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Yayın A new late holocene eolianite record from Altinkum Beach, North Cyprus(Scientific technical research council Turkey-Tubitak, 2012-06) Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Ertek, Topçu AhmetIn this study, we investigated the main depositional characteristics and obtained Optically Stimulated Luminescence (OSL) ages of coastal eolianite on the north coast of Cyprus, where this occurrence had not previously been recorded. Based on EDX/SEM and XRD data and field observations, the studied eolianite that crops out between elevations of 1 m and 14 m a.s.l. is made up predominantly of quartz grains, most of which consist of medium- to fine-grained sand. The rock comprises aragonite, calcite and quartz with lesser amounts of bornite and hematite as accessory minerals. OSL ages indicated that the initial deposition of eolianite sands took place at 1.51 +/- 0.21 ka years ago.Yayın Component resolved OSL dose response and sensitization of various sedimentary quartz samples(Elsevier Ltd, 2007-02) Güneç Kıyak, Nafiye; Polymeris, George S.; Kitis, GeorgeThe structure of the linearly modulated optically stimulated luminescence (LM-OSL) signal was studied for four sedimentary quartz samples, collected from different sites around Istanbul, Turkey. Applying a computerized deconvolution analysis to the LM-OSL curves, at least six individual components of first-order kinetics were identified and photoionization cross-section of each component was evaluated. The OSL dose-response curve of each component for each quartz sample was obtained, showing a remarkable differentiation from component to component. The behavior of a highly dosed sample to successive LM-OSL measurements was also studied showing a stable recuperation signal in the position of the "slow" and "medium" components and high resistance to OSL bleaching of the "slow" component. The individual sensitivity of each component as a function of the activation temperature was obtained. The sensitivity of each component was normalized over the respective sensitivity of the glow-peak at 110 degrees C of quartz in order to investigate the ability of the 110 degrees C glow-peak to act as a correction factor for all components of the LM-OSL curves examined.Yayın A comparative morphological, compositional and tl study of tenedos (Bozcaada) and Sile aeolianites, Turkey(Univ Agean, 2012) Polymeris, George S.; Erginal, Ahmet Evren; Güneç Kıyak, NafiyeAeolianites are carbonate-cemented deposits of coastal dune sands, mostly of Quaternary age. Even though aeolianite exposures on the coasts of the Mediterranean Sea are frequent, very few records have been documented from the coasts of either the Aegean or the Black Sea. The present study deals with evaluating and comparing both compositions and thermoluminescence (TL) ages of two recently reported samples of coastal aeolianites. Both were recovered at the Turkish coasts of Tenedos (Bozcaada) island, Aegean Sea and Şile, Western Black Sea. In the latter case, being the first record for the specific coastal area, the oldest age obtained was dated at 158±25 ka while the youngest age yielded was 108±14 ka. These values imply that both deposition and cementation occurred during the high sea stand of marine isotope stage 5 (MIS 5). In the case of Tenedos, the aeolianites were deposited between the early stage of the oxygen isotope stage 2 period (OIS 2) and the very late phase of the oxygen isotope stage 3 period (OIS 3). These latter TL results are in excellent agreement with a previous study of the same complex after applying OSL. Besides the ages, a number of luminescent features and properties in conjunction with compositional data suggest the dissimilarity for the quartz samples extracted from the aeolianites recovered at these two sampling sites, excluding thus any transport from one sampling site to the other, despite the short distance of the two sampling sites and the meteorological data regarding the preferable wind directions between them.Yayın The firing temperature of pottery from ancient Mesopotamia, Turkey, using luminescence methods: a case study for different grain-size fractions(Wiley-Blackwell, 2014-10) Polymeris, George S.; Güneç Kıyak, Nafiye; Koul, Dileep K.; Kitis, GeorgeThe assessment of the firing temperature of a prehistoric pottery sample collected from ancient Mesopotamia, Turkey was studied using luminescence techniques. The methods for this estimation involved the observation of the thermal and pre-dose sensitization with various re-firing temperatures for both TL and the OSL signals. In the former case, the 110 degrees C TL peak and the rest of the glow curve were used as proxies in this study. In the framework of a first attempt to investigate the impact of grain-size dependence on the sensitization of the luminescence signals, the aforementioned study was performed with four different pottery grain-size fractions: (i) less than 60m, (ii) 60-90m, (iii) 90-180m and (iv) 180-250m. The results clearly demonstrated the firing temperature mark of approximate to 500 degrees C in for the grain size of 90-180m, whileas in the case of the lower grain-size fractiona third proxy, the ratio of the pre-dosed to the thermal sensitization, was seen to indicate the firing temperature. The remaining two grain-size fractions failed to provide any meaningful results with regard to the firing temperature estimation. The dependence of the TL characteristics on the grain size was explained in the framework of the mixed mineralogy.Yayın Optical stimulated luminescence dating study of eolianite on the Island of Bozcaada, Turkey: Preliminary results(The Coastal Education and Research Foundation, 2010-07) Güneç Kıyak, Nafiye; Erginal, Ahmet EvrenIn the present paper, eolianite exposed on the south coast of the semiarid island of Bozcaada, Turkey, was investigated on the basis of geomorphologic and petrographic data, and optically stimulated luminescence (OSL) dating results. The eolianite is lithic arenite in composition and contains abundant quartz, calcite, and various lithoclasts amalgamated with micritic calcite, sparitic calcite, and meniscus cements. Within the youngest layers standing at 1-2 m above sea level, the rock contains rhizoliths with or without carbonaceous fills. The OSL ages obtained ranged between 24.21 +/- 1.53 ka and 16.18 +/- 1.70 ka, suggesting that eolianite constitutes an example of low stand deposits coinciding with oxygen isotope stage 2 (OIS-2).Yayın Effect of annealing temperature on determining trap depths of quartz by various heating rates method(Pergamon-Elsevier Science, 2001-12) Güneç Kıyak, Nafiye; Buluş, E.The aim of this study is to determine the trap parameters (trap depth E, frequency factors) of quartz using various heating rates method and also to investigate the effect of annealing temperature on determining trap depths. The method is based on the positions of the thermoluminescence peaks, obtained from the change in temperature of the peak at maximum caused by changing the heating rate at which the sample is measured. In the present work, powder quartz samples were annealed first at different temperatures before irradiation. Then samples irradiated to different doses were measured with a TL reader at different heating rates and the glow curves were recorded. In order to calculate the trap depth E and the frequency factor s, the glow parameter T-m was determined experimentally from the glow curve by measuring the shift of the maximum peak temperature depending on heating rate beta. The calculation of trap parameters was repeated for each annealing temperature. Then the effect of annealing temperature on trap depths calculated by the various heating rates method was evaluated.Yayın Equivalent dose in quartz from young samples using the SAR protocol and the effect of preheat temperature(Pergamon-Elsevier Science Ltd, 2006-09) Güneç Kıyak, Nafiye; Canel, TimurMajor concerns in the dating of samples younger than a few hundred years by the optically stimulated luminescence (OSL) technique are thermal transfer and partial bleaching. Thermal transfer during preheating enhances the OSL signal due to the charge transfer from thermally sensitive, but light-insensitive, traps to optical centres of quartz and results in an overestimate in equivalent dose, especially for very young samples. In this study, the single-aliquot regenerative-dose protocol is used to obtain values of equivalent dose (D-e) from young samples taken from various environments around Istanbul. Within this framework, we aim to investigate the effect of preheat temperature on equivalent dose from 150 to 300 degrees C, the reproducibility of De measurements for young deposits and the contribution from thermal transfer of charge to the equivalent dose estimation. It was observed that the measured dose is influenced significantly by preheat temperature and the increase in the De is clearly due to thermal transfer of charge from deep thermally sensitive traps to OSL trap during preheating of the samples prior to the main OSL measurements.Yayın Luminescence dating of prehistoric site of smintheion (Gulpinar) in NW Turkey(Univ Agean, Dept Mediterranean Stud, 2010) Güneç Kıyak, Nafiye; Takaoğlu, Turan; Erginal, Ahmet Evren; Özcan, HalilThis study aims to place the prehistoric settlement of Smintheion in northwestern Turkey in its temporal setting on the basis of the dating of the quartz from pottery and sediments collected from the site employing Optically Stimulated Luminescence and Thermoluminescence techniques. The site belongs to the problematic Middle Chalcolithic period in western Anatolia. This period represents a cultural upheaval in western Anatolia as it has a completely different material culture when compared to that of the preceding Early Chalcolithic period. The pottery and sediment samples were collected from two different locations of the Middle Chalcolithic settlement at Smintheion for dating study. The fact that this examined settlement is represented by a single cultural level provides an opportunity to obtain secure and reliable dates for the settlement. Results of this study show that the site can be dated to a period between 4800 and 4500 B.C.Yayın Age, composition and paleoenvironmental significance of a Late Pleistocene eolianite from the western Black Sea coast of Turkey(Pergamon-Elsevier Science Ltd, 2013-05-16) Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Ekinci, Yunus Levent; Demirci, Alper; Ertek, Topçu Ahmet; Canel, TimurOn 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.Yayın Investigation of the OSL signal from very deep traps in natural quartz(Univ Agean, Dept Mediterranean Stud, 2010) Kitis, George; Güneç Kıyak, Nafiye; Polymeris, George S.; Pagonis, VasilisIt has been recently reported by several studies that a thermally transferred optically stimulated luminescence (TT-OSL) signal from quartz grains can be used to extend the dating range for quartz samples. The TT-OSL signals are believed to consist of a recuperated OSL (ReOSL) component and a basic-transferred OSL (BT-OSL) component. In the present work the TT-OSL signals from several types of unfired quartz samples were studied. A special protocol was used, which allowed the measure the OSL from very deep traps (VDT) as a function of the OSL stimulation temperature. It was found that all quartz samples exhibit TT-OSL signals, which are depended on sample and on the OSL stimulation temperature. The activation energy of the process was evaluated and the influences of the TT-OSL on the ReOSL dating protocol are discussed.
