Search results for "Quartz"
showing 10 items of 239 documents
Experimental alteration of granitic rocks: Implications for the evolution of geothermal brines in the Upper Rhine Graben, Germany
2020
Abstract Geothermal energy exploitation in the Upper Rhine Graben (URG) chiefly has targeted faults and fractures within or connected with the crystalline basement, where hot fluids of c. 200 °C circulate at depths of c. 5 km. Formation fluids of the crystalline basement are highly saline, NaCl-dominated brines, whereas shallow crystalline basement water ( The trace element concentrations of the leachates are hereby related to the composition and stability of minerals in the rocks and can be directly linked to the proposed and observed dissolution processes at the different temperatures. In experiments with pure water at 70 °C, representing the recharge or infiltration conditions, water-roc…
Pleistocene and Holocene aeolian sediments of different location and geological history: A new insight from rounding and frosting of quartz grains
2014
Abstract Rounding and frosting of quartz grains in aeolian sediments of the known stratigraphic position and unique geological setting was explored in Finnish, Estonian, Latvian, and Polish localities and in Fuerteventura Island. The aim of the study is to characterize the variability of the spatial pattern of rounding and frosting of quartz grains in the sandy (0.5–0.8 mm) fraction and to evaluate the factors influencing it. The relationships between rounded and non-abraded, as well as matt- and shiny-type quartz grains were calculated for 159 samples and evaluated against the aeolian subenvironment, substratum and presumed age of the locations. The obtained relations do not confirm meridi…
Age, geodynamic setting, and mantle enrichment processes of a K-rich intrusion from the Meissen massif (northern Bohemian massif) and implications fo…
1997
The plutonic complex of the Meissen massif (northern margin of the Bohemian massif) comprises dioritic to mainly monzonitic and granitic rocks. The diorite to monzonite intrusions show major and trace element patterns typical for shoshonitic series. The chemical signatures of less crustally contaminated diorites are similar to arc-related shoshonitic rocks derived from continental lithospheric mantle (CLM) sources previously enriched by subduction of altered oceanic crust. Laser step heating 40Ar/39Ar analyses on actinolitic to edenitic amphiboles from geographically different occurrences of the monzonitic intrusion yielded concordant plateau ages as well as total gas ages ranging from 329.…
Label-free piezoelectric biosensor for prognosis and diagnosis of Systemic Lupus Erythematosus
2017
[EN] An autoantigen piezoelectric sensor to quantify specific circulating autoantibodies in human serum is developed. The sensor consisted on a quartz crystal microbalance with dissipation monitoring (QCM-D) where TRIM21 and TROVE2 autoantigens were covalently immobilized, allowing the selective determination of autoantibodies for diagnosis and prognosis of Systemic Lupus Erythematosus (SLE). The sensitivity of the biosensor, measured as IC50 value, was 1.51 U/mL and 0.32 U/mL, for anti-TRIM21 and anti-TROVE2 circulating autoantibodies, respectively. The sensor is also able to establish a structural interaction fingerprint pattern or profile of circulating autoantibodies, what allows scorin…
Riedel-shear control on the development of pennant veins: Field example and analogue modelling
2006
Abstract The wall rocks of a crustal scale sinistral ductile shear zone in Namibia, the Purros Mylonite Zone, contain two types of asymmetric quartz veins. Bedding surfaces contain sigmoidal quartz veins with limited thickness along their symmetry axes that can be classified as tension gashes. A second type of veins consists of a striated central fault vein separating pennant-type quartz filled terminations. The tips of these “pennant veins” have a different orientation to those of the tension gashes. Analogue experiments were carried out using a sheet of silicone powder suspended on a slab of poly-dimethyl-siloxane (PDMS), both deformed in simple shear. These experiments produced open frac…
Elucidation of Carbohydrate Molecular Interaction Mechanism of Recombinant and Native ArtinM
2013
[EN] The quartz crystal microbalance (QCM) technique has been applied for monitoring the biorecognition of ArtinM lectins at low horseradish peroxidase glycoprotein (HRP) concentrations, using a simple kinetic model based on Langmuir isotherm in previous work.(18) The latter approach was consistent with the data at dilute conditions but it fails to explain the small differences existing in the jArtinM and rArtinM due to ligand binding concentration limit. Here we extend this analysis to differentiate sugar-binding event of recombinant (rArtinM) and native (jArtinM) ArtinM lectins beyond dilute conditions. Equivalently, functionalized quartz crystal microbalance with dissipation monitoring (…
Bivergent extension in orogenic belts: The Menderes massif (southwestern Turkey)
1995
The central Menderes massif is characterized by an overall dome-shaped foliation pattern and a north-northeast-trending stretching lineation. The asymmetry of shear bands and quartz c-axis fabrics on either side of the structural dome demonstrate a top to the north-northeast shear sense in the northern part and a top to the south-southwest shear sense in the southern part of the submassif, i.e., a bivergent downdip movement. This suggests a symmetric collapse of the Alpine Menderes orogenic belt along two extensional shear zones. Conjugate shear bands and symmetric quartz c-axis fabrics in the east-trending transition zone demonstrate a coaxial deformation between the two extension domains.…
Characterization of an early metamorphic stage through inclusions in zircon of a diamondiferous quartzofeldspathic rock from the Erzgebirge, Germany
2003
About 1000 zircon grains from a diamondiferous quartzofeldspathic rock of the Saxonian Erzgebirge were investigated for inclusions using optical microscopy and confocal laser-Raman spectroscopy. Cathodoluminescence imagery was applied to characterize the growth zone of zircon where the inclusions occurred. The most abundant inclusion minerals are microdiamonds. Coesite was not detected. However, garnet and jadeite occur as rare inclusions in zircon cores where diamonds are lacking. Jadeite was detected for the first time in quartzofeldspathic rocks from the crystalline complex of the Erzgebirge. The compositions of the pristine garnets in the zircons are similar to those of core areas of mi…
Porous organic cage compounds as highly potent affinity materials for sensing by quartz crystal microbalances.
2012
Porosity makes powerful affinity materials for quartz crystal microbalances. The shape-persistent organic cages and pores create superior affinity systems to existing ones for direct tracing of aromatic solvent vapors. A shape and size selectivity for the analytes is observed. These organic cages can be processed to thin films with highly reproducible sensing properties.
A New LA ‐ ICP ‐ MS Method for Ti in Quartz: Implications and Application to High Pressure Rutile‐Quartz Veins from the Czech Erzgebirge
2016
Experimental determination of the pressure and temperature controls on Ti solubility in quartz provides a calibration of the Ti-in-quartz (TitaniQ) geothermometer applicable to geological conditions up to ~ 20 kbar. We present a new method for determining 48Ti mass fractions in quartz by LA-ICP-MS at the 1 μg g−1 level, relevant to quartz in HP-LT terranes. We suggest that natural quartz such as the low-CL rims of the Bishop Tuff quartz (determined by EPMA; 41 ± 2 μg g−1 Ti, 2s) is more suitable than NIST reference glasses as a reference material for low Ti mass fractions because matrix effects are limited, Ca isobaric interferences are avoided, and polyatomic interferences at mass 48 are i…