68 results on '"Simon, Klaus"'
Search Results
2. Zum ältesten Erzbergbau in Ostthüringen und Sachsen
- Author
-
Simon, Klaus
- Published
- 2022
- Full Text
- View/download PDF
3. Montanarchäologie in Europa
- Author
-
Steuer, Heiko, Zimmermann, Ulrich, Bachmann, Hans-Gert, Craddock, Paul T., Pingel, Volker, Nothdurfter, Hans, Eibner, Clemens, Simon, Klaus, Keesmann, Ingo, Wahl, Jürgen, Gechter, Michael, Wegener, Wolfgang, Brockner, Wolfgang, Klappauf, Lothar, Zotz, Thomas, Goldenberg, Gert, Hoppe, Andreas, Foellmer, Ansgar, Noeltner, Thomas, Hildebrandt, Ludwig H., Fluck, Pierre, Klein, Sabine, Urban, Hans, Stephan, Hans-Georg, König, Andreas, Bollingberg, Haldis Johanne, Rehren, Thilo, Lietz, Egon, Hauptmann, Andreas, Deutmann, Karl Heinrich, Lobbedey, Uwe, Schwabenicky, Wolfgang, Lindner, Harald, Käppler, Rolf, Dallmann, Wolfgang, Gühne, Arndt, Strienitz, Rolf, Ullrich, Bernd, Szydlowski, Jerzy, Molenda, Danuta, Labuda, Jozef, Waldhauser, Jiří, Daněček, Vladimír, Nováček, Karel, Kudrnáč, Jaroslav, Michálek, Jan, Bogosavljević, Dragan, Vuković, Sofija, Tasser, Rudolf, Francovich, Riccardo, Bailly-Maître, Marie-Christine, Ploquin, Alain, Sperl, Gerhard, Magnusson, Gert, Gassmann, Guntram, Kempa, Martin, Jockenhövel, Albrecht, Willms, Christoph, Pott, Richard, and Speier, Martin
- Published
- 2022
- Full Text
- View/download PDF
4. kleiner Prinz
- Author
-
Bertram, Marion, Melisch, Claudia M., Dodt, Michael, Friedrich, Ronny, Geppert, Maria, Gröcke, Darren R., Hartmann, Sonngard, Kronz, Andreas, Montgomery, Janet, Nagy, Marion, Nowell, Geoff, Powers, Natasha, Rath, Kristin, Rothe, Jessica, and Simon, Klaus
- Abstract
Acta Praehistorica et Archaeologica, Bd. 50 (2018)
- Published
- 2021
- Full Text
- View/download PDF
5. High-resolution stalagmite stratigraphy supports the Late Holocene tephrochronology of southernmost Patagonia
- Author
-
Klaes, Björn, Wörner, Gerhard, Kremer, Katrina, Simon, Klaus, Scholz, Denis, Mueller, Carsten, Hoschen, Carmen, Struck, Julian, Arz, Helge, Thiele-Bruhn, Sören, Schimpf, Daniel, and Kilian, Rolf
- Published
- 2021
6. Ein 'Siebheber' der älteren Eisenzeit von Golzen, Kr. Nebra
- Author
-
Simon, Klaus
- Abstract
Jahresschrift für mitteldeutsche Vorgeschichte, Bd. 65 (1982): Jahresschrift für Mitteldeutsche Vorgeschichte
- Published
- 2018
- Full Text
- View/download PDF
7. Zur Datierung des säulenförmigen Briquetages im Saalegebiet
- Author
-
Simon, Klaus
- Abstract
Jahresschrift für mitteldeutsche Vorgeschichte, Bd. 68 (1985): Jahresschrift für Mitteldeutsche Vorgeschichte
- Published
- 2018
- Full Text
- View/download PDF
8. Geochemical evolution of Bolshaya Udina, Malaya Udina, and Gorny Zub volcanoes, Klyuchevskaya Group (Kamchatka)
- Author
-
Churikova Tatiana, Gordeychik Boris, Wörner Gerhard, Flerov Gleb, Hartmann Gerald, and Simon Klaus
- Subjects
38.37.25 Вулканология ,Зимины - Abstract
The Klyuchevskaya group of volcanoes (KGV) located in the northern part of Kamchatka has the highest magma production rate for any arc worldwide and several of its volcanoes have been studied in considerable detail [e.g. Kersting & Arculus, 1995; Pineau et al., 1999; Dorendorf et al., 2000; Ozerov, 2000; Churikova et al., 2001, 2012, 2015; Mironov et al., 2001; Portnyagin et al., 2007, 2015; Turner et al., 2007]. However, some volcanoes of the KGV including Late-Pleistocene volcanoes Bolshaya Udina, Malaya Udina, Ostraya Zimina, Ovalnaya Zimina, and Gorny Zub were studied only on a reconnaissance basis [Timerbaeva, 1967; Ermakov, 1977] and the modern geochemical studies have not been carried out at all. Among the volcanoes of KGV these volcanoes are closest to the arc trench and may hold information on geochemical zonation with respect to across arc source variations. We present the first major and trace element data on rocks from these volcanoes as well as on their basement. All rocks are medium-calc-alkaline basaltic andesites to dacites except few low-Mg basalts from Malaya Udina volcano. Phenocrysts are mainly olivine, pyroxene, plagioclase and magnetite, Hb-bearing andesites and dacites are rarely found only in subvolcanic intrusions at Bolshaya Udina volcano. Lavas are geochemically similar to the active Bezymianny volcano, however, individual variations for each volcano exist in both major and trace elements. Trace element geochemistry is typical of island arc volcanism. Compared to KGV lavas all studied rocks form very narrow trends in all major element diagrams, which almost do not overlap with the fields of other KGV volcanoes. The lavas are relatively poor in alkalis, TiO2, P2O5, FeO, Ni, Zr, and enriched in SiO2 compared to other KGV volcanics and show greater geochemical and petrological evidence of magmatic differentiation during shallow crustal processing. Basement samples of the Udinskoe plateau lavas to the east of Bolshaya Udina volcano have similar geochemical composition (trace element enriched high-K basaltic andesites and andesites) and similar eruption age of 274 ka [Calkins et al., 2004] as typical plateau lavas below the northern KGV. This research was supported by RFBR-DFG grant # 16-55-12040.
- Published
- 2017
9. Isotope and REE Characterization of Groundwater Aquifers within the Aquifer Storage and Recovery Programme in Sukhothai (N.-Thailand)
- Author
-
Hengsuwan, Manussawee, Yongprawat, Monthon, Simon, Klaus, and Hansen, Bent T.
- Subjects
Sr-Isotope ,Rare Earth Elements (REE) ,Aquifer Storage and Recovery (ASR) ,Thailand - Abstract
Aquifer Storage and Recovery (ASR) was a pilot project for solving flood and drought problem in the northern part of Chao Phraya River basin, Thailand. This part of Thailand always faces flooding in rainy season and drought during dry season every year. The overexploitation of groundwater during dry season leads to continuously decline of water level in this area. In this project, the excessive surface water during rainy season was stored by injection of this treated surface water through recharge wells into the underground aquifers. This would serve to raise the water level, which can be extracted for use during the dry season. To assess the efficiency of the ASR process some tracers are required. The aim of this study is to prove the suitability of natural tracers to follow up the artificial recharge process; emphasis will be placed on Strontium (Sr) isotopic composition. The results showed that the change in 87Sr/86Sr ratios could be observed during an artificial recharge due to the different isotopic fingerprint of surface water and groundwater. However, the flow direction of the injected water cannot be clearly interpreted because of the limited number of monitoring wells, small distance between each monitoring well and the short duration of injection., Open-Access-Publikationsfonds 2016
- Published
- 2016
10. Bewegungstherapie in der Rehabilitation nach Knie- oder Hüft-TEP-Implantation
- Author
-
Simon Klaus Hendrich
- Abstract
In der Rehabilitation nach Knie- oder Hufttotalendoprothese (TEP) stellen bewegungstherapeutische Interventionen den zentralen Inhalt dar. Die entsprechende Evidenz ist allerdings luckenhaft, und es mangelt an tragfahigen Aussagen uber Dosis-Wirkungs-Beziehungen, wodurch der Einfluss der Bewegungstherapie auf den Rehabilitationsverlauf unklar bleibt. Dies wirft, auch angesichts der hohen und voraussichtlich weiter ansteigenden Fallzahlen sowie der bestehenden Resourcenknappheit im Gesundheitssystem, die Frage nach der Legitimitat fur die umfangreiche bewegungstherapeutische Leistungserbringung in der Rehabilitation nach Knieoder Huft-TEP auf.
- Published
- 2016
11. Prediction of Monochrome Reflectance Spectra with an Extended Kubelka-Munk Model
- Author
-
Mourad, Safer, Emmel, Patrick, Simon, Klaus, and Hersch, Roger David
- Subjects
Photographic equipment ,Printers (computer) ,Error analysis ,Density (optical) ,Light scattering ,Color Reproduction - Abstract
We present a prediction model for digital printers and more specifically for electrophotographic devices. On the one hand, we propose an electrophotographic simulation model which estimates the microscopic structure of any printed toner layer based on its input halftone bitmap. Applying BOUGUER-BEER-LAMBERT's law, the obtained spatial toner arrangement yields the spectral transmittance distribution for non-light scattering colors. On the other hand, we introduce an extension to the KUBELKA-MUNK (KM) model, which allows to compute the halftone reflectance spectra from the estimated transmittance spectra. The extended KM model bridges the gap between the mathematical description of the optical point spread function of common office papers and the experimental results of simple reflectance measurements. With the combination of the models, we are capable of predicting the reflectance spectra of a printed monochrome wedge with a mean estimation error of less than CIELAB ΔE*94 = 1.
- Published
- 2002
12. New data on trace element composition of feldspar from Morasko meteorite
- Author
-
Moszumanska, Izabela, Slaby, Ewa, Wirth, Richard, Lukasz Karwowski, Muszynski, Andrzej, Simon, Klaus, and Majzner, Katarzyna
- Published
- 2014
- Full Text
- View/download PDF
13. [Untitled]
- Author
-
Heim, Christine, Quéric, Nadia-Valérie, Ionescu, Danny, Thiel, Volker, and Simon, Klaus
- Subjects
Palaeontology ,FOS: Biological sciences ,Zoology - Abstract
Frank Wiese, Mike Reich and Gernot Arp (Eds.) “Spongy, slimy, cosy & more ; 99-112
- Published
- 2014
- Full Text
- View/download PDF
14. Extending Kubelka-Munk's Theory with Lateral Light Scattering
- Author
-
Mourad, Safer, Emmel, Patrick, Simon, Klaus, and Hersch, Roger David
- Subjects
Light reflection ,Differential equations ,Photons ,Boundary conditions ,Transfer functions ,Approximation theory ,Refractive index ,Printing ,Light scattering ,Ink ,Color Reproduction ,Fluorescence - Abstract
Due to its simplicity, the theory of KUBELKA-MUNK [1] has found a wide acceptance for modeling the optical properties of light scattering materials. However, the concept is not explicitly adapted to predict halftone prints on paper. In this respect, a recent improvement was given by BERG. Our approach is an extension of BERG'S model in order to reduce the gap between the mathematical description of the paper's point spread function and the experimental results of simple reflectance measurements.
- Published
- 2001
15. Obesity in children upon school entry in North Rhine-Westphalia, Germany
- Author
-
Simon, Klaus, Rosenkoetter, N., International Health, and RS: CAPHRI School for Public Health and Primary Care
- Subjects
Public health reporting ,School-entry screening ,Indicators ,Obesity ,Child and adolescent health - Abstract
To monitor time trends of obesity in children, data from the school-entry screening programs (SEU) are widely used. By using data from the SEU in North Rhine-Westphalia (NRW), Germany, from 1996 to 2008, it was investigated, if age distribution is changing over time and if changes influence the overall proportion of obese children in NRW. In addition, the time trend of obesity in three age groups of children before school entry is shown. Children who were examined during SEU are becoming younger (1996: 75.3 months; 2008: 71.3 months, on average). The observed stagnation of obesity in NRW in recent years also persists when the influence of different age patterns are taken into account. Younger children are less obese than older ones. A sustained increase in the proportion of younger children during SEU might influence the overall proportion of obese children in the future. Thus, it should be discussed which procedures should be used to increase the quality of the indicator that is used for public health reporting and is generated by data from SEU.
- Published
- 2010
16. Programmieren für Mathematiker und Naturwissenschaftler
- Author
-
Simon Klaus
- Published
- 2000
17. Using blocks for constraint satisfaction
- Author
-
Seybold, Bernhard, Metzger, Felix, Ogan, Gül, and Simon, Klaus
- Subjects
Data processing, computer science ,PROGRAMS AND ALGORITHMS FOR THE SOLUTION OF SPECIAL PROBLEMS ,CONSTRAINT SATISFACTION ALGORITHMEN (GRAPHENTHEORIE) ,PROGRAMME UND ALGORITHMEN ZUR LÖSUNG SPEZIELLER PROBLEME ,CONSTRAINT SATISFACTION ALGORITHMS (GRAPH THEORY) ,ddc:004 - Abstract
Technical report, 297
- Published
- 1998
18. On the P₄-components of graphs
- Author
-
Raschle, Thomas and Simon, Klaus
- Subjects
Data processing, computer science ,GRAPHENALGORITHMEN + GEOMETRISCHE ALGORITHMEN (GRAPHENTHEORIE) ,GRAPH ALGORITHMS + GEOMETRIC ALGORITHMS (GRAPH THEORY) ,PROGRAMS AND ALGORITHMS FOR THE SOLUTION OF SPECIAL PROBLEMS ,PROGRAMME UND ALGORITHMEN ZUR LÖSUNG SPEZIELLER PROBLEME ,ddc:004 - Abstract
Technical Report / ETH Zurich, Department of Computer Science, 261
- Published
- 1997
19. Markov processes involving q-Stirling numbers
- Author
-
Crippa, Davide, Simon, Klaus, and Trunz, Paul
- Subjects
MARKOV DECISION PROCESSES (OPERATIONS RESEARCH) ,MARKOV-ENTSCHEIDUNGSPROZESSE (OPERATIONS RESEARCH) ,Markov processes ,SPECIAL PROGRAMMING METHODS ,SPEZIELLE PROGRAMMIERMETHODEN ,q-Stirling numbers ,Approximate counting ,Random graphs ,Data processing, computer science ,FOS: Mathematics ,ddc:004 ,ddc:510 ,Mathematics - Abstract
ETH, Eidgenössische Technische Hochschule Zürich, Departement Informatik, Institut für Theoretische Informatik, 224
- Published
- 1994
20. DETEXTIVE optical character recognition with pattern matching on-the-fly.
- Author
-
Caluori, Ursina and Simon, Klaus
- Subjects
- *
OPTICAL character recognition , *PATTERN matching , *COMPUTER vision , *DIGITIZATION , *GLYPHS (Graphic methods) , *COMPUTER software , *PROTOTYPES - Abstract
In this paper we present a new OCR-concept designed for the requirements of historic prints in the context of mass-digitizations. The core part is the glyph recognition, based on pattern matching with patterns that are derived from computer font glyphs and are generated on-the-fly. The classification of a sample is organized as a search process for the most similar glyph pattern. This results in consistently good hit rates for arbitrary fonts without any training. In particular, we investigate the performance of our prototype in comparison to popular commercially available OCR-software. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
21. On transitive orientation
- Author
-
Trunz, Paul and Simon, Klaus
- Subjects
UNGERICHTETE GRAPHEN (GRAPHENTHEORIE) ,UNDIRECTED GRAPHS (GRAPH THEORY) ,Undirected graphs ,FOS: Mathematics ,ddc:510 ,Mathematics - Abstract
ETH, Eidgenössische Technische Hochschule Zürich, Departement Informatik, Institut für Theoretische Informatik, 171
- Published
- 1991
22. Stabile Isotope (O, H, C) an Gesteinen und Mineralen der KTB-Vorbohrung
- Author
-
Simon, Klaus, Hoefs, Jochen, Grimmeisen, Wolfgang, and Hoernes, Stefan
- Subjects
Earth sciences and geology ,Earth Science - Abstract
Die Geowissenschaften
- Published
- 1990
- Full Text
- View/download PDF
23. DATA ON 61 CHEMICAL ELEMENTS FOR THE CHARACTERIZATION OF THREE MAJOR GLASS COMPOSITIONS IN LATE ANTIQUITY AND THE MIDDLE AGES.
- Author
-
WEDEPOHL, KARL HANS, SIMON, KLAUS, and KRONZ, ANDREAS
- Subjects
- *
GLASS , *CHEMICAL elements , *STANDARD deviations , *INDUCTIVELY coupled plasma mass spectrometry , *ANALYSIS of variance , *RARE earth metals , *OXIDE minerals , *HEAVY minerals , *MIDDLE Ages - Abstract
Sets of 20 soda ash, 16 soda lime and 23 wood ash glasses mainly from excavations in Europe were analysed by microprobe and LA-ICP-MS for 61 elements and are presented as average concentrations with standard deviations. Concentrations of sodium, potassium and magnesium allow the major glass type to be identified. Specific compositions of the raw materials of glass production indicate certain sources, technical processes and ages. Heavy minerals etc. of quartz sands contain rare earth elements (REE) from crustal fractionations that are different for the three major glass types. Accumulations of P, B, Ba, Mn and K in wood from soils by organic processes can characterize glass from certain regions. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
24. Retaining Local Image Information in Gamut Mapping Algorithms.
- Author
-
Zolliker, Peter and Simon, Klaus
- Subjects
- *
IMAGE processing , *ALGORITHMS , *PIXELS , *DIGITAL images , *IMAGING systems - Abstract
Our topic is the potential of combining global gamut mapping with spatial methods to retain the percepted local image information in gamut mapping algorithms. The main goal is to recover the original local contrast between neighboring pixels in addition to the usual optimization of preserving lightness, saturation, and global contrast. Special emphasis is placed on avoiding artifacts introduced by the gamut mapping algorithm itself. We present an unsharp masking technique based on an edge-preserving smoothing algorithm allowing to avoid halo artifacts. The good performance of the presented approach is verified by a psycho-visual experiment using newspaper printing as a representative of a small destination gamut application. Furthermore, the improved mapping properties are documented with local mapping histograms. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
25. Finding a minimal transitive reduction in a strongly connected digraph within linear time
- Author
-
Simon, Klaus
- Subjects
GRAPH ALGORITHMS + GEOMETRIC ALGORITHMS (GRAPH THEORY) ,GERICHTETE GRAPHEN (GRAPHENTHEORIE) ,Programs and algorithms for the solution of special problems ,Data processing, computer science ,GRAPHENALGORITHMEN + GEOMETRISCHE ALGORITHMEN (GRAPHENTHEORIE) ,DIRECTED GRAPHS (GRAPH THEORY) ,FOS: Mathematics ,Directed graphs ,PROGRAMS AND ALGORITHMS FOR THE SOLUTION OF SPECIAL PROBLEMS ,Graph algorithms ,PROGRAMME UND ALGORITHMEN ZUR LÖSUNG SPEZIELLER PROBLEME ,ddc:004 ,ddc:510 ,Mathematics - Abstract
ETH, Eidgenössische Technische Hochschule Zürich, Departement Informatik, Institut für Theoretische Informatik, 103
- Published
- 1989
26. Chemical characteristics (REE, etc.) of Paleozoic and Mesozoic graywackes and sandstones from Central Europe
- Author
-
Wedepohl, Karl Hans and Simon, Klaus
- Subjects
13. Climate action - Abstract
During the Variscan orogeny in Central Europe, partial melting in the lower continental crust formed granitic magmas, which intruded into the upper crust and left compounds of Ca (plus Eu2+), Mg, etc. in the lower crust. From the late Paleozoic decomposition of the tonalitic upper crust, sedimentary graywackes were produced reflecting the composition of this crust. The repeated reworking of the sedimentary cover caused the formation of sands. Sandstones as their products of consolidation contain increasing fractions of quartz and decreasing feldspar from Carboniferous and Triassic to Cretaceous age. A distinct negative Eu anomaly characterizes the majority of these rocks. The latter is imprinted by the Variscan magmatism. Quartz as used for numerous Medieval wood ash glasses is marked for its Central European origin by a distinct negative Eu anomaly in contrast to many soda glasses produced outside Germany mostly with a small or none Eu anomaly.
27. Fluid/rock interaction and mass transfer in continental subduction zones: constraints from trace elements and isotopes (Li, B, O, Sr, Nd, Pb) in UHP rocks from the Chinese Continental Scientific Drilling Program, Sulu, East China
- Author
-
Xiao, Yilin, Hoefs, Jochen, Hou, Zhenhui, Simon, Klaus, and Zhang, Zeming
- Subjects
13. Climate action - Abstract
In order to better understand the role of fluids during subduction and subsequent exhumation, we have investigated whole-rock and mineral chemistry (major and trace elements) and Li, B as well as O, Sr, Nd, Pb isotopes on selected continuous drill-core profiles through contrasting lithological boundaries from the Chinese Continental Scientific Drilling Program (CCSD) in Sulu, China. Four carefully selected sample sets have been chosen to investigate geochemical changes as a result of fluid mobilization during dehydration, peak metamorphism, and exhumation of deeply subducted continental crust. Our data reveal that while O and Sr-Nd-Pb isotopic compositions remain more or less unchanged, significant Li and/or B isotope fractionations occur between different lithologies that are in close contact during various metamorphic stages. Samples that are supposed to represent prograde dehydration as indicated by veins formed at high pressures (HP) are characterized by element patterns of highly fluid-mobile elements in the veins that are complementary to those of the host eclogite. A second sample set represents a UHP metamorphic crustal eclogite that is separated from a garnet peridotite by a thin transitional interface. Garnet peridotite and eclogite are characterized by a >10% difference in MgO, which, together with the presence of abundant hydroxyl-bearing minerals and compositionally different clinopyroxene grains demonstrate that both rocks have been derived from different sources that have been tectonically juxtaposed during subduction, and that hydrous silicate-rich fluids have been added from the subducting slab to the mantle. Two additional sample sets, comprising retrograde amphibolite and relatively fresh eclogite, demonstrate that besides external fluids, internal fluids can be responsible for the formation of amphibolite. Li and B concentrations and isotopic compositions point to losses and isotopic fractionation during progressive dehydration. On the other hand, fluids with isotopically heavier Li and B are added during retrogression. On a small scale, mantle-derived rocks may be significantly metasomatized by fluids derived from the subducted slab. Our study indicates that during high-grade metamorphism, Li and B may show different patterns of enrichment and of isotopic fractionation.
28. Effects of sample storage and shell orientation on LA-ICPMS trace element measurements on deep-sea mussels
- Author
-
Génio, Luciana, Simon, Klaus, Kiel, Steffen, and Cunha, Marina R.
- Subjects
14. Life underwater - Abstract
Geochemical markers are being increasingly applied to fundamental questions in population and community ecology in marine habitats because they allow inferences on individuals dispersal, but vital effects, small sample size and instrumental limitation are still challenging particularly in deep-sea studies. Here we use shells of the deep-sea bivalve Idas modiolaeformis to assess potential effects of sample storage, mineralogy, and valve orientation on LA-ICPMS measurements. Trace element concentrations of (24)Mg, (43)Ca, (88)Sr, (137)Ba, (208)Pb, and (238)U are not affected by the two most commonly used storage methods of biologic deep-sea samples (frozen at -20°C and fixed in 95% ethanol); thus combined analysis of differently preserved specimens is possible when the number of individuals is insufficient and distinct sample fixation is needed for multiple purposes. Valve orientation had a strong impact on quantification of trace elements in the calcitic but not in the aragonitic layer of adult shells. Hence, to enable comparisons between adult shells and entirely aragonitic embryonic shells, a reference map of site-specific signatures can potentially be generated using the aragonitic layer of the adult shells. Understanding ontogenetic changes and environmental effects in trace element incorporation is critical before geochemical fingerprinting can be used as a tool for larval dispersal studies in the deep-sea.
29. Trachyte weathering in the urban built environment related to air quality
- Author
-
Germinario, Luigi, Siegesmund, Siegfried, Maritan, Lara, Simon, Klaus, and Mazzoli, Claudio
- Subjects
13. Climate action ,11. Sustainability - Abstract
Decay of trachyte used as building stone in urban environment was investigated through the analysis of crusts and patinas found on trachyte of the Euganean Hills in the Renaissance city walls of Padua, northeastern Italy. Mineralogical and microstructural characteristics of the alteration products, as well as major- and trace-element chemical composition, were determined by optical microscopy, SEM–EDS and X-ray mapping, XRPD, and LA-ICPMS. The results are discussed referring to environmental parameters, in particular concerning air quality and anthropic pollution sources. The influence of composition of the stone and other neighboring materials on specific weathering processes is also debated. The formation of crusts and patinas turns out to be mainly due to exogenous processes. Enrichment in heavy metals and carbonaceous matter derives from the deposition of particulate emitted during fuel combustion by road vehicles, domestic heating and, secondarily, industrial activities. The particulate is typically cemented by calcite, mainly mobilized after dissolution from nearby mortar joints, or iron, released by leaching from iron-bearing minerals, reprecipitated according to pH fluctuations. Gypsum layers were rarely observed. Generally, composition of the weathering crusts and patinas of Euganean trachyte proves to be an informative marker for the relevant environmental conditions and their evolution.
30. Isotope and REE Characterization of Groundwater Aquifers within the Aquifer Storage and Recovery Programme in Sukhothai (N.-Thailand)
- Author
-
Hengsuwan, Manussawee, Yongprawat, Monthon, Simon, Klaus, and Hansen, Bent T.
- Subjects
13. Climate action ,6. Clean water - Abstract
Aquifer Storage and Recovery (ASR) was a pilot project for solving flood and drought problem in the northern part of Chao Phraya River basin, Thailand. This part of Thailand always faces flooding in rainy season and drought during dry season every year. The overexploitation of groundwater during dry season leads to continuously decline of water level in this area. In this project, the excessive surface water during rainy season was stored by injection of this treated surface water through recharge wells into the underground aquifers. This would serve to raise the water level, which can be extracted for use during the dry season. To assess the efficiency of the ASR process some tracers are required. The aim of this study is to prove the suitability of natural tracers to follow up the artificial recharge process; emphasis will be placed on Strontium (Sr) isotopic composition. The results showed that the change in 87Sr/86Sr ratios could be observed during an artificial recharge due to the different isotopic fingerprint of surface water and groundwater. However, the flow direction of the injected water cannot be clearly interpreted because of the limited number of monitoring wells, small distance between each monitoring well and the short duration of injection., Open-Access-Publikationsfonds 2016
31. Assessing the utility of trace and rare earth elements as biosignatures in microbial iron oxyhydroxides
- Author
-
Heim, Christine, Simon, Klaus, Ionescu, Danny, Reimer, Andreas, De Beer, Dirk, Quéric, Nadia-Valérie, Reitner, Joachim, and Thiel, Volker
- Subjects
13. Climate action ,6. Clean water - Abstract
Microbial iron oxyhydroxides are common deposits in natural waters, recent sediments, and mine drainage systems. Along with these minerals, trace and rare earth elements (TREE) are being accumulated within the mineralizing microbial mats. TREE patterns are widely used to characterize minerals and rocks, and to elucidate their evolution and origin. However, whether and which characteristic TREE signatures distinguish between a biological and an abiological origin of iron minerals is still not well-understood. Here we report on long-term flow reactor studies performed in the Tunnel of Äspö (Äspö Hard Rock Laboratory, Sweden). The development of microbial mats dominated by iron-oxidizing bacteria (FeOB), namely Mariprofundus sp. and Gallionella sp were investigated. The feeder fluids of the flow reactors were tapped at 183 and 290 m below sea-level from two brackish, but chemically different aquifers within the surrounding, ~1.8 Ga old, granodioritic rocks. The experiments investigated the accumulation and fractionation of TREE under controlled conditions of the subsurface continental biosphere, and enabled us to assess potential biosignatures evolving within the microbial iron oxyhydroxides. After 2 and 9 months, concentrations of Be, Y, Zn, Zr, Hf, W, Th, Pb, and U in the microbial mats were 103- to 105-fold higher than in the feeder fluids whereas the rare earth elements and Y (REE+Y) contents were 104- and 106-fold enriched. Except for a hydrothermally induced Eu anomaly, the normalized REE+Y patterns of the microbial iron oxyhydroxides were very similar to published REE+Y distributions of Archaean Banded Iron Formations (BIFs). The microbial iron oxyhydroxides from the flow reactors were compared to iron oxyhydroxides that were artificially precipitated from the same feeder fluid. Remarkably, these abiotic and inorganic iron oxyhydroxides show the same REE+Y distribution patterns. Our results indicate that the REE+Y mirror closely the water chemistry, but they do not allow to distinguish microbially mediated from inorganic iron precipitates. Likewise, all TREE studied showed an overall similar fractionation behavior in biogenic, abiotic, and inorganic iron oxyhydroxides. Exceptions are Ni and Tl, which were only accumulated in the microbial iron oxyhydroxides and may point to a potential utility of these elements as microbial biosignatures.
32. The Erbisberg drilling 2011: Implications for the structure and postimpact evolution of the inner ring of the Ries impact crater.
- Author
-
Arp, Gernot, Reimer, Andreas, Simon, Klaus, Sturm, Sebastian, Wilk, Jakob, Kruppa, Corina, Hecht, Lutz, Hansen, Bent T., Pohl, Jean, Reimold, Wolf Uwe, Kenkmann, Thomas, and Jung, Dietmar
- Subjects
- *
IMPACT craters , *CRYSTALLINE rocks , *HYDROTHERMAL alteration , *PETROLOGY , *LAKE sediments , *MOLTEN glass - Abstract
The 26 km diameter Nördlinger Ries is a complex impact structure with a ring structure that resembles a peak ring. A first research drilling through this "inner crystalline ring" of the Ries was performed at the Erbisberg hill (SW Ries) to better understand the internal structure and lithology of this feature, and possibly reveal impact‐induced hydrothermal alteration. The drill core intersected the slope of a 22 m thick postimpact travertine mound, before entering 42 m of blocks and breccias of crystalline rocks excavated from the Variscan basement at >500 m depth. Weakly shocked gneiss blocks that show that shock pressure did not exceed 5 GPa occur above polymict lithic breccias of shock stage Ia (10–20 GPa), with planar fractures and planar deformation features (PDFs) in quartz. Only a narrow zone at 49.20–50.00 m core depth exhibits strong mosaicism in feldspar and {101¯2} PDFs in quartz, which are indicative of shock stage Ib (20–35 GPa). Finally, 2 m of brecciated Keuper sediments at the base of the section point to an inverse layering of strata. While reverse grading of clast sizes in lithic breccias and gneiss blocks is consistent with lateral transport, the absence of diaplectic glass and melt products argues against dynamic overthrusting of material from a collapsing central peak, as seen in the much larger Chicxulub structure. Indeed, weakly shocked gneiss blocks are rather of local provenance (i.e., the transient crater wall), whereas moderately shocked polymict lithic breccias with geochemical composition and 87Sr/86Sr signature similar to Ries suevite were derived from a position closer to the impact center. Thus, the inner ring of the Ries is formed by moderately shocked polymict lithic breccias likely injected into the transient crater wall during the excavation stage and weakly shocked gneiss blocks of the collapsing transient crater wall that were emplaced during the modification stage. While the presence of an overturned flap is not evident from the Erbisberg drilling, a survey of all drillings at or near the inner ring point to inverted strata throughout its outer limb. Whether the central ring of the Ries represents remains of a collapsed central peak remains to be shown. Postimpact hydrothermal alteration along the Erbisberg section comprises chloritization, sulfide veinlets, and strong carbonatization. In addition, a narrow zone in the lower parts of the polymict lithic breccia sequence shows a positive Eu anomaly in its carbonate phase. The surface expression of this hydrothermal activity, i.e., the travertine mound, comprises subaerial as well as subaquatic growth phases. Intercalated lake sediments equivalent to the early parts of the evolution of the central crater basin succession confirm a persistent impact‐generated hydrothermal activity, although for less time than previously suggested. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
33. Effects of sample storage and shell orientation on LA-ICPMS trace element measurements on deep-sea mussels.
- Author
-
Génio, Luciana, Simon, Klaus, Kiel, Steffen, and Cunha, Marina R.
- Published
- 2015
- Full Text
- View/download PDF
34. Long-term Investigation of Sr- Isotope and Rare Earth Element Fractionation Processes Within Three Major Aquifers in the Äspö Hard Rock Laboratory (Sweden).
- Author
-
Hengsuwan, Manussawee, Heim, Christine, Simon, Klaus, and Hansen, Bent T.
- Subjects
- *
AQUIFERS , *RARE earth metals , *GROUNDWATER research , *ROCKS , *MARINE ecology - Abstract
The 450 m deep Äspö Hard Rock Laboratory (Äspö HRL) provides a unique opportunity to access different aquifer systems within the Precambrian granodioritic basement of the Baltic Shield. In this study, emphasis will be placed on systematic variations of the isotopic and chemical composition including fractionation patterns of rare earth elements (REE) of three different aquifers. The aim is to identify end-member groundwater compositions and increase the knowledge and understanding of the groundwater evolution, and water rock interaction, parameters which are important for the subsurface microbial activity in the Äspö HRL. Groundwaters at the shallow and intermediate aquifers were influenced most from Baltic Sea water and meteoric water. The analyses of Sr-data and REE show especially long-term groundwater-rock interaction and δ18O values indicate the presence of glacial meltwater in the deep aquifer. During the 5 years of investigation, significant chemical changes caused by internal mixing processes or present microbial activity were not observed. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
35. New evidence for persistent impact-generated hydrothermal activity in the Miocene Ries impact structure, Germany.
- Author
-
Arp, Gernot, Kolepka, Claudia, Simon, Klaus, Karius, Volker, Nolte, Nicole, and Hansen, Bent T.
- Subjects
- *
IMPACT craters , *MIOCENE Epoch , *MINERALOGY , *CARBONATES , *INCRUSTATIONS - Abstract
The extent of impact-generated hydrothermal activity in the 24 km sized Ries impact structure has been controversially discussed. To date, mineralogical and isotopic investigations point to a restriction of hydrothermal activity to the impact-melt bearing breccias, specifically the crater-fill suevite. Here, we present new petrographic, geochemical, and isotopic data of postimpact carbonate deposits, which indicate a hydrothermal activity more extended than previously assumed. Specifically, carbonates of the Erbisberg, a spring mound located upon the inner crystalline ring of the crater, show travertine facies types not seen in any of the previously investigated sublacustrine soda lake spring mounds of the Ries basin. In particular, the streamer carbonates, which result from the encrustation of microbial filaments in subaerial spring effluents between 60 and 70 °C, are characteristic of a hydrothermal origin. While much of the primary geochemical and isotopic signatures in the mound carbonates have been obliterated by diagenesis, a postimpact calcite vein from brecciated gneiss of the subsurface crater floor revealed a flat rare earth element pattern with a clear positive Eu anomaly, indicating a hydrothermal fluid convection in the crater basement. Finally, the strontium isotope stratigraphic correlation of the travertine mound with the crater basin succession suggests a hydrothermal activity for about 250,000 yr after the impact, which would be much longer than previously assumed. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
36. Catshark egg capsules from a Late Eocene deep-water methane-seep deposit in western Washington State, USA.
- Author
-
KIEL, STEFFEN, PECKMANN, JÖRN, and SIMON, KLAUS
- Subjects
- *
CHONDRICHTHYES , *SCYLIORHINIDAE , *TAPHONOMY , *COLLAGEN , *EOCENE paleontology - Abstract
Fossil catshark egg capsules, Scyliorhinotheca goederti gen. et sp. nov., are reported from a Late Eocene deep-water methane-seep calcareous deposit in westernWashington State,USA. The capsules are preserved three-dimensionally and some show mineralized remnants of the ribbed capsule wall consisting of small globular crystals that are embedded in a microsparitic matrix. The globules are calcitic, but a strontium content of 2400-3000 ppm suggests that they were originally aragonitic. The carbonate enclosing the egg capsules, and the capsule wall itself, show δ13C values as low as -36.5%, suggesting that formation was induced by the anaerobic oxidation of methane and hence in an anoxic environment. We put forward the following scenario for the meralization of the capsule wall: (i) the collagenous capsules experienced a sudden change fromoxic to anoxic conditions favouring an increase of alkalinity; (ii) this led to the precipitation of aragonitic globules within the collagenous capsule wall; (iii) subsequently the remaining capsule wall was mineralized by calcite or aragonite; (iv) finally the aragonitic parts of the wall recrystallized to calcite. The unusual globular habit of the early carbonate precipitates apparently represents a taphonomic feature, resulting from mineralization mediated by an organic matrix. Taphonomic processes, however, are at best contributed to an increase of alkalinity, which was mostly driven by methane oxidation at the ancient seep site. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
37. Declining prevalence rates for overweight and obesity in German children starting school.
- Author
-
Moss, Anja, Klenk, Jochen, Simon, Klaus, Thaiss, Heidrun, Reinehr, Thomas, and Wabitsch, Martin
- Subjects
- *
OVERWEIGHT children , *CHILDHOOD obesity , *JUVENILE diseases , *PEDIATRIC research - Abstract
To estimate the development of prevalence rates for overweight and obesity in children starting school in Germany, data for children's height and weight out of the compulsory school enrolment examinations (SEE), conducted annually in every German federal state, were available. A former analysis of these data showed a marked increase of prevalence of overweight and obesity until 2004. The aim of this project was to give an updated overview on the development of prevalence rates for overweight and obesity in children upon school entry by including recent data until 2008. Data on measured height and weight from the yearly conducted SEE were obtained from all 16 German federal states. Overweight and obesity were defined by BMI > 90th and BMI > 97th age- and gender-related percentiles of German reference values, respectively. In 2008, the prevalence for overweight varied from 8.4% in Saxony to 11.9% in Bremen and Thuringia. The current prevalence rates for obesity ranged from 3.3% in Brandenburg and Saxony till 5.4% in Saarland. The current data from SEE by the majority of the individual states showed that the prevalence for both overweight and obesity did not increase any more after 2004 and is even declining in some states compared to the former data inquiry. Absolute decrease of prevalence rates was up to 3% for overweight and 1.8% for obesity. Conclusion: The current data from the SEE of individual German states are based on census and showed by the majority that the prevalence of overweight and obese children starting school did not increase anymore and even declined in the last 4 years, respectively. It is supposed that the measures for prevention initiated in the 1990s and implemented afterwards have contributed to this positive development in Germany. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
38. Image-Dependent Gamut Mapping as Optimization Problem.
- Author
-
Giesen, Joachim, Schuberth, Eva, Simon, Klaus, Zolliker, Peter, and Zweifel, Oliver
- Subjects
- *
MATHEMATICAL mappings , *COLOR , *CARTOGRAPHY , *ALGORITHMS , *MATHEMATICAL optimization , *COMPUTER graphics , *COLOR in cartography , *IMAGE processing , *MATHEMATICAL analysis - Abstract
We explore the potential of image-dependent gamut mapping as a constrained optimization problem. The performance of our new approach is compared to standard reference gamut mapping algorithms in psycho-visual tests. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
39. Birth Processes and Symmetric Polynomials.
- Author
-
Bickel, Thomas, Galli, Nicola, and Simon, Klaus
- Subjects
- *
POLYNOMIALS , *DISCRETE-time systems , *RANDOM variables - Abstract
Investigates the functions of symmetric polynomials. Computation of discrete time equation; Discussion on state dependent random variables; Presentation of theorems and proofs.
- Published
- 2001
- Full Text
- View/download PDF
40. q-SERIES ARISING FROM THE STUDY OF RANDOM GRAPHS.
- Author
-
Andrews, George E., Crippa, Davide, and Simon, Klaus
- Subjects
- *
RANDOM graphs , *GRAPH theory , *DIRECTED graphs , *POLYNOMIALS , *DISTRIBUTION (Probability theory) , *PROBABILITY theory - Abstract
This paper deals with q-series arising from the study of the transitive closure problem in random acyclic digraphs. In particular, it presents an identity involving divisor generating functions which allows us to determine the asymptotic behavior of polynomials defined by a general class of recursive equations, including the polynomials for the mean and the variance of the size of the transitive closure in random acyclic digraphs. [ABSTRACT FROM AUTHOR]
- Published
- 1997
- Full Text
- View/download PDF
41. Evidence of Batrachochytrium dendrobatidis and other amphibian parasites in the Green toad (Bufotes viridis), syntopic amphibians and environment in the Cologne Bay, Germany.
- Author
-
SACHS, MARIA, SCHLUCKEBIER, RIEKE, POLL, KATINKA, SCHULZ, VANESSA, SABINO-PINTO, JOANA, SCHMIDT, ELMAR, SIMON, KLAUS, KÜNZEL, SVEN, ZIEGLER, THOMAS, ARNDT, HARTMUT, and VENCES, MIGUEL
- Subjects
- *
BATRACHOCHYTRIUM dendrobatidis , *OOMYCETES , *AMPHIBIANS , *AMPHIBIAN declines , *TOADS , *PARASITES , *ENVIRONMENTAL sampling - Abstract
Chytridiomycosis, a disease induced by the chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), has strongly contributed to the ongoing worldwide amphibian conservation crisis. While Bd infection has caused amphibian declines for decades on several continents, Bsal is a novel threat to Central European salamanders and newts, being responsible for the collapse of Fire Salamander populations in the Netherlands, Belgium, and Germany. However, numerous other parasites causing harm to amphibians exist, yet have received much less attention than the chytrid fungi. The goal of the present study was to contribute to the understanding of declines of the Green Toad, Bufotes viridis, at its northwestern distribution border, in the area of Cologne, Germany. We combined the data from four years of Bd monitoring with a metabarcoding approach to detect other, mainly unicellular parasites, from amphibian feces and environmental samples, and also report results from Bsal testing in 2019. Skin swabs of approximately 280 amphibians were tested for Bd and 66 for Bsal, and 150 cloacal swabs and environmental samples from five sites were tested for other pathogens and parasites.We found Bd in all sampled locations with high prevalences and partly high individual infection loads but without clinical signs of chytridiomycosis. None of the samples tested for Bsal was positive for this pathogen. We further detected eight additional potential amphibian pathogens from fecal samples: three metamonads (Tritrichomonas augusta, Trichomitus batrachorum and Hexamita inflata), three ciliates (Balantidium duodeni, Nyctotherus cordiformis and N. hubeiensis), one stramenopile (Blastocystis sp.) and one metazoan (the nematode Rhabdias ranae). In the environmental samples, we detected OTUs of nine organisms potentially harmful for amphibians: Blastocystis sp., Hexamita inflata, Tritrichomonas augusta, Trichomitus batrachorum, two oomycetes (Leptolegnia sp., Saprolegnia sp.), two ichthyosporeans (Amphibiocystidium ranae, Anurofeca sp.) and the myxozoan Myxobolus sp. [ABSTRACT FROM AUTHOR]
- Published
- 2020
42. The Preparation and Preliminary Characterisation of Three Synthetic Andesite Reference Glass Materials (ARM‐1, ARM‐2, ARM‐3) for In Situ Microanalysis.
- Author
-
Wu, Shitou, Wörner, Gerhard, Jochum, Klaus Peter, Stoll, Brigitte, Simon, Klaus, and Kronz, Andreas
- Subjects
- *
GLASS , *REFERENCE sources , *ANDESITE , *REFERENCE values , *TRACE elements , *NICKEL-chromium alloys - Abstract
Three synthetic reference glasses were prepared by directly fusing and stirring 3.8 kg of high‐purity oxide powders to provide reference materials for microanalytical work. These glasses have andesitic major compositions and are doped with fifty‐four trace elements in nearly identical abundance (500, 50, 5 µg g−1) using oxide powders or element solutions, and are named ARM‐1, 2 and 3, respectively. We further document that sector‐field (SF) ICP‐MS (Element 2 or Element XR) is capable of sweeping seventy‐seven isotopes (from 7Li to 238U, a total of sixty‐eight elements) in 1 s and, thus, is able to quantify up to sixty‐eight elements by laser sampling. Micro‐ and bulk analyses indicate that the glasses are homogeneous with respect to major and trace elements. This paper provides preliminary data for the ARM glasses using a variety of analytical techniques (EPMA, XRF, ICP‐OES, ICP‐MS, LA‐Q‐ICP‐MS and LA‐SF‐ICP‐MS) performed in ten laboratories. Discrepancies in the data of V, Cr, Ni and Tl exist, mainly caused by analytical limitations. Preliminary reference and information values for fifty‐six elements were calculated with uncertainties [2 relative standard error (RSE)] estimated in the range of 1–20%. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
43. Development of new microsatellite markers for the Green Toad, Bufotes viridis, to assess population structure at its northwestern range boundary in Germany.
- Author
-
VENCES, MIGUEL, PERL, R. G. BINA, GIESEN, KATINKA, SCHLUCKEBIER, RIEKE, SIMON, KLAUS, SCHMIDT, ELMAR, STEINFARTZ, SEBASTIAN, and ZIEGLER, THOMAS
- Subjects
- *
MICROSATELLITE repeats , *TOADS , *MITOCHONDRIAL DNA , *NUCLEOTIDE sequence , *WILDLIFE conservation - Abstract
The Green Toad (Bufotes viridis) in Germany is mostly confined to secondary habitats and is experiencing severe population declines especially at its northwestern range boundary in the city of Cologne. As a basis for conservation management of this species, viz. to investigate the status of the population structure, we used a library of over 15,000 short tandem repeats to establish a new set of 12 microsatellite markers for this species. We applied these markers to B. viridis individuals from six sampling sites in Cologne, and included outgroup samples from sites in northern and central Germany. The results suggest the sampled Cologne toads form four distinct populations, without an obvious distinction between sites east and west of the river Rhine. Only the green toads of three neighbouring sampling sites clustered as one population, supporting the initial hypothesis that individuals from proximate sampling sites are genetically more similar than those from more isolated sampling sites. However, mitochondrial DNA sequences revealed a haplotype east of the Rhine that was absent west of the river. Toads from the northernmost sampled population in Cologne "Ginsterpfad" were not genetically depauperate, indicating that the severe declines at this site did not lead to a loss of genetic variation and were not related to inbreeding. Some Ginsterpfad individuals were genetically highly distinct from others, which may be explained by human introduction. Despite the encountered population structure, the low number of private alleles in the populations west of the Rhine, and the uniformity in mitochondrial haplotypes with the exception of one deviant allele east of the Rhine, lead us to recommend a pragmatic approach for conservation management. We suggest to consider all Cologne Green toads as belonging to a single management unit, but propose that, wherever possible, populations east and west of the Rhine should not be mixed in reintroduction measures. [ABSTRACT FROM AUTHOR]
- Published
- 2019
44. Comparison of Ultrafine Powder Pellet and Flux‐free Fusion Glass for Bulk Analysis of Granitoids by Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry.
- Author
-
Wu, Shitou, Karius, Volker, Schmidt, Burkhard C., Simon, Klaus, and Wörner, Gerhard
- Subjects
- *
LASER ablation , *INDUCTIVELY coupled plasma mass spectrometry , *SILICA , *NICKEL , *COPPER - Abstract
Two sample preparation techniques (ultrafine powder pellet and flux‐free fusion glass) for LA‐ICP‐MS bulk analysis of granitoids were compared. Ultrafine powder particles produced by wet milling were characterised as d50: ~ 1.0 μm, d90: ~ 5.0 μm. Agate abrasion (balls and vial) during wet milling affects only SiO2 measurements and is negligible for other elements. For the flux‐free fusion glass, a second grinding of the initial fused glass and re‐melting were necessary to produce compositionally homogeneous glasses. Nickel and Cu can be contaminated during the fusion procedure, and Sn and Pb were depleted after the melting process. The homogeneity of fusion glasses was comparable to that of MPI‐DING glasses, while the powder pellets were less homogeneous. This heterogeneity is ascribed to large (up to 10 μm) crystal fragments (e.g., biotite) persisting in powders even after 45 min of milling. For most elements of interest, both preparation techniques give reliable LA‐ICP‐MS results of granitoid reference materials within 10% of the reference values. Thus, we can recommend both techniques to avoid common problems associated with acid dissolution ICP‐MS. For high‐precision measurements (especially Zr, Hf, Th and U), the flux‐free fusion glass technique is a better choice than ultrafine powder pellets. Key Points: Ultrafine powder particles produced by wet milling were characterised as d50 ∼1.0 μm, d90 ∼5.0 μm. For the flux‐free fusion glass, a second grinding of the initial fused glass and re‐melting was necessary to produce compositionally homogeneous glasses. Homogeneity of fusion glasses was comparable to that of MPI‐DING glasses, while the powder pellets were less homogeneous. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
45. The hydrothermal Waterberg platinum deposit, Mookgophong (Naboomspruit), South Africa. Part II: Quartz chemistry, fluid inclusions and geochronology.
- Author
-
van den Kerkhof, Alfons M., Sosa, Graciela M., Oberthür, Thomas, Melcher, Frank, Fusswinkel, Tobias, Kronz, Andreas, Simon, Klaus, and Dunkl, István
- Subjects
- *
QUARTZ , *LASER ablation inductively coupled plasma mass spectrometry , *FLUID inclusions , *RADIOACTIVE dating - Abstract
The historic Waterberg platinum deposit, ~15 km WNW of Mookgophong (formerly Naboomspruit), Limpopo Province, South Africa, is a rare fault-bound hydrothermal vein-type quartz-hematite-platinum-group mineralization. As a continuation of the geochemistry and ore mineralogy studies (Part I, Oberthür et al. , 2018), this paper concentrates on the ore-bearing quartz and on the age constraints of ore formation. The state-of-the-art methods used include cathodoluminescence microscopy, electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of trace elements, stable isotope (δ18O) analysis and fluid-inclusion studies. U-Pb and (U-Th)/He radiometric age determination gave ages of 900–1075 Ma suggesting platinum-group element (PGE) mineralization as a result of upwelling fluids with connection to the Bushveld complex during Kibaran tectonic movements along the Thabazimbi–Murchison Lineament. Felsic fragments containing Qtz-1 were cemented by different quartz generations (Qtz-2 to Qtz-4) and enable the characterization of the changing physicochemical parameters during multistage mineralization and cooling. The PGE minerals are associated with the earliest hydrothermal stage represented by botryoidal radial-fibrous quartz aggregates (Qtz-2a) which formed on brecciated felsite. The other quartz types are essentially barren. Cathodoluminescence studies of quartz indicate very high Al, Fe and K concentrations as confirmed by EPMA and LA-ICP-MS, whereas Ti is always very low. The varying Al concentrations in the quartz mainly indicate pH fluctuations, the high Fe3+ points at high oxygen fugacity. Micro-inclusions of iron oxide are associated with Pt ore (Fe, Pt, Pd, Au, W, Sb, As), rutile, kaolinite and muscovite. The hydrothermal activity must have been characterized by low saline (<10 wt%) H2O–NaCl solutions. These fluids mixed with original high-saline NaCl ± CaCl2 ± CO2 brines in the brecciated felsite (Qtz-1). According to the quartz-hematite geothermometer the ore depositional temperatures were ~370–330°C (Qtz-2a), whereas the successive quartz veins formed during cooling towards ~295°C. The transport of PGE must have been facilitated by strongly oxidizing chloride complexes of relatively low salinity and moderate acidity. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
46. Halogen chemistry and hydrogen isotopes of apatite from the >3.7 Ga Isua supracrustal belt, SW Greenland.
- Author
-
Wudarska, Alicja, Wiedenbeck, Michael, Słaby, Ewa, Lepland, Aivo, Birski, Łukasz, and Simon, Klaus
- Subjects
- *
APATITE , *HALOGENS , *HYDROGEN isotopes , *GEOCHEMISTRY - Abstract
The origin and evolution of volatiles, particularly water, in the abiotic early Earth environment have been intensively studied, and this is a topic of high relevance when considering the timing and conditions of life’s emergence. Investigation of hydrogen isotopes in the oldest crystals of minerals from the apatite group Ca 10 (PO 4 ) 6 (F,Cl,OH) 2 should bring new insight to this topic as the D/H ratio of apatite has proved useful for establishing the evolution of volatiles in other solar system bodies. Apatite crystals from metasedimentary and metavolcanic rocks collected from a low-strain domain of the Eoarchean Isua supracrustal belt have been investigated for their D/H signatures using secondary ion mass spectrometry and for major and trace element abundances using EPMA and laser ablation ICP-MS. Apatite crystals from Isua have a broad range in volatile compositions, both within samples from the same lithology (e.g., banded iron formation; BIF) and between different lithologies (BIF, metacarbonate, mafic dyke). Most of the crystals are chlorine-rich, which is in contrast to typical modern sedimentary apatite that is predominantly carbonate fluorapatite. We have used the REE distribution patterns from Isua apatite to distinguish those crystals having sedimentary, metasomatic and magmatic origins. The D/H ratios for all samples were determined to be very low with δD VSMOW values falling within the range from −93 to −56‰. δD values of Isua apatite do not correlate with REE signatures of crystals nor could we relate δD to the host lithologies. We conclude that this geochemical system has been reset during long and multi-phase geologic history, making it difficult, if not impossible, to use hydrogen isotopes for assessment of the primary signatures of the Archean hydrosphere. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. Trachyte weathering in the urban built environment related to air quality.
- Author
-
Germinario, Luigi, Siegesmund, Siegfried, Maritan, Lara, Simon, Klaus, and Mazzoli, Claudio
- Subjects
- *
TRACHYTE , *WEATHERING , *AIR quality - Abstract
Decay of trachyte used as building stone in urban environment was investigated through the analysis of crusts and patinas found on trachyte of the Euganean Hills in the Renaissance city walls of Padua, northeastern Italy. Mineralogical and microstructural characteristics of the alteration products, as well as major- and trace-element chemical composition, were determined by optical microscopy, SEM-EDS and X-ray mapping, XRPD, and LA-ICPMS. The results are discussed referring to environmental parameters, in particular concerning air quality and anthropic pollution sources. The influence of composition of the stone and other neighboring materials on specific weathering processes is also debated. The formation of crusts and patinas turns out to be mainly due to exogenous processes. Enrichment in heavy metals and carbonaceous matter derives from the deposition of particulate emitted during fuel combustion by road vehicles, domestic heating and, secondarily, industrial activities. The particulate is typically cemented by calcite, mainly mobilized after dissolution from nearby mortar joints, or iron, released by leaching from iron-bearing minerals, reprecipitated according to pH fluctuations. Gypsum layers were rarely observed. Generally, composition of the weathering crusts and patinas of Euganean trachyte proves to be an informative marker for the relevant environmental conditions and their evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
48. Feldspar megacrysts from the Santa Angélica composite pluton — Formation/transformation path revealed by combined CL, Raman and LA-ICP-MS data.
- Author
-
Słaby, Ewa, Gros, Katarzyna, Moszumańska, Izabela, De Campos, Cristina P., Majzner, Katarzyna, Simon, Klaus, and Jokubauskas, Petras
- Subjects
- *
IGNEOUS intrusions , *FELDSPAR , *GEOCHEMISTRY , *CRYSTALLIZATION , *MORPHOLOGY - Abstract
The studied feldspar megacrysts from the Santa Angélica hybrid rock unit feature complex growth morphologies and geochemical compositions. Early crystallization formed zoned K–Na alkali-feldspar and unzoned oligoclase–andesine. The chemical composition of the zoned alkali-feldspar reflects crystallization in contact with different magma batches, and the chemical composition of the plagioclase indicates growth from a homogeneous magma. Further feldspar development produced mineral chemistry and growth morphology patterns (in both alkali feldspar and plagioclase) that indicate a multi-stage process caused by the combination of chaotic mixing and replenishment. Alkali feldspar and plagioclase megacrysts show dissolution and regrowth textures. Their compositional fields are not separated. Different crystallized and recrystallized domains pass smoothly from one to another. A multiple reequilibration process limited the ordering of the feldspar domain structure. A younger generation of feldspar strongly enriched in K and Na grew over the dissolved margins of the alkali feldspar and plagioclase megacrysts, filling all embayments. Some domains of the alkali feldspar megacrysts recrystallized, resulting in a K- and Ba-rich composition. The trace element patterns of these domains define relatively consistent trends, which may indicate a new stage of equilibrium. In turn, the trace element patterns of previously crystallized and recrystallized domains are irregular, pointing to blurring of the original compositional relationship. Some voids in the megacrysts, formed due to dissolution, are cemented with quartz. The sequential early to late crystallization, recrystallization, and alteration processes are clearly revealed by Polytopic Vector Analysis (PVA). This analysis shows the changes in the alkali-feldspar and plagioclase compositions in two different directions: an initial shift from megacryst crystallization environment towards alkali-rich magma and a second shift towards silica-rich magma. The recognition of the whole sequence of the processes is possible due to the preserved relics of each phase in different feldspar domains. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
49. The soda lake-mesosaline halite lake transition in the Ries impact crater basin (drilling Löpsingen 2012, Miocene, southern Germany).
- Author
-
Arp, Gernot, Hansen, Bent, Pack, Andreas, Reimer, Andreas, Schmidt, Burkhard, Simon, Klaus, and Jung, Dietmar
- Subjects
- *
SALT , *LAKE hydrology , *SUPERIMPOSED coding - Abstract
Lacustrine sediments of impact craters form valuable climate archives, although chemical evolution and changes in the catchment area potentially superimpose, distort, or obliterate primary climate signals. The 15 Ma Nördlinger Ries in southern Germany, one of the most intensively studied terrestrial impact structures, harbors a well-preserved but controversially interpreted lacustrine sedimentary fill. While earlier studies proposed a climate-driven development from a playa to a mesosaline soda lake (Units A and B), which then decreased in salinity (Units C and D), new investigations suggest a chemical evolution from a playa and soda lake (Units A-C) to a mesosaline halite lake (Unit D), which then turned into a hypersaline halite lake, until an outlet formed. However, problems in the stratigraphic correlation of basin center and margin sediments impeded the recognition of the hypothetical soda to halite lake transition to date. A new drilling in the central crater now provides a solution for the problem. Unit C still comprises analcime-rich dolomite marl with reversely correlated δC and δO values, thereby reflecting a shallow, highly alkaline, saline meromictic lake (Na-Mg-CO-SO). In turn, Unit D is characterized by a change to cycles composed of lignite, diatomite, claystone, marl, and limestone. Gypsum pseudomorphs at the cycle tops indicate saline lake water (Na-Mg-Cl-SO) with increased Ca concentrations. Reworked, previously aragonitic, green algal tubes prove that early parts of Unit D sediments formed contemporaneously to basin margin green algal bioherms, contrary to previous assumptions. Therefore, the change from a highly alkaline soda lake to a mesosaline halite lake reflects increasing influx of waters from the Bunte Breccia into the lake, while suevite-derived weathering solutions decreased. Low-salinity conditions during Unit D are temporary phases during lake-level rise at the beginning of short-term cycles, whereas stable oxygen isotope ratios indicate meso- to hypersaline conditions at cycle tops. However, the long-term increase in salinity leading to continuous hypersaline conditions is only preserved in carbonates at the crater rim. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
50. Biosignatures of mineralizing microbial mats in a deep biosphere environment.
- Author
-
Leefmann, Tim, Heim, Christine, Simon, Klaus, Quéric, Nadia-Valérie, Hansen, Bent, Reitner, Joachim, Thiel, Volker, Lausmaa, Jukka, and Sjövall, Peter
- Subjects
- *
BIOFILMS , *BIOMINERALIZATION , *GEOCHEMISTRY , *IRON oxidation , *CHEMICAL reactors , *DIORITE , *FLUORITE , *CALCITE - Abstract
The article focuses on a study which explored subsurface biofilm and biomineral formation under controlled settings and examined the geochemistry of biosignatures in mineralized fracture fillings of Äspö Diorite host rock. Results of the study showed microbially mediated iron oxidation was an important process in all flow reactors. It also found that the fracture fillings were composed of high-temperature fluorite and low-temperature calcite phases.
- Published
- 2012
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.