Search

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]

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]

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]

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]

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]

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]

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]

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]

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]

Investigates the functions of symmetric polynomials. Computation of discrete time equation; Discussion on state dependent random variables; Presentation of theorems and proofs.

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.

Data on micromechanical properties of ancient and medieval glass fragments and glasses of early modern and today's manufacturing were compiled to offer a tentative look on changes in the brittleness of glass over the past 2000 years. Chronology of glass making was based on glass chemistry using rare earth element (REE) pattern, fluxing agents and provenance analysis while cracking and brittleness were evaluated from Vickers indentation in the course of the mean crack initiation load CR and the crack length-to-half diagonal ratio c / a . A structural analysis revealed that CR increases and c / a decreases with increasing molar volume i.e. decreasing atomic packing fraction, which allows us to classify periods of high and low crack-resistant and brittle glasses along the time line of historic glass technology. [ABSTRACT FROM AUTHOR]

Abstract: Magmatism at Andean Central Volcanic Zone (CVZ), or Central Andes, is strongly influenced by differentiation and assimilation at high pressures that occurred at lower levels of the thick continental crust. This is typically shown by high light to heavy rare earth element ratios (LREE/HREE) of the erupted lavas at this volcanic zone. Increase of these ratios with time is interpreted as a change to magma evolution in the presence of garnet during evolution of Central Andes. Such geochemical signals could be introduced into the magmas be high-pressure fractionation with garnet on the liquidus and/or assimilation from crustal rocks with a garnet-bearing residue. However, lavas erupted at San Pedro–Linzor volcanic chain show no evidence of garnet fractionation in their trace element patterns. This volcanic chain is located in the active volcanic arc, between 22°00′S and 22°30′S, over a continental crust ∼70 km thick. Sampled lavas show Sr/Y and Sm/Yb ratios <40 and <4.0, respectively, which is significantly lower than for most other lavas of recent volcanoes in the Central Andes. In addition, 87Sr/86Sr ratios from San Pedro–Linzor lava flows vary between 0.7063 and 0.7094. This is at the upper range, and even higher than those observed at other recent Central Andean volcanic rocks (<0.708). The area in which the San Pedro–Linzor volcanic chain is located is constituted by a felsic, Proterozoic upper crust, and a thin mafic lower crustal section (<25 km). Also, the NW–SE orientation of the volcanic chain is distinctive with respect to the N–S orientation of Central Andean volcanic front in northern Chile. We relate our geochemical observations to shallow crustal evolution of primitive magmas involving a high degree of assimilation of upper continental crust. We emphasize that low pressure AFC- (Assimilation Fractional Crystallization) type evolution of the San Pedro–Linzor volcanic chain reflects storage, fractionation, and contamination of mantle-derived magmas at the upper felsic crust (<40 km depth). The ascent of mantle-derived magmas to mid-crustal levels is related with the extensional regime that has existed in this zone of arc-front offset since Late-Miocene age, and the relatively thin portion of mafic lower crust observed below the volcanic chain. [Copyright &y& Elsevier]

Abstract: The Late Jurassic Jingshan granite located at the south-eastern margin of the North China Craton contains abundant garnets which can be subdivided into three types based on texture and composition: (i) euhedral garnet in mafic biotite and garnet rich enclave (Grt I), (ii) coarse-grained garnet (Grt II) in the host granite, and (iii) small euhedral garnet in aplite (Grt III). In general, Grt I has higher FeO, CaO and lower MnO contents than Grt II. Grt III has higher Mn, but lower Ca contents than others. Grt I has lower MREE and HREE contents than Grt II. Grt III has prominent and distinctly negative Eu anomaly as well as higher MREE composition compared to the others. Systematic variations in oxygen isotope compositions are observed among the three garnet types, with δ18O values of <3.8‰ in most of Grt I, 3.8–4.7‰ in most Grt II (for inclusion-free garnets), and typically >4.7‰ in Grt III. Some of the Grt II and Grt III display two distinct zonings with cores having similar major and trace element compositions to Grt I. Cathodoluminescence (CL) images revealed that the zircons from different garnet-bearing samples possess fine-scale oscillatory zoned magmatic rims with inherited cores. In situ zircon U–Pb dating and trace element analyses show that the dark-luminescent magmatic rims all have Jurassic concordia ages (∼160Ma) and similar trace element patterns. Most of the inherited cores also display similar Triassic ages of 210–236Ma, which is similar to the ages of ultrahigh pressure (UHP) metamorphic rocks of the Dabie–Sulu orogen (230Ma). In addition, Jurassic concordia ages were also found in a zircon inclusion in Grt I, implying that the Grt I was formed shortly before the main magmatic event. The age data suggest that the three different garnet types may be genetically related and modified by cogenetic magmatic events. Based on the zircon U–Pb ages from different garnet-bearing samples, the major element, trace element, oxygen isotope, and zoning textures of the three kinds of garnet we suggest that Grt I may be peritectic garnet, whereas Grt II and III are probably the results of magmatic dissolution–precipitation processes and re-equilibration of garnets with changing magmatic conditions during melting, differentiation, crystallization, and cooling within the granite. We conclude from the oxygen isotopic character of the garnets and ages of the zircons that the source rocks for the Jingshan granites are from Dabie–Sulu orogen representing the South China Craton. [Copyright &y& Elsevier]

School-entry screening data from North Rhine-Westphalia (NRW), Germany from 2007 were used to investigate child health care utilisation. We focussed on the influence of migratory background and parental education on children's (1) participation in regularly scheduled early recognition examinations, (2) immunisation uptake and (3) referrals due to a school-entry screen-detected complaint. The study sample consisted of 52,171 children out of 17 NRW districts. Bivariable, stratified and multivariable analyses were performed to identify relevant associations between social determinants and health care utilisation outcome parameters. Multivariable logistic regression showed that children belonging to families with a migratory background or low parental education were more likely to have an incomplete documentation of early recognition examinations and to be referred due to a new diagnosis. Children with migratory background were more likely to be sufficiently immunised than children with parents of German ethnicity. For all studied health care utilisation outcomes, kindergarten visit had a supportive effect. Conclusion: In general, the results of our regional study were in line with the results from national population-based studies. Additionally, a larger likelihood of referrals due to school-screen-detected deficits in children with migratory background or low parental education was detected. [ABSTRACT FROM AUTHOR]

Growth and regrowth textures, trace element and oxygen isotope compositions, and water content or species have been studied in alkali feldspars from the late Archaean Closepet igneous bodies. Feldspar crystals grew from mixed magmas that are characterized by a high degree of homogenization. The 3D depiction of trace element distribution indicates that the crystallization process was followed by interaction with fluids. The magmatic system involved in feldspar formation shows non-linear dynamics. The interaction with fluids is also deterministic, but in contrast to magmatic crystallization, it shows an increasing persistency in element behaviour. The degree of persistency of the element activities in both processes has been calculated using the Hurst exponent. The recrystallization (regrowth) process induced by fluids proceeded along crystal fractures and cleavages, causing selective enrichment in large ion lithophile elements (light rare earth elements), Pb, Y, and in various water species. It did not change the feldspar oxygen isotope signature. In turn, the incorporation of hydrogen species into feldspar domains reduced Al–O−–Al defect densities in the structure, decreasing their luminescence. Water speciation shows persistent behaviour during heating, the process being reversible at least up to 600°C. Carbonate crystals with a mantle isotope signature are associated with the re-equilibrated feldspar domains. The feldspar compositions, the abundance of water species in them and the refractory nature of the residuum after heating, the unchanged oxygen isotopes and the mantle signature of co-precipitated carbonates testify that the observed recrystallization has taken place at temperatures above 600°C with H2O–CO2 fertile, mantle-derived fluids. The paper draws special attention to some methodological aspects of the problem. The multi-method approach used here (major element, trace element and isotope geochemistry, infra-red, cathodoluminescence, 3D depiction of geochemical data and fractal statistics) may help to recognize and separate the various processes throughout the alteration history of the pluton. [ABSTRACT FROM AUTHOR]

Abstract: Stalagmites are important palaeo-climatic archives since their chemical and isotopic signatures have the potential to record high-resolution changes in temperature and precipitation over thousands of years. We present three U/Th-dated records of stalagmites (MA1–MA3) in the superhumid southern Andes, Chile (53°S). They grew simultaneously during the last five thousand years (ka BP) in a cave that developed in schist and granodiorite. Major and trace elements as well as the C and O isotope compositions of the stalagmites were analysed at high spatial and temporal resolution as proxies for palaeo-temperature and palaeo-precipitation. Calibrations are based on data from five years of monitoring the climate and hydrology inside and outside the cave and on data from 100 years of regional weather station records. Water-insoluble elements such as Y and HREE in the stalagmites indicate the amount of incorporated siliciclastic detritus. Monitoring shows that the quantity of detritus is controlled by the drip water rate once a threshold level has been exceeded. In general, drip rate variations of the stalagmites depend on the amount of rainfall. However, different drip-water pathways above each drip location gave rise to individual drip rate levels. Only one of the three stalagmites (MA1) had sufficiently high drip rates to record detrital proxies over its complete length. Carbonate-compatible element contents (e.g. U, Sr, Mg), which were measured up to sub-annual resolution, document changes in meteoric precipitation and related drip-water dilution. In addition, these soluble elements are controlled by leaching during weathering of the host rock and soils depending on the pH of acidic pore waters in the peaty soils of the cave’s catchment area. In general, higher rainfall resulted in a lower concentration of these elements and vice versa. The Mg/Ca record of stalagmite MA1 was calibrated against meteoric precipitation records for the last 100 years from two regional weather stations. Carbonate-compatible soluble elements show similar patterns in the three stalagmites with generally high values when drip rates and detrital tracers were low and vice versa. δ13C and δ18O values are highly correlated in each stalagmite suggesting a predominantly drip rate dependent kinetic control by evaporation and/or outgassing. Only C and O isotopes from stalagmite MA1 that received the highest drip rates show a good correlation between detrital proxy elements and carbonate-compatible elements. A temperature-related change in rainwater isotope values modified the MA1 record during the Little Ice Age (∼0.7–0.1 ka BP) that was ∼1.5 °C colder than today. The isotopic composition of the stalagmites MA2 and MA3 that formed at lower drip rates shows a poor correlation with stalagmite MA1 and all other chemical proxies of MA1. ‘Hendy tests’ indicate that the degassing-controlled isotope fractionation of MA2 and MA3 had already started at the cave roof, especially when drip rates were low. Changing pathways and residence times of the seepage water caused a non-climatically controlled isotope fractionation, which may be generally important in ventilated caves during phases of low drip rates. Our proxies indicate that the Neoglacial cold phases from ∼3.5 to 2.5 and from ∼0.7 to 0.1 ka BP were characterised by 30% lower precipitation compared with the Medieval Warm Period from 1.2 to 0.8 ka BP, which was extremely humid in this region. [Copyright &y& Elsevier]

The development of new improved catalysts for the selective hydrogenation of aromatic nitrogroups is still a field of high interest for the chemical industry. Hydrogenation of aromatic nitrogroups to the corresponding aromatic amines is one of the most important applications for precious metal powder catalysts (PMPC). In this paper various commercial PMPC technologies such as palladium, platinum, platinum modified with copper and platinum modified with vanadium on activated carbon powder supports were compared to each other in regard to activity and selectivity for hydrogenation of 1-chloro-2-nitrobenzene. In this reaction, catalysts comprised of vanadium modified platinum on activated carbon showed excellent activities and selectivities towards 2-chloroaniline. Catalyst performance was affected by the ratio of platinum to vanadium and the properties of the carbon. The role of vanadium as an effective modifier to avoid accumulation of hazardous aromatic hydroxylamines was explained. [ABSTRACT FROM AUTHOR]

Background: In aerodynamic levitation, solids and liquids are floated in a vertical gas stream. In combination with CO2-laser heating, containerless melting at high temperature of oxides and silicates is possible. We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments. Results: Liquid silicate droplets (∼2 mm) were maintained stable in levitation using a nozzle with a 0.8 mm bore and an opening angle of 60°. The gas flow was ∼250 ml min-1. Rock powders were melted and homogenized for microchemcial analyses. Laser melting produced chemically homogeneous glass spheres. Only highly (e.g. H2O) and moderately volatile components (Na, K) were partially lost. The composition of evaporated materials was determined by directly combining levitation and inductively coupled plasma mass spectrometry. It is shown that the evaporated material is composed of Na > K ⪢ Si. Levitation of metal oxide-rich material in a mixture of H2 and Ar resulted in the exsolution of liquid metal. Conclusions: Levitation melting is a rapid technique or for the preparation of bulk rock powders for major, minor and trace element analysis. With exception of moderately volatile elements Na and K, bulk rock analyses can be performed with an uncertainty of ± 5% relative. The technique has great potential for the quantitative determination of evaporated materials from silicate melts. Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal. [ABSTRACT FROM AUTHOR]

Abstract: The crystallization history of zoned K-feldspar phenocrysts in microgranular magmatic enclaves in the Karkonosze granite (SW Poland) reveals that the crystals grew in stirred coeval magmas of contrasting compositions. The growth mechanism and crystal compositions are investigated using cathodoluminescence and profiling by Electron Microprobe and Laser Ablation ICP-MS. These methods provide insight into the crystallization process and the varying compositions of the host melt. The phenocrysts show two types of growth patterns — with or without resorption interfaces. The trace-element distribution, heterogeneous across different zones and within single phenocryst zones, reflects a dynamic process of crystal growth from compositionally heterogeneous magma. Hybridization is also reflected in the density of structural Al–O−–Al defects — features that relate to coupled Ba–Al incorporation into the crystal structure. Differences in structural-defect densities and crystal composition trace the degree of hybridization in the granitic magma during the growth of the K-feldspar phenocrysts. [Copyright &y& Elsevier]

Abstract: The formation of the continental crust (CC) is one of the most important processes in the evolution of the silicate Earth. Exactly how the CC formed is the subject of ongoing debate that focuses on its subchondritic Nb/Ta ratio. Nb and Ta are “geochemical identical twins,” so they usually do not fractionate from each other. Here, we show that rutile grains from hydrous rutile-bearing eclogitic layers recovered from drillcores in the Dabie-Sulu ultrahigh pressure terrain have highly variable Nb/Ta values (ranging from 5.4 to 29.1, with an average of 9.8±0.6), indicating major fractionation of Nb and Ta most likely occurred during blueschist to amphibole–eclogite transformation in the absence of rutile. It is suggested that the released fluids with subchondritic Nb/Ta were transported to, and retained by, hydrous rutile-bearing eclogite in colder regions, resulting in suprachondritic Nb/Ta ratios for drier eclogite in hotter regions. Further dehydration of hydrous rutile-bearing eclogites cannot transfer the fractionated Nb/Ta values to the CC due to the low solubility of Nb and Ta in fluids in the presence of rutile, while dehydration-melting results in a major component of the CC, the tonalite–trondhjemite–granodiorite (TTG) component, which is responsible for the low Nb/Ta of the CC. Consequently, residual eclogites have variable but overall suprachondritic Nb/Ta. [Copyright &y& Elsevier]

The Dabie Shan ultrahigh-pressure (UHP) metamorphic terrane is located in the eastern part of the east–west-striking Qinling–Dabie orogenic belt in China. A major mylonitized contact zone of 200–300 m width divides Dabie Shan into the South Dabie Terrane (SDT) and the North Dabie Complex (NDC). Combined investigation of major and trace element geochemistry, fluid inclusions, and oxygen and hydrogen isotopes constrains the fluid history during the metamorphic evolution of the two metamorphic belts, which differ in their fluid and metamorphic evolution. Fluid inclusions in rocks from the SDT are mainly aqueous with varying salinities, whereas those from the NDC are dominated by CO2. Low δ18O values in the SDT rocks (−2·8 to 8·6‰) indicate meteoric water–rock interactions before UHP metamorphism, whereas rocks from the NDC show ‘normal’ δ18O values (6·7–9·0‰) with no obvious meteoric water–rock signature. Whole-rock rare earth element (REE) contents correlate with oxygen isotope compositions: samples from the SDT have higher REE contents and lower δ18O values, whereas samples from the NDC have lower REE contents and higher δ18O values. During retrograde metamorphism fluids with different hydrogen isotope compositions interacted with the rocks from the SDT. [ABSTRACT FROM PUBLISHER]

The aim of this paper is to determine the composition and age of high-temperature (HT) hydrothermal fluids in Closepet granites (Dharwar craton, India). The magmatic origin of the Neoarchaean Closepet batholith has been recognized and dated many times, whereas a HT fluid system, strong evidence for which has been partly investigated, has never been dated. Titanite was chosen for a geochemical study on its pristine and altered domains to illustrate the fluid composition; the domains were dated to recognize the timing of fluid activity. Titanite presents distinct trace element enrichments in non-altered domains and strong depletions in trace elements in marginal, irregular, patchy zones. The high total rare earth element (REE) concentrations and the marked negative Eu anomalies suggest crystallization from a residual melt. The negative Eu anomalies diminish progressively in the REE patterns of altered parts and become positive. Trace element ratios (Nb/Ta, Y/Ho, and U/Th) indicate fluid-crystal interactions. Strong U/Th fractionation might be linked to the presence of CO 2 and Cl−. Zr-in-titanite thermometry yields a crystallization/recrystallization temperature of ~700 °C for both magmatic and altered domains. The titanite factor Ti+4/(Al+3 + Fe+3) reveals an affinity with significant mantle input to the fluid system. Pristine and altered titanite domains have been successfully dated by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Reversely discordant apparent ages suggest interaction with fluids, which modified the Pb composition of the magmatic titanite. The oldest semi-concordant analyses of titanite cores indicate an age of approximately 2500 Ma, which we interpret as the minimum age of magmatic titanite crystallization. Narrow dark rims of titanite with considerably lower Th/U ratios form a more coherent group of analyses defining an upper concordia intercept age of 2345 ± 0.016 Ma, interpreted as the best estimate for the time of complete titanite resetting associated with the metasomatic event. The HT fluid system appears to have remained active into the Palaeoproterozoic. Confirmation by dating that the tested fluids belonged to the Archaean hydrothermal system gives us information about this system at the time, but the information that it worked at least until the Palaeoproterozoic provides additional valuable information about the hydrothermal systems during the Neoarchaean-Palaeoproterozoic transition. [Display omitted] • Sustained HT fluid of mantle-crust origin operating in the Neoarchaean granite • First Neoarchaean fluids system dating using pristine/altered titanite domains • Indication of the extension of the fluids activity timing to the Palaeoproterozoic • Unique and relevant processes in the Neoarchaean - Palaeoproterozoic transition [ABSTRACT FROM AUTHOR]