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61.
Kuster-Toksöz and Biot-Gassmann models for estimating velocities of longitudinal and shear waves on the basis of well-logging data were analysed. P-wave and S-wave velocity models are crucial for interpretation of seismic data. Discussed models enable determination with quite good accuracy, in some cases higher than the acoustic full wavetrains interpretation. Because velocity strongly depends on lithology and saturation of pore space, the selection of parameters of rock matrix, hydrocarbons and formation waters has a strong effect on the quality of velocities estimation. 相似文献
62.
Marcin Słowik Tadeusz Sobczyński Zygmunt Młynarczyk 《Environmental Earth Sciences》2010,59(5):957-966
Research concerning chemical constitution of alluvial sediments was done in the lower course of the Obra river (Western Poland).
The fragment of vertical profile, which consisted of various alluvial sediments (fine sands, peats, and sandy silts) was chosen
for detailed analysis. The main research problem was to determine if lithology and chemical constitution of alluvial deposits
are interconnected in a distinct way within studied section of the Obra river valley, and, if changes of chemical elements’
concentration could be used to illustrate depositional processes, which take place in riverbed and floodplain. Concentrations
of Fe, Mn, Cu, Zn, Ca, Mg, and K were determined in collected sediment samples. Next, geochemical groups of alluvial sediments
were distinguished using cluster analysis. Investigated changes of chemical elements’ concentration show that there is a distinct
border between the environment of organic sediments, which marks the place of former functioning of the Obra riverbed, and
sandy silts, which were deposited within floodplain during floods. Besides, floodplain sediments, riverbed sediments, and
reductive environment within peat deposits were singled out on the basis of the analysis. 相似文献
63.
Paul Augustinus Charles E. Barton Atun Zawadzki Kate Harle 《Environmental Earth Sciences》2010,61(3):625-639
Macquarie Harbour in southwest Tasmania, Australia, has been affected severely by the establishment of mines in nearby Queenstown
in the 1890s. As well as heavy metal-laden acid rock drainage from the Mount Lyell mine area, over 100 Mt of mine tailings
and slag were discharged into the Queen and Ring Rivers, with an estimated 10 Mt of mine tailings building a delta of ca.
2.5 km2 and ca. 10 Mt of fine tailings in the harbour beyond the delta. Coring of sediments throughout Macquarie Harbour indicated
that mine tailings accreted most rapidly close to the King River delta source with a significant reduction in thickness of
tailings and heavy metal contamination with increasing distance from the King River source. Close to the King River delta
the mine tailings are readily discriminated from the background estuarine sediments on the basis of visual logging of the
core (laminations, colour), sediment grain size, sediment magnetic susceptibility and elemental geochemistry, especially concentrations
of the heavy metals Cu, Zn and Pb. The high heavy metal concentrations are demonstrated by the very high contamination factors
(CF > 6) for Cu and Zn, with CF values mostly >50 for Cu for the mine-impacted sediments. Although the addition of mine waste
into the King River catchment has ceased, the catchment continues to be a source of these heavy metals due to acid rock drainage
and remobilisation of mine waste in storage in the river banks, river bed and delta. The addition of heavy metals to the harbour
sourced from the Mount Lyell mines preceded the advent of direct tailings disposal into the Queen River in 1915 with the metals
probably provided by acid rock drainage from the Mount Lyell mining area. 相似文献
64.
The paper presents the problem of a simulation of the greenhouse gases emission permits market where only low accuracy emission amounts are known. An organization of the market with uncertain emissions is proposed and trading rules for individual market participants are discussed. Simulation of the market is based on a multi-agent system. Negotiation of purchase/sale prices between the parties are introduced, where the trading parties adopt one of two options: (i) bilateral negotiations, and (ii) sealed bid reverse auctions. Results of simulation runs show trajectories of transaction prices, as well as probability distributions of learning agents’ bidding prices. 相似文献
65.
The chemical composition of metamorphosed siliciclastic rocks in the Orlica-?nie?nik Dome (Bohemian Massif) identifies the main sources for the Neoproterozoic [the M?ynowiec Formation (MF)], Early Cambrian [the Stronie Formation (SF)] and Late Cambrian/Early Ordovician [the Goszów quartzites (GQ)] sediments. The MF developed from erosion of a Cadomian magmatic arc along the northern Gondwana margin. The variegated SF, with supra-subduction affinities, shows chemical characteristics pointing to erosion of the freshly exhumed Cadomian orogen and detritus deposition in the back-arc basin. The very different chemical features of the GQ indicate deposition in a basin sited on a passive continental margin. The explanation proposed for the observed changes in chemical composition involves three main stages: (1) The pre ~540 Ma evolution of an active continental margin and related back-arc basin ceased with the collision and accretion of the magmatic arc to the Gondwana margin; (2) Early Cambrian rift to drift transition (540–500 Ma) and development of a depositional basin filled with detritus derived from remnants of the magmatic arc; (3) Peri-Gondwana break-up leading to the formation of shallow-water passive margin depositional basins filled with quartz-rich detritus resembling Early Ordovician Armorican quartzites known from other parts of the Variscan Belt. 相似文献
66.
The paper presents study results obtained for the bottom sediment samples of fjords Kongsfjord, Isfjord, Hornsund in the form of surface samples and their core profiles. The concentrations of labile form of aluminum and heavy metals were determined using the single-stage extraction with 3 mol L?1 HCl. The obtained results allowed defining the occurrence of variability of labile aluminum form in the samples of bottom sediments of the studied fjords depending on the point and depth of sample collection. The conducted chemometric analysis allowed for the study of spatial variability of aluminum occurrence in the area of the investigated fjords. Based on the analysis, the correlations between aluminum and heavy metals were determined. 相似文献
67.
Maria Czaja Mariola Kądziołka-Gaweł Radosław Lisiecki Sabina Bodył-Gajowska Zbigniew Mazurak 《Physics and Chemistry of Minerals》2014,41(2):115-126
For the first time ever, the luminescence spectra of Cr3+ centers in two chlorite crystals are presented. Chromium ions occupy the strong crystal-field site M4 in the brucite sheet and the intermediate crystal-field site in the inner octahedral sheet for purple and green chlorite, respectively. We discuss the influence of an effective positive charge on the Cr3+ ion and an effective negative charge of ligands on the differences in the values of the Dq and B parameters. It is concluded that the presence of Fe2+ ions and other point defects, as well as concentration quenching, causes the very short luminescence lifetimes of chromium ions. 相似文献
68.
69.
Periglacial and Fluvial Factors Controlling the Sedimentation of Pleistocene Breccia in NW Poland
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Piotr Weckwerth Małgorzata Pisarska‐Jamroży 《Geografiska Annaler: Series A, Physical Geography》2015,97(2):415-430
Breccias were investigated on the terrace of the Toruń‐Eberswalde ice‐marginal valley at Rozwarzyn (NW Poland). Breccia layers include soft‐sediment clasts with diameters between 2 and 256 mm and soft‐sediment megaclasts with diameters from 256 mm to 7 m. The shape of the soft‐sediment clasts and megaclasts (derived from frozen sediments) in the breccia is diverse: from angular and irregular in the case of debris‐flow breccias to slightly rounded and tabular in fluvial breccias. These two types of breccias were developed during the Late Weichselian when the periglacial climate favored extensive lateral erosion by currents of frozen braided channels in the ice‐marginal valley. The dual presence of breccias of fluvial and debris‐flow origin in channel deposits is unique for Quaternary sediments. Zones of breccias existed in the channels where scours and obstacle marks related to megaclasts developed. The study of breccias shed new light on the fluvial processes in ice‐marginal valleys during the Pleistocene and can be considered as diagnostic for fluvio‐periglacial conditions. 相似文献
70.