Search results for "Mineral"
showing 10 items of 2711 documents
Microstructure, porosity and mineralogy around fractures in Olkiluoto bedrock
2012
3D distributions of minerals and porosities were determined for rock-core samples that included water-conducting fractures. The analysis of these samples was performed using conventional petrography methods, C-14-PMMA porosity analysis and X-ray tomography. It seems that the properties of rock around a water-conducting fracture depend on so many uncorrelated factors that no clear pattern emerged even for rock samples with a given type of fracture. We can conclude, however, that the present combination of methods can be used to infer novel structural information about alteration zones adjacent to fracture surfaces.
Comparative tests on different multi-electrode arrays using models in near-surface geophysics
2008
In this paper, the response of different synthetic models to geoelectrical multi-electrode surveys is studied. The models considered are related to two main problems, which are very common in geophysical research regarding hydrogeology and engineering. The first class of models represents buried walls, similar archaeological remains or remains of buried foundations; the other class corresponds to a sea-water intrusion of a fresh water aquifer, which is generally studied in hydrogeophysics. A set of 2D simulations, starting from the synthetic models, was carried out to compare the behaviour of the different arrays when acquiring measurements of electrical resistivity tomography. For each mod…
The shell matrix of the freshwater mussel Unio pictorum (Paleoheterodonta, Unionoida). Involvement of acidic polysaccharides from glycoproteins in na…
2007
13 pages; International audience; Among molluscs, the shell biomineralization process is controlled by a set of extracellular macromolecular components secreted by the calcifying mantle. In spite of several studies, these components are mainly known in bivalves from only few members of pteriomorph groups. In the present case, we investigated the biochemical properties of the aragonitic shell of the freshwater bivalve Unio pictorum (Paleoheterodonta, Unionoida). Analysis of the amino acid composition reveals a high amount of glycine, aspartate and alanine in the acid-soluble extract, whereas the acid-insoluble one is rich in alanine and glycine. Monosaccharidic analysis indicates that the in…
STUDIO ETNOARCHEOMETRICO DI MALTE AEREE A LEGANTE GESSOSO NELL’AREA DELLE MADONIE (SICILIA SETTENTRIONALE)
2010
The Madonie Regional Park, which covers an area of about 400 square kilometres, is an ideal context where environment and man activities are still mixed harmoniously. In the last years a variety of ethno-archaeometric investigations have been carried out in order to study various aspects of the "material culture" of this territory. In particular, the research was focused on the production of majolica which have had a great importance since the early decades of the 16th century thanks to the geolithological features of the Madonie area, particularly rich in clayey raw material. The traditional building techniques of the Madonie which involve several typologies of building materials (used for…
Actualisation des références nutritionnelles françaises en vitamines et minéraux
2021
En 2016, l’Anses a proposé une mise à jour des références nutritionnelles pour la population adulte (femmes de 18 à 54 ans et hommes de 18 à 64 ans) dans le cadre de l’actualisation des repères de consommation alimentaire (saisine 2012-SA-0103). Par la suite, des rapports dédiés aux repères de consommation alimentaire pour les populations spécifiques (personnes âgées, enfants, femmes enceintes et allaitantes) ont été publiés en 2019, sans toutefois quede nouvelles références nutritionnelles ne soient définies par l’agence.Par ailleurs, la mise à jour de 2016 n’a concerné que les vitamines et minéraux indispensables pour lesquelles des données de consommation étaient disponibles. De ce fait,…
Short-term effects of potassium fertilization on the hydraulic conductance of Laurus nobilis L.
2011
This study reports experimental evidence on the effect of short term potassium fertilization on potassium uptake, tissue concentration and hydraulic conductance of pot-grown laurel plants. Potassium uptake and loading into the xylem of laurel seedlings increased within 24 h from fertilization. Potassium was not accumulated in roots and leaves, but the [K+] of xylem sap was 80% higher in fertilized plants (+K) than in potassium starved plants (-K), likely as a result of recirculation between xylem and phloem. This increase in xylem sap [K+] resulted in a 45% increase in transpiration rate, a 30% increase in plant hydraulic conductance (Kplant) and a 120% increase in leaf specific conductivit…
Chemical-physical parameters, major, minor and trace elements composition of thermo-mineral groundwaters of Greece
2022
This dataset comprises samples of thermo-mineral waters collected by the same team over the period from October 2004 to March 2020 and analysed in the same laboratory. Samples were collected on the whole territory of Greece.
Numerical modelling of gas-water-rock interactions in volcanic-hydrothermal environment: the Ischia Island (Southern Italy) case study.
2012
Hydrothermal systems hosted within active volcanic systems represent an excellent opportunity to investigate the interactions between aquifer rocks, infiltrating waters and deep-rising magmatic fluids, and thus allow deriving information on the activity state of dormant volcanoes. From a thermodynamic perspective, gas-water-rock interaction processes are normally far from equilibrium, but can be represented by an array of chemical reactions, in which irreversible mass transfer occurs from host rock minerals to leaching solutions, and then to secondary hydrothermal minerals. While initially developed to investigate interactions in near-surface groundwater environments, the reaction path mode…
Geochemical fingerprints of brannerite (UTi 2 O 6 ): an integrated study
2020
AbstractBrannerite (UTi2O6) is among the major uranium-bearing minerals found in ore deposits, however as it has been long considered as a refractory mineral for leaching it is currently disregarded in ore deposits. Brannerite is found in a variety of geological environments with the most common occurrences being hydrothermal and pegmatitic. On the basis of scanning electron microscopy observations coupled with electron probe micro-analyses and laser ablation inductively-coupled plasma mass spectrometer analyses, this study describes the morphological features and the major- and trace-element abundances of brannerite samples from five hydrothermal and five pegmatitic localities across the w…
In situ micro-Raman and X-ray diffraction study of diamonds and petrology of the new ureilite UAE 001 from the United Arab Emirates
2008
International audience; A new olivine-pigeonite ureilite containing abundant diamonds and graphite was found in the United Arab Emirates. This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo79.8-81.8) and pyroxene (En73.9-75.2, Fs15.5-16.9, Wo8.8-9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo96.1-96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro-Raman and in situ synchrotron X-ray diffraction. The main diamond Raman band (LO=TO mode at ~1332 c…