Yazar "Kapan, Sevinc" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • [ X ]
    Öğe
    Dose estimation, kinetics and dating of fossil marine mollusc shells from northwestern part of Turkey
    (Pergamon-Elsevier Science Ltd, 2015) Aydas, Canan; Engin, Birol; Kapan, Sevinc; Komut, Tolga; Aydin, Talat; Paksu, Ufuk
    Electron spin resonance (ESR) spectroscopy was used to determine the geological formation age of fossil mollusc shells taken from marine terrace deposits (Ikizlerceme-Canakkale) in northwestern part of Turkey. This work reports the first results obtained by the ESR technique on shells collected from this region. In the ESR spectra of the natural and gamma-irradiated shell samples, two different signals attributed to orthorombic (g(xx)=2.0030, g(zz)=2.0015, g(yy)=1.9980) and isotropic (g=2.0006) CO2- ion radicals were overlaped (Signal C). Annealing and kinetic experiments suggest the possibility of using the ESR signal at g=2.0015 (C signal) for the estimation of accumulated geological doses. The ESR signal growth curve on additional gamma irradiation has been best fitted by a combination of two single exponential saturation functions. This may support the existence of at least two components of the g=2.0015 ESR dating signal. Based on this model, the accumulated dose of the samples was determined as 110 +/- 11 Gy. Also the isothermal decay curves of the ESR dating signal could be best described by the combination of two first order decay functions. Activation energy and meanlifetime values at 15 C of the two components were calculated as E-1 = 1.4 +/- 0.1 eV, E-2 = 1.1 +/- 0.1 eV, tau(1) = 7.2 x 10(6) years and tau(2)=33 x 10(3) years, respectively. Uranium content of the studied shells was found to be high according to their chemical analysis. This may point out that the marine shell has received uranium from outside particularly in carbonate sediment. Therefore, the ESR age of the samples was also calculated using Early Uptake (EU), Linear Uptake (LU) and Combined Uptake (CU) models and results were discussed. (C) 2015 Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Geochemical Evidences of Paleoenvironmental Changes in Late Quaternary Lacustrine Sediments of the Konya Closed Basin (Konya, Turkey)
    (Springer International Publishing Ag, 2019) Orhan, Hukmu; Delikan, Arif; Demir, Ahmet; Kapan, Sevinc; Olgun, Kemal; Ozmen, Ayhan; Sayin, Ulku
    Important geochemical evidence reflecting Quaternary climatic changes was obtained by evaluating geochemical data from 51 samples and datings from 3 samples by ESR method from sediments of a 7-m-deep trench in Great Konya lake area at the southwest of Adakale village (Konya, Turkey). The geochemical data indicate that the study area was influenced, four times, by a climate having strong precipitation, which caused strong erosion and high detrital input between 25,276 +/- 1732-year BP and approximately 50,000-year BP. These periods correspond to climatic changes during the last glacial periods, the warm climate of D-O-2, D-O-5, D-O-6 and D-O-14 events and the cold climate of H2, H3, H4 or H5 and H6 events.
  • [ X ]
    Öğe
    PALEOGENE STRATIGRAPHY AND MOLLUSCA FAUNA OF NORTHERN PART OF THE BIGA PENINSULA: FICITEPE FORMATION BETWEEN LAPSEKI-SEVKETIYE, CANAKKALE
    (Stef92 Technology Ltd, 2016) Gursoy, Birben; Kapan, Sevinc
    In this work, it is planned that to rearrange the Paleogene stratigraphy of the study area and interpret paleogeographic and paleoecological properties of the Paleogene sediments are exposed northeastern part of the Biga Peninsula (Ficitepe Formation and Danismen Formation) by using the data obtained from gastropoda-bivalvia fauna. Eleven measured stratigraphic sections were taken from sedimentary rocks which are outcroped in the study field. According to lithostratigraphic and biostratigraphic correlation of these sections, it was determined the stratigraphic positon of the investigation area. Systematic sampling was also carried out during the stratigraphic section measurement. It is identified that; 11 genus, 10 species from the samples are belonging to Fcitepe Formation. According to the stratigraphic level and paleogeographic distribution of the fauna, Fcitepe Formation's age is found as Late Eocene. Identified fauna represent that the shallow marine brackish water envorinment during the Late Eocene. At the same time, 36 genera, 34 species have been identified belonging to Danismen Formation which unconformably overlying on Ficitepe Formation. In the light of these fauna, the age of Danismen Formation is found as Late Oligocene and interpreted that warm, shallow, sublitoral and brackish water conditions were dominant.
  • [ X ]
    Öğe
    Paramagnetic characterization of fossil mollusc shells at eastern part of the old Konya lake: its importance for EPR dating
    (Oxford Univ Press, 2023) Ekici, Gamze; Sayin, Ulku; Isik, Mesut; Kapan, Sevinc; Demir, Ahmet; Aydin Karaaslan, Hulya; Delikan, Arif
    Fossil mollusc shells are used for dating geological materials because they are well preserved throughout geological time. In this study, the radicals in the structure of fossil mollusc shells (Dreissena iconica, Valvata piscinalis, Bithynia tentaculate, Unio pictorum) collected from the Eastern Part of Old Konya Lake in Turkiye were investigated by EPR technique. For all fossil shells, microwave and temperature dependence of the signals were examined, and the signals suitable for dating are discussed. Characteristic features of intrinsic and impurity-related radicals were identified and the importance of paleontological evaluation of molluscs to get a reliable equivalent dose in EPR dating studies was emphasised.
  • [ X ]
    Öğe
    The Importance of Pre-Annealing Treatment for ESR Dating of Mollusc Shells: A Key Study for Ismil in Konya Closed Basin/Turkey
    (Amer Inst Physics, 2018) Ekici, Gamze; Sayin, Ulku; Aydin, Hulya; Isik, Mesut; Kapan, Sevinc; Demir, Ahmet; Engin, Birol
    In this study, Electron Spin Resonance (ESR) spectroscopy is used to determine the geological ages of fossil mollusc shells systematically collected from two different geological splitting at Ismil Location (37.72769 degrees N, 33.17781 degrees E) in eastern part of Konya. According to the assessment of obtained ESR ages, the importance of pre-annealing treatment emphasize in the case of g=2.0007 dating signal is overlapped with the other signals arisen from short lived radicals that cause the wrong age calculation. To overcome this problem, the samples are pre-annealed at 180 degrees C for 16 minutes and, in this case ESR ages are recalculated for g=1.9973 dating signal. Dose response curves are obtained using 1.9973 signals after pre-annealing treatments for each samples. ESR ages of samples are obtained in the range of 138 +/- 38 ka and 132 +/- 30 ka (Upper Pleistocene) according to the Early Uranium Uptake model and the results are in good agreement with the estimated ages from stratigraphic and paleontological correlation by geologists. Thus, it is suggested that especially in the case of g=2.0007 dating signal cannot been used due to superimposition case, the signal with 1.9973 g value can be used for dating after pre-annealing treatment. The results reports the first ESR ages on shells collected from Ismil Location and highlight the importance of pre-annealing treatment. This study is supported by TUBITAK 114Y237 research project.