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91.
Erik Swietlicki Jingchuan Zhou David S. Covert Kaarle Hämeri Bernhard Busch Minna Väkeva Ulrike Dusek Olle H. Berg Alfred Wiedensohler Pasi Aalto Jyrki Mäkelä Bengt G. Martinsson Giorgos Papaspiropoulos Besim Mentes Göran Frank Frank Stratmann 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):201-227
92.
Halogens in water from the crystalline basement of the Gotthard rail base tunnel (central Alps) 总被引:3,自引:0,他引:3
Ulrike Seelig 《Geochimica et cosmochimica acta》2010,74(9):2581-2595
Drilling of the new Gotthard rail base tunnel (central Alps) opened a large number of water-conducting fractures in granite and gneiss of the crystalline basement. The overburden reaches locally more than 2000 m and water and rock temperature is up to 45 °C. The tunnel crosses a series of steeply dipping fractured rock units that also crop out at the surface above the tunnel. Recharge water enters the fractured rocks in the high mountainous area, migrates gravity driven to the sampling locality in the tunnel. Along its flow path it reacts with rocks exposed on the fractures where it dissolves the principal granite minerals, resulting in high-pH Na2CO3 waters.The tunnel waters contain unusually high concentrations of fluoride ranging from 5 to 29 mg/L. Alteration of F-bearing biotite to F-free chlorite is one of the sources of fluorine. The highest F-concentrations result from the equilibration of low-Ca waters with fluorite. Fluoride concentration is strongly lithology-dependent and sharp discontinuities in both, concentration and saturation state with respect to fluorite occur at the contacts of the different gneiss and granite slabs.Chloride concentrations vary between 1 and 1300 mg/L. In contrast, the Cl/Br mass ratio exhibits small variations and centers around 110 suggesting a common source for the Cl and Br, which is independent of the lithology. In the northern part of the tunnel, Cl and Br are chiefly derived from saline pore fluids of one lithology which is then mixed with low-salinity water along flow paths. Cl/Br ratios of the waters in the southern part of the tunnel section are similar to those measured in experimental leachates from different tunnel rocks, suggesting that leaching of metamorphic fluids in the pore space is the main source of both Cl and Br. 相似文献
93.
Ulrike Kienel Peter Dulski Florian Ott Sebastian Lorenz Achim Brauer 《Journal of Paleolimnology》2013,50(4):535-544
The recent sediments of two lakes in the NE German lowland became seasonally laminated at different times. Anoxic bottom conditions resulted from a surplus of organic matter (OM), in the early stage indicated by irregularly laminated sediments comprising abundant iron-sulfide framboids. Their diagenetic formation predates the preservation of biochemical calcite varves. In the larger, deeper Lake Tiefer See near Klocksin, anoxia developed stepwise. A first anoxic pulse was contemporary with inflow narrowing by railway-dam construction and accumulation of OM. It was favored by a decrease of the intensity of lake circulation (turnover). Nutrients introduced from artificial fertilizer then increased the primary production (diatoms) to the point of OM surplus and seasonal laminae formation started 40 years later in 1924. In the smaller, shallower Lake Tiefer See in the Uckermark, a massive pulse of iron sulfide was centered around 1960, seven years after installation of piped field drainage into the lake. Anoxia developed rapidly with the nutrients drained from a fertilized groundwater catchment that is 10 times larger than the surface catchment, while surface erosion was reduced. Reducing bottom conditions became regular and the seasonal lamination was preserved after 1967. Morphological criteria to screen lakes for varved sediments should include reductions of natural lake inflow and catchment increase, such as by inflow of field drainage. Similar developments of increased nutrient input or intensity decrease of lake circulation may result from historical human activities but also from natural processes. 相似文献
94.
Anita Peter Hendrik Lamert Matthias Beyer G?tz Hornbruch Ben Heinrich Alexandra Schulz Helmut Geistlinger Ben Schreiber Peter Dietrich Ulrike Werban Carsten Vogt Hans-Hermann Richnow Jochen Gro?mann Andreas Dahmke 《Environmental Earth Sciences》2012,67(2):335-349
A small scale and temporally limited CO2 injection test was performed in a shallow aquifer to investigate the geochemical impact of CO2 upon such aquifers and to apply and verify different monitoring methods. Detailed site investigation coupled with multiphase simulations were necessary to design the injection experiment and to set up the monitoring network, before CO2 was injected over a ten-day period at three injection wells, at a depth of 18?m below surface level into a quaternary sand aquifer located close to the town of Wittstock in Northeast Germany. Monitoring methods comprised groundwater sampling and standard analyses, as well as trace element analyses and isotope analyses; geoelectrical borehole monitoring; passive samplers to analyse temporally integrated for cations and multi-parameter probes that can measure continuously for dissolved CO2, pH and electrical conductivity. Due to CO2 injection, total inorganic carbon concentrations increased and pH decreased down to a level of 5.1. Associated reactions comprised the release of major cations and trace elements. Geoelectrical monitoring, as well as isotope analyses and multi-parameter probes proved to be suitable methods for monitoring injected CO2 and/or the alteration of groundwater. 相似文献
95.
Michael Wiedenbeck Roxana Bugoi M. John M. Duke Tibor Dunai Jacinta Enzweiler Mary Horan Klaus Peter Jochum Kathryn Linge Jan Košler Silke Merchel Luiz F.G. Morales Lutz Nasdala Roland Stalder Paul Sylvester Ulrike Weis Arnaud Zoubir 《Geostandards and Geoanalytical Research》2012,36(4):337-398
Advances in the chemical and isotopic characterisation of geological and environmental materials can often be ascribed to technological improvements in analytical hardware. Equally, the creation of novel methods of data acquisition and interpretation, including access to better reference materials, can also be crucial components enabling important breakthroughs. This biennial review highlights key advances in either instrumentation or data acquisition and treatment, which have appeared since January 2010. This review is based on the assessments by scientists prominent in each of the given analytical fields; it is not intended as an exhaustive summary, but rather provides insight from experts of the most significant advances and trends in their given field of expertise. In contrast to earlier reviews, this presentation has been formulated into a unified work, providing a single source covering a broad spectrum of geoanalytical techniques. Additionally, some themes that were not previously emphasised, in particular thermal ionisation mass spectrometry, accelerator‐based methods and vibrational spectroscopy, are also presented in detail. 相似文献
96.
97.
Crystal structure data are presented for seven synthetic samples of disordered zirconium-titanate solid solution (Zr,Ti)O2, ranging in composition from x Ti=0.43 to 0.67, thus covering compounds such as ZrTiO4, Zr5Ti7O24, and ZrTi2O6 (srilankite). The compounds, synthesized at high temperatures and various pressures in their respective stability fields, are well crystallized and of homogeneous composition. The resulting structure data are less scattered compared to previous studies that were based on compounds synthesized metastably at low temperatures and room pressure. The compounds have the structure of scrutinyite (α-PbO2) with space group Pbcn, Z=4, unit cell parameters a=4.8495(3) Å, b=5.4635(3) Å, c=5.0462(3) Å at x Ti=0.425 to a=4.7112(2) Å, b=5.4944(1) Å, c=4.9962(1) Å at x Ti=0.666. The first structure refinement of pure, synthetic srilankite is presented, which is in good agreement with that of the natural counterpart. Structural trends observed in disordered zirconium-titanate solid solution along the binary join ZrO2–TiO2 are relatively smooth and continuous, except for rapid lengthening of an unshared octahedral edge which is anomalously short in scrutinyite-structure TiO2. The shortness of this edge may explain the observed instability of this structure with the relatively small Ti as the dominant cation. With increasing Zr content, the average cation position moves off-centre inside the octahedron, away from two shared edges, which permits the 12 closest cation–cation distances in the structure to become more equal. The shortening of the b dimension with increasing amount of the larger cation Zr decreases the distance between octahedral Zr and two additional oxygens in an adjacent chain of edge-sharing octahedra, implying that the Zr environment is evolving towards eightfold coordination. If the two additional oxygens are considered as part of the Zr coordination polyhedron, the bonding topology of tetragonal zirconia is obtained. The compositional evolution of the cell parameters, Zr atomic coordinates and Zr coordination environment is consistent with the idea that the structure is evolving towards that of tetragonal ZrO2. Group-theoretical relationships between scrutinyite, tetragonal zirconia, baddeleyite and fluorite structures show that the sequence of structures fluorite > tetragonal zirconia > scrutinyite > baddeleyite are all related by potentially diffusionless phase transitions driven by wavelike displacements of the oxygen substructure. The scrutinyite and tetragonal structures can act outside their stability fields as “transition states” between the structures on either side. 相似文献
98.
In order to contribute to a reliable, easy-to-handle and economically viable erosion risk assessment of contaminated riverine sites, the present study aims to implement master-variables best characterising the sediment stability. Thus, a wide range of sediment properties was related to the critical shear stress for mass erosion, determined in the SETEG (Stroemungskanal zur Ermittlung der tiefenabhaengigen Erosionsstabilitaet von Gewaessersedimenten) pressurised channel, with special emphasis on vertical and temporal gradients in the Lauffen reservoir on the River Neckar. Over the course of 1 year, positive impacts of some macrofauna species and benthic diatoms on the sediment stability were detected for the sediment surface (0.5 cm). However, a high seasonal variability of biological parameters caused varying relations with erosion resistance in the upper sediment layers as shown for the colloidal carbohydrates. Considering only deeper sediment layers (5–35 cm), a more general pattern could be revealed with correlations between the critical shear stress and single sediment properties such as depth, grain size, total organic carbon (TOC), cation exchange coefficient (CEC), carbohydrates and proteins. Firstly, the influence of physico-chemical and biological properties on erosion resistance became evident, even over depths at 0–35 cm. Secondly, inter-particle forces are most important for erosion resistance. These are enhanced in fine-grained sediment layers, offering high binding capacities but also strengthened by polymeric substances permeating the void space and coating particles. These covariance patterns of sedimentological and biological parameters are addressed by multivariate statistical tests (principal component analysis), resulting in a higher magnitude of the correlation coefficient between critical shear stress and the master-variables in main component II (polymeric substances, grain size, TOC, CEC; R=0.77) compared to single correlations. 相似文献
99.
Calorimetric and experimental data on AlF-bearing titanite are presented that yield thermodynamic properties of CaAlFSiO4, as well as activity-composition relations of binary titanite CaTiOSiO4-CaAlFSiO4. The heat capacity of synthetic CaAlFSiO4 was measured with differential scanning calorimetry between 170 and 850 K: CP=689.96-0.38647T+2911300T-2-8356.1T-0.5+0.00016179T2 Based on low-temperature heat capacity calculations with lattice vibrational theory (Debye model), the calorimetric entropy of CaAlFSiO4 can be expected to lie between 104.7 and 118.1 J mol-1 K-1. The temperature of the P21/a to A2/a phase change was determined calorimetrically for a titanite with XAl=0.09 (Ttransition=390 K). The decrease of the transition temperature at a rate of about 11 K per mol% CaAlFSiO4 is in good agreement with previous TEM investigations. The displacement of the reaction anorthite + fluorite = CaAlFSiO4 in the presence of CaTiOSiO4 was studied with high P-T experiments. Titanite behaves as a non-ideal, symmetrical solid-solution. The thermodynamic properties of CaAlFSiO4 consistent with a multi-site mixing model are: % MathType!MTEF!2!1!+- % feaaeaart1ev0aaatCvAUfKttLearuavTnhis1MBaeXatLxBI9gBam % XvP5wqSXMqHnxAJn0BKvguHDwzZbqegm0B1jxALjhiov2Daebbnrfi % fHhDYfgasaacH8srps0lbbf9q8WrFfeuY-Hhbbf9v8qqaqFr0xc9pk % 0xbba9q8WqFfea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9 % Fve9Ff0dmeaabaqaciaacaGaaeqabaWaaeaaeaaakeaafaqaaiWaca % aabaGaeeyrauKaeeOBa4MaeeiDaqNaeeiAaGMaeeyyaeMaeeiBaWMa % eeiCaaNaeeyEaKNaeeiiaaIaee4Ba8MaeeOzayMaeeiiaaIaeeOzay % Maee4Ba8MaeeOCaiNaeeyBa0MaeeyyaeMaeeiDaqNaeeyAaKMaee4B % a8MaeeOBa4MaeeiiaaIaeeikaGIaeeyzauMaeeiBaWMaeeyzauMaee % yBa0MaeeyzauMaeeOBa4MaeeiDaqNaee4CamNaeeykaKIaeeiiaaIa % emizaq2aaSbaaSqaaiabdAgaMbqabaGccqWGibasdaahaaWcbeqaai % abicdaWaaaaOqaaiabg2da9iabgkHiTiabikdaYiabiEda3iabisda % 0iabicdaWiabc6caUiabiIda4iabgglaXkabiodaZiabc6caUiabic % daWiabbccaGiabbUgaRjabbQeakjabb2gaTjabb+gaVjabbYgaSnaa % CaaaleqabaGaeyOeI0IaeGymaedaaaGcbaGaee4uamLaeeiDaqNaee % yyaeMaeeOBa4MaeeizaqMaeeyyaeMaeeOCaiNaeeizaqMaeeiiaaIa % ee4CamNaeeiDaqNaeeyyaeMaeeiDaqNaeeyzauMaeeiiaaIaeeyzau % MaeeOBa4MaeeiDaqNaeeOCaiNaee4Ba8MaeeiCaaNaeeyEaKNaeeii % aaIaee4uam1aaWbaaSqabeaacqqGWaamaaaakeaacqqG9aqpcqqGXa % qmcqqGWaamcqqG0aancqqGUaGlcqqG5aqocqGHXcqScqqGXaqmcqqG % UaGlcqqGXaqmcqqGGaaicqqGkbGscqqGTbqBcqqGVbWBcqqGSbaBda % ahaaWcbeqaaiabgkHiTiabigdaXaaakiabbUealnaaCaaaleqabaGa % eyOeI0IaeGymaedaaaGcbaGaeeyta0KaeeyyaeMaeeOCaiNaee4zaC % MaeeyDauNaeeiBaWMaeeyzauMaee4CamNaeeiiaaIaeeiCaaNaeeyy % aeMaeeOCaiNaeeyyaeMaeeyBa0MaeeyzauMaeeiDaqNaeeyzauMaee % OCaiNaeeiiaaYaamWaaeaacqWGxbWvdaWgaaWcbaGaemisaG0aaWba % aWqabeaacqGHsislaaaaleqaaOGaeeivaqLaem4vaC1aaSbaaSqaai % abdohaZbqabaaakiaawUfacaGLDbaaaeaacqGH9aqpcqaIXaqmcqaI % ZaWmcqGGUaGlcqaI2aGncqGHXcqScqaIWaamcqGGUaGlcqaI0aanca % aMe8UaeeOsaOKaeeyBa0Maee4Ba8MaeeiBaW2aaWbaaSqabeaacqGH % sislcqaIXaqmaaaaaaaa!E403!