Multi-stage zeolite facies mineralization in the Hvalfjördur area,Iceland     

Tobias Weisenberger  Rune S. Selbekk 《International Journal of Earth Sciences》2009,98(5):985-999

The Hvalfjördur area, 30 km north of Iceland’s capital Reykjavik, belongs to the sequence of Late Tertiary to early Quaternary flood basalts with minor intercalations of hyaloclastites and rhyolites. The basalts are affected by progressive low-temperature metamorphism, caused by the burial of the lava succession and higher heat flow from nearby central volcanoes. Low-grade zeolite facies metamorphism of basaltic lavas in the Hvalfjördur area results in two distinct mineral parageneses that can be correlated to events in the burial and hydrothermal history of the lava pile. Stage Ia represents syn-eruptive near-surface alteration in which celadonite and silica were precipitated along primary pores. During regional burial metamorphism (stage Ib), hydrolysis of olivine and glass led to the formation of mixed-layer chlorite/smectite clays. The chlorite content of stage Ib phyllosilicate vesicle rims increases with increasing burial depth and temperature. Stage II occurred after the burial and is marked by zeolite mineralization caused by higher heat flow from the Laxárvogur and Hvalfjördur central volcanoes. Altogether 11 different zeolites were found in the Hvalfjördur area: analcime, chabazite, epistilbite, heulandite, laumontite, levyne, mesolite, stilbite, stellerite, thomsonite and yugawaralite. In total, three separate depth and temperature-controlled “zeolite zones” occur in the Hvalfjördur area.  相似文献   

On the sources of ultraviolet absorption in spectra of Titan and the outer planets     

Thomas Scattergood  Tobias Owen 《Icarus》1977,30(4):780-788

In response to the observations of the ultravioler deficiencies shown by all of the outer planets and Titan, models have been proposed to explain the low albedos by absorption by particles in the upper atmospheres of these objects. These particles are generally believed to be photochemically formed from gases in the upper atmospheres, primarily methane and hydrogen. Such processes may also be operative on Titan. The results of some laboratory experiments of the proton irradiation of mixtures of gases including CH₄ H₂, NH₃, etc., have shown that liquid and solid materials are produced that are strong ultraviolet absorbers. However, the material produced from the CH₄ + H₂ mixture was colorless, indicating that species containing elements other than carbon and hydrogen are necessary for the production of color. Two such elements are nitrogen (as NH₃ or N₂) and sulfur (as H₂S) and colored materials have been produced from such mixtures. None of these materials has spectral properties identical to those shown by the planets. Therefore it is necessary that mixtures (and/or cloud layers) of the photochemical materials be present.  相似文献   

Separating physical and physiological effects of temperature on zooplankton feeding rate     

Benjamin?Loiterton  Marcus?Sundbom  Tobias?VredeEmail author 《Aquatic Sciences - Research Across Boundaries》2004,66(1):123-129

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Halogenation processes linked to red wood ant nests (<Emphasis Type="Italic">Formica</Emphasis> spp.) and tectonics     

Gabriele M. Berberich  Tobias Sattler  Dietrich Klimetzek  Simon A. Benk  Martin B. Berberich  Daniela Polag  Heinz Friedrich Schöler  Elliot Atlas 《Journal of Atmospheric Chemistry》2017,74(2):261-281

We investigated and evaluated the occurrence of fault zone tracer gases (CO₂, He, Rn), volatile organohalogens (CH₃Cl, CHCl₃, CHBr₃), alkanes and limonene in soil and nest gases of red wood ants (RWA) in comparison to ambient air, in a seismically active area. In this new approach, we compared RWA-free areas to RWA-areas by combining different investigation and analytical methods. In soil gas, the fault zone tracer gas Rn was surprisingly highly correlated to limonene, suggesting a combination of biotic production of limonene and abiotic degassing of Rn in a seismically active area; moderate correlations were found with trihalomethanes and other halocarbons. In RWA nests a variety of elevated concentrations of haloforms were found, while remaining below the atmospheric background values in RWA-free areas. The evidence of CHCl₃ in RWA nests is the first record. Its average concentrations in nests of F. rufa and F. polyctena were up to 3 fold higher than atmospheric background and up to 28–70 fold higher compared to e.g. volcanic emissions being considered as one of its main geogenic sources. Thus, RWA nests could possibly be an additional source for CHCl₃ liberation. Consequently, apart from RWA being bioindicators for seismically active degassing faults, they might also be used as bioindicators for CHCl₃ formation in forest soils. Although we cannot yet differentiate between a geogenic/abiotic and a biotic formation. RWA nests will have to be reconsidered for halocarbon formation in future quantifications of geochemical cycles at global scale, since they impact organic soil chemistry through biotic and/or abiotic pathways. Therefore, further larger-scale research in different tectonic settings but also in well-known CHCl₃ “hot spot” study areas such as the Klosterhede area (Denmark) should focus directly on gas sampling from confirmed active fault systems. Nests of other ant species should be addressed to compare seasonal, diurnal and nocturnal variations of degassing procedures in relation to earth tides, different geologic settings, and tectonic events such as earthquakes and on quantifying the fluxes to the atmosphere.  相似文献   

Temporal Scales of the Nocturnal Flow Within and Above a Forest Canopy in Amazonia     

Daniel M. Santos  Otávio C. Acevedo  Marcelo Chamecki  José D. Fuentes  Tobias Gerken  Paul C. Stoy 《Boundary-Layer Meteorology》2016,161(1):73-98

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Six temperature and precipitation regimes of the contiguous United States between 1895 and 2010: a statistical inference study     

Samuel S. P. Shen  Olaf Wied  Alexander Weithmann  Tobias Regele  Barbara A. Bailey  Jay H. Lawrimore 《Theoretical and Applied Climatology》2016,125(1-2):197-211

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Transfer patterns in Phase I of the EU Emissions Trading System: a first reality check based on cluster analysis   总被引：1，自引：0，他引：1  

Regina A. Betz  Tobias S. Schmidt 《Climate Policy》2016,16(4):474-495

In 2005, the world's largest Emissions Trading System (ETS) was introduced in the EU. Economic theory assumes high efficiency of such market-based instruments since companies have the flexibility to trade allowances. However, to date there is a lack of understanding on how companies have participated in the allowance markets. This article uses data on transfers of allowances between 2005 and the end of 2007, published by the EU in the Community Independent Transaction Log (CITL) after a five-year delay. We use cluster analysis to detect patterns in the data and differentiate transfer behaviour. We find that the vast majority of participants (7212 accounts) are rather passive in terms of transfers. Of these, more than half are hardly participating in the market at all, whereas one-third are accounts managed by another account belonging to the parent company. Opposed to that, 143 accounts show more active, but relatively diverse transfer behaviour. We also identify differences in sectoral representations, account types, and primary allocation across the seven clusters. While the passive accounts mostly belong to installations regulated under the EU ETS, the most active accounts are classified as ‘non-regulated account type'.  相似文献   

3D modelling and sheath folding at the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit and implications for exploration in a 1.9 Ga ore district,Fennoscandian Shield,Sweden     

Tobias C. Kampmann  Michael B. Stephens  Pär Weihed 《Mineralium Deposita》2016,51(5):665-680

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School-based environmental education in the context of a research and development project on integrated water resources management: experiences from Mongolia     

Daniel Karthe  Tobias Reeh  Michael Walther  Steffen Niemann  Alexander Siegmund 《Environmental Earth Sciences》2016,75(18):1286

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Case study: characterization of source-separated blackwater and greywater in the ecological housing estate Lübeck “Flintenbreite” (Germany)     

Jan Christian Sievers  Tobias Wätzel  Jörg Londong  Eckhard Kraft 《Environmental Earth Sciences》2016,75(22):1428

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