A new occurrence of argentopentlandite and gold from the Au-Ag-rich copper mineralisation in the Paliomylos area, Serbomacedonian massif, Central Macedonia, Greece

The Au-Ag-Cu mineralisation in the Paliomylos area is associated with quartz segregations and pegmatoids in the form of boudinaged bodies. The Au, Ag and Cu contents in the ore bodies reach 6.8 ppm, 765 ppm and 0.80 wt%. The ore minerals consist of pyrite, chalcopyrite, sphalerite, pyrrhotite, galena, bismuthinite, argentopentlandite, gersdorffite, cobaltite, aikinite, hessite, native bismuth and gold. Pentlandite contains significant amounts in Ag (13.15 wt%), Au (1.59 wt%) and PGM, demonstrating a formula of Fe5.37 Ni2.56 Ag1.03 Ir0.03 S8.01. On the basis of geological, textural and chemical data, the mineralisation in the studied area was formed under high temperatures

Characterization and Weathering of the Building Materials of Sanctuaries in the Archaeological Site of Dion, Greece

The sanctuaries of Demeter and Asklepios are part of the Dion archaeological site that sits among the eastern foothills of Mount Olympus. The main building materials are limestones and conglomerates. Sandstones, marbles, and ceramic plinths were also used. The materials consist mainly of calcite and/or dolomite, whereas the deteriorated surfaces contain also secondary and recrystallized calcite and dolomite, gypsum, various inorganic compounds, fluoroapatite, microorganisms and other organic compounds. Cracks and holes were observed in various parts of the stones. The influence of specific weathering agents and factors to the behavior of the materials was examined. The particular environmental conditions in Dion combine increased moisture and rain fall, insolation and great temperature differences, abundance of intensive surface and underground water bodies in the surrounding area, an area full of plants and trees, therefore, they can cause extensive chemical, biological and mechanical decay of the monuments. The following physical characteristics of the building materials have been studied: bulk density, open porosity, pore size distribution, water absorption and desorption, capillary absorption and desorption. The chemical composition of bulk precipitation, surface and underground water was investigated. The salts presence and crystallization was examined. The influence of the water presence to the behavior of the materials was examined by in situ IR thermometer measurements. Temperature values increased from the lower to the upper parts of the building stones and they significantly depend on the orientation of the walls. The results indicate the existence of water in the bulk of the materials due to capillary penetration. The existence of water in the bulk of the materials due to capillary penetration, the cycles of wet-dry conditions, correlated with the intensive surface and underground water presence in the whole surrounding area, lead to partial dissolution-recrystallization of the carbonate material and loss of the structural cohesion and the surface stability

MINERALOGICAL AND GEOCHEMICAL CHARACTERIZATION OF THE OLYMPIAS MINE TAILINGS, NE CHALKIDIKI, GREECE

Τα τέλματα της Ολυμπιάδας στην ΒΑ Χαλκιδική, αποτελούν τα κατάλοιπα του εμπλουτισμού του κοιτάσματος Pb-Zn-Au-Ag που εντοπίζεται στα ανθρακικά πετρώματα της Ενότητας Κερδυλίων. Στην παρούσα εργασία, η ορυκτολογική σύσταση των τελμάτων προσδιορίστηκε με τη χρήση περιθλασιμετρίας ακτίνων-Χ (XRD), ηλεκτρονικής μικροσκοπίας σάρωσης (SEM) και οπτικής μικροσκοπίας, ενώ επιπλέον πραγματοποιήθηκαν χημικές αναλύσεις και μετρήσεις pH. Τα αποτελέσματα έδειξαν πως τα τέλματα συνίστανται από σύνδρομα ορυκτά (χαλαζίας, ροδοχρωσίτης, ασβεστίτης, άστριοι, μαρμαρυγίες, καολινίτης και ακτινόλιθος) και σουλφίδια (σιδηροπυρίτης, αρσενοπυρίτης, σφαλερίτης, χαλκοπυρίτης και γαληνίτης), κάτι που δείχνει ότι υπάρχει σχέση με την ορυκτολογική σύσταση της μεταλλοφορίας και των 2089 μητρικών πετρωμάτων. Επίσης, τα τέλματα αποτελούνται από ίχνη οξειδίων Fe (μαγνητίτης, αιματίτης), οξείδια-υδροξείδια Fe (γκαιτίτης) και οξείδια Mn, συχνά εμπλουτισμένα σε Zn και Pb και σε ορισμένες περιπτώσεις Fe, Sb και As. Επιπλέον εντοπίστηκαν δευτερογενή θειικά άλατα (γύψος, ιαροσίτης) και επανθίσματα θειικών αλάτων (σιδηροεξαϋδρίτης, εξαϋδρίτης, αλοτριχίτης). Τα τέλματα της Ολυμπιάδας είναι γενικά μη οξειδωμένα, δημιουργώντας ένα αλκαλικό περιβάλλον. Παρόλα αυτά, λόγω μεταβολών στη σύσταση, σχηματίζονται ξεχωριστές φάσεις περιορισμένης έκτασης, όπως λεπτές στρώσεις και φακοί οξειδωμένου υλικού, οι οποίες δημιουργούν όξινο περιβάλλον. Από την άποψη της περιεκτικότητας σε πολύτιμα μέταλλα, τα τέλματα της Ολυμπιάδας είναι εμπλουτισμένα σε Au (έως 12 g/t) και Ag (έως 20 g/t).The Olympias tailings of NE Chalkidiki, Greece represent the mine wastes produced by the beneficiation of the Pb-Zn-Au-Ag ore deposit, which is hosted within the carbonate rocks of the Kerdylia Unit. In the present study X-Ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical analyses and pH measurements were conducted to determine the tailings mineralogy and chemical composition. The results indicated that they consist of gangue (quartz, rhodochrosite, calcite, dolomite, feldspars, micas, kaolinite and actinolite) and sulfide minerals (pyrite, arsenopyrite, sphalerite, chalcopyrite and galena), reflecting the source ore and its host rock composition, accompanied by traces of Fe-oxides (magnetite, hematite), Fe oxyhydroxides (goethite) and Mn-oxides, often enriched in Zn and Pb and in some cases Fe, Sb and As. Secondary sulfates (gypsum, jarosite) and surface efflorescent salts (ferrohexahydrite, hexahydrite, halotrichite) have also been recognized. The Olympias tailings are generally unoxidized, generating an alkaline environment. However, variations in composition result in the formation of restricted separate phases, such as thin layers and lenses of oxidized material that generates an acidic environment. In terms of precious metals content, the Olympias tailings are enriched in Au (up to 12 g/t) and Ag (up to 20 g/t)

Tellurides and bismuth sulfosalts in gold occurrences of Greece: mineralogical and genetic considerations

Pre-Tertiary to Tertiary gold deposits in Greece occur in a wide range of genetic types including volcanic massive sulfides, orogenic, intrusion-hosted, skarn, manto-, porphyry- and epithermal-type ores. Almost all of the gold mineralization hosts various Bi-tellurides and Bi-sulfosalts, which in addition to Au-Ag-tellurides, are indicators of specific physicochemical conditions of ore formation. The Bi-bearing mineralization can be subdivided into three groups regarding their spatial relationship to gold: (a) mineralization which lacks tellurides but includes Bi-sulfosalts and native gold, (b) mineralization where Bi-tellurides of the reduced-type (joseite-A, joseite-B, pilsenite) accompany Bi-sulfosalts, native bismuth and native gold, (c) deposits/prospects where Au-Ag-tellurides are abundant and Bi-tellurides and Bi-sulfosalts are absent. Bi-telluride and -sulfosalt mineralization in Greece underwent several stages of remobilization during successive accretionary episodes in active continental margins and arc terranes during the Carboniferous to Pleistocene

Fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province, NE Greece. A review.

Characterization of various fluid parameters in magmatic-hydrothermal ore mineralizations is potentially essential for interpretation of the conditions of formation and therefore for mineral exploration. Fluid inclusions can provide a useful and promising tool in the research of the ore forming processes in these systems. This review focuses on the nature, composition and origin of magmatic-hydrothermal ore forming fluids involved in the formation of representative Tertiary ore deposits at the Rhodope metallogenic province in NE Greece. These deposits are spatially related to Tertiary magmatism in NE Greece. Case studies are presented here and include an intrusion-hosted sheeted vein system (Kavala), a Au-rich carbonate replacement and quartz-vein mineralization (Asimotrypes), mineralized veins in Eptadendro-Rachi and Thasos island (Kapsalina and Panagia), porphyry Cu-MoRe-Au deposits in Pagoni Rachi and Maronia and epithermal Au-Ag mineralizations in Perama and Loutros. Hydrothermal fluids rich in CO2 together with elevated Au and Te content are common and occur at the Kavala intrusion hosted sheeted vein system, at the Asimotrypes Au-rich carbonate replacement mineralization and at the Panagia (Thasos) vein system. We classify all these ore mineralizations as intrusion-related gold systems (IRGS). Transport and precipitation of metals including Au and Te is favoured when CO2 is present. Precipitation of the ore mineralization takes place due to the immiscibility of the carbonic and the aqueous fluids which have a magmatic origin with the contribution of meteoric water. Cooling of magmatic hydrothermal fluids and dilution with meteoric water is a common cause for ore mineral formation in the vein mineralizations of Eptadendro/ Rachi and Kapsalina Thasos. At the Pagoni Rachi and Maronia porphyry deposits, boiling and the high proportion of the vapour phase are the most essential fluid processes which affected ore formation. The epithermal veins overprinting the Pagoni Rachi and the Maronia porphyry systems and the HS-IS epithermal system in Perama Hill and the IS epithermal mineralization in Loutros are characterized by low to moderate temperatures and low to moderate salinities. Cooling and dilution of the ore fluids are the main process for gold precipitation. We conclude that the different fluid parameters and microthermometric data indicate a variety of fluid origin conditions and sources which can affect the strategy for exploration and prospecting for gold, rare and critical metals. © 2016, Institute of Geology. All rights reserved