The Geology, Geochemistry, and Origin of the Porphyry Cu-Au-(Mo) System at Vathi, Serbo-Macedonian Massif, Greece

The Vathi porphyry Cu-Au ± Mo mineralization is located in the Serbo-Macedonian metallogenic province of the Western Tethyan Metallogenic Belt. It is mainly hosted by a latite and is genetically associated with a quartz monzonite intrusion, which intruded the basement rocks of the Vertiskos Unit and the latite, 18 to 17 Ma ago. A phreatic breccia crosscuts the latite. The quartz monzonite was affected by potassic alteration, whereas the latite was subjected to local propylitic alteration. Both styles of alteration were subsequently overprinted by intense sericitic alteration. M-type and A-type veins are spatially associated with potassic alteration, whereas D-type veins are related to the sericitic alteration. Three ore assemblages are associated with the porphyry stage: (1) pyrite + chalcopyrite + bornite + molybdenite + magnetite associated with potassic alteration; (2) pyrite + chalcopyrite related to propylitic alteration; and (3) pyrite + chalcopyrite + native gold ± tetradymite associated with sericitic alteration. A fourth assemblage consisting of sphalerite + galena + arsenopyrite + pyrrhotite + pyrite ± stibnite ± tennantite is related to an epithermal overprint. Fluid inclusion data indicate that the A-type veins and related porphyry-style mineralization formed at 390–540 °C and pressures of up to 646 bars

The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant “Al-Fe-Ca-Ti-Si-Na-Cr matrix”, appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g−1), along with minor U (15 μg g−1), which are responsible for radioactivity (355 and 133 Bq kg−1 for 232Th and 238U, respectively) with a total dose rate of 295 nGy h−1. Leaching experiments, in conjunction with SFICP- MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS & HR-STEMHAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th4+ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th LIII-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely the reason of no Th release in Mediterranean seawater

NEUTRALIZATION OF DYEING INDUSTRY WASTEWATER AND SLUDGE BY FIXATION OF POLLUTANTS IN VERY HIGH QUALITY HEU-TYPE ZEOLITIC TUFF

Treatment of dyeing industry wastewater of pH 7.5 with very high quality zeolitic tuff and coagulants, resulted in clear water of pH 7.2, free of odours and improved quality characteristics (colour, suspended particles, COD: Chemical Oxygen Demand, P2O5, NO3-, Cr) by 74 to 98%. The very high quality zeolitic tuff is 3 to 60% more effective than the coagulants, concerning COD, Cr and NO3-. The treatments produced sludge (using coagulants) and zeo-sludge (using very high quality zeolitic tuff and coagulants). The zeo-sludge is odourless and cohesive. The leaching by deionised water of sludge reached values up to 100% for the quality characteristics, while that of the zeo-sludge reached significantly lower values (only up to 18%). The chemical composition of the seepage water from the zeo-sludge proved the fixation of pollutants, such as NO3- and Cr by the very high quality zeolitic tuff

Hellenic Natural Zeolite as a Replacement of Sand in Mortar: Mineralogy Monitoring and Evaluation of Its Influence on Mechanical Properties

HEU-type zeolite-rich volcaniclastic tuff (Hellenic natural zeolite) is used as a raw material for the production of lighter mortars. The addition of natural zeolite in mortar mixtures of sand and Portland cement leads to a decrease of up to 18.35% unit weight. The increase of the natural zeolite proportions increases the porosity and water absorption of the mortar and, at the same time, decreases the uniaxial compressive strength. These variations in the mortar’s mechanical properties are due to the addition of natural zeolite, which causes incomplete hydration of C2S (2CaO.SiO2) and retardation of the mortar’s hardening

Arsenic distribution in sea sediments of Filippos B port, Kavala, Northern Greece

7 páginas.Nine sampling sites in the eastern Kavala coast, Northern Greece, were selected to collect sediments and analyze their content in arsenic. In past and recent years, arsenic has raised a lot of attention since it is considered to be a potentially toxic element. Arsenic concentrations ranged from 2.7 to 44.8 mg kg-1, and its average was 15.3 mg kg-1. Two samples with concentrations higher than 20 mg kg-1 were in front of the industrial facilities of the study area. However, a possible contribution from the sulphide mineralization present in the area may not be excluded. The sediments of Filippos B port have a similar range of arsenic concentrations compared to that of larger international ports. Comparison between the concentrations found in the present study and internationally accepted guidelines showed that the aforementioned samples exceeded the suggested optimum level, although no sampling location reached such a level where remediation actions are necessary.Peer reviewe