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71.
Eide MS Endresen O Breivik O Brude OW Ellingsen IH Røang K Hauge J Brett PO 《Marine pollution bulletin》2007,54(10):1619-1633
This paper presents a new dynamic environmental risk model, with intended use within a new, dynamical approach for risk based ship traffic prioritisation. The philosophy behind this newly developed approach is that shipping risk can be reduced by directing efforts towards ships and areas that have been identified as high priority (high risk), prior to a potential accident. The risk model proposed in this paper separates itself from previous models by drawing on available information on dynamic factors and by focusing on the ship's surroundings. The model estimates the environmental risk of drift grounding accidents for oil tankers in real time and in forecast mode, combining the probability of grounding with oil spill impact on the coastline. Results show that the inherent dynamic risk introduced by an oil tanker sailing along the North Norwegian coast depends, not surprisingly, significantly upon wind and ocean currents, as well as tug position and cargo oil type. Results of this study indicate that the risk model is well suited for real time risk assessment, and effectively separates low risk and high risk situations. The model is well suited as a tool to prioritise oil tankers and coastal segments. This enables dynamic risk based positioning of tugs, using both real-time and projected risk, for effective support in case of a drifting ship situation. 相似文献
72.
Identification of estrogen-like alkylphenols in produced water from offshore oil installations 总被引:1,自引:0,他引:1
Produced water released into the sea from oil installations contains a vast number of organic compounds. This work focuses on the analysis and identification of phenols in produced water, in particular long-chain para-substituted alkylphenols, which act as endocrine disruptors for marine biota. Some alkylphenol standards, unavailable commercially, have been synthesised and some compounds of interest identified. However, a complete identification is not possible since conventional GC techniques cannot achieve the desired degree of separation. An overview of the levels of the 52 known alkylphenols in produced water from nine oil installations in the North and Norwegian Seas has been made. The previously unidentified alkylphenols in produced water have been characterised by means of alkylphenol retention indices (APRI) and mass spectrometry, and their total amounts estimated for the same nine locations. Our results confirm the presence of naphthols and other as yet unidentified compounds in produced water, while thiophenols were not detected by the used technique. 相似文献
73.
Helmut Tenzer Chan-Hee Park Olaf Kolditz Christopher Ian McDermott 《Environmental Earth Sciences》2010,61(4):853-880
Earth-reservoirs are increasingly exploited today with the extraction of resources, such as heat and hydrocarbons, and the
large-scale emplacement of waste, such as CO2 sequestration. The characterization, site investigation, predictive modeling and long-term monitoring are dependent on the
processes being investigated and modeled. In most cases complex coupled processes have to be addressed in a geologically complex
rock mass system. In this paper we present a conceptual holistic framework known as geomechanical facies linking all the scales
of investigation, characterization and reservoir development methods. We demonstrate this concept on the work undertaken during
the design and development of the enhanced geothermal systems (EGS) systems at the forefront of European Hot-Dry-Rock (HDR)
technology, Soultz-sous-Forêts (France) and Spa Urach (Germany). Soultz-sous-Forêts is situated within granitic rocks and
an active tectonic graben system in the central part of the Rhine Graben. It presents conditions of lithology, temperature,
stress, hydraulics and geochemistry that are very different from those at Spa Urach, located in a very dense gneiss formation
in the South German crystalline complex. Spa Urach exhibits more elastic behavior and is set tectonically within an almost
inactive strike-slip stress field described in more detail in Sects. “Drill core analysis” and “Hydraulic stimulation at Spa Urach”. This paper compares the exploration and field development methods used at these two sites against the back drop of the
geomechanical facies concept. Issues addressed include the key parameters for flow and heat transport properties, coupled
hydro-mechanical process identification, the success of the HDR reservoir as a heat exchanger and exploration techniques applicable
to the different facies. Identification of the key geomechanical facies gives an indication as to which technologies will
prove more efficient in the application of HDR technology. The results of this study will hopefully help in developing heat
recovery schemes for the long-term economical operation of future HDR plants and EGS as well as assist in the understanding
of engineered geosystems. 相似文献
74.
Olaf M. Svenningsen 《International Journal of Earth Sciences》1995,84(3):649-664
The structural evolution of a part of the late Precambrian Baltoscandian passive margin just before the inception of seafloor spreading is described, recording the change from deformation by faulting to dominantly magmatic extension of the crust. The allochthon of the Scandinavian Caledonides contains the imbricated passive margin of continental Baltica overlain by various exotic terranes. The Sarektjåkkå Nappe in the Seve Nappe Complex, which contains the outer parts of Baltica's passive margin, consists of sedimentary rocks, occurring as screens between Vendian (573±74 Ma) diabase dykes. These dykes constitute 70–80% of the nappe and locally form sheeted dyke complexes. The Sarektjåkkå Nappe largely escaped penetrative Caledonian deformation and preserves igneous, metamorphic and structural elements that are linked to the evolution of a pre-Caledonian rift to a passive continental margin. Extensional deformation before dyke emplacement is recorded by normal faults, pull-apart structures and folds. Unconformities, dykes affected by brittle deformation, and fluidization of sediments during dyke emplacement indicate close relations between the deposition of sediments, extensional deformation and dyke emplacement. The Sarektjåkkå Nappe is compared with other parts of the Baltica's passive margin and its tectonic evolution is discussed. 相似文献
75.
76.
Explorative data analysis of heavy metal contaminated soil using multidimensional spatial regression 总被引:1,自引:0,他引:1
To obtain data on heavy metal contaminated soil requires laborious and time-consuming data sampling and analysis. Not only has the contamination to be measured, but also additional data characterizing the soil and the boundary conditions of the site, such as pH, land use, and soil fertility. For an integrative approach, combining the analysis of spatial distribution, and of factors influencing the contamination, and its treatment, the Mollifier interpolation was used, which is a non-parametric kernel density regression. The Mollifier was capable of including additional independent variables (beyond the spatial dimensions x and y) in the spatial interpolation and hence explored the combined influence of spatial and other variables, such as land use, on the heavy metal distribution. The Mollifier could also represent the interdependence between different heavy metal concentrations and additional site characteristics. Although the uncertainty measure supplied by the Mollifier at first seems somewhat unusual, it is a valuable feature and supplements the geostatistical uncertainty assessment. 相似文献
77.
Birger Dahl 《Organic Geochemistry》2004,35(11-12):1551
This paper discusses the occurrence of 28,30-dinor-17α,18α,21β-hopane (bisnorhopane) in stratigraphically, fairly well preserved Viking Group sections from wells in local depressions in the North Viking Graben Area. The results show the presence of high relative amounts of bisnorhopane in the “Syn-rift sections”, whilst the “Post-rift sections” contain little or no bisnorhopane. Since most exploration wells are drilled on structural highs, primarily penetrating the “Post-rift Draupne”, this may explain why many analyzed source rock sections in this area contain little bisnorhopane.As a correlation of Draupne sections using the vertical, relative bisnorhopane distributions, it is suggested to be a potential stratigraphic marker for the area, indicating the presence of “Syn-rift Draupne” sediments.The relative bisnorhopane amounts follow a logarithmic reduction with depth and thermal maturity. The bisnorhopane signal is nearly extinguished at 3700 m depth at a maturity of Ro = 0.9–1.0%. 相似文献
78.
Thomas Kalbacher Wenqing Wang Chris McDermott Olaf Kolditz Takeo Taniguchi 《Environmental Geology》2005,47(7):1017-1027
79.
A crystal-chemical basis for Pb retention and fission-track annealing systematics in U-bearing minerals, with implications for geochronology 总被引:9,自引:0,他引:9
This study develops an empirical crystal-chemical framework for systematizing the kinetics of Pb loss and fission-track annealing in U-bearing minerals. Ionic porosity, Z (the fraction of a mineral's unit-cell volume not occupied by ions) potentially accounts for kinetic behavior by monitoring mean metal-oxygen bond length/strength. Various tests of a general kinetics-porosity relationship are presented, based upon diverse mineral data including: (1) Pb diffusion parameters; (2) measured closure temperatures (TC) for fission-track annealing and (3) retentivities of both Pb and fission tracks, from apparent-age data. Every kinetic parameter (including TC and mineral age for both the U/Pb and fission-track systems) is inversely correlated with Z within the sub-assemblage: zircon (Z ≈ 29%), titanite ( 34%) and apatite ( 38%). Assuming a diffusional closure model, Pb isotopic transport phenomena are described by a TC-Z scale “calibrated” with field-based TC data for titanite (≥ 680 ± 20°C) and apatite ( 500°C). Extrapolation of this scale yields TC estimates for the following minerals: staurolite (TC ≥ 1060°C, Z ≈ 25%); garnet (≥ 1010°C, 26.5%); zircon (≥900°C); monazite, xenotime, and epidote (≥ 750°C, 32%); and Ca-clinopyroxene (≥ 670 ± 30°C, 34 ± 1%, depending on composition). These empirical results imply that a (U/)Pb/Pb date for staurolite or garnet records the time of mineral growth, not post-growth isotopic closure, as also concluded in recent field studies. Because Z systematizes fission-track annealing, this recrystallization process, like volume-diffusion, must also be rate-limited by the strength of chemical bonds. The extent to which other recrystallization processes are likewise rate-limited is important to U/Pb geochronology because they potentially compete with diffusion as mechanisms for Pb-isotopic resetting in nature. 相似文献
80.
Christian Chopin Rolf Klaska Olaf Medenbach Dominique Dron 《Contributions to Mineralogy and Petrology》1986,92(3):316-321
Ellenbergerite occurs as purple millimetre-size grains associated with talc, kyanite, clinochlore, rutile, and zircon in composite inclusions within decimetre-large pyrope crystals (90–98 mole percent end-member) in the quartzite layer of the Dora Maira massif, Western Alps, from which coesite has been recently reported (Chopin 1984). It is hexagonal, a=12.255(8), c=4.932(4) Å, Z=1, space group P63. Mohs hardness 6.5; Dmes 3.15, Dcal 3.10; no cleavage. Uniaxial negative and vividly pleochroic, colourless, colourless to deep lilac with colour zoning. The intensely coloured variety has 1.6789(5), 1.670(1); microprobe analysis yields SiO2 39.1, P2O5 0.45, Al2O3 25.1, TiO2 4.0, MgO 22.2, FeO 0.20, sum 99.05 wt.% including H2O 8.0 (coulometrically). The formula calculated on a O28(OH)10 basis (implying 7.5 wt.% H2O) is Mg6.71 Fe0.03 Ti0.61 Al6.00 Si7.92 P0.08 O28(OH)10 The colour zoning is due to nearly complete TiZr substitution. In addition ellenbergerite may contain more than 8 wt.% P2O5 with strictly correlated changes of Si, Mg, Al and Ti+Zr contents, over 80% of which represent the SiAlPMg substitution.The structure has been determined from 1049 observed independent reflections and refined to R=0.034, Rw=0.031, including six of ten protons. It consists of single chains of face-sharing octahedra with one third vacancies extending along the six-fold screw axes, and of pairs of fully occupied face-sharing octahedra linked by edge-sharing to form octahedral double chains parallel to the twofold screw axes, all interconnected by SiO4 tetrahedra. It may be compared with the dumortierite polymorph with space group P63mc derived hypothetically by Moore and Araki (1978). The structural formula is (Mg,Ti,Zr,)2 Mg6(Al,Mg)6 (Si,P)2 Si6 O28(OH)10 Face-sharing octahedra are an unusual feature in silicates which results in a dense structure and reflects, considering the common bulk composition, the uncommon high-pressure formation conditions (about 25–30 kbar, 700–800° C). Ti4+-Fe2+ charge transfer between face-sharing octahedra on the six-fold screw axes most likely accounts for the absorption scheme. 相似文献