Browsing by Subject "Sediment"
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Item Open Access Dating of Black sea sediments from Romanian coast using natural 210Pb and fallout 137CS(Akademiai Kiado Rt., 2004) Ayçık, G. A.; Çetaku, D.; Erten, H. N.; Salihoǧlu, İ.The sediment samples collected near the shore from Romania were used for the determination of levels of natural 210Pb, 226Ra and fallout 137Cs radionuclides. The sediment samples were dried and ground to a fine powder. Airtight sealed samples were counted by gamma-spectrometer with 110 cm3 well-type HPGe detector for one week each. By using the isotopic analysis results, sediment accumulation rate was determined. A sedimentation rate of 0.20±0.01 cm·y-1 was determined using 210Pb method and 0.15±0.03 cm·y-1 using 137Cs isotope. Fallout peak from Chernobyl reactor accident, as well as the peaks due to nuclear tests, act as time markers.Item Open Access Dating the sea of Marmara sediments by a uniform mixing model(Elsevier, 1996) Gökmen, A.; Yıldız, M.; Erten, H. N.; Salihoğlu, İ.The sedimentation rates and ‘t”Pb fluxes on sediment surfaces were measured in the north, northwestern and southwestern parts of the Sea of Marmara. Each core had varying thickness of constant 2’0Pb activity regions followed by a decreasing part with sediment depth. The sedimentation rates of the samples collected from the Bosporus and the Dardanelles could not be analysed due to the homogenization of activity in the strong currents of these straits. A untform mixing model is proposed for the simultaneous analysis of sedimentation rates, “‘Pb fluxes and mixing depths from the experimental data. In this model, the parameters were obtained by minimizing the multi-dimensional parameter space using a grid search algorithm. The 2’0Pbfluxes were found to be about 0.048 Bqcm-’ year-t for all sampling sites. The mass sedimentation rates were 0.19 and 0.073gcm-2 year-’ at the shelves of the Bosporus and the Dardanelles and 0.055 and 0.064 g cm-’ year -’ in the northwestern and middle northern basins, respectively, of the Sea of Marmara.Item Open Access Radiochronology of sediments from the Mediterranean sea using natural 210Pb and fallout 137Cs(Kluwer Academic Publishers, 1994) Tadjiki, S.; Erten, H. N.The210Pb and137Cs profiles of sediment cores from two locations in southern Spain, three locations in southern Turkey and two locations in northern Cyprus were determined by direct γ-ray spectroscopy. Sedimentation rates were derived for all locations using the210Pb data. The rates range from 1.39±0.12 cm · y-1 (0.50±0.04 g · cm-2 · y-1) to 0.08±0.01 cm · y-1 (0.039±0.003 g · cm-2 · y-1). Except for one core, the137Cs profiles were also used to compute sedimentation rates. The results are in good agreement with those of210Pb values. The results of the Constant Initial Concenration and Constant Rate of Supply dating models are in good agreement with each other. The flux of unsupported210Pb varies between 0.11±0.03 to 0.74±0.01 pCi · cm-2. The average depositional flux was found to be considerably lower for cores from the Eastern Mediterranean. © 1994 Akadémiai Kiadó.