Institution
United States Geological Survey
Government•Reston, Virginia, United States•
About: United States Geological Survey is a government organization based out in Reston, Virginia, United States. It is known for research contribution in the topics: Population & Groundwater. The organization has 17899 authors who have published 51097 publications receiving 2479125 citations. The organization is also known as: USGS & US Geological Survey.
Topics: Population, Groundwater, Volcano, Aquifer, Sediment
Papers published on a yearly basis
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TL;DR: In this paper, support for the North Temperate Lakes LTER program was provided by NSF DEB DEB0822700, which was used to train a LTER classifier.
Abstract: "Support for this paper was provided by funding from the North Temperate Lakes LTER program, NSF DEB‐0822700."
361 citations
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TL;DR: Miller et al. as mentioned in this paper proposed a relativized version of the Normalized Burn Ratio (RdNBR) to remove the biasing effect of the pre-fire condition, which allows creating categorical classifications for fires occurring in similar vegetation types without acquiring additional calibration field data on each fire.
361 citations
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TL;DR: A complex sequence of pyroclastic flows and surges erupted by Nevado del Ruiz volcano on 13 November 1985 interacted with snow and ice on the summit ice cap to trigger catastrophic lahars (volcanic debris flows), which killed more than 23,000 people living at or beyond the base of the volcano.
361 citations
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TL;DR: In this article, the authors found evidence of magma interactions resulting in both hybridization and mingling in a diverse suite of gabbroic to intermediate rocks associated with the compositionally zoned hornblende-biotite Lamarck Granodiorite of the eastern Sierra Nevada, California.
Abstract: Evidence of magma interactions resulting in both hybridization and mingling are preserved in a diverse suite of gabbroic to intermediate rocks associated with the compositionally zoned hornblende-biotite Lamarck Granodiorite of the eastern Sierra Nevada, California. Ellipsoidal mafic enclaves were formed by quenching of small amounts of high-alumina basaltic magma upon injection into and dispersal through granodiorite magma early in its crystallization. Synplutonic intrusions of hornblende gabbro through hybridized mafic granodiorite represent injection of mafic magma at a later stage of crystallization of the granodiorite, as they crosscut regional trends in foliation and compositional zoning in the host pluton. Where compositional contrasts between intrusion and host granodiorite are large, contacts are sharp and abundant enclaves derived from the mafic intrusion are present in the granodiorite. Where the host is relatively mafic or where the local-scale proportion of mafic magma is large, contacts are zones of extensive hybridization that contain both enclaves and hybrid schlieren. Uncontaminated mafic intrusions have high-alumina basaltic compositions, whereas hybridized intrusions have silica contents as high as 63.5%. Mafic intrusions locally contain coarse-grained cumulus gabbro inclusions. Mafic schlieren in granodiorite far from mafic intrusions represent localized accumulations of hornblende, Fe-Ti oxides, and biotite from the granodiorite. Intrusion of late mafic dikes mobilized and entrained granitic residue from the granodiorite and formed composite dikes of aplite and pillowed diorite.
Whether interacting magmas mix or mingle is a function of the heat contents and mass fractions of the end members. Calculations that account for compositions, heats of fusion, heat capacities of liquids and crystals, and a range of initial temperatures, crystallinities, crystal sizes, and magma water contents indicate that in most circumstances the basalt end member quenches; the resulting large viscosity contrast between the end members prevents hybridization. Homogenization is likely only if the compositional difference between host and injected mafic magma is less than 10% SiO2 or if the mass fraction of mafic magma is greater than 0.5. Resulting mixtures have the composition of tonalite or mafic granodiorite; thus, the more silicic rocks of the granodiorite pluton must represent differentiation products rather than direct hybrids of mafic or intermediate magma and felsic magma.
360 citations
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TL;DR: A review of the literature indicates that numerous microorganisms can reduce ferric iron during the metabolism of organic matter as mentioned in this paper, and that the reduction of iron appears to be enzymatically catalyzed and may be coupled to an electron transport chain that could generate ATP.
Abstract: A review of the literature indicates that numerous microorganisms can reduce ferric iron during the metabolism of organic matter. In most cases, the reduction of ferric iron appears to be enzymatically catalyzed and, in some instances, may be coupled to an electron transport chain that could generate ATP. However, the physiology and biochemistry of ferric iron reduction are poorly understood. In pure culture, ferric iron‐reducing organisms metabolize fermentable substrates, such as glucose, primarily to typical fermentation products, and transfer only a minor portion of the electron equivalents in the fermentable substrates to ferric iron. However, fermentation products, especially hydrogen and acetate, may be important electron donors for ferric iron reduction in natural environments. The ability of some organisms to couple the oxidation of fermentation products to the reduction of ferric iron means that it is possible for a food chain of iron‐reducing organisms to completely mineralize nonrecal...
360 citations
Authors
Showing all 18026 results
Name | H-index | Papers | Citations |
---|---|---|---|
Derek R. Lovley | 168 | 582 | 95315 |
Steven Williams | 144 | 1375 | 86712 |
Thomas J. Smith | 140 | 1775 | 113919 |
Jillian F. Banfield | 127 | 562 | 60687 |
Kurunthachalam Kannan | 126 | 820 | 59886 |
J. D. Hansen | 122 | 975 | 76198 |
John P. Giesy | 114 | 1162 | 62790 |
David Pollard | 108 | 438 | 39550 |
Alan Cooper | 108 | 746 | 45772 |
Gordon E. Brown | 100 | 454 | 32152 |
Gerald Schubert | 98 | 614 | 34505 |
Peng Li | 95 | 1548 | 45198 |
Vipin Kumar | 95 | 614 | 59034 |
Susan E. Trumbore | 95 | 337 | 34844 |
Alfred S. McEwen | 92 | 624 | 28730 |