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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]

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]

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]

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]

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]

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 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]