Search

The distribution and the chemical composition of Suspended Particulate Matter (SPM), in the northern Thermaikos Gulf, were studied during an annual experiment, carried out from June 2004 to June 2005. Water samples were collected at three depths (1 m below surface, 10 m depth, and 2 m above bottom) and filtered to obtain SPM, particulate organic carbon (POC), total particulate nitrogen (PN tot ) and particulate phosphorus (PP) concentrations. SPM and POC concentrations exhibited strong spatial and temporal variations, related to the different environmental characteristics in the study area such as river network, biological productivity, anthropogenic interferences, wind regime, and resuspension of the bottom sediments. The highest SPM concentrations were recorded at the surface (mean = 1.45 ± 0.75 mg/l, maximum value = 11.60 mg/l) and close to the bottom (mean = 1.49 ± 0.67 mg/l, maximum value = 11.72 mg/l), creating surface and bottom nepheloid layers (SNL and BNL), respectively. The maximum values were recorded close to the river mouths; the rivers are identified as the major sources of SPM. The Axios and Aliakmon rivers supplied the gulf with particulate matter, during the entire sampling period. Chemical analysis has revealed the significant correlation among the elements Al, Si, Fe, Ti, K, V, Mg and Ba suggesting the presence of terrigenous aluminosilicate minerals. Silica and Ca have terrigenous origin, but also come from autochthonous biogenic fraction. Chromium, Ni and Co, are of natural origin and derived from mafic and ultramafic rocks of the Axios and Aliakmon watersheds. Copper and Zn are correlated with each other and their distributions follow that of POC; these two metals are derived from partially treated domestic and industrial effluents. The vertical distribution of organic matter implies increased primary production within the upper layer of the water column. Phosphorus is present mainly in an organic form. During the sampling period, the water column was well-oxygenated. Early diagenesis only affected the concentrations of Mn and to a lesser extent Fe in the recently deposited seabed sediment.

The genesis and the physical characteristics of the Neogene red beds of the cedar hills surrounding Thessaloniki are studied in this paper. The peri-urban forest, which covers these hills, has a 3,022 ha area. The topographic relief is smooth and is divided in eight small drainage basins, tapped through small creeks. The elevation of the surrounding hills varies between 85 and 560 m. The dominant land slopes vary between 20 and 55%. All the samples are coarse grained, poorly sorted and friable and present earthy lustre and red colour because of the extensive presence of iron oxides. Angular to sub-angular rock fragments derived from the metamorphic bedrock are very common. Petrographically, the studied red beds belong to the clayey sands. The extended presence (41-66%) of coarse silt and sand size grains (>20 pm) in the samples suggests a mild intensity of in situ weathering of the bedrock. X-ray diffraction analysis of the coarsest fractions 250-20 pm and 20-2 μιτι revealed in decreasing abundance the presence of quartz, feldspars, epidote, micas, chlorite, pyroxenes, amphiboles, and talc. These fractions contain the 2M polytype of mica, while in the fraction

Today Greece produces and exports raw bauxite and alumina, concentrates of galena and sphalerite and ferronickel. The indicated reserves of bauxite, located in the Mt Helikon-Mt Parnassus-Mt Giona-Mt Iti zone, are estimated at approximately 100 mt and those of aluminum 2.5 mt. The probable and indicated reserves of lead and zinc from Chalkidiki are approximately 3.125 mt. The total production of concentrates of galena and sphalerite is approximately 220,000 tpa. The proven reserves of nickel are approximately 1.392 mt and the production of ferronickel is approximately 18,500 tpa. Production of copper, silver and gold is pending in 2015. The probable and indicated reserves of copper from Skouries Chalkidiki are approximately 1.943 mt. In the Prefecture Units of Chalkidiki and Evros the probable and indicated reserves of gold are approximately 19.37 million ounces and those of silver 131.6 million ounces. Chromium, manganese and molybdenum present good prospects of exploitation. Calculated at current prices, the total gross value of the probable and indicated reserves of the metallic minerals of Greece is €79.4 billion.

Modern sand samples were collected from the Vertiskos Unit of the Serbomacedonian Massif, northern Greece, and were examined for their texture and mineralogical composition. They were collected from active channels and torrents. The textural study demonstrated that these modern sands are moderately to very-poorly sorted, often polymodal in grain size distribution, texturally and mineralogically immature to submature, and consist of coarse-grained gravelly sands to slightly-gravelly muddy sands. The dominant composition is quartzofeldspathic. All samples contain detrital minerals of metamorphic origin, mainly amphibole and garnet, in addition to minor amounts of pyroxene and detrital calcite. These sediments were deposited rapidly and close to their source, the metamorphic basement of the Vertiskos Unit. The mineral constituents of the samples indicate that the Vertiskos Unit is undergoing rapid physical weathering due to the temperate and seasonal climate. The results of this study suggest that these modern sands constitute one sedimentary petrologic province comprised of primarily of amphibole-garnet.

A high-calcium limestone was calcined in order to study its thermal decomposition using P-wave velocity. The onset of calcination is at approximately 750 °C, while its completion according to the size of the cubic specimens is noted between 1000 and 1150 °C. We found that P-wave velocities are a very good index for the study and estimation of calcination. P-wave velocity decreases due to a temperature rise from 650 to 1150 °C for the cubic specimens of 4, 6 and 8 cm mean edge, while for 1 and 2 cm cubic specimens mixed behavior is observed, with a considerable increase in velocities at calcination temperature higher than 1050 °C.

The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite). The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the

Representative carbonate rock samples collected from the broader area of Kozani (NW Macedonia, Greece) are examined. The participation of constituents in the formations was determined combining three different methods of analysis, atomic absorption spectroscopy (AAS), X-ray diffraction analysis (XRD) and thermogravimetry (TG). The three methods are used in a complimentary way in order to specify the exact composition of the samples. Although the question about the composition can be answered by AAS, the percentage of the included calcite and dolomite can be determined with accuracy, only through TG analysis, under the appropriate conditions, regarding the gas carrier. The results of the analysis lead to a more complete view of the geological conditions that predominated in the studied area.

The gray and white crystalline limestones from Agios Panteleimonas Florina have almost the same mineralogical composition. They are mainly composed of calcite (96%), while the percentage of the contained organic matter is 0.8% in the gray and 0.09% in the white crystalline limestone. After heating both crystalline limestones at 500°C no serious change was observed concerning their mineralogical composition. However, the velocity of P waves and the porosity in the gray limestone are changed significantly while this trend is not noticed in the white limestone. These changes are mainly attributed to the burning of organic matter, which is contained with greater percentage in the gray crystalline limestone. At 1000°C both crystalline limestones are completely calcined. The dissociation of calcite and dolomite increases significantly the porosity of the produced quicklime. The quicklime from gray crystalline limestone presents higher porosity value (by 5.2 percentage units) and it is more reactive (by 4.9 percentage units) in comparison with the quicklime from white crystalline limestone. This difference in the reactivity is mainly attributed to the difference in the percentage of organic matter contained in the two crystalline limestones.

Τριάντα δύο (32) θέσεις ζεολιθικών πετρωμάτων της Θράκης (29 της ΠΕ Έβρου και 3 της ΠΕ Ροδόπης) μελετήθηκαν ως προς την ορυκτολογική τους σύσταση με την μέθοδο της περιθλασιμετρίας ακτίνων Χ (XRD). Σύμφωνα με τον Kανονισμό της ΕΕ αριθ. 651/2013, κλινοπτιλόλιθος ιζηματογενούς προέλευσης (ζεολιθικοί τόφφοι) με ≥80% κ.β. κλινοπτιλόλιθο, ≤20% κ.β. αργιλικά ορυκτά, χωρίς ίνες και χαλαζία, μπορεί να χρησιμοποιηθεί ως πρόσθετη ύλη ζωοτροφών για όλα τα ζωικά είδη. Τα ζεολιθικά πετρώματα της Θράκης κατά μέσο όρο περιέχουν, 23 89% κ.β. ζεόλιθο τύπου- HEU (κλινοπτιλόλιθο-ευλανδίτη), 8-45% κ.β. μορντενίτη (δέκα θέσεις), 24% κ.β. ανάλκιμο (μία θέση), 1-11% κ.β. μαρμαρυγία, 1-11% κ.β. αργιλικά ορυκτά, 3-37% κ.β. χαλαζία, 2-29% κ.β. χριστοβαλίτη, 3-34% κ.β. αστρίους και 0-22% κ.β. άμορφα υλικά. Μόνο μία θέση περιέχει 89% κ.β. ζεόλιθο τύπου-HEU (κλινοπτιλόλιθο-ευλανδίτη), 2% κ.β. αργιλικά ορυκτά, είναι χωρίς ίνες, αλλά δυστυχώς περιέχει 3% κ.β. χαλαζία και 2% κ.β. χριστοβαλίτη. Λαμβάνοντας υπόψη την ορυκτολογική σύσταση, τα ζεολιθικά πετρώματα της Θράκης δεν πληρούν τις απαιτήσεις του Kανονισμού της ΕΕ αριθ. 651/2013, και γι’ αυτό δεν μπορούν να χρησιμοποιηθούν ως πρόσθετη ύλη ζωοτροφών για όλα τα ζωικά είδη και επομένως ως συμπληρώματα διατροφής, επειδή τα ζεολιθικά πετρώματα όλων των θέσεων, περιέχουν κατά μέσο όρο 3-37% κ.β. χαλαζία, 2-29% κ.β. χριστοβαλίτη, 8-45% κ.β. μορντενίτη (ινώδη ζεόλιθο) σε 10 θέσεις, 24-65% κ.β. ζεόλιθους (τύπου-HEU ± μορντενίτη ± ανάλκιμο) σε 28 θέσεις, 74% κ.β. ζεόλιθο τύπου- HEU σε 2 θέσεις και 77% κ.β. ζεόλιθο τύπου-HEU σε 1 θέση., Thirty two (32) locations of zeolitic rocks from Thrace (29 from Evros prefecture and 3 from Rhodope prefecture) were investigated for their mineralogical composition by X-Ray Diffraction (XRD) method. According to EU Regulation No 651/2013, clinoptilolite of sedimentary origin (zeolitic tuffs) with ≥80 wt% clinoptilolite, ≤20 wt% clay minerals, free of fibres and quartz, can be used as feed additive for all animal species. The zeolitic rocks of Thrace on average contain, 23-89 wt% HEUtype zeolite (clinoptilolite-heulandite), 8-45 wt% mordenite (ten locations), 24 wt% analcime (one location), 1-11 wt% mica, 1 11 wt% clay minerals, 3-37 wt% quartz, 2-29 wt% cristobalite, 3-34 wt% feldspars and 0-22 wt% amorphous materials. Only one location contains 89 wt% HEU-type zeolite (clinoptilolite-heulandite), 2 wt% clay minerals, is free of fibres, but unfortunately it contains 3 wt% quartz and 2 wt% cristobalite. Considering the mineralogical composition, the zeolitic rocks of Thrace do not meet the requirements of the EU Regulation No 651/2013, and thus cannot be used as feed additives for all animal species and consequently as nutrition supplements, since the zeolitic rocks in all locations, contain on average 3-37 wt% quartz, 2-29 wt% cristobalite, 8-45 wt% mordenite (fibrous zeolite) in 10 locations, 24-65 wt% zeolites (HEU-type ± mordenite ± analcime) in 28 locations, 74 wt% HEUtype zeolite in 2 locations and 77 wt% HEU-type zeolite in 1 location.

The examined dolomite is composed of 98% of mineral dolomite and 2% of calcite. Other silicates (i.e. quartz) exist only in trace amounts. This dolomite presents intense orange luminescence colour, indicating the absence of impurities and thus high purity. Its chemical composition is: CaO=32.9%, MgO=20.2%, CO2=46.7%, others=0.14% and its isotopic composition is δ18O=−3.10‰ and δ13C=+3.40‰. These values indicate that this dolomite has been formed mainly by recrystallisation of pre-existing limestone with simultaneous or subsequent partial substitution of CaCO3 by MgCO2 (dolomitisation). The data of its most important physicochemical properties are: water absorption=0.2%, water dissolution=0.17%, surface area=1.10 m2/g, pH=10.0, oil absorption=24 ml/100 g and brightness=97%. These data satisfy almost all the quality demands for use of its wastes after processing for the production of many industrial products. The most significant fields of use of the dolomite from Potamia, except its main world-wide demand as decorative stone, may be: as filler, whitening, and extender product in many paper, paint, and rubber industries; in addition, it can be used for the production of fertilisers.

The mechanisms of clay mineral distribution in Alexandroupolis Gulf are studied. The annual solid supply of the Evros River, flowing into the Gulf, amounts to at least 1 000 000 m3. The surficial bottom sediments are commonly fine-grained and are distributed along zones almost parallel to the coastline. In the central part of the Gulf clay-silt size sediments predominate. The main clay minerals in the size fractions (2–1, 1–0·25 and

Extensive metasomatic zones of vermiculite-, tremolite-, chlorite-, and talc-rich rocks have been developed at the contacts of serpentinized ultramafic bodies and surrounding two-mica gneisses in the Askos area, Macedonia, Greece. These zones are probably related to the intrusion of acid magmatic bodies in the area. X-ray and EPMA studies confirmed the formation of vermiculite through a layer-by-layer transformation of original micas. In decreasing abundance, the following mixed-layer and discrete phases were identified: biotite/trioctahedral vermiculite (hydrobiotite), biotite/smectite, trioctahedral chlorite/trioctahedral vermiculite (corrensite), vermiculite/smectite and discrete biotite, vermiculite, chlorite and talc. The 2–20 μm fraction of the vermiculitic samples consists mostly of biotite/vermiculite (>40%) with the biotite percentage dominating in the mixed phase. Lower abundances (20–40%) of biotite/smectite and chlorite/vermiculite occur in both finer fractions (2–20 and

The hydrothermal and weathering alteration products of the gabbroic rocks at Griva, Macedonia, Greece, are examined using petrographic, mineralogical and chemical data. The kaolin crusts have a thickness of 1 to 8 m and extend over an area of about 5 km 2 . Many gabbro-pegmatitic veins crosscut the semi-friable kaolins. The crusts have not been intensively washed and thus the primary minerals exist within the weathered profile in significant amounts. Essential constituents are plagioclase, actinolite, clinopyroxene, clinozoisite, dolomite, kaolinite, corrensite and pyrophyllite, with varying proportions in the different particle size fractions. The 18 O values. According to the classification of Konta the kaolins studied are of the low grade type and probably only suitable for the ceramic industry.

The conditions of alteration of the upper Eocene zeolite-bearing volcaniclastic sediments at Metaxades, Thrace, Greece, were examined using a variety of petrographic and mineralogical techniques. A fine silt- to clay-size matrix, containing abundant altered glass shards, predominates. The primary minerals include quartz, K-feldspar, plagioclase, micas (especially biotite) and some opaque minerals. The diagenetic phases, clinoptilolite, smectite and cristobalite, occur as microcrystalline aggregates within the matrix or as replacements of glass shards. The abundances of cristobalite and clinoptilolite are related chiefly to the original composition of the rocks. The abundance of cristobalite increases and that of clinoptilolite + smectite decreases as the abundance of the matrix increases. The formation of clinoptilolite and cristobalite took place either at near-surface temperatures or at slightly elevated temperatures (lower than 70°C). The smectite content of the altered volcaniclastics decreases with increasing depth in the 15 m thick exposed section. No other systematic variation in mineral assemblages with depth was observed. However, the ratio clinoptilolite/smectite increases systematically with depth suggesting to us that smectite may have formed subsequent to the formation of clinoptilolite and as an alteration product of clinoptilolite. The initial composition of the volcanic material and to a less extent the interstitial fluids, greatly affected the diagenetic mineral assemblages of the final alteration products.

The suitability of Kozani's broader area carbonate rocks for use in cement production and as aggregates, is studied in terms of their mineralogical, chemical and mechanical characteristics. The studied carbonate rocks belong to the Pelagonian zone and are represented mainly by pure limestones with subordinate dolomites and dolomitic limestones. Examination concerning their insoluble residue, organic matter and milling behavior, together with their mineralogical and chemical composition showed that all carbonate formations of Kozani's broader area, except the dolomitic ones, fulfill the requirements for use as raw material in the cement industry and all the carbonate formations meet the specifications for their use as aggregates in various constructions.