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Simplified geological map of the Lavrion area (Lavreotiki Peninsula). Modified after Photiades and Carras (2001).
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The Lavrion area corresponds to the northwestern end of the Attic-Cycladic Complex and mainly consists of metamorphic rocks formed during the Eocene high-pressure/low-temperature (HP/LT) event and the Upper Oligocene-Lower Miocene medium-pressure metamorphic event. These metamorphic rocks are found in two superimposed tectonic units: the Kamariza U...
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... The upper unit, also known as the phyllite nappe or the Lavrion Blueschists tectonic unit, is composed of a 100 to 250 m thick alternation of the Lavrion schists, including boudins of metavolcanites, and marbles. The top of the Lavrion schists contains mafic and ultramafic boudins interpreted as meta-ophiolite remnants ( Photiades and Carras, 2001;Photiades and Saccani, 2006). The Lavrion schists are rich in muscovite, quartz, albite, chlorite, glaucophane and epidote indicating greenschist to blueschist facies metamorphism ( Baziotis et al., 2009). ...
... The L 1-2 stretching lineation orientation is consistent with an ENE-WSW direction of extension (Figs. 1, 3). The schists are intruded by dioritic dykes and are overlain by a 20 m thick layer made of carbonates including mafic and ultramafic boudins ( Photiades and Carras, 2001;Photiades and Saccani, 2006) ( Fig. 3). Besides the absence of mineralised levels, the lithologic-structural succession of the Simonet quarry section is similar to the Velatouri section. ...
... Such intermingled textures have been described in the Pyrenees by Boulvais et al. (2006) and interpreted as being induced by Ca release during dolomitisation and calcite reprecipitation in the dolomite micro-porosity. The source of Mg responsible for dolomitisation is likely related to mafic and ultramafic boudins hosted within the Lavrion schists ( Photiades and Saccani, 2006). These might have been altered by surface-derived fluids carrying Mg down to the DBT along high-angle faults. ...
The impact of lithological heterogeneities on deformation, fluid flow and ore deposition is discussed based on the example of the Lavrion low-angle detachment partly accommodating gravitational collapse of the Hellenides orogenic belt in Greece. The Lavrion peninsula is characterised by a multiphase Pb-Zn-Fe-Cu-Ag ore system with a probable pre-concentration before subduction followed by progressive remobilisation and deposition coeval with the development of a low-angle ductile to brittle shear zone. The mylonitic marble below the detachment shear zone is composed of white layers of pure marble alternating with blue layers containing impurities (SiO2, Al2O3, carbonaceous material). Ductile mylonitic deformation is more pervasive in the less competent impure blue marble. We propose that localised deformation in the impure marble is associated with fluid circulation and dolomitisation, which in turn causes an increase in competence of these layers. Mineralised cataclastic zones, crosscutting the mylonitic fabric, are preferentially localised in the more competent dolomitic layers. Oxygen and carbon isotopic signatures of marble invaded by carbonate replacement deposits during ductile to ductile-brittle deformation are consistent with decarbonation coeval with the invasion of magmatic fluids. Mineralised cataclastic zones reflecting brittle deformation evolve from low ¹³C to low ¹⁸O signatures, interpreted as local interaction with carbonaceous material that trends toward the contribution of a surface-derived fluid. These features indicate that the Lavrion area records a complex deposition history influenced by the evolution of fluid reservoirs induced by the thermal and mechanical evolution of the marble nappe stack. Ore remobilisation and deposition associated with the activity of the low-angle detachment is (i) firstly related to the intrusion of the Plaka granodiorite leading to porphyry-type and carbonate replacement mineralisation during ductile-brittle deformation and (ii) then marked by progressive penetration of surface-derived fluids guided by strain localisation in the more competent levels leading to epithermal mineralisation associated with brittle deformation.
... Altherr et al., 1982; Buick and Holland, 1989; Bröcker et al., 1993; Avigad, 1998; Trotet et al., 2001; Parra et al., 2002; Bröcker and Franz, 2005; Duchêne et al., 2006; Groppo et al., 2009). Most metabasites and metavolcanics from the middle unit of the nappe stack exposed in the Lavrion peninsula show a geochemical signature typical of MORB composition (mainly E-MORB, rarely N-MORB) but some display a calc-alkaline affinity (Photiades and Saccani, 2006). These features are consistent with a geodynamic evolution encompassing a Triassic continental rift followed by the opening of the Pindos ocean along the southern margin of the Pelagonian continent. ...
... scale of the Cyclades, dated at ca. 25 Ma (Andriessen et al., 1979; Altherr et al., 1982; Ring et al., 2001; Ring and Reischmann, 2002; Duchêne et al., 2006). Metavolcanics from the basal unit attributed to the Trias (Fig. 2d) have a calc-alkaline affinity consistent with an emplacement in a magmatic arc environment associated with the opening of a back-arc basin (Photiades and Saccani, 2006). ...
The Lavrion peninsula is located along the western boundary of the Attic-Cycladic metamorphic complex in the internal zone of the Hellenic orogenic belt. The nappe stack is well exposed and made, from top to bottom, of (i) a non-metamorphic upper unit composed of an ophiolitic melange, (ii) a middle unit mainly composed of the Lavrion schists in blueschist facies, (iii) and a basal unit mainly composed of the Kamariza schists affected by pervasive retrogression of the blueschist facies metamorphism in greenschist facies. The middle unit is characterized by a relatively steep-dipping foliation associated with isoclinal folds of weakly organized axial orientation. This foliation is transposed into a shallow-dipping foliation bearing a N-S trending lineation. The degree of transposition increases with structural depth and is particularly marked at the transition from the middle to the basal unit across a low-angle mylonitic to cataclastic detachment. The blueschist facies foliation of the Lavrion schists (middle unit) is underlined by high pressure phengite intergrown with chlorite. The Kamariza schists (basal unit) contains relics of the blueschist mineral paragenesis but is dominated by intermediate pressure phengite also intergrown with chlorite and locally with biotite. Electron probe micro-analyzer chemical mapping combined with inverse thermodynamic modeling (local multi-equilibrium) reveals distinct pressure–temperature conditions of crystallization of phengite and chlorite assemblages as a function of their structural, microstructural and microtextural positions. The middle unit is characterized by two metamorphic conditions grading from high pressure (M1, 9–13 kbar) to lower pressure (M2, 6–9 kbar) at a constant temperature of ca. 315 °C. The basal unit has preserved a first set of HP/LT conditions (M1–2, 8–11 kbar, 300 °C) partially to totally transposed-retrogressed into a lower pressure mineral assemblage (M3, 5–8.5 kbar) associated with a slight but significant increase in temperature (∼350 °C).
... Typical examples of CABs included in mélange are found in the Dinaride-Albanide-Hellenide ophiolites ( Monjoie et al., 2008;Saccani et al., 2008b;Chiari et al., 2011) and in the Ankara and Misis ophiolites in Turkey ( Floyd et al., 1991;Tankut et al., 1998;Bortolotti et al., 2013). CABs from coherent volcanic sequences mostly include rocks generated at ensialic volcanic arcs, such as the Jurassic Transylvanian Depression in Romania ( Ionescu et al., 2009), Attic-Cycladic zone in Greece ( Photiades and Saccani, 2006;Koglin et al., 2009a,b), Guevgueli complex in Greece ( Saccani et al., 2008d), Cascades ophiolites in N America ( Metzger et al., 2002), as well as the Paleozoic Marlborough Terrane ) and Glympie Group ( Sivel and McCulloch, 2001) in Australia and the Bampo Complex ( Jian et al., 2009) in the Yaxinqiao ophiolite (SW China). ...
In this paper, a new discrimination diagram using absolute measures of Th and Nb is applied to post-Archean ophiolites to best discriminate a large number of different ophiolitic basalts. This diagram was obtained using >2000 known ophiolitic basalts and was tested using ∼560 modern rocks from known tectonic settings. Ten different basaltic varieties from worldwide ophiolitic complexes have been examined. They include two basaltic types that have never been considered before, which are: (1) medium-Ti basalts (MTB) generated at nascent forearc settings; (2) a type of mid-ocean ridge basalts showing garnet signature (G-MORB) that characterizes Alpine-type (i.e., non volcanic) rifted margins and ocean-continent transition zones (OCTZ). In the Th-Nb diagram, basalts generated in oceanic subduction-unrelated settings, rifted margins, and OCTZ can be distinguished from subduction-related basalts with a misclassification rate
... A detachment fault separates the Basal Unit from the Cycladic–Blueschist Unit, even though the original contact formed a major thrust fault (Marinos and Petrascheck 1956; Skarpelis 2007). The Cycladic–Blueschist Unit consists of HP–LT metapelites and metasandstones with minor intercalations of carbonates and blueschistfacies basic metaophiolites retrogressed to greenschists (Baltatzis 1996; Photiades and Saccani 2006). Miocene igneous rocks intruded the Basal Unit causing intense contact metamorphism and ore deposition. ...
Agardite-(Nd), ideally NdCu6(AsO4)3(OH)6·3H2O, has been approved by the IMA Commission on New Minerals, Nomenclature and Classification as a new mineral species, a Nd-dominant analogue of agardite-(Y), -(La) and -(Ce), a member of the mixite group. The material considered as the holotype was found in the Hilarion Mine, Agios Konstantinos (Kamariza), Lavrion District, Attikí Prefecture, Greece. Agardite-(Nd) occurs as thin, acicular to hair-like crystals up to 0.5 mm long and up to 5 μm thick, elongate along [001], with hexagonal cross section. More commonly, agardite-(Nd), agardite-(Y) and/or agardite-(La) form rims (up to 3 μm thick) of zoned acicular crystals (up to 0.015 × 1.2 mm) with a core consisting of zálesíite. They are usually combined in sprays or radiating clusters up to 2 mm. Gradual compositional transitions among zálesíite, agardite-(Nd), agardite-(Y) and agardite-(La) are typical. The minerals of the agardite–zálesíite solid-solution system are associated here with zincolivenite, azurite, malachite and calcite in cavities of an oxidized ore mainly consisting of goethite and in cracks of supergene altered mica schist. Agardite-(Nd) is transparent, light bluish green, with white streak, and lustre vitreous in crystals and silky in aggregates. Crystals are brittle, cleavage is none observed, and fracture is uneven. Calculated density is 3.81 g/cm3. Optically, agardite-(Nd) is uniaxial positive, ω = 1.709–1.712, ε = 1.775–1.780. Pleochroism is strong: O = pale turquoise-coloured, E = bright green-blue. Chemical composition of agardite-(Nd) (averaged of 6 electron microprobe analyses, H2O by difference) is: CuO 42.63, ZnO 3.52, CaO 2.15, Y2O3 1.27, La2O3 2.16, Ce2O3 0.38, Pr2O3 0.79, Nd2O3 3.05, Sm2O3 0.32, Gd2O3 0.40,
Dy2O3 0.31, As2O5 33.65, H2Ocalc. 9.37, total 100.00 wt. %. The empirical formula based on 3 As atoms is:
[(Nd0.19La0.14Y0.12Pr0.05Gd0.02Ce0.02Sm0.02Dy0.02)ΣREE0.58Ca0.39]Σ0.97(Cu5.49Zn0.44)Σ5.93 (AsO4)3(OH)5.38·2.64H2O. Chemical data on other minerals of the agardite–zálesíite system from the Hilarion Mine are also given and discussed. Agardite-(Nd) is hexagonal, space group P63/m; unit cell parameters are: a = 13.548(8), c = 5.894(6) Å, V = 937(2) Å3, Z = 2. The strongest reflections of the X-ray powder diagram (d,Å-I[hkl]) are: 11.70–100[100]; 4.443–22[111, 120]; 3.545–18[211,121]; 2.935–18[221, 400]; 2.695–13[112, 320, 230], 2.559–10[410], 2.453–30[212, 122, 231]. The type specimen is deposited in the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.
... The phyllitic nappe consists of a volcano-sedimentary formation (schist, marble, quartzite), a mafic meta-ophiolite formation, and crystalline limestone (Marinos and Petrascheck 1956;Baltatzis 1981Baltatzis , 1996Arikas et al. 2001;Bassi et al. 2004). The Upper Unit is represented in the Lavrion area by a non-metamorphic limestone of Cretaceous age that has basal ophiolite (Photiades andCarras 2001, Photiades andSaccani 2006). East–west trending mafic dikes dip towards the north and crosscut the lower marble and the Kessariani schists in the Kamariza area. ...
... The phyllitic nappe consists of a volcano-sedimentary formation (schist, marble, quartzite), a mafic meta-ophiolite formation, and crystalline limestone (Marinos and Petrascheck 1956;Baltatzis 1981Baltatzis , 1996Arikas et al. 2001;Bassi et al. 2004). The Upper Unit is represented in the Lavrion area by a non-metamorphic limestone of Cretaceous age that has basal ophiolite (Photiades andCarras 2001, Photiades andSaccani 2006). East–west trending mafic dikes dip towards the north and crosscut the lower marble and the Kessariani schists in the Kamariza area. ...
Carbonate-replacement Pb–Zn–Ag ± Au deposits in the Kamariza area, Lavrion district, Attica, Greece, are genetically related
to the emplacement of Miocene andesitic dikes within a rapidly extending continental back-arc basin, which formed during exhumation
of the Attic-Cycladic Crystalline Belt. Replacement veins as well as chimneys and mantos of massive sulfides are the major
orebody types with mantos grading into chimneys and veins. Ore minerals are similar among the various types of orebodies in
the Kamariza area and consist of sulfides and sulfarsenides (pyrite, arsenopyrite, chalcopyrite, galena, sphalerite, gersdorffite,
marcasite), native metals (Au and Bi), Sn-bearing phases (petrukite), sulfosalts and sulfbismuthites of Ag, Bi, Cu, Pb, As,
Sb (tetrahedrite-group minerals, bournonite, boulangerite, stephanite, pyrargyrite, semseyite, enargite, bismuthinite, lillianite
homologues, Cu-matildite, aikinite, Ag-aikinite, mummeite, emplectite, wittichenite). The elemental association of Bi, Au,
and Ag is common. The assemblages gersdorffite-bismuthinite-native gold and native gold-native bismuth are evidence for a
contribution of magmatic components to the hydrothermal system. A fluctuation in the sulfidation states of the ore fluid during
the evolution of the Kamariza system is evident from the deposition of early arsenopyrite, as well as of enargite-luzonite
and both low-Fe and Fe-rich sphalerite in the same samples. Microthermometry of fluid inclusion assemblages show that carbonate
replacement mineralization was deposited from a warm to hot (100°C to 400°C), low to moderately saline (1.8 to 17.3 wt% NaCl
equiv) fluid. Eutectic temperatures of fluid inclusions as low as −55°C suggest the presence of CaCl2 in addition to NaCl, in the ore fluid. The Kamariza deposit occurs distal to the Plaka granodiorite intrusion and the associated
porphyry-Mo mineralization, but is likely to be genetically related to a granitoid buried at depth.
The main aspect of this field trip is the geological synopsis of the Lavrion area, the specific geological features of each deposit, the mode of occurrence of the ore mineralizations and information concerning their mineralogical composition . The aim of this trip is to raise questions about magma genesis, emplacement and the dynamics of magmatic-hydrothermal activity in the area.
The Lavrion area forms the westernmost part of the Attic–Cycladic crystalline belt (ACCB) and is built up by two tectonic units metamorphosed at HP/LT conditions. In the Upper Tectonic Unit metabasic rocks occur as greenschists and blueschists. Major and trace elements plotted against Mg# show a systematic increase in TiO2, Fe2O3*, Na2O, Zr, Y, V, La and Yb and a decrease in Al2O3, Ni and Cr with decreasing Mg#. Typically, the blueschists always exhibit a more evolved basaltic composition. The greenschists are characterized by LREE depleted chondrite-normalized REE patterns and Zr/Nb values that range from 15 to 24. The blueschists are characterized by slightly LREE-enriched chondrite-normalized REE patterns and lower Zr/Nb ratios (6.6–11.3). Both rock types share common geochemical features like flat HFSE patterns or slight positive Nb anomalies with La/Nbb1. The protoliths of both greenschists and blueschists show that two different suites generated their protoliths and that their magmatic evolution at low pressures has also been different. The observed Zr/Nb vs. Ce/Y ratios span the compositions of greenschists and blueschists out on hyperbolae at an
ideal spectrum from intermediate N-MORB to E-MORB. However, the REE patterns of the studied metabasites cannot be explained by fractional crystallization processes alone. We interpret that the protoliths of the Lavrion metabasites support a dual origin; the blueschist's protoliths are comparable to rift-related mildly alkaline basalts whereas the greenschist's protoliths probably formed as typical N-MORB at an oceanic spreading center or in an evolved back-arc basin. A mélange setting with two distinct provenances of the basic protoliths is the proposed genetic model, similar to that envisioned for other parts of the ACCB, e.g. the islands of Syros, Sifnos and Tinos.
The Upper Tectonic Unit of the Lavrion area is part of the Attic-Cycladic blueschist belt and was affected by high-pressure, low-temperature metamorphism. Blueschists and greenschists occur in the same outcrop and are believed to have experienced the same pressure–temperature (P–T) history which has been quantified using geothermobarometry and pseudosections for specific bulk-rock compositions. Calculated P–T conditions indicate minimum pressure of � 0.9 GPa and temperature of� 370 �C for the peak of metamorphism. The prograde and retrograde paths followed a very similar low geothermal gradient (10–12 �C/km) with cooling during decompression. Pseudosections show that both blueschists and greenschists can exist stably at the metamorphic peak, the dominant amphibole being a function of bulk composition: the blueschists, on average, have lower Mg# than the greenschists, which results in a larger P–T stability field of blue amphibole. A pseudosection analysis of the dehydration behaviour indicates that blueschists and some greenschists can preserve their peak assemblages (no dehydration along the retrograde path), whereas greenschist assemblages, in general, are rather prone to undergo dehydration and hence re-equilibration to lower P–T conditions during exhumation.
The large volume and areal extent of metallurgical processing wastes in the Lavrion urban area, and their subsequent movement
by aerial and fluvial processes, as well as by human activities resulted in the contamination of overburden materials, including
residual and alluvial soil. The bioaccessibility of contaminants, such as Pb and As, is verified by the high concentrations
of Pb in blood and deciduous teeth, and As in urine of children and adults alike. The present work, apart from the review
of all available data and information, studied in detail every possible aspect of the Lavrion environment, i.e. overburden
materials (including residual and alluvial soil), house dust, lithology, metallurgical processing wastes, and produced a multitude
of geochemical distribution and other thematic maps, leading to risk assessment and the production of an environmental management
plan for the rehabilitation of contaminated surficial materials. Although cost-effective solutions were proposed, no action
has as yet been taken by the relevant authorities.
KeywordsGeochemistry-Health-Soil-House dust-Lead-Arsenic-Blood-Teeth-Urine-Lavrion-Greece
