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1.
Benjamin G. Petri Radek Fučík Tissa H. Illangasekare Kathleen M. Smits John A. Christ Toshihiro Sakaki Carolyn C. Sauck 《Ground water》2015,53(5):685-698
The generation of vapor‐phase contaminant plumes within the vadose zone is of interest for contaminated site management. Therefore, it is important to understand vapor sources such as non‐aqueous‐phase liquids (NAPLs) and processes that govern their volatilization. The distribution of NAPL, gas, and water phases within a source zone is expected to influence the rate of volatilization. However, the effect of this distribution morphology on volatilization has not been thoroughly quantified. Because field quantification of NAPL volatilization is often infeasible, a controlled laboratory experiment was conducted in a two‐dimensional tank (28 cm × 15.5 cm × 2.5 cm) with water‐wet sandy media and an emplaced trichloroethylene (TCE) source. The source was emplaced in two configurations to represent morphologies encountered in field settings: (1) NAPL pools directly exposed to the air phase and (2) NAPLs trapped in water‐saturated zones that were occluded from the air phase. Airflow was passed through the tank and effluent concentrations of TCE were quantified. Models were used to analyze results, which indicated that mass transfer from directly exposed NAPL was fast and controlled by advective‐dispersive‐diffusive transport in the gas phase. However, sources occluded by pore water showed strong rate limitations and slower effective mass transfer. This difference is explained by diffusional resistance within the aqueous phase. Results demonstrate that vapor generation rates from a NAPL source will be influenced by the soil water content distribution within the source. The implications of the NAPL morphology on volatilization in the context of a dynamic water table or climate are discussed. 相似文献
2.
Eduard Petrovský Radek Zbořil Tomáš Matys Grygar Bohumil Kotlík Jiří Novák Aleš Kapička Hana Grison 《Studia Geophysica et Geodaetica》2013,57(4):755-770
Magnetic measurements of deposited atmospehric dust can serve as an additional parameter in assessing environmental pollution. This method is based on the assumption that atmospherically deposited particles contain significant portion of ferrimagnetic iron oxides of anthropogenic origin, which can be easily detected. Aim of this paper is to identify clearly magnetic fraction of daily samples of particulate matter less than 10 μm (PM10), routinely used for air quality assessment and monitoring. We used combination of thermomagnetic analyses and other physical and chemical methods, including scanning electron microscopy (SEM) and Mössbauer spectroscopy. Our results show that daily samples of PM10, collected at sites with different degree of atmospheric pollution, contain magnetite of spherical shape, which is presumably of industrial origin. Thus, magnetic methods can be applied directly to the same substances, which are used routinely in air quality assessment and monitoring. 相似文献
3.
Katja Ruschel Lutz Nasdala Andreas Kronz John M. Hanchar Daniel M. T?bbens Radek ?koda Friedrich Finger Andreas M?ller 《Mineralogy and Petrology》2012,105(1-2):41-55
This study addresses whether Raman spectra can be used to estimate the degree of accumulated radiation damage in monazite-(Ce) samples whose chemical composition was previously determined. Our results indicate that the degree of disorder in monazite–(Ce), as observed from increasing Raman band broadening, generally depends on both the structural state (i.e., radiation damage) and the chemical composition (i.e., incorporation of non-formula elements). The chemical effects were studied on synthetic orthophosphates grown using the Li-Mo flux method, and non radiation-damaged analogues of the naturally radiation-damaged monazite–(Ce) samples, produced by dry annealing. We found that the “chemical” Raman-band broadening of natural monazite–(Ce) can be predicted by the empirical formula, $$ {\hbox{FWHM}} {\hbox{[c}}{{\hbox{m}}^{ - {1}}}{]} = {3}{.95} + {26}{.66} \times {\hbox{(Th}} + {\hbox{U}} + {\hbox{Ca}} + {\hbox{Pb)}} {\hbox{[apfu]}} $$ where, FWHM = full width at half maximum of the main Raman band of monazite–(Ce) (i.e., the symmetric PO4 stretching near 970?cm?1), and (Th+U+Ca+Pb) = sum of the four elements in apfu (atoms per formula unit). Provided the chemical composition of a natural monazite–(Ce) is known, this “chemical band broadening” can be used to estimate the degree of structural radiation damage from the observed FWHM of the ν1(PO4) band of that particular sample using Raman spectroscopy. Our annealing studies on a wide range of monazite–(Ce) reference materials and other monazite–(Ce) samples confirmed that this mineral virtually never becomes highly radiation damaged. Potential advantages and the practical use of the proposed method in the Earth sciences are discussed. 相似文献
4.
Nb-Ta-Ti-bearing oxide minerals (Nb-Ta-bearing rutile, columbite-group minerals) represent the most common Nb-Ta host in topaz-albite granites and related rocks from the Krásno-Horní Slavkov ore district. Tungsten-bearing columbite-(Fe), W-bearing ixiolite, wodginite and tapiolite-(Fe) are extremely rare in these rocks. Rutile contains significant levels of Ta (up to 37?wt.% Ta2O5) and Nb (up to 24?wt.% Nb2O5), with Ta/(Ta?+?Nb) ratio ranging from 0.04 to 0.61. Columbite-group minerals are represented mostly by columbite-(Fe) and rarely by columbite-(Mn), with Mn/(Mn?+?Fe) ratio ranging from 0.23 to 0.94. The exceptionally rare Fe-rich, W-bearing ixiolite occurs only as inclusions in Nb-Ta-bearing rutile from quartz-free alkali-feldspar syenites (Vysoky Kámen stock). Wodginite was found only in the topaz-albite microgranite of gneissic breccia matrix that occurs in the upper most part of the Hub topaz-albite granite stock. In wodginite, the Mn/(Mn?+?Fe) ratio is 0.42?C0.51, whereas the coexisting tapiolite-(Fe) has a distinctly lower Mn/(Mn?+?Fe) ratio close to 0.06. 相似文献
5.
Christoph Lenz Dominik Talla Katja Ruschel Radek Škoda Jens Götze Lutz Nasdala 《Mineralogy and Petrology》2013,107(3):415-428
In this paper, possibilities and limits of the application of REE3+ luminescence (especially the Nd3+ 4F3/2 → 4I9/2 emission) as structural probe are evaluated. Important factors controlling the Nd3+ luminescence signal are discussed, including effects of the crystal-field, crystal orientation, structural state, and temperature. Particular attention was paid to the study of the accessory minerals zircon (ZrSiO4), xenotime–(Y) (YPO4), monazite–(Ce) (CePO4) and their synthetic analogues. Based on these examples we review in short that (1) REE3+ luminescence can be used as non-destructive phase identification method, (2) the intensities of certain luminescence bands are strongly influenced by crystal orientation effects, and (3) increased widths of REE3+-related emission bands are a strong indicator for structural disorder. We discuss the potential of luminescence spectroscopy, complementary to Raman spectroscopy, for the quantitative estimation of chemical (and potentially also radiation-induced) disorder. For the latter, emissions of Nd3+-related centres are found to be promising candidates. 相似文献
6.
Vratislav Blecha Tomáš Fischer Petr Tábořík Jan Vilhem Radek Klanica Jan Valenta Petra Štěpančíková 《Studia Geophysica et Geodaetica》2018,62(4):660-680
The western part of the Bohemian Massif hosts an intersection of two regional fault zones, the SW-NE trending Oh?e/Eger Graben and the NNW-SSE trending Mariánské Lázně Fault, which has been reactivated several times in the geological history and controlled the formation of the Tertiary Cheb Basin. The broader area of the Cheb Basin is also related to permanent seismic activity of ML 3+ earthquake swarms. The Eastern Marginal Fault of the Cheb Basin (northern segment of the Mariánské Lázně Fault) separates the basin sediments and underlying granites in the SW from the Kru?né Hory/Erzgebirge Mts. crystalline unit in the NE. We describe a detailed geophysical survey targeted to locating the Eastern Marginal Fault and determining its geometry in the depth. The survey was conducted at the Kopanina site near the Nový Kostel focal zone, which shows the strongest seismic activity of the whole Western Bohemia earthquake swarm region. Complex geophysical survey included gravimetry, electrical resistivity tomography, audiomagnetotellurics and seismic refraction. We found that the rocks within the Eastern Marginal Fault show low resistivity, low seismic velocity and density, which indicates their deep fracturing, weathering and higher water content. The dip of the fault in shallow depths is about 60° towards SW. At greater depths, the slope turns to subvertical with dip angle of about 80°. Results of geoelectrical methods show blocky fabric of the Cheb Basin and deep weathering of the granite bedrock, which is consistent with geologic models based on borehole surveys. 相似文献
7.
Spectroscopic and bond-topological investigation of interstitial volatiles in beryl from Slovakia 总被引：1，自引：0，他引：1
Jana Fridrichová Peter Bačík Valéria Bizovská Eugen Libowitzky Radek Škoda Pavel Uher Daniel Ozdín Martin Števko 《Physics and Chemistry of Minerals》2016,43(6):419-437
Nine beryl samples from Western Carpathians, Slovakia, were investigated by infrared and Raman spectroscopy and differential thermal analysis. Two types of water H2O I and H2O II were detected. Infrared spectroscopy proved the presence of water type I and II in the presence of alkali cations with several bands: (1) symmetric stretching vibration—ν1; (2) antisymmetric stretching mode—ν3; (3) bending vibration—ν2. The presence of singly and doubly coordinated type II water (IIs and IId) was confirmed by single-crystal IR spectroscopy. From Raman spectra a band at 3606 cm?1 was assigned to ν1 of water type I and the range of 3597–3600 cm?1 to water type II. The presence of doubly coordinating water indicates a relatively highly hydrated environment with the presence of alkali ions including Na as the dominant cation coordinated by H2O II. CO2 bands were detected only by single-crystal IR spectroscopy. Thermal analysis proved total water loss in the range of 1.4–2.0 wt% and three main dehydration events. Based on the study of bond-topological arrangements two molecules of H2O IId are each bound with two H···O1 bonds and one Na–OW bond with an angular distortion, and by releasing one H2O molecule more stable H2O IIs is produced. The H2O I molecule is bound only by two equivalent hydrogen bonds. The H2O IIs molecule with a Na–OW bond strength of 0.28 vu and two H···O1 bonds of 0.14 vu without any forced angular distortion is the most stable of all. 相似文献
8.
Ond?ej?BábekEmail author Radek?Mikulá? Jan?Zapletal Tomá??Lehotsky 《International Journal of Earth Sciences》2004,93(2):241-261
The Lower Carboniferous Moravian–Silesian Culm Basin (MSCB) represents the easternmost part of the Rhenohercynian system of collision-related, deep-water foreland basins (Culm facies). The Upper Viséan Moravice Formation (MF) of the MSCB shows a distinct cyclic stratigraphic arrangement. Two major asymmetric megacycles bounded by basal sequence boundary, each about 500 to 900 m thick, have been revealed. The megacycles start with 50- to 250-m-thick, basal segments of erosive channels: overbank successions and slope apron deposits interpreted as lowstand turbidite systems. Up-section they pass into hundred metre-thick, fine-grained, low-efficiency turbidite systems. Palaeocurrent data show two prominent directions, basin axis-parallel, SSW–NNE directions, which are abundant in the whole MF, and basin axis-perpendicular to oblique, W–E to NW–SE directions, which tend to be confined to the basal parts of the megacycles or channel-lobe transition systems in their upper parts. Based on the facies characteristics, palaeocurrent data, sandstone composition data and trace-fossil distribution data, we suggest a combined tectonics–sediment supply-driven model for the MF basin fill. Periods of increased tectonic activity resulted in slope oversteepening probably combined with increased rate of lateral W–E sediment supply into the basin, producing the basal sequence boundary and the subsequent lowstand turbidite systems. During subsequent periods of tectonic quiescence, the system was filled mainly from a distant southern point source, producing the thick, low efficiency turbidite systems. Consistently with the previous models, our own sediment composition data indicate a progressively increasing sediment input from high-grade metamorphic and magmatic sources up-section, most probably related to an uplift in the source area and progressive unroofing of its structurally deeper crustal parts. The first occurrence of the Cruziana–Nereites ichnofacies in sand-rich turbidite systems in the youngest parts of the MF (Goel to Gospi Zone), supported by rapidly increasing quartz concentrations in sandstones, is thought to indicate a transition from generally underfilled to generally overfilled phase in evolution of the MSCB basin. This transition may be linked to the onset of Upper Viséan phase of northward basin-fill progradation assumed by previous authors. 相似文献
9.
Marcela Stárková Karel Martínek Radek Mikuláš Nicholas Rosenau 《International Journal of Earth Sciences》2015,104(5):1277-1298
10.
Mineralogy and Petrology - Hafnium contents and Zr/Hf ratios were studied in zircons and their parent rocks from three magmatic suites associated with the Teplice caldera, Eastern Erzgebirge:... 相似文献