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    Age, composition and paleoenvironmental significance of a Late Pleistocene eolianite from the western Black Sea coast of Turkey
    (Pergamon-Elsevier Science Ltd, 2013) Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Ekinci, Yunus Levent; Demirci, Alper; Ertek, Ahmet; Canel, Timur
    On the basis of field observations, thin section interpretations, microanalytical data, electrical resistivity survey and luminescence dating, the age, composition and internal structure of coastal eolianite on the west Black Sea coast at Sile, Istanbul, was studied for a combined interpretation of dune rock development and facies characteristics. Results demonstrate that the eolianite is made up of south-dipping, large-scale dune stratification, consisting mainly of quartz sand and, in particular, abundant ooids, as well as the binding cement which is composed of calcite and aragonite. Based on Electrical Resistivity Tomography (ERT) images, the eolianite has a thickness of between 3.5 m and 8 m and overlies a buried rugged topography that has developed on the Pliocene unit. This suggests the predominance of northerly winds that account for the landward removal of dune sands by offshore wind drift prior to carbonate cementation. Optically Stimulated Luminescence (OSL) dating estimations revealed that the initial deposition of the laminated eolianite layers on the underlying older unit took place at 138.57 +/- 13.65 ka, matching the Karangatian highstand or Marine Isotope Stage (MIS) 5e. (C) 2012 Elsevier Ltd and INQUA. All rights reserved.
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    On the origin and age of the Ar?burnu beachrock, Gelibolu Peninsula, Turkey
    (2008) Erginal, Ahmet Evren; Kiyak, Nafiye Güneç; Bozcu, Mustafa; Ertek, Ahmet; Güngüneş, Hakan; Sungur, Ali; Türker, Gülen
    The beachrock formation on the Ariburnu coast situated in the Gelibolu Peninsula has been studied by field observation, thin-section interpretation, physicochemical analyses including ICP-AES and SEM/EDS, and OSL dating. These analyses reveal the presence of different amounts of major (Si, Ca, Mg, K. Fe, Al and Na) and trace elements within the beachrock cement with Si (36.2%) and Ca (32.68%) dominating the overall composition. Beachrocks composed of highly-fractured and friable beds reach a total thickness of 80 cm extending from +60 cm at the uppermost level down to -1 m at their most seaward extent and grade from conglomerate to lithic arkose in vertical section. The total amount of CaCO3 ranges between 59.08% and 36% and the cement consists of high-Mg calcite based on EDS analysis. From SEM examination, four main morphologies were identified in cement material: (1) micritic coatings, (2) cryptocrystalline pore-filling cement, (3) meniscus cement and (4) microbial cement and suggest the presence of marine phreatic conditions with the exception of meniscus bridges, which imply that cementation may have been dominated by carbonate-rich meteoric waters at any successive stage of cementation. Five buried beachrock samples under unconsolidated beach sand were sampled for Optically Stimulated Luminesce (OSL) dating and show that the minimum and maximum ages of beachrock are 1.42±0.20 ka and 2.28±0.28 ka BP, respectively. Copyright © TÜBİTAK.
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    Öğe
    On the Origin and Age of the Ariburnu Beachrock, Gelibolu Peninsula, Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2008) Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Bozcu, Mustafa; Ertek, Ahmet; Gungunes, Hakan; Sungur, Ali; Turker, Gulen
    The beachrock formation on the Ariburnu coast situated in the Gelibolu Peninsula has been studied by field observation, thin-section interpretation, physicochemical analyses including ICP-AES and SEM/EDS, and OSL dating. These analyses reveal the presence of different amounts of major (Si, Ca, Mg, K, Fe, Al and Na) and trace elements within the beachrock cement with Si (36.2%) and Ca (32.68%) dominating the overall composition. Beachrocks composed of highly-fractured and friable beds reach a total thickness of 80 cm extending from + 60 cm at the uppermost level down to-1 m at their most seaward extent and grade from conglomerate to lithic arkose in vertical section. The total amount of CaCO3 ranges between 59.08% and 36% and the cement consists of high-Mg calcite based on EDS analysis. From SEM examination, four main morphologies were identified in cement material: (1) micritic coatings, (2) cryptocrystalline pore-filling cement, (3) meniscus cement and (4) microbial cement and suggest the presence of marine phreatic conditions with the exception of meniscus bridges, which imply that cementation may have been dominated by carbonate-rich meteoric waters at any successive stage of cementation. Five buried beachrock samples under unconsolidated beach sand were sampled for Optically Stimulated Luminescence (OSL) dating and show that the minimum and maximum ages of beachrock are 1.42 +/- 0.20 ka and 2.28 +/- 0.28 ka BP, respectively.