CYAMEX, the first submersible program to be conducted on the East Pacific Rise, is part of the French-American-Mexican project RITA (Rivera-Tamayo), a 3-year study devoted to detailed geological and geophysical investigations of the East Pacific Rise Crest. On the basis of the 15 dives made by CYANA in the axial area of the Rise, a morphological and tectonic zonation can be established for this moderately-fast spreading center. A narrow, 0.6 to 1.2 km wide zone of extrusion (zone 1), dominated by young lava flows, is flanked by a highly fissured and faulted zone of extension (zone 2) with a width of 1 to 2 km. Further out, zone 3 is dominated by outward tilted blocks bounded by inward-facing fault scarps. Active or recent faults extend up to 12 km from the axis of extrusion of the East Pacific Rise. This represents the first determination from direct field evidence of the width of active tectonism associated with an accreting plate boundary. Massive sulfide deposits, made principally of zinc, copper and iron, were found close to the axis of the Rise. Other signs of the intense hydrothermal activity included the discovery of benthic fauna of gian size similar to that found at the axis of the Galapagos Rift. We emphasize the cyclic character of the volcanicity. The main characteristics of the geology of this segment of the East Pacific Rise can be explained by the thermal structure at depth below this moderately-fast spreading center. The geological observations are compatible with the existence of a shallow magma reservoir centered at the axis of the Rise with a half-width of the order of 10 km.
","language":"English","publisher":"Elsevier","doi":"10.1007/BF00286034","issn":"00253235","usgsCitation":"Francheteau, J., Needham, H., Choukroune, P., Juteau, T., Seguret, M., Ballard, R.D., Fox, P., Normark, W.R., Carranza, A., Cordoba, D., Guerrero, J., and Rangin, C., 1981, First manned submersible dives on the East Pacific Rise at 21°N (project RITA): general results: Marine Geophysical Research, v. 4, no. 4, p. 345-379, https://doi.org/10.1007/BF00286034.","productDescription":"35 p.","startPage":"345","endPage":"379","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":220941,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205076,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00286034"}],"volume":"4","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a1058e4b0c8380cd53c27","contributors":{"authors":[{"text":"Francheteau, Jean","contributorId":34262,"corporation":false,"usgs":false,"family":"Francheteau","given":"Jean","email":"","affiliations":[],"preferred":false,"id":362305,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Needham, H.D.","contributorId":53947,"corporation":false,"usgs":true,"family":"Needham","given":"H.D.","email":"","affiliations":[],"preferred":false,"id":362309,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Choukroune, P.","contributorId":68458,"corporation":false,"usgs":true,"family":"Choukroune","given":"P.","email":"","affiliations":[],"preferred":false,"id":362310,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Juteau, Tierre","contributorId":43496,"corporation":false,"usgs":false,"family":"Juteau","given":"Tierre","email":"","affiliations":[],"preferred":false,"id":362307,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Seguret, M.","contributorId":74514,"corporation":false,"usgs":true,"family":"Seguret","given":"M.","email":"","affiliations":[],"preferred":false,"id":362311,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Ballard, Richard D.","contributorId":40729,"corporation":false,"usgs":true,"family":"Ballard","given":"Richard","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":362306,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Fox, P.J.","contributorId":79233,"corporation":false,"usgs":true,"family":"Fox","given":"P.J.","email":"","affiliations":[],"preferred":false,"id":362312,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Normark, W. R.","contributorId":87137,"corporation":false,"usgs":true,"family":"Normark","given":"W.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":362315,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Carranza, A.","contributorId":84076,"corporation":false,"usgs":true,"family":"Carranza","given":"A.","email":"","affiliations":[],"preferred":false,"id":362314,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Cordoba, D.","contributorId":47522,"corporation":false,"usgs":true,"family":"Cordoba","given":"D.","email":"","affiliations":[],"preferred":false,"id":362308,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Guerrero, J.","contributorId":81248,"corporation":false,"usgs":true,"family":"Guerrero","given":"J.","email":"","affiliations":[],"preferred":false,"id":362313,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Rangin, C.","contributorId":105853,"corporation":false,"usgs":true,"family":"Rangin","given":"C.","email":"","affiliations":[],"preferred":false,"id":362316,"contributorType":{"id":1,"text":"Authors"},"rank":12}]}} ,{"id":70011932,"text":"70011932 - 1981 - Minor and trace element geochemistry of volcanic rocks dredged from the Galapagos spreading center: Role of crystal fractionation and mantle heterogeneity","interactions":[],"lastModifiedDate":"2024-07-16T16:01:57.636035","indexId":"70011932","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","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":"Minor and trace element geochemistry of volcanic rocks dredged from the Galapagos spreading center: Role of crystal fractionation and mantle heterogeneity","docAbstract":"A wide range of rock types (abyssal tholeiite, Fe-Ti-rich basalt, andesite, and rhyodacite) were dredged from near 95°W and 85°W on the Galapagos spreading center. Computer modeling of major element compositions has shown that these rocks could be derived from common parental magmas by successive degrees of fractional crystallization. However, the P2O5/K2O ratio averages 0.83 at 95°W and 1.66 at 85°W and implies distinct mantle source compositions for the two areas. These source regions also have different rare earth element (REE) abundance patterns, with [La/Sm]EF = 0.67 at 95°W and 0.46 at 85°W. The sequence of fractionated lavas differs for the two areas and indicates earlier fractionation of apatite and titanomagnetite in the lavas from 95°W. The mantle source regions for these two areas are interpreted to be depleted in incompatible (and volatile?) elements, although the source region beneath 95°W is less severely depleted in La and K. Incompatible trace element abundances in 26 samples are used to infer that the range of Fe-Ti-rich basalt from 85°W represents 19 to 35% residual liquid following crystal fractionation of a mineral assemblage of plagioclase, clinopyroxene, and lesser olivine. The most highly differentiated samples have also had less than 1% titanomagnetite removed. Most samples from 85°W can be related to a common parental magma that contained approximately 9 wt % FeO*, 1 wt % TiO2, and had an Mg number (Mg# = 100 Mg/(Mg + Fe2+)) of about 65. Although the samples from 95°W cannot all be derived from a common parental magma, the inferred parental magmas may have been derived by varying degrees of partial melting of a common source. The fractionation sequence consists of two parts: an initial iron enrichment trend followed by a silica enrichment trend. We interpret the trace element data to indicate that the most iron rich lavas represent about 32% residual liquid derived by crystal fractionation of plagioclase, clinopyroxene, and lesser olivine from a parental magma with an Mg number of about 66. The silica enrichment trend results from crystallization of titanomagnetite and some apatite. Fractionation of pigeonite, which is a minor phase in the major element models, cannot be distinguished from clinopyroxene fractionation by using trace elements.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB086iB10p09469","issn":"01480227","usgsCitation":"Clague, D., Frey, F., Thompson, G., and Rindge, S., 1981, Minor and trace element geochemistry of volcanic rocks dredged from the Galapagos spreading center: Role of crystal fractionation and mantle heterogeneity: Journal of Geophysical Research Solid Earth, v. 86, no. B10, p. 9469-9482, https://doi.org/10.1029/JB086iB10p09469.","productDescription":"14 p.","startPage":"9469","endPage":"9482","numberOfPages":"14","costCenters":[],"links":[{"id":221005,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"B10","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a5b1fe4b0c8380cd6f340","contributors":{"authors":[{"text":"Clague, D.A.","contributorId":36129,"corporation":false,"usgs":true,"family":"Clague","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":362326,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Frey, F.A.","contributorId":12618,"corporation":false,"usgs":true,"family":"Frey","given":"F.A.","email":"","affiliations":[],"preferred":false,"id":362325,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Thompson, G.","contributorId":55958,"corporation":false,"usgs":true,"family":"Thompson","given":"G.","affiliations":[],"preferred":false,"id":362327,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Rindge, S.","contributorId":55959,"corporation":false,"usgs":true,"family":"Rindge","given":"S.","email":"","affiliations":[],"preferred":false,"id":362328,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70011933,"text":"70011933 - 1981 - Chrysophyte cysts as potential environmental indicators","interactions":[],"lastModifiedDate":"2024-01-04T01:50:16.705788","indexId":"70011933","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","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":"Chrysophyte cysts as potential environmental indicators","docAbstract":"Many Chrysophyte algae produce morphologically distinctive, siliceous, microscopic cysts during a resting stage of their life cycles; these cysts are often preserved in sediments. Scanning electron microscopy and Nomarski optics permit much more detailed observation of these cysts than was heretofore possible. We have used an ecologic and biogeographic approach to study the distribution of cyst forms in sediments and have established that many cyst types are found only in specific habitats, such as montane lakes, wet meadows, ephemeral ponds, and Sphagnum bogs. In the samples we have studied, cysts seem to be most common in fluctuating fresh-water habitats of low to moderate pH and some winter freezing. Numerous taxonomic problems have yet to be resolved. We believe that chrysophyte cysts have the potential to become a useful tool for both modern environmental assessments and paleoecological studies of Cenozoic fresh-water lacustrine deposits.
Two new geodetic measurements of strain accumulation in the state of Washington for the interval 1972–1979 are reported. Near Seattle the average principal strain rates are 0.07 ± 0.03 μstrain/yr N 19°W and −0.13 ± 0.02 μstrain/yr N71°E, and near Richland (south central Washington) the average principal strain rates are −0.02 ± 0.01 μstrain/yr N36°W and −0.04 ± 0.01 μstrain/yr N54°E. Extension is taken as positive, and the uncertainties quoted are standard deviations. A measurement of shear strain accumulation (dilatation not determined) in the epoch 1914–1966 along the north coast of Vancouver Island by the Geodetic Survey of Canada indicates a marginally significant accumulation of right-lateral shear (0.06 ± 0.03 μrad/yr) across the plate boundary (N40°W strike). Although there are significant differences in detail, these strain measurements are roughly consistent with a crude dislocation model that represents subduction of the Juan de Fuca plate. The observed accumulation of strain implies that large, shallow, thrust earthquakes should be expected off the coast of Washington and British Columbia. However, this conclusion is not easily reconciled with either observations of elevation change along the Washington coast or the focal mechanism solutions for shallow earthquakes in Washington.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB086iB06p04929","issn":"01480227","usgsCitation":"Savage, J., Lisowski, M., and Prescott, W., 1981, Geodetic strain measurements in Washington: Journal of Geophysical Research Solid Earth, v. 86, no. B6, p. 4929-4940, https://doi.org/10.1029/JB086iB06p04929.","productDescription":"12 p.","startPage":"4929","endPage":"4940","numberOfPages":"12","costCenters":[],"links":[{"id":221007,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"B6","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a173fe4b0c8380cd5544a","contributors":{"authors":[{"text":"Savage, J.C. 0000-0002-5114-7673","orcid":"https://orcid.org/0000-0002-5114-7673","contributorId":102876,"corporation":false,"usgs":true,"family":"Savage","given":"J.C.","affiliations":[],"preferred":false,"id":362333,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lisowski, M.","contributorId":70381,"corporation":false,"usgs":true,"family":"Lisowski","given":"M.","email":"","affiliations":[],"preferred":false,"id":362331,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Prescott, W.H.","contributorId":96337,"corporation":false,"usgs":true,"family":"Prescott","given":"W.H.","email":"","affiliations":[],"preferred":false,"id":362332,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70011938,"text":"70011938 - 1981 - New maps of Federal coal","interactions":[],"lastModifiedDate":"2024-01-04T01:48:12.113669","indexId":"70011938","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","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":"New maps of Federal coal","docAbstract":"Compilation and analysis of publicly available data on Federal coal are resulting in voluminous map sets showing coal isopachs, structure contours, and overburden isopachs on each known minable coal bed. As of the spring of 1981, there are available from the U.S. Geological Survey Open-File Services Section in Denver map sets at 1:24,000 scale or microfiche sets covering approximately 470 of the ultimately 1,400 quadrangles in the program. Because Congress in 1976 mandated the prompt “inventorying” of all unleased Federal coal for Government land-use planning, and because dollars but not employee positions were provided for the work, the U.S. Geological Survey was obliged to contract for the compilations.
A typical map set has a short text and about 20 plates, including a data sheet; a Federal mineral ownership map; and correlation charts. For each coal bed, there are isopachs, structure contours, stripping limits, and mining ratios extending as far as the data will permit, regardless of coal ownership. Reserve base tonnages and relative development potentials are calculated, but only for unleased Federal coal areas.
Termed “minable” are coal beds at least 1.524 m (5 ft) thick and less than 914.4 m (3,000 ft) deep. For conventional underground mining methods, beds dipping more than 15° are excluded; also excluded are all but 3.66 m (12 ft) of thick beds. For in situ conversion methods, the minimum dip is 15° except for the deep thick beds in the Powder River Basin.
Arbitrary parameters classify the development potential of each unleased 16.19-hectare (40-acre) tract as high, moderate, low, unknown, or negative. The former Secretary of the Interior announced his intention to restrict leasing in general to tracts classified as having high to moderate potential for development.
Many geologists will find these systematic map compilations to be useful bases for adding new data points and making their own interpretations, correlations, extrapolations, and reserve estimates.
The fractionation of 13C between calcite and graphite, Δ(Cc-Gr). is consistently small (2.6–4.8 permil) in 34 assemblages from upper amphibolite- and granulite-facies marbles of the Grenville Province. In 25 samples from the Adirondack Mountains, New York, it decreases regularly with increasing metamorphic temperature. The fractionations are independent of absolute δ13C values of calcite (−2.9 to +5.0). For T = 600–800°C, the Adirondack data are described by Δ(Cc-Gr) = −0.00748T (°C) + 8.68. This good correlation between Δ and T suggests that carbon isotope equilibrium was attained in these high-grade marbles and that the theoretical calculations of this fractionation by Bottinga are approximately 2 permil too large in this temperature range. Because of the relatively high temperature sensitivity suggested by these results and by Bottinga's calculations, and the pressure independence of isotope fractionation, Δ(Cc-Gr) may provide a very good thermometer for high-grade marbles.
Comparison of this field calibration for Δ(Cc-Gr) vs temperature with results from other terranes supports the utility of Δ(Cc-Gr) for geothermometry and suggests that graphite is much more sluggish to exchange than calcite, that exchange between calcite and graphite occurs at temperatures as low as 300°C, and that equilibrium may normally be attained only when peak metamorphic temperatures are greater than 500–600°C.
Because 13C exchange is an unavoidable metamorphic process at temperatures above 300°C, high values of δ13C(Gr) in moderate- to high-grade carbonate-bearing rocks do not provide a sufficient criterion to infer an abiogenic origin for the graphite.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(81)90249-0","issn":"00167037","usgsCitation":"Valley, J., and O’Neil, J.R., 1981, 13C 12C exchange between calcite and graphite: A possible thermometer in Grenville marbles: Geochimica et Cosmochimica Acta, v. 45, no. 3, p. 411-419, https://doi.org/10.1016/0016-7037(81)90249-0.","productDescription":"9 p.","startPage":"411","endPage":"419","numberOfPages":"9","costCenters":[],"links":[{"id":480581,"rank":2,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"http://hdl.handle.net/2027.42/24452>","text":"External Repository"},{"id":221204,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e224e4b0c8380cd459ba","contributors":{"authors":[{"text":"Valley, J.W.","contributorId":28741,"corporation":false,"usgs":true,"family":"Valley","given":"J.W.","email":"","affiliations":[],"preferred":false,"id":362367,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"O’Neil, J. R.","contributorId":69633,"corporation":false,"usgs":true,"family":"O’Neil","given":"J.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":362368,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70011949,"text":"70011949 - 1981 - Estimation of surface temperature variations due to changes in sky and solar flux with elevation","interactions":[],"lastModifiedDate":"2024-02-15T01:16:26.948532","indexId":"70011949","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1807,"text":"Geophysical Research Letters","active":true,"publicationSubtype":{"id":10}},"title":"Estimation of surface temperature variations due to changes in sky and solar flux with elevation","docAbstract":"Sky and solar radiance are of major importance in determining the ground temperature. Knowledge of their behavior is a fundamental part of surface temperature models. These two fluxes vary with elevation and this variation produces temperature changes. Therefore, when using thermal-property differences to discriminate geologic materials, these flux variations with elevation need to be considered. From a representative set of field observations, it was found that flux variations with elevation can cause changes in the mean diurnal temperature gradient from −4° to −14°C per km evaluated at 2000 m. Changes in the temperature-difference gradient of 1°-2°C per km are also produced which is equivalent to an effective thermal-inertia gradient of 100 W s1/2 m−2 K−1 per km. Thus, exposed bedrock on topographic ridges will appear to have a lower thermal inertia due to the additional effect.
Quantitative calculations for the effect of a fault creep event on observations of changes in water level in wells provide an approach to the tectonic interpretation of these phenomena. For the pore pressure field associated with an idealized creep event having an exponential displacement versus time curve, an analytic expression has been obtained in terms of exponential-integral functions. The pore pressure versus time curves for observation points near the fault are pulselike; a sharp pressure increase (or decrease, depending on the direction of propagation) is followed by more gradual decay to the normal level after the creep event. The time function of the water level change may be obtained by applying the filter—derived by A. G. Johnson and others to determine the influence of atmospheric pressure on water level—to the analytic pore pressure versus time curves. The resulting water level curves show a fairly rapid increase (or decrease) and then a very gradual return to normal. The results of this analytic model do not reproduce the steplike changes in water level observed by Johnson and others. If the procedure used to obtain the water level from the pore pressure is correct, these results suggest that steplike changes in water level are not produced by smoothly propagating creep events but by creep events that propagate discontinously, by changes in the bulk properties of the region around the well, or by some other mechanism. In addition, simplistic calculations show that significant pressure field variations and water level changes near the surface may be expected to accompany a propagating creep event on a buried fault. Water level changes of as much as several meters may be expected at the surface for a creep event having a dislocation amplitude of l m on a semi-infinite dislocation surface extending downward from a depth of 10 km and propagating horizontally at a rate of 10 km/day. The maximum near-surface effect should be observed at a horizontal distance from the fault about equal to the depth of the top of the dislocation surface. These results are consistent with the observations made in China of large water level changes preceding large earthquakes, if some sort of aseismic creep event at depth precedes these earthquakes.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB086iB10p09259","issn":"01480227","usgsCitation":"Wesson, R.L., 1981, Interpretation of changes in water level accompanying fault creep and implications for earthquake prediction: Journal of Geophysical Research Solid Earth, v. 86, no. B10, p. 9259-9267, https://doi.org/10.1029/JB086iB10p09259.","productDescription":"9 p.","startPage":"9259","endPage":"9267","numberOfPages":"9","costCenters":[],"links":[{"id":221266,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"B10","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a3d6ae4b0c8380cd6355f","contributors":{"authors":[{"text":"Wesson, R. L.","contributorId":51752,"corporation":false,"usgs":true,"family":"Wesson","given":"R.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":362379,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70011957,"text":"70011957 - 1981 - Systems for measuring thickness of temperate and polar ice from the ground or from the air.","interactions":[],"lastModifiedDate":"2024-05-07T00:16:51.493199","indexId":"70011957","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2328,"text":"Journal of Glaciology","active":true,"publicationSubtype":{"id":10}},"title":"Systems for measuring thickness of temperate and polar ice from the ground or from the air.","docAbstract":"Equipment has been designed and tested for ground-based and airborne sounding of temperate glaciers. The transmitter is a free-running pulse generator that uses avalanche-mode transistor breakdown to create high-voltage pulses. The transmit and receive antennas are resistively loaded dipoles; for the airborne system, a twin-lead transmit element and a three-layer coaxial receive element are used on the inboard end of the respective antennas. The sounders are broadband systems; oscilloscopes are used for receivers. The oscilloscope trace is recorded photographically in the ground-based systems. A sampling oscilloscope is used in the airborne system—the sampling process strobes the waveform to audio frequencies so that it can be recorded on magnetic tape. Echoes have been obtained from ice depths of 550 m using the airborne system and about 1 000 m using the ground-based system.
Seawater and NaCl solutions were reacted with basalt (basalt glass and diabase) for several months at 300°C, 500 bars and a water/rock ratio of 10.
\nDuring reaction, seawater was significantly modified, increasing in Ca, H2S, CO2. SiO2, K. Fe, Mn. Ba, Al and H+, and decreasing in Mg and SO4. Basalt glass was completely replaced by smectite, wairakite, anhydrite and hematite, and diabase was partially replaced by mixed layered smectite-chlorite, anhydrite and magnetite (?). Diabase was altered more slowly than basalt glass and the corresponding changes in seawater chemistry were less pronounced.
\nBasalt glass reacted with a 0.45 m NaCl solution resulted in the formation of smectite, albite. truscottite and wairakite. Solutions from this experiment were characterized by a relatively high pH and dominated by Ca for Na exchange reactions. At no point in this experiment were heavy metals solubilized, in contrast to the seawater experiments. This behavior illustrates the fundamental importance of seawater chemistry to heavy-metal solubility; that is, the removal of Mg from seawater generates acidity which maintains heavy metals in solution. Apparently seawater chlorinity is not capable of enhancing heavy-metal solubility by chloride complexing.
\nSeafloor heavy-metal deposits can result from the following:
\nA highly reproducible seeded growth technique was used to study calcite crystallization from calcium bicarbonate solutions at 25°C and fixed carbon dioxide partial pressures between 0.03 and 0.3 atm. The results are not consistent with empirical crystallization models that have successfully described calcite growth at low PCO2 (< 10−3 atm). Good agreement was found between observed crystallization rates and those calculated from the calcite dissolution rate law and mechanism proposed by Plummer et al. (1978).
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(81)90222-2","issn":"00167037","usgsCitation":"Reddy, M.M., Plummer, N., and Busenberg, E., 1981, Crystal growth of calcite from calcium bicarbonate solutions at constant PCO2 and 25°C: a test of a calcite dissolution model: Geochimica et Cosmochimica Acta, v. 45, no. 8, p. 1281-1289, https://doi.org/10.1016/0016-7037(81)90222-2.","productDescription":"9 p.","startPage":"1281","endPage":"1289","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":220730,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fcfbe4b0c8380cd4e565","contributors":{"authors":[{"text":"Reddy, Michael M. mmreddy@usgs.gov","contributorId":684,"corporation":false,"usgs":true,"family":"Reddy","given":"Michael","email":"mmreddy@usgs.gov","middleInitial":"M.","affiliations":[{"id":145,"text":"Branch of Regional Research-Central Region","active":false,"usgs":true}],"preferred":true,"id":362456,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Plummer, Niel 0000-0002-4020-1013 nplummer@usgs.gov","orcid":"https://orcid.org/0000-0002-4020-1013","contributorId":190100,"corporation":false,"usgs":true,"family":"Plummer","given":"Niel","email":"nplummer@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":362458,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Busenberg, E.","contributorId":56796,"corporation":false,"usgs":true,"family":"Busenberg","given":"E.","affiliations":[],"preferred":false,"id":362457,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70011990,"text":"70011990 - 1981 - The late-Neoglacial histories of the Agassiz and Jackson glaciers, Glacier National Park, Montana.","interactions":[],"lastModifiedDate":"2017-05-04T16:38:58","indexId":"70011990","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":898,"text":"Arctic and Alpine Research","active":true,"publicationSubtype":{"id":10}},"title":"The late-Neoglacial histories of the Agassiz and Jackson glaciers, Glacier National Park, Montana.","docAbstract":"Twenty-one tree-ring stations, totaling 116 trees, were sampled at various localities within the forest trimlines fronting the Agassiz and Jackson glaciers, Glacier National Park, Montana. Tree ages within these zones became progressively younger from the region of the maximum late-Neoglacial position to the bases of the bedrock slopes on which these glaciers are now confined. The age of the oldest tree plus 15 yr was used to estimate the date of glacier withdrawal from a given station. It was found that both the Agassiz and Jackson glaciers began to retreat from their maximum late-Neoglacial positions about 1860. Hence, Matthes's (1940) estimate of glacial advances culminating about 1850 to 1855 for many glaciers in the western United States seems reasonable for the Glacier National Park region. Retreat rates, derived from the tree-ring data, appear to have been modest (<7 m yr-1) until about 1910 when they increased reaching more than 40 m yr-1 for the Agassiz Glacier between 1917 and 1926. Retreat rates after the late 1920s could not be monitored by tree-ring analysis as both glaciers had retreated onto bare bedrock dip slopes. However, from various literature descriptions and National Park Service records, both glaciers experienced rapid retreat (>100 m yr-1) from this time until 1932. In addition, while the Agassiz Glacier was monitored by the National Park Service (1932 to 1942) retreat continued at a rapid rate (>90 m yr-1). This period of rapid retreat corresponds with a period of above-average summer temperatures and decreased precipitation in the climatic record of the region. Since the mid-1940s the retreat rate of both glaciers has slowed markedly.
","language":"English","publisher":"INSTAAR, University of Colorado","doi":"10.2307/1551194","usgsCitation":"Carrara, P., and McGimsey, R.G., 1981, The late-Neoglacial histories of the Agassiz and Jackson glaciers, Glacier National Park, Montana.: Arctic and Alpine Research, v. 13, no. 2, p. 183-196, https://doi.org/10.2307/1551194.","productDescription":"14 p.","startPage":"183","endPage":"196","costCenters":[],"links":[{"id":220733,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Montana","otherGeospatial":"Glacier National Park","volume":"13","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bad88e4b08c986b323c93","contributors":{"authors":[{"text":"Carrara, P. E.","contributorId":33727,"corporation":false,"usgs":true,"family":"Carrara","given":"P. E.","affiliations":[],"preferred":false,"id":362461,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"McGimsey, R. G.","contributorId":93921,"corporation":false,"usgs":true,"family":"McGimsey","given":"R.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":362462,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70011998,"text":"70011998 - 1981 - Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200–350°C","interactions":[],"lastModifiedDate":"2015-06-10T14:04:41","indexId":"70011998","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200–350°C","docAbstract":"Sulfate reduction during seawater reaction with fayalite and with magnetite was rapid at 350°C, producing equilibrium assemblages of talc-pyrite-hematite-magnetite at low water/rock ratios and talc-pyrite-hematite-anhydrite at higher water/rock ratios. At 250°C, seawater reacting with fayalite produced detectable amounts of dissolved H2S, but extent of reaction of solid phases was minor after 150 days. At 200°C, dissolved H2S was not detected, even after 219 days, but mass balance calculations suggest a small amount of pyrite may have formed. Reaction stoichiometry indicates that sulfate reduction requires large amounts of H+, which, in subseafloor hydrothermal systems is provided by Mg metasomatism. Seawater contains sufficient Mg to supply all the H+ necessary for quantitative reduction of seawater sulfate.
\nSystematics of sulfur isotopes in the 250 and 350°C experiments indicate that isotopic equilibrium is reached, and can be modeled as a Rayleigh distillation process. Isotopic composition of hydrothermally produced H2S in natural systems is strongly dependent upon the seawater/basalt ratio in the geothermal system, which controls the relative sulfide contributions from the two important sulfur sources, seawater sulfate and sulfide phases in basalt. Anhydrite precipitation during geothermal heating severely limits sulfate ingress into high temperature interaction zones. Quantitative sulfate reduction can thus be accomplished without producing strongly oxidized rocks and resultant sulfide sulfur isotope values represent a mixture of seawater and basaltic sulfur.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(81)90054-5","issn":"00167037","usgsCitation":"Shanks, W.C., Bischoff, J.L., and Rosenbauer, R.J., 1981, Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200–350°C: Geochimica et Cosmochimica Acta, v. 45, no. 11, p. 1977-1995, https://doi.org/10.1016/0016-7037(81)90054-5.","productDescription":"19 p.","startPage":"1977","endPage":"1995","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":220870,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b8902e4b08c986b316cb3","contributors":{"authors":[{"text":"Shanks, Wayne C. III","contributorId":100527,"corporation":false,"usgs":true,"family":"Shanks","given":"Wayne","suffix":"III","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":362478,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bischoff, James L. jbischoff@usgs.gov","contributorId":1389,"corporation":false,"usgs":true,"family":"Bischoff","given":"James","email":"jbischoff@usgs.gov","middleInitial":"L.","affiliations":[],"preferred":true,"id":362476,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rosenbauer, Robert J. brosenbauer@usgs.gov","contributorId":204,"corporation":false,"usgs":true,"family":"Rosenbauer","given":"Robert","email":"brosenbauer@usgs.gov","middleInitial":"J.","affiliations":[{"id":520,"text":"Pacific Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":362477,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70012000,"text":"70012000 - 1981 - Correlation of natural gas content to iron species in the New Albany shale group","interactions":[],"lastModifiedDate":"2023-10-02T17:15:17.117744","indexId":"70012000","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1709,"text":"Fuel","active":true,"publicationSubtype":{"id":10}},"title":"Correlation of natural gas content to iron species in the New Albany shale group","docAbstract":"Mössbauer parameters were obtained for four Illinois Basin shales and their corresponding < 2μm clay fractions from wells drilled through the New Albany Shale Group in Henderson, Tazewell, and Effingham counties in Illinois and Christian County in Kentucky. Off-gas analysis indicated that the Illinois cores were in an area of low gas potential, while the Kentucky core was in an area of moderate-to-good potential. Iron-rich dolomite (ankerite) was found in the Kentucky core but not in the Illinois cores. In the Kentucky core, gas content could be correlated with the ankerite in the bulk sample, the Mössbauer M (2) species in the clay fraction, and a ferrous iron species in the clay fraction. The location of the greatest concentration of natural gas in the Kentucky core could be predicted by following the changes in percentage concentration of these iron species when plotted against the depth of burial of the core sample.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-2361(81)90228-3","issn":"00162361","usgsCitation":"Shiley, R., Cluff, R., Dickerson, D.R., Hinckley, C., Smith, G.V., Twardowska, H., and Saporoschenko, M., 1981, Correlation of natural gas content to iron species in the New Albany shale group: Fuel, v. 60, no. 8, p. 732-738, https://doi.org/10.1016/0016-2361(81)90228-3.","productDescription":"7 p.","startPage":"732","endPage":"738","costCenters":[],"links":[{"id":220944,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Illinois, Kentucky","county":"Christian County, Effingham County, Henderson County, Tazewell County","otherGeospatial":"New Albany Shale 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R.H.","contributorId":44282,"corporation":false,"usgs":true,"family":"Shiley","given":"R.H.","email":"","affiliations":[],"preferred":false,"id":362482,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cluff, R.M.","contributorId":53948,"corporation":false,"usgs":true,"family":"Cluff","given":"R.M.","email":"","affiliations":[],"preferred":false,"id":362484,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Dickerson, D. R.","contributorId":66837,"corporation":false,"usgs":true,"family":"Dickerson","given":"D.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":362485,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hinckley, C.C.","contributorId":50656,"corporation":false,"usgs":true,"family":"Hinckley","given":"C.C.","email":"","affiliations":[],"preferred":false,"id":362483,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Smith, Gerard V.","contributorId":93629,"corporation":false,"usgs":true,"family":"Smith","given":"Gerard","email":"","middleInitial":"V.","affiliations":[],"preferred":false,"id":362486,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Twardowska, H.","contributorId":98038,"corporation":false,"usgs":true,"family":"Twardowska","given":"H.","email":"","affiliations":[],"preferred":false,"id":362487,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Saporoschenko, Mykola","contributorId":31905,"corporation":false,"usgs":true,"family":"Saporoschenko","given":"Mykola","email":"","affiliations":[],"preferred":false,"id":362481,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":70012007,"text":"70012007 - 1981 - Aeromagnetic and radio echo ice-sounding measurements over the Dufek intrusion, Antarctica","interactions":[],"lastModifiedDate":"2024-07-16T15:37:43.971318","indexId":"70012007","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","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":"Aeromagnetic and radio echo ice-sounding measurements over the Dufek intrusion, Antarctica","docAbstract":"A combined aeromagnetic and radio echo ice-sounding survey (4200 km of traverse) made in 1978 in Antarctica over the Dufek layered mafic intrusion of Jurassic age suggests a minimum area of about 50,000 km2, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and subglacial topographic profiles illustrate the usefulness of this combination of methods in studying bedrock geology beneath ice-covered areas. Rocks are exposed in only 3% of the inferred area of the intrusion. Magnetic anomalies measured a few hundred meters above outcrops of the intrusion range in peak-to-trough amplitude from ∼50 nT over the lowermost exposed portion of the section in the Dufek Massif to ∼3600 nT over the uppermost part of the section in the Forrestal Range. Theoretical magnetic anomalies, computed from models based on the subice topography fitted to the highest-amplitude observed magnetic anomalies, required normal and reversed magnetizations ranging from 10−4 to 10−2 emu/cm3 having directions and magnetizations consistent with measurements previously made on oriented samples. This result is interpreted as indicating that the Dufek intrusion cooled through the Curie isotherm during one or more reversals of the earth's magnetic field.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB086iB04p03014","issn":"01480227","usgsCitation":"Behrendt, J.C., Drewry, D., Jankowski, E., and Grim, M.S., 1981, Aeromagnetic and radio echo ice-sounding measurements over the Dufek intrusion, Antarctica: Journal of Geophysical Research Solid Earth, v. 86, no. B4, p. 3014-3020, https://doi.org/10.1029/JB086iB04p03014.","productDescription":"7 p.","startPage":"3014","endPage":"3020","numberOfPages":"7","costCenters":[],"links":[{"id":480578,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/jb086ib04p03014","text":"Publisher Index Page"},{"id":222177,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"B4","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"5059e72ee4b0c8380cd478b2","contributors":{"authors":[{"text":"Behrendt, John C. jbehrendt@usgs.gov","contributorId":25945,"corporation":false,"usgs":true,"family":"Behrendt","given":"John","email":"jbehrendt@usgs.gov","middleInitial":"C.","affiliations":[{"id":218,"text":"Denver Federal Center","active":false,"usgs":true},{"id":213,"text":"Crustal Imaging and Characterization Team","active":false,"usgs":true}],"preferred":false,"id":362505,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Drewry, D.J.","contributorId":41968,"corporation":false,"usgs":true,"family":"Drewry","given":"D.J.","email":"","affiliations":[],"preferred":false,"id":362506,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Jankowski, E.","contributorId":7420,"corporation":false,"usgs":true,"family":"Jankowski","given":"E.","email":"","affiliations":[],"preferred":false,"id":362504,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Grim, M. S.","contributorId":102884,"corporation":false,"usgs":true,"family":"Grim","given":"M.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":362507,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70012015,"text":"70012015 - 1981 - Seismic amplitude anomalies associated with thick First Leo sandstone lenses, eastern Powder River basin, Wyoming","interactions":[],"lastModifiedDate":"2024-04-18T16:37:38.604821","indexId":"70012015","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1808,"text":"Geophysics","active":true,"publicationSubtype":{"id":10}},"title":"Seismic amplitude anomalies associated with thick First Leo sandstone lenses, eastern Powder River basin, Wyoming","docAbstract":"Several new discoveries of oil production in the Leo sandstone, an economic unit in the Pennsylvanian middle member of the Minnelusa formation, eastern Powder River basin, Wyoming-Nebraska-South Dakota, have renewed exploration interest in this area. Vertical seismic profiles (VSP) and model studies suggested that a measurable seismic amplitude anomaly is frequently associated with the thick First Leo sandstone lenses. To test this concept, a surface reflection seismic profile was run between two wells about 12 miles apart. The First Leo was present and productive in one well and thin and barren in the other. The surface profile shows the predicted amplitude anomaly at the well where a thick lens is known to exist. Two other First Leo amplitude anomalies also appear on the surface seismic profile between the two wells, which may indicate the presence of additional lenses.
","language":"English","publisher":"Society of Exploration Geophysicists","doi":"10.1190/1.1441158","issn":"00168033","usgsCitation":"Balch, A.H., Lee, M.W., Miller, J.J., and Ryder, R.T., 1981, Seismic amplitude anomalies associated with thick First Leo sandstone lenses, eastern Powder River basin, Wyoming: Geophysics, v. 46, no. 11, p. 1519-1527, https://doi.org/10.1190/1.1441158.","productDescription":"9 p.","startPage":"1519","endPage":"1527","numberOfPages":"9","costCenters":[],"links":[{"id":222284,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"46","issue":"11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b8aece4b08c986b317475","contributors":{"authors":[{"text":"Balch, A. H.","contributorId":104892,"corporation":false,"usgs":true,"family":"Balch","given":"A.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":362522,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lee, Myung W.","contributorId":84358,"corporation":false,"usgs":true,"family":"Lee","given":"Myung","middleInitial":"W.","affiliations":[],"preferred":false,"id":362520,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Miller, J. J.","contributorId":54588,"corporation":false,"usgs":true,"family":"Miller","given":"J.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":362519,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ryder, R. T.","contributorId":96673,"corporation":false,"usgs":true,"family":"Ryder","given":"R.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":362521,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70012018,"text":"70012018 - 1981 - Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan","interactions":[],"lastModifiedDate":"2024-03-18T14:00:26.881376","indexId":"70012018","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan","docAbstract":"The Sm-Nd isotopic system of a tonalitic augen gneiss and its constituent minerals from northern Michigan was disturbed during metamorphism. Sm-Nd zircon ages are lower than the wholerock Sm-Nd model age. However, closely associated pairs of minerals (for example, sphene and biotite or apatite and plagioclase) retain their apparent metamorphic ages. The Sm-Nd model age for the tonalitic augen gneiss of 3919 ± 30myr, appears to reflect open system behavior during metamorphism. A mineralogically different gneiss from the same location has a Sm-Nd model age of 3520 ± 70 myr. The two whole rocks differ in their Sm-Nd and Rb-Sr systematics and in their chondrite-normalized rare earth element (REE) patterns. The whole-rock-normalized mineral REE patterns show the contribution of the major and trace minerals to the REE content of the whole rock. The trace minerals contain a significant amount of the total REE.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(81)90148-4","issn":"00167037","usgsCitation":"Futa, K., 1981, Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan: Geochimica et Cosmochimica Acta, v. 45, no. 7, p. 1245-1249, https://doi.org/10.1016/0016-7037(81)90148-4.","productDescription":"5 p.","startPage":"1245","endPage":"1249","numberOfPages":"5","costCenters":[],"links":[{"id":222287,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b917ce4b08c986b319925","contributors":{"authors":[{"text":"Futa, K.","contributorId":26435,"corporation":false,"usgs":true,"family":"Futa","given":"K.","affiliations":[],"preferred":false,"id":362531,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70012021,"text":"70012021 - 1981 - Dating of Archean basement in northeastern Wyoming and southern Montana.","interactions":[],"lastModifiedDate":"2013-02-24T08:44:50","indexId":"70012021","displayToPublicDate":"1981-01-01T00:00:00","publicationYear":"1981","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":"Dating of Archean basement in northeastern Wyoming and southern Montana.","docAbstract":"Rb-Sr whole-rock and U-Pb zircon ages of granite and gneiss cores from three deep drill holes extend known occurrences of Archean rocks in the subsurface of NE Wyoming and S Montanta. Rb-Sr and K- Ar mineral ages are discordant and reflect early or middle Proterozoic disturbance. Highly altered rocks occur in a thin zone immediately below the sub-Cambrian unconformity. Samples from a few metres deeper in the basement are much fresher but show the effects of this alteration in filled fractures and thin adjacent alteration haloes. Whole-rock Rb-Sr systems have retaioned a fair degree of integrity in spite of increased susceptibility to modification because of the disturbed mineral systems. Interaction of the rocks with water a few metres below the sub-Cambrian unconformity probably occurred for only a relatively short time. Fractures filled rapidly with secondary minerals such as chlorite, anhydrite, and carbonate to maintain a relatively impermeable crystalline basement in which the silicates and their contained isotopic systems were preserved.- Author","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Geological Society of America Bulletin","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Geological Society of America","doi":"10.1130/0016-7606(1981)92<139:DOABIN>2.0.CO;2","usgsCitation":"Peterman, Z.E., 1981, Dating of Archean basement in northeastern Wyoming and southern Montana.: Geological Society of America Bulletin, v. 92, no. 3 pt 1, p. 139-146, https://doi.org/10.1130/0016-7606(1981)92<139:DOABIN>2.0.CO;2.","startPage":"139","endPage":"146","numberOfPages":"8","costCenters":[],"links":[{"id":222335,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":268108,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1130/0016-7606(1981)92<139:DOABIN>2.0.CO;2"}],"volume":"92","issue":"3 pt 1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fde1e4b0c8380cd4e9b3","contributors":{"authors":[{"text":"Peterman, Z. E.","contributorId":63781,"corporation":false,"usgs":true,"family":"Peterman","given":"Z.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":362537,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}