NE Greece Research Articles

Detrital supply from subduction/accretion complexes to the Eocene–Oligocene post-collisional southern Thrace Basin (NW Turkey and NE Greece)

The Thrace Basin is a large, mostly Eocene–Oligocene post-collisional sedimentary basin which developed following the closure of the Vardar–İzmir–Ankara oceanic domain (latest Cretaceous–Paleocene). Sandstone petrologic data (framework and heavy-mineral analyses) and the synthesis of preexisting and new sedimentological observations along representative stratigraphic sections show that the basin fill of the southern Thrace Basin was mostly derived from the İzmir–Ankara and Biga (?Intra-Pontide) subduction/accretion complexes to the south. Proximal facies consistently show northward paleocurrents whereas most paleocurrent indicators measured downcurrent point to an eastward paleoflow, likely the result of the deflection of primary gravity flows originated along the southern margin of the basin. Detrital contributions from the Rhodopian basement complex to the west are virtually absent within the southern Thrace Basin fill. Conversely, Rhodopes-derived, Eocene proximal facies in northeastern Greece are characterized by a series of coarse-grained fan-deltas prograding eastward and likely feeding the basin–plain turbidites of the depocentral portion of the Thrace basin, now concealed in the subsurface to the north of our study area. Arenites of the southern Thrace Basin are mostly lithic arkoses and arkosic litharenites. Provenance from the İzmir–Ankara and Biga suture zones to the south is characterized by ophiolitic, granitoid/gneissic, low-grade metamorphic, and extrabasinal carbonate rock fragments, as well as by picotite and glaucophane. The application of detailed petrographic observations for discriminating paleo- vs. neovolcanic and penecontemporaneous vs. noncoeval terrigenous sands lead to a substantial revision of the geodynamic interpretation of the Thrace Basin, formerly considered a forearc basin. A significant penecontemporaneous volcanic component is common in the Upper Eocene–Lower Oligocene section and can be related to extensive post-collisional volcanism following the closure of the Vardar–İzmir–Ankara ocean. The coexistence of pure neovolcanic layers (crystal tuffs and cinerites) and hybrid arenites rich in penecontemporaneous carbonate grains with sands derived from a continental basement and ophiolitic suites indicates the presence of episutural basins where shallow-water carbonates were deposited on top of the exhuming subduction–accretion prism. These carbonates were mixed with penecontemporaneous neovolcanic and terrigeneous components and redeposited in deeper marine environments.

PUBLIC HEALTH RISK ASSESSMENT ASSOCIATED WITH HEAVY METAL AND ARSENIC EXPOSURE NEAR AN ABANDONED MINE (KIRKI, GREECE)

Background and Aims: The “Agios Philippos” lead-zinc mine in the Kirki region (NE Greece) is now closed but its legacy of heavy metal contaminated land remains at the site (Loupasakis and Konstantopoulou 2009, Nikolaidis et al. 2010). A risk assessment approach was elaborated in order to address the potential adverse health effects associated with lead, cadmium, zinc and arsenic exposure. Methods: Soil samples from the proximity of the mine were collected and analyzed using standard procedures (Chen et al. 2006). Risk assessment guidelines developed by US EPA were employed in order to assess exposures related to i) inhalation of dust particles, ii) dermal absorption of trace elements adhered to the skin and iii) soil ingestion (US EPA 1997). The average daily dose (ADD) was calculated taking into account both the carcinogenic and non-carcinogenic risk. The reference dose (RfD) for each element was used to yield a hazard quotient (HQ) of non-carcinogenic effects. The hazard index (HI) was then generated by summing up all individual HQs. A slope factor (SF) was used to calculate the carcinogenic risk (CR) for arsenic (IRIS 2009). Results: The majority (69.2%) of samples approximating the source of heavy metal contamination produced an increased toxicological risk for arsenic and lead. The overall hazard index near the mine portal exceeded the accepted value (HI•1) by 4.3- fold. An unacceptable carcinogenic risk for arsenic (CR> 1 x10-5) was evident near the contamination source, which gradually faded out with distance from the mine. Conclusions: These findings indicate that heavy metal contamination in the “Agios Philippos” mine poses a significant risk to the exposed population (Kirki, NE Greece). These exposures have to be carefully evaluated at the biological level and validated by appropriate epidemiological methods before any further conclusions can be made.

Pressure–temperature evolution of eclogites from the Kechros complex in the Eastern Rhodope (NE Greece)

The Rhodope Domain in NE Greece consists of different tectonometamorphic complexes involved in the Alpine collisional history between the Eurasian and African plates. In the Kechros Complex, which is the lowermost tectonic unit in the East Rhodope, a lense of kyanite eclogite occurs within orthogneiss and common eclogites are found between serpentinized peridotite and underlying pelitic gneisses. In kyanite eclogite, the high-pressure (HP) mineral assemblage is Grt + Omp (Jd35–55) + Ky + Ph + Qz + Rt + (indirectly inferred Tlc + Law); a Na-rich tremolite and zoisite formed at or near peak metamorphic conditions. In common eclogites, the HP mineral assemblage is Grt + Omp (Jd29–41) + Rt and, with less certainty, Amp (Gln-rich + Brs + Wnc + Hbl) ± Czo. The inclusions in garnet are glaucophane, actinolite, barroisite, hornblende, omphacite, clinozoisite, titanite, rutile and rarely paragonite and albite. In kyanite eclogite, peak P–T conditions are constrained at 2.2 GPa and 615°C using garnet–omphacite–phengite geothermobarometry and very similar values of 585 ± 32°C and 2.17 ± 0.11 GPa with the average P–T method, by which conditions of formation could also be narrowed down for the common eclogite (619 ± 53°C and 1.69 ± 0.17 GPa) and for a retrogressed eclogite (534 ± 36°C and 0.77 ± 0.11 GPa). Ages for the HP metamorphism in the Kechros Complex are not yet available. A Rb–Sr white mica age of 37 Ma from orthogneiss records a stage of the exhumation. The HP event may be coeval with the Eocene HP metamorphism (49–55 Ma) recorded in the Nestos Shear Zone in Central Rhodope and in the Attic-Cycladic crystalline belt, where it is interpreted as the result of subduction and final closure of the Axios/Vardar ocean and subsequent subduction of the Apulian continental crust (a promontory of the Africa continent) under the southern margin of the European continent in the late Cretaceous and early Tertiary.

Mineralogy and geochemical environment of formation of the Perama Hill high-sulfidation epithermal Au-Ag-Te-Se deposit, Petrota Graben, NE Greece

The Perama Hill deposit is a high-sulfidation Au-Ag-Te-Se epithermal system hosted in silicic- and argillic altered andesitic rocks and overlying sandstones, which were emplaced on the eastern margin of the Petrota graben, northeastern Greece. The deposit evolved from an early stage silica-pyrite rock and argillic alteration followed by the deposition of sulfide-, sulfosalt- and telluride-bearing quartz-barite veins and stockworks. Early ore formation is characterized by a high-sulfidation-type enargite-galena-bearing ore assemblage (consisting of enargite, watanabeite, Fe-free sphalerite, covellite, kesterite, bismuthinite, selenian bismuthinite, lillianite homologues, kawazulite-tetradymite, goldfieldite, and native gold), followed by the formation of an intermediate-sulfidation-type tennantite-bearing assemblage characterized by ferrian/zincian tennantite, tellurobismuthite, tetradymite, melonite, native tellurium, Au-Ag-tellurides (calaverite, krennerite, sylvanite, hessite, petzite, stutzite), altaite and electrum. Quartz, barite, kaolinite, sericite and minor aluminum-phosphate-sulfate minerals are gangue minerals. Fluid inclusion data demonstrate that the ore system evolved from an initial high temperature (up to 330°C) and low salinity (up to 4.9 wt.% NaCl equiv.) fluid towards a cooler (200°C) and very low salinity (0.7 wt.% NaCl equiv.) hydrothermal fluid suggesting progressive cooling and dilution of the ore fluid. The ore minerals at Perama Hill reflect variable fS2 and fTe2 conditions during base and precious metal deposition. Early ore deposition took place at ~300°C, at logfS2 values between ≈−8.2 and −5.5, and logfTe2 from −11.8 and −7.8. Late ore deposition occurred at logfS2 = −11.8 to −9.8 and logfTe2 of ≈−9.2 and −7.8. These data and paragenetic studies indicate a shift towards higher logfTe2 and lower logfS2 and logfSe2 values for the mineralizing fluids with time. The kawazulite/tetradymitess-gold association at Perama Hill suggests that it formed from a sulfide melt in the Bi-Au-Se-Te system as Au was scavenged from the hydrothermal ore-forming fluid at elevated temperatures. The presence of tellurides, and Bi- and Sn-bearing minerals in the ore system is compatible with direct deposition of metals from the vapor phase of a degassing magmatic (porphyry) body.

Microbial ecology of the watery ecosystems of Evros river in North Eastern Greece and its influence upon the cultivated soil ecosystem

The aim of the present study was to evaluate the microbial ecosystem of cultivated soils along the Evros river in NE Greece. Evros river together with its derivative rivers constitute the capital source of life and sustainable development of the area. Along this riverside watery ecosystem systematic agro-cultures were developed such as wheat, corn and vegetable cultures. The evaluation of the ecosystem microbial charge was conducted in both axes which are the watery ecosystem and the riverside cultivated soil area. Considerable discrimination of water quality was observed when considering chemical and microbiological parameters of the Evros river ecosystem. Ardas river possesses a better water quality than Evros and Erythropotamos, which is mainly due to the higher quantities that these two rivers accumulate from industrial, farming and urban residues leading to higher degree of pollution. An increased microbial pollution was recorded in two of the three rivers monitored and a direct relation in microbial and chemical charging between water and cultivated-soil ecosystems was observed. The protection of these ecosystems with appropriate cultivated practices and control of human and animal activities will define the homeostasis of the environmental area.

Microbiological quality and related factors of sheep milk produced in farms of NE Greece

Sheep herds are a significant capital of dairy industry in Greece, but as dairy farming becomes more complex and intense the need to provide assistance to dairy producers on milk quality is critical. In this study, the quality of raw milk produced in sheep farms of NE Greece was surveyed and the role of various factors was explored. In total, 21 dairy ewe’s farms from the regions of Xanthi and Evros, in the north-eastern Greece were monitored. Milk samples were sampled after the morning milking every 15 days throughout the dairy period (March–June). For the study, a questionnaire was also filled by personal interview with the owners in order to collect information about herd characteristics, health status, handling practices etc. From each farm, air was also sampled for microbiological analysis. Milk samples were examined for chemical components: fat content, protein, lactose, non-fat dry matter (NFDM) and somatic cells count (SCC). Microbiological examination involved the estimation of Total Bacterial Counts (TBC), coliform count (CC), Staphylococcus aureus, Streptococcus sp., and preliminary incubation count (PIC). The possible correlation among different bacterial species and their interaction with SCC and chemical components of milk was also considered. It was examined whether farm management practices could influence the hygiene and the quality of milk. Our results show that as an average TBCs were 5.48 log cfu/ml, SCC: 6.05 log cells/ml, CC: 4.49 log cfu/ml, S. aureus: 3.94 log cfu/ml, Streptococcus sp.: 4.95 log cfu/ml and PIC: 5.7 log cfu/ml. The mean fat, protein, lactose and NFDM were 6.17%, 5.28%, 4.73% and 10.95% respectively. The study revealed significant positive correlation between TBC and PIC (0.825), while SCC was marginally positive correlated with protein and NFDM. No statistically significant correlations observed among SCC with any of the bacterial species. Herd size and farm management practices had considerable influence on SCC and bacterial species.

Geometry and sequence stratigraphy of the Late Eocene-Early Oligocene shelf and basin floor to slope turbidite systems, Lemnos Island, NE Greece

The Late Eocene-Early Oligocene sedimentary fill of the Lemnos Island, NE Greece, is represented by a submarine fan and shelf deposits. Turbidites in the system occur as a laterally isolated body, with one sediment influx center present. The influx center is a proximal distributary channel that occupies a position approximately in the fan’s center and displays the coarsest sediment in the study area. It also suggests in association with the main palaeocurrent direction toward NE a curved shape for the fan. The stratigraphic succession of the submarine fans indicates that their sedimentation started during the base level fall and completed shortly after the base level rise. As a consequence, the study area was filled by turbidites that correspond to forced regressive, lowstand normal regressive, and transgressive genetic units. The progradational bedsets, within the basal part of the turbidite deposits, recorded the history of the base level fall. The mixed progradational/aggradational style of the upper part of the submarine fan system suggests that the regression of the shoreline is driven by sediment supply during a period of base-level rise at the shoreline, or at a time of baselevel stillstand. The overlying shelf facies consist of thick to medium bedded sandstones and mudstones, which display a general thinning upward trend. The base of the mudstone facies that overlie the thick-bedded, amalgamated sandstones corresponds to a transgressive surface. This surface separates the low-stand deposits (thick-bedded sandstones) from the high stand deposits (mudstone facies), suggesting that deposition of shelf facies occurred during a transgressive system tract.

Conditions of formation of the Mavrokoryfi high-sulfidation epithermal Cu–Ag–Au–Te mineralization (Petrota Graben, NE Greece)

The Mavrokoryfi Cu–Ag–Au–Te prospect, northeastern Greece, consists of atypical, high-sulfidation mineralization where precious metals were introduced contemporaneously with advanced argillic alteration from magmatic vapors. It occurs as veins of massive sulfides in zones of silicic and advanced argillic alteration spatially associated with an andesitic lava dome and hyaloclastites. Mineralogical data demonstrate an unusual ore and gangue mineralogy that is compatible with formation under very oxidizing conditions (logfO2 values of >−31.8) at temperatures of 200°C to 250°C. Oxidizing conditions favored the formation of hypogene lead sulfates (anglesite and barian celestite) instead of galena. Selenian acanthite, cadmian freibergite, and argentian goldfieldite are the main carriers of silver in the deposit and are reported in Greece for the first time. They were deposited at logfS2 of −9 to −7 and logfTe2 values of −9 to −12.5 (250°C). Ag-poor goldfieldite at Mavrokoryfi has up to 3.7 apfu Te and is the most Te-rich goldfieldite yet reported. The mineralization is accompanied by aluminum–phosphate–sulfate minerals of magmatic-hydrothermal origin and an unusual Pb-enrichment. Ore-forming components were likely derived from andesite porphyries.

Heavy Metal Pollution Associated with an Abandoned Lead–Zinc Mine in the Kirki Region, NE Greece

The "Agios Philippos" mine in the Kirki region (NE Greece) has been abandoned in 1998 after half a century of ore exploration without a reclamation or remediation plan. This article aims at elucidating the potential environmental risks associated with this site by quantifying pollution in tailing basins, stream waters, stream sediments and agricultural fields. Concentrations of heavy metals in the abandoned mine tailings reached 12,567 mg/kg for Pb, 22,292 mg/kg for Zn, 174 mg/kg for Cd and 241 mg/kg for As. The geoaccumulation index and enrichment factor for these metals were indicative of extremely high contamination (I(geo) > 5) and extremely high enrichment (EF > 40), respectively. Stream waters in the proximity of the mine had an acidic pH equal to 5.96 and a high sulfate content (SO(4)(-2) = 545.5 mg/L), whereas concentrations of Mn, Zn and Cd reached 2,399 microg/L, 7,681 microg/L and 11.2 microg/L. High I(geo) and EF values for Cd, Zn and As in stream sediments indicates that surface water pollution has a historic background, which is typically associated with acid mine drainage. Agricultural fields in the proximity of the mine exhibited high I(geo) and EF values, which were in decreasing order Cd > Pb > Zn > As. These findings urge for an immediate remediation action of the afflicted area.

Petrography and geochemistry of the late Eocene–early Oligocene submarine fans and shelf deposits on Lemnos Island, NE Greece. Implications for provenance and tectonic setting

AbstractProvenance and tectonic history of the late Eocene‐early Oligocene submarine fans and shelf deposits on Lemnos Island, NE Greece, were studied using sandstone framework composition, sedimentological data and sandstone and mudstone geochemistry. The resulting tectonic–sedimentological model is based on the late Eocene–early Oligocene Lemnos Island being in a forearc basin with the outer arc ridge as a major sediment source. Modal petrographic analysis of the studied sandstones shows that the source area comprises sedimentary, metamorphic and plutonic igneous rocks deposited in the studied area in a recycled orogenic environment. Moreover, within the above sediments, the minor occurrence of volcanic fragments suggests little or no influence of a volcanic source. Provenance results, based on major, trace and rare earth element (REE) data, suggest an active continental margin/continental island arc signature. All the samples are LREE, enriched relative to HREE, with a flat HREE pattern and positive Eu anomalies, suggesting that the processes of intracrustal differentiation (involving plagioclase fractionation) were not of great importance. Results derived from the multi‐element diagrams also suggest an active margin character, and a mafic/ultramafic source rock composition, while the positive anomaly of Zr that can be attributed to a passive continental margin source, is most likely associated with reworking and sorting during sediment transfer. Palaeocurrents, with a NE–NNE direction, indicate a northeast flow, towards the location of the late Eocene–early Oligocene magmatic belt in the north‐east Aegean region. Conglomerates are composed of chert, gneiss and igneous fragments, such as basalts and gabbros, suggesting this outer arc ridge as a likely source area. Copyright © 2009 John Wiley & Sons, Ltd.

Mineral chemical and geochronological constraints on the age and provenance of the eastern Circum-Rhodope Belt low-grade metasedimentary rocks, NE Greece

In north-eastern Greece the mid-greenschist facies Makri Unit and the anchizonal Melia Formation belong to the eastern Circum-Rhodope Belt that forms the uppermost tectonostratigraphic unit of the Rhodope metamorphic nappe pile. The two metasedimentary successions had different source areas, although they now lie in close proximity in the Rhodope Massif. The U–Pb isotopic ages of detrital zircons from a metasandstone of the Makri Unit analysed using LA–SF–ICP–MS and SHRIMP-II gave age clusters at ca. 310–290 Ma and at ca. 240 Ma for magmatic zircons, which may have been derived from Carboniferous–Permian basement rocks of the Thracia Terrane (Lower Tectonic Unit of the Rhodope Massif) that subsequently underwent Triassic rifting. The youngest detrital zircon grains found so far indicate that the metasedimentary succession of the Makri Unit, or at least parts of it, cannot be older than Late Triassic. By contrast, clastic sedimentary rocks of the Melia Formation contain the primary detrital mineral assemblage of epidote, zoisite, garnet, and phengitic mica, which is absent in the Makri Unit, and clearly points to metamorphic rocks being the major source for these sediments. U–Pb analyses of detrital zircons gave a prominent age cluster at ca. 315–285 Ma for magmatic zircons. Inherited cores indicate the involvement of Pan-African and Late Ordovician–Early Silurian crustal sources during Late Carboniferous–Early Permian igneous event(s). Moreover, U–Pb detrital zircon geochronology indicates that the Melia Formation cannot be older than latest Middle Jurassic. We suggest that the Melia Formation was deposited in front of a metamorphic nappe pile with Rhodopean affinities in Tithonian or Cretaceous times. Both the Makri Unit and the Melia Formation have been tectonically juxtaposed from different sources to their present location during Balkan and Alpine orogenic processes.

Non-target Screening of Organic Contaminants in Sediments from the Industrial Coastal Area of Kavala City (NE Greece)

Lipophilic anthropogenic contaminants enter the environment from different kinds of human activities and corresponding emission sources. In the hydrosphere, they accumulate frequently in specific sedimentary zones, among others, and at coastal areas, forming reservoirs of pollutants. Marine and freshwater sediment samples as well as soil samples from a highly industrialized coastal area in Northern Greece have been analyzed in order to have a detailed view on the state of the particle-associated pollution. Noteworthy, based on extended GC/MS non-target screening analyses, interesting, so far unknown, or rarely documented contaminants have been identified and quantified comprising, e.g., mono- and dichlorocarbazoles, bromocarbazole, 2,6-di-tert-butyl-4-nitrophenol, etc. However, all relevant contaminants are discussed with respect to their spatial concentration profiles, their emission sources, and their pathway. In addition, numerous pollutants are suggested to become selected for environmental monitoring programs. Hence, this study can act as an example for adapting individual monitoring programs to the individual contamination in coastal areas.

Geochemistry and biostratigraphy of Eocene sediments from Samothraki Island, NE Greece

Elevated whole-rock concentrations in Cr, Ni and V as well as the occurrence of detrital chrome spinel suggest an input of (ultra)mafic detritus into the Eocene elastic sediments of Samothraki Island. Detrital chrome spinel chemistry indicates a mixed source of MOR-type peridotites and supra-subduction zone (SSZ) peridotites, and minor volcanic rocks, supposedly island-arc basalts and MORB-type rocks, most likely derived from Vardarian ophiolites. Wackestones from the southwest of Samothraki contain a moderately well-preserved calcareous microfossil assemblage, comprising Nummulites fabianii (PREVER), Nummulites striatus (BRUGUIERE), Pellatispim sp., and Operculina sp., indicating an early Priabonian age (Late Eocene). The sedimentation of the Eocene succession was influenced by regional tectonic and volcanic activity. The rocks have been deposited contemporaneous with the extensional exhumation of the eastern Rhodope Massif.

Physicochemical characterization of the shallow mixing zone of two estuaries, Lesvos Island, NE Aegean, Greece

We assessed the physicochemical status of the mixing zone along two shallow estuaries within a Natura 2000 site, NE Greece, in order to establish a baseline and evaluate their trophic state. Distribution patterns of dissolved oxygen and chlorophyll a of water and of chlorophyll a, total phosphorus, and percent organic matter of sediment along the mixing zone of the studied estuaries during spring 2005 indicated oligotrophic conditions in autotrophic estuaries. In both estuarine systems, chlorophyll a concentration of water did not correlate with chlorophyll a of sediment indicating that different processes may control primary production in waters and sediments. Nevertheless, primary production in water was linked to phosphorus pool in sediment.

Organic geochemical characteristics of the late Eocene–early Oligocene submarine fans and shelf deposits on Lemnos Island, NE Greece

The Paleogene deep-sea clastic and shelf deposits on Lemnos Island, NE Greece were studied regarding their organic geochemical characteristics. This study suggests that the above rocks can be designated as source rocks that have some moderate to fair potential for gaseous hydrocarbons. Studied sediments have been deposited in a forearc basin, with the outer arc ridge as a major sediment source. During late Eocene–early Oligocene Lemnos was the site of accumulation of submarine fans that underlay shelf deposits, with tectonic activity being responsible for the upward shallowing of the depositional environment. Areas of turbidites have been seen in parts of a sand-rich submarine fan, on the base of the slope to basin floor environment. On these rocks the Rock-Eval 6 pyrolysis method was performed to evaluate their hydrocarbon potential. Kerogens of both environments and subenvironments are of Type III and Type IV. Both submarine fans present considerable TOC content, but the ‘basin floor’ fan is the most enriched sub-environment. Shelf is presented in an immature oil stage, whereas both ‘slope’ and ‘basin floor’ fans are in the immature/mature oil stage.

Comments on “Geochemistry, petrogenesis and tectonic setting of the Samothraki mafic suite, NE Greece: Trace-element, isotopic and zircon age constraints” by Nikola Koglin, Dimitrios Kostopoulos and Thomas Reischmann, Tectonophysics 473 (2009), 53–68

The manuscript “Geochemistry, petrogenesis and tectonic setting of the Samothraki mafic suite, NE Greece: Trace-element, isotopic and zircon age constraints” presented by Koglin et al. (2009a) tries to re-interpret the Samothraki ophiolite as a non ophiolitic mafic suite, which has been generated in a propagated fore-arc rift setting. However, incomplete sampling by the authors and overinterpretation of the few data are suspicious. The geochemical and petrological similarity of the Samothraki mafic sequence with other well-known ophiolites is not acknowledged and the proposed geotectonic regime is unrealistic.

Comment on “Geochemistry, petrogenesis and tectonic setting of the Samothraki mafic suite, NE Greece: Trace-element, isotopic and zircon age constraints” by N. Koglin, D. Kostopoulos & T. Reischmann [Tectonophysics 473, 53–68 (doi:10.1016/j.tecto.2008.10.028)

The work by Koglin et al. (Koglin, N., Kostopoulos, D., Reichmann, T., 2009. Geochemistry, petrogenesis and tectonic setting of the Samothraki mafic suite, NE Greece: Trace-element, isotopic and zircon age constraints. Tectonophysics 473, 53–68. doi:10.1016/j.tecto.2008.10.028), where the authors have proposed to nullify the scenario presented by Bonev and Stampfli (Bonev, N., Stampfli, G., 2008. Petrology, geochemistry and geodynamic implications of Jurassic island arc magmatism as revealed by mafic volcanic rocks in the Mesozoic low-grade sequence, eastern Rhodope, Bulgaria. Lithos 100, 210–233) is here put under discussion. The arguments for this proposal are reviewed in the light of available stratigraphic and radiometric age constraints, geochemical signature and tectonics of highly relevant Jurassic ophiolitic suites occurring immediately north of the Samothraki mafic suite. Our conclusion is that the weak arguments and the lack of knowledge on the relevant constraints from the regional geologic information make inconsistent the proposal and the model of these authors.

Neogene–Recent extension on the eastern flank of Mount Olympus, Greece

The Olympus massif of NE Greece comprises metamorphosed and deformed Triassic and Cretaceous–Eocene carbonates considered to represent part of the passive southwestern margin of Neotethys, which separated the Apulia plate of mainland Greece from southern Europe in the Mesozoic. Ocean closure in the Early Tertiary led to subduction of this passive margin, as a result of which the Olympus carbonates were tectonically overridden in the Eocene by a series of thrust sheets consisting of locally high P/T (blueschist) metamorphosed continental margin sediments, basement granitoid gneisses, and ophiolitic rocks. Following collision, uplift of the Olympus carbonates by ~ 6–8 km was accomplished by Early Neogene ductile and Late Neogene–Recent brittle normal faulting, which exposed the carbonates in the form of a structural window through the overriding thrust stack. The focus of this exhumation occurred on the eastern flank of the massif where a thick calc–mylonite with down-to-the-east sense-of-shear indicators and a prominent zone of NNW- to NW-trending brittle normal faults separate the carbonates from telescoped structurally overlying units. Published 40Ar/ 39Ar microcline ages that indicate a thermal perturbation close to the contact zone in excess of 100–150 °C at 16–23 Ma (Early Miocene) are taken to date the onset of ductile extension, and imply long-term uplift rates of ~ 0.4 to 1 km/m.y. Degradation of Pleistocene glacial features on the Olympus massif and the presence on its eastern piedmont of deeply incised streams, erosional terraces, and fault scarps that offset the sedimentary deposits of three cycles of Pleistocene glacial deposition (Units 1–3), testify to its continuing uplift. A prominent frontal fault offsets Unit 2 by > 150 m and several subsidiary NW-trending normal faults with a cumulative displacement of ~ 130 m offset a paleosol developed on Unit 1. Kinematic indicators indicate normal dip-slip movement. Cumulative fault displacement for Unit 1 exceeds 277 m, yielding a minimum uplift rate of ~ 1.3 mm/yr, given the oxygen isotope stage 7 (Mindel/Riss) age of 210 ka proposed for the Unit 1 paleosol. Cumulative offset of > 196 m for the paleosol developed on Unit 2 yields an uplift rate of ~ 1.6 mm/yr, given its proposed isotope stage 5e (Riss/Würm) age of 125 ka. This estimate is supported by longitudinal valley profile data that document ~ 200 m of stream incision since Unit 2 deposition and show the offset as reflecting uplift of the Olympus massif rather than subsidence of the adjacent Gulf of Thermaikos. Assuming 1.8 Ma for the base of the Pleistocene, these rates yield a total uplift range for the Quaternary of 2.3–4.1 km, consistent with the present 2.6 km height of Olympus above the exposed frontal fault. Neogene uplift of Olympus was likely facilitated by extension accompanying the opening of the Aegean back-arc basin during the Miocene as a result of the southward retreat of the Hellenic subduction zone. For the Pliocene–Recent, uplift was likely facilitated by extension linked to the termination of dextral motion at the western end of the North Anatolian Fault associated with the westward tectonic escape of Anatolia .

Community structure of spiders in coastal habitats of a Mediterranean delta region (Nestos Delta, NE Greece)

Habitat zonation and ecology of spider assemblages have been poorly studied in Mediterranean ecosystems. A first analysis of spider assemblages in coastal habitats in the east Mediterranean area is presented. The study area is the 250 km² Nestos Delta, located in East Macedonia in the North-East of Greece. Spiders were caught in pitfall traps at 17 sites from the beginning of April to the end of June 2004. Nonparametric estimators were used to determine species richness and alpha diversity. Ordination analysis (redundancy analysis) indicated four clearly separable spider species groups (salt meadows, dunes, mea-dows and floodplain forests), along a soil salinity and moisture gradient. Based on these results we discuss the habitat preferences of these spiders and include the first ecological data on several species.

Single and multiphase inclusions in metapelitic garnets of the Rhodope Metamorphic Province, NE Greece

Single and multiphase inclusions in garnet porphyroblasts from the diamond-bearing pelitic gneisses were studied by means of combined Raman Spectroscopy and Electron Scanning Microscopy (SEM/EDX). They are either randomly distributed or with preferred orientation within the garnet host and their dimensions vary from less than 5 up to 60 μm. In the single-phase inclusions quartz, rutile, kyanite and graphite dominate. Biotite, zircon, apatite, monazite and allanite are also common. Two types of multiphase inclusions were recognized, hydrous silicate (Type I) and silicate–carbonate (Type II) ones. The carbon-bearing multiphase inclusions predominantly consist of Mg-siderite + graphite + CO 2 + muscovite + quartz formed by a high density carboniferous fluid rich in Fe, Mg, Si and less Ca, Mn, Al and K trapped in the growing garnet in a prograde stage of metamorphism at high-pressure (HP) conditions. The carbon-free multiphase inclusions predominantly consist of biotite + quartz + rutile ± kyanite + muscovite formed through decompression-dehydration/melting reactions of pre-existing phengite. Single and multiphase inclusions are characterized by polygonal to negative crystal shape formed by dissolution-reprecipitation mechanism between the garnet host and the inclusions during the long lasting cooling period (>100 Ma) of the Kimi Complex.