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Yayın Akdağ Kütlesi’nde (Batı Toroslar) Pleistosen buzullaşmalarının jeomorfolojik özellikleri ve optik uyarmalı lüminesans (OSL) ile yaşlandırılması(Türk Coğrafya Kurumu, 2017) Bayrakdar, Cihan; Güneç Kıyak, Nafiye; Turoğlu, Hüseyin; Öztürk, Tuğba; Canel, TimurBatı Torosların en yüksek ikinci zirvesine (Uyluk T. 3014 m) sahip olan Akdağ, batıda Eşen Ovası (60 m) doğuda Elmalı Ovası (1100 m) arasında yer alan ve 2700 m üzerinde birçok zirve barındıran, çevresine göre oldukça yüksek bir kütle görünümündedir. Akdağ Kütlesi'nde Kuvaterner'de meydana gelen buzul şekillerini incelemek ve OSL ile tarihlendirmek çalışmanın temel amacıdır. Bu çalışmada coğrafi bilgi sistemleri ve morfometrik analizler, OSL tarihlendirme yöntemi ve sedimantolojik analizlerden faydalanılmıştır. Akdağ Kütlesi'nin jeomorfolojik gelişiminde birden fazla etken ve sürecin rolü olmuştur. Bu süreçlerin başında karst, buzul, tektonik ve flüviyal gelmektedir. Akdağ Kütlesi'nde etkili olan Pleistosen buzullaşmaları, büyük ölçüde karstik yapıya uyumlu gelişmiş ve 2500 m ve üzerindeki paleo-karstik depresyonlarda kalın plato buzulları oluşmuştur. Akdağ Kütlesi'nde üçü büyük, beş buzul vadisi tespit edilmiştir. Bu buzul vadileri gelişmiş sirklerle başlayıp 2500 m seviyelerinde paleokarstik depresyonlara uyumlu olarak düşük eğimli, geniştabanlı ve büyük ölçüde taban ve yanal morenleri ile kaplı iken 2500 m seviyelerinden sonra vadiler daralıp klasik tekne vadi formu alıp 2000 m seviyelerinde cephe morenleri ile sonlanırlar. Akdağ Kütlesi'nde morenlerden alınan örneklere ait OSL tarihlendirmelerinde 17-21 bin yaşları çıkmıştır ki bu da son buzul dönemi MIS 2 ye denk gelmektedir.Yayın Did amphistegina lobifera Larsen reach the mediterranean via the Suez Canal?(Elsevier Ltd., 2016-05-16) Meriç, Engin; Yokeş, Mehmet Baki Aki; Avşar, Niyazi; Güneç Kıyak, Nafiye; Öner, Ertuğ; Nazik, Atike; Demirtaşlı, Erdoğan; Dinçer, Feyza; Öztürk, Muhammed ZeynelIt has been accepted by many researchers that Amphistegina lobifera Larsen migrated to the Mediterranean Sea via Suez Canal like many other Indo-Pacific originated foraminifers and organisms. This idea was also supported in the studies performed on the Turkish Aegean and Mediterranean coast in the last ten years, due to the discovery of alien benthic foraminifers. However, during field research in the Akkuyu (Mersin) region, a rich benthic foraminifera assemblage was found in the sediment samples, in which Amphistegina lobifera Larsen was abundant. In the present study, when and how Amphistegina lobifera Larsen migrated to the Mediterranean was investigated.Most of the Amphistegina lobifera Larsen individuals observed are found to show similar morphological characteristics with recent samples collected from Turkish coastline, which at first indicated that the individuals from Akkuyu might also be of Holocene age, but the OSL method produced dates of 227.3 ± 17.8, 87.7 ± 9.6 and 6.0 ± 0.6 ka. These ages are Middle Pleistocene, Late Pleistocene and Holocene. In one sample, aged 427.5 ± 29.4 ka, Spiroloculina antillarum d'Orbigny, which was suggested to be introduced to Mediterranean via the Suez Canal, was found together with Articulina carinata Wiesner. The presence of Spiroloculina antillarum d'Orbigny with Amphistegina lobifera Larsen together with in an other sample, aged 227.3 ± 17.8 ka, indicates that these foraminifers have been introduced to the Mediterranean in Middle Pleistocene and they might have been living in the Eastern Mediterranean since then. As a result, these age data show that Amphistegina lobifera Larsen individuals did not migrate to the eastern Mediterranean via the Suez Canal which was opened in 1869, but much earlier than that via a different natural water way connecting Indo-Pacific to the Eastern Mediterranean.Yayın Records of repeated drought stages during the Holocene, Lake Iznik (Turkey) with reference to beachrock(Pergamon-Elsevier Science Ltd., 2016-07-15) Öztürk, Muhammed Zeynel; Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Demirci, Alper; Ekinci, Yunus Levent; Cürebal, İsa; Avcıoğlu, Mustafa; Öztürk, TuğbaThe cement fabrics, subsurface nature and optically stimulated luminescence age of beachrocks along the shores of Lake Iznik in NW Turkey were studied within the context of Holocene lake level changes. With a maximum thickness of 1.5 m, the low-angle (average 5-10 degrees) beds are composed of coarse grains and small gravels and extend up to 5 m offshore at their most lakeward extremities. Cement textures on and around the poorly-rounded grains are made up of micrite envelopes and meniscus bridges as well as acicular aragonite rims. Geoelectrical resistivity sections taken from a representative location along the beach where the beds have maximum thickness showed that the sand-buried beds are followed up to about 24 m landward. Based on the OSL ages of 33 samples, the cemented beds occurred at four drier periods of the following: Pre- and Early Holocene (dated to 15-9 ka), Holocene Climatic Optimum (7.9-5.6 ka), Middle Holocene (4.9 ka-2.8 ka) and Late Holocene (2.0 ka-0.9 ka).Yayın Preliminary results towards the equivalence of transformed continuous-wave Optically Stimulated Luminescence (CW-OSL) and linearly-modulated (LM-OSL) signals in quartz(Versita, 2011-09) Kitis, George; Polymeris, George S.; Güneç Kıyak, Nafiye; Pagonis, VasilisThe present paper presents a comparative experimental study of two commonly measured Optically Stimulated Luminescence (OSL) signals in quartz. The experimental study measures both the continuous wave OSL (CW-OSL) and the linearly modulated (LM-OSL) signals from the same quartz sample for a range of stimulation temperatures between 180 and 280A degrees C, while the former is transformed to pseudo LM-OSL (ps LM-OSL). A computerized deconvolution curve analysis of the LM-OSL and ps LM-OSL signals was carried out, and the contributions of several OSL components to the initial OSL signal (0.1 s) were shown to be independent of the stimulation temperature used during the measurement. It was also found that the composite OSL (0.1 s) signal consists mainly of the first two OSL components present in the OSL curves. The equivalence of the ps LM-OSL (transformed CW-OSL) and of LM-OSL measurements was also examined by an appropriate choice of the experimental stimulation times, and of the stimulation power of the blue LEDs used during the measurement.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 Luminescence ages of feldspar contaminated quartz from fluvial terrace sediments(Wind-J Wojewoda Publ Co, 2008-01-01) Güneç Kıyak, Nafiye; Erturaç, Mehmet KorhanThis study focuses on obtaining luminescence ages in feldspar contaminated quartz from well-developed fluvial terraces of the Yesilirmak (Iris) river located inside the eastern North Anatolian Fault Shear Zone (NAFZ). We applied a technique based on conventional single-aliquot regenerative-dose (SAR) protocol, modified with an IR pre-treatment to reduce the OSL contribution from feldspar for accurately measuring the dose in quartz. All investigated samples showed an ability to measure a beta dose given in the laboratory, a so called dose recovery test. The dependence of the equivalent dose on thermal treatment was also examined. Dose rate calculations were based on spectral analysis of gamma measurements by a field spectrometer on site. The efforts to establish a chronology using the IR modified SAR technique produced reliable dose results in stratigraphic order. Results were reproducible and grouped broadly between 35-109 ka for Bektemur, 32-36 ka for Kizilca, 19-47 ka for Aksalur and 35-44 ka for Sahinkaya. Obtained results show that the studied area was controlled by tectonic activities within the last 50 ka and the sample Aksalur 2 was the loess deposit formed by aeolian activity.Yayın Quaternary rock uplift rates and their implications for the western flank of the North Anatolian Fault restraining bend; inferences from fluvial terrace ages(Blackwell Publishing Ltd, 2020-10-01) McClain, Kevin P.; Yıldırım, Cengiz; Ciner, Attila; Şahin, Sefa; Sarıkaya, Mehmet Akif; Özcan, Orkan; Güneç Kıyak, Nafiye; Öztürk, TuğbaIn the western flank of the North Anatolian Fault restraining bend (i.e., Central Pontides), the Filyos River incises through the uplifting Karabük Range, creating the ~1.7-km-deep Filyos River Gorge on the hanging wall of the reverse Karabük Fault. Seven fluvial strath terrace levels are preserved in this gorge. optically stimulated luminescence ages from quartz-rich sediments of five terrace levels reveal an average long-term rock uplift rate of 0.45 ± 0.02 mm yr?1 with an unsteady pattern of uplift during the last 542 ± 24 kyr. Uplift rates of 1.52 ± 0.6 and 0.74 ± 0.3 mm yr?1 occurred before 366 ± 19 kyr, followed by lower rates of ~0.1 and 0.31 mm yr?1 through present. These later uplift rates may reflect relatively slower tectonic rates since ~366 kyr, with closer similarity to regional uplift rates of ~0.3 mm yr?1 yielded from the eastern flank of the Central Pontides. The Karabük Range fluvial terraces are near the North Anatolian Fault, meaning pre- ~366 kyr uplift rates may be a glimpse of the highest Central Pontides Quaternary rock uplift rates on uplifting hanging wall blocks activated by the restraining bend. When we consider offshore seismic reflection data, the focal mechanism solution of the Bartın Earthquake, onshore structural data, and regional tectonic geomorphology, the western flank of the Central Anatolian Plateau's northern margin is propagating northward as a growing orogenic wedge with a positive flower-structure geometry.Yayın River, alluvial fan and landslide interactions in a tributary junction setting: Implications for tectonic controls on Quaternary fluvial landscape development (Central Anatolian Plateau northern margin, Turkey)(Elsevier B.V., 2021-03-01) McClain, Kevin P.; Yıldırım, Cengiz; Çiner, Tahsin Attila; Sarıkaya, M. Akif; Özcan, Orkan; Görüm, Tolga; Köse, Oğuzhan; Şahin, Sefa; Güneç Kıyak, Nafiye; Öztürk, TuğbaAlong the western flank of the northern margin (Central Pontides) of the Central Anatolian Plateau, the humidity from the Black Sea is much higher than the central and eastern flanks and creates a complex relationship between surface and tectonic processes by triggering intense mass wasting activity and aggradation within narrow valleys. We identified three incised fill terrace levels and used Optically Stimulated Luminescence (OSL) dating to calculate fluvial sediment ages and cosmogenic 36Cl exposure dating to calculate limestone boulders exposure ages across the terrace surface. Stratigraphical interpretations and OSL ages of the lowest levels revealed that a fluvial fill terrace formed in the main valley at 275.6 ± 12.8 ka and was overlain by a main river-tributary junction alluvial fan that was abandoned at 39.5 ± 3.5 ka. The results collectively show the influence of climate, topography, hillslope processes, and lithology on aggradation-incision patterns of main rivers. Prolonged aggradation can prevent the channel equilibrium required to calculate rock uplift rates while also causing a new base-level and aggradation upstream. This effect can be exacerbated in uplifting mountainous regions with limited depositional areas. Bedrock incision rates based on the fluvial terrace age were between 0.15 and 0.2 mm/a since 39.5 ± 3.5 ka. However, the high aggradation within this segment of the main valley prevented incision of the channel bedrock for long periods, causing a potential underestimation of the rock uplift rate calculation. Our local period of aggradation appears to be related to increased aggradation and decreased bedrock incision rates measured 14 km upstream that were previously assumed to be the result of decreased tectonic uplift rates. This demonstrates the importance of corroborating strath terrace incision rate estimations with ages and incision rates of downstream fill terraces, if present, to check for potential interference with the tectonic signal.
