Stable carbon isotope geochemistry provides important information for the recognition of fundamental exchange processes related to movement in lithosphere and permits elaboration models global cycle. Carbon ratios fluid-deposited graphite are powerful tools unravelling ultimate origin (organic matter, mantle, or carbonates) help constrain fluid history mechanisms involved deposition. Graphite precipitation occurrences results from CO2- and/or CH4-bearing aqueous fluids. Fluid flow can be...

Abstract Magnetite-(apatite) ore deposits are interpreted as being formed by the crystallization of iron-rich ultrabasic melts, dominantly generated interaction silicate melts with oxidized P-F-SO 4 -bearing sedimentary rocks. This hypothesis is supported geologic evidence, experimental studies, numerical modeling, stable and radiogenic isotope geochemistry, mineralogy, melt- mineral-inclusion data. Assimilation crustal rocks during ascent promotes separation from a magma Fe-rich, Si-Al-poor...

A volcaniclastic formation, known as Cangahua, found in the Andes of Ecuador and Colombia is focused on. The deposit composed moderately cemented fine sand silt‐sized particles. pronounced linear correlation shown between strengh, terms both uniaxial compressive Brazil tensile strengths, dry unit weight deposit. strength unusually high for soil, being 18 29% strength. tensile, compressive, triaxial characteristics depend on initial void ratio degree saturation. As saturation declines from 90...

The presence of high level heavy metals involves a human healthy risk that could induce chronic diseases. This work reports on the metal contamination due to heaps steel-slag accumulated during more than 40 years in allotments and industrial areas southern part Madrid (Spain). Several slag soil samples were collected an area 10 km² characterized by different conventional (XRD XRF) no so common methods (ESEM, thermoluminescence EDS-WDS). analysis reveal of: (i) important amounts Fe (43%), Mg...

This work presents an integral methodological approach to assess the environmental potential hazards posed by metals and metalloids hosted spolic technosols derived from old tailings a mining operation for galena (PbS, with high Ag contents)-sphalerite (ZnS, varied cohort of trace elements contents) in central Spain. We studied total soluble concentrations spatial distribution Pb, Zn, Cd, As, Fe mineralogy these soils, as well ecotoxicological evaluation means bioassays. The indices...

Abstract This paper examines the effects of shear stress on structural parameters that define ‘crystallinity’ graphite. The results show highly crystalline graphite samples ground for up to 120 min do not undergo detectable changes in three-dimensional arrangement carbon layers but crystallite sizes ( L c and a ) decrease consistently with increasing grinding time. Grinding also involves particle-size diminution lower temperatures beginning combustion exothermic maxima differential thermal...

The significance of syngenetic and epigenetic graphite occurrences from the Variscan high-temperature/low-pressure Aracena Metamorphic Belt is discussed in framework tectono-thermal evolution this southern zone Iberian Massif. Syngenetic associated with both low- to medium-grade metamorphic rocks (La Umbría series, Precambrian age) high-grade, granulite facies (the Fuente del Oro series a Cambrian calc-silicate series). Epigenetic, fluid-deposited correspond overgrowths on existing grains...

Arthropod eyes are built of repeating units named ommatidia. Each single ommatidium unit contains a cluster photoreceptor cells surrounded by support and pigment cells. The insect Copium eye ommatidia include additional calcium-phosphate deposits, not described in insects to date, which can be examined today using combined set modern microscopy spectroscopy techniques. Teucrium gnaphalodes L'Her plants, growing central Spain, develop galls induced insects. A survey C. teucrii adult specimens...

The geochemical characterization of the mine deposits and soils in metal mining areas is essential order to develop an effective reclamation strategy. determination total potentially toxic element (PTE) content, together with application chemical extraction procedures, can give insight into behavior contaminants after different solutions, as well identify where urgent action needed. This work presents a practical evaluation pollution potential trace elements affected by activities, be used...

The speed at which climate change is happening leading to a demand for new pozzolanic materials that improve the quality of cements and, same time, limit emission greenhouse gases into atmosphere. main objective this work detailed characterization an ignimbrite sample (IGNS) demonstrate its effectiveness as natural pozzolan. To meet objective, series tests were carried out. In first stage, mineral and chemical analyses performed, such petrographic analysis by thin section (TSP), X-ray...

The phase transition of metavariscite into berlinite has been studied by means different techniques, namely electron probe micro analysis, environmental scanning microscopy, high-temperature X-ray diffraction, differential thermal thermogravimetry, thermoluminescence, and thermo Raman. application these techniques indicates that: (i) from room temperature to 150°C (monoclinic dimorph AlPO4 ⋅ 2H2O) appears as the main phase, (ii) in range 100–300°C starts lose water molecules giving rise form...

Abstract This paper describes a vein-shaped graphite occurrence in which, for the first time, geological, mineralogical and isotopic evidence support its formation by physical remobilization of previously formed syngenetic graphite. The deposit studied is located Spanish Central System it occurs along contact between hydrothermal Ag-bearing quartz vein graphite-bearing quartzite layer. characteristics this differ from those fluid-deposited vein-type mineralization that: (1) flakes are...

The Miocene to Present Mazarrón basin provides a window on the metallogenic role of an evolving magmatic series. High-K calc–alkaline magmas gave rise important cluster Pb–Zn–Ag–Cu vein and stockwork deposits emplaced in dacitic rhyodacitic domes, part complex volcanic–metallogenic province (Au, Hg, Pb–Zn–Cu–Ag, Sn) stretching for ∼150 km along Mediterranean coast SE Spain. By Pliocene time former series had been replaced by intraplate alkaline basaltic volcanism, thus becoming southern...

This study aims to use geochemical, mineralogical, ecotoxicological and biological indicators for a comprehensive assessment of the ecological risks related mobility, ecotoxicity bioavailability potentially harmful elements in Lousal mining district. Particularly, toxicity was evaluated using four assays: algae, cytotoxicity assays with HaCaT cell line (dermal), earthworms Daphnia magna. The geochemical mineralogical characterization studied area shows that mine wastes underwent intense...