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Yayın Quaternary uplift of the northern margin of the Central Anatolian Plateau: New OSL dates of fluvial and delta-terrace deposits of the Kizilirmak River, Black Sea coast, Turkey(Pergamon-Elsevier Science Ltd, 2018-12-01) Berndt, Christopher; Yıldırım, Cengiz; Çiner, Tahsin Attila; Strecker, Manfred R.; Ertunç, Gülgün; Sarıkaya, Mehmet Akif; Özcan, Orkan; Öztürk, Tuğba; Güneç Kıyak, NafiyeWe analysed the interplay between coastal uplift, sea level change in the Black Sea, and incision of the Kizilirmak River in northern Turkey. These processes have created multiple co-genetic fluvial and marine terrace sequences that serve as excellent strain markers to assess the ongoing evolution of the Pontide orogenic wedge and the growth of the northern margin of the Central Anatolian Plateau. We used high-resolution topographic data, OSL ages, and published information on past sea levels to analyse the spatiotemporal evolution of these terraces; we derived a regional uplift model for the northward advancing orogenic wedge that supports the notion of laterally variable uplift rates along the flanks of the Pontides. The best-fit uplift model defines a constant long-term uplift rate of 0.28 +/- 0.07 m/ka for the last 545 ka. This model explains the evolution of the terrace sequence in light of active tectonic processes and superposed cycles of climate-controlled sea-level change. Our new data reveal regional uplift characteristics that are comparable to the inner sectors of the Central Pontides; accordingly, the rate of uplift diminishes with increasing distance from the main strand of the restraining bend of the North Anatolian Fault Zone (NAFZ). This spatial relationship between the regional impact of the restraining bend of the NAFZ and uplift of the Pontide wedge thus suggests a strong link between the activity of the NAFZ, deformation and uplift in the Pontide orogenic wedge, and the sustained lateral growth of the Central Anatolian Plateau flank.Yayın RegCM4.3.5 Bölgesel iklim modelini kullanarak Türkiye ve çevresi bölgelerin yakın gelecekteki hava sıcaklığı ve yağış klimatolojileri için öngörülen değişikliklerin incelenmesi(Ege Üniversitesi, 2014-06-01) Turp, Mustafa Tufan; Öztürk, Tuğba; Türkeş, Murat; Kurnaz, Mehmet LeventBu çalışmada 1970 – 2000 referans dönemi iklimine göre 2020 – 2050 dönemi için Türkiye’nin ortalama hava sıcaklığı ve yağış klimatolojilerinde öngörülen değişiklikler, bölgesel iklim modeli benzetimleri kullanılarak araştırıldı. Yakın gelecekteki iklim koşullarında öngörülen değişimleri incelemek için Uluslararası Teorik Fizik Merkezi’ne ait olan RegCM4.3.5 isimli bölgesel iklim modeli üç farklı küresel modelden yararlanılarak koşuldu. Max Planck Meteoroloji Enstitüsü’ne ait MPI-ESM-MR, Met Office Hadley Merkezi’ne ait HadGEM2 ve Amerikan Ulusal Okyanus ve Atmosfer Dairesi Jeofiziksel Akışkanlar Dinamiği Laboratuvarı’na ait GFDL-ESM2M modelleri Türkiye ve çevresi için dinamik olarak 50 km’ye alt ölçeklendirildi. Öngörüler, Hükümetlerarası İklim Değişikliği Paneli’nin (IPCC) RCP4.5 ve RCP8.5 salım senaryolarına göre gerçekleştirildi. Model sonuçlarına göre, Türkiye’de ortalama hava sıcaklıklarında 1970 – 2000 dönemine göre 2020 – 2050 döneminde 0.5 °C ile 4 °C arasında değişen artışlar olacaktır. Bu artış, sıcak mevsimlerde soğuk mevsimlere göre daha fazla olacaktır. Türkiye’nin yağış klimatolojisinde ise, bölgesel iklim modeli sonuçlarına göre, özellikle ülkenin Akdeniz ikliminin egemen olduğu batı ve güney bölgelerinde ve tüm mevsimlerde, yaklaşık 0.4 mm/gün ile 1.2 mm/gün arasında değişen belirgin yağış azalışlarının oluşması beklenir.Yayın Cement fabrics and optical luminescence ages of beachrock, North Cyprus: Implications for Holocene sea-level changes(Elsevier Ltd., 2016-05-16) Öztürk, Muhammed Zeynel; Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Öztürk, TuğbaCaCO3-cemented beachrocks are widely found along the northern coast of Cyprus. In this study, we aim to discuss the cementation history of beachrocks at ten particular sites within the context of Holocene sea-level changes. Cement fabrics, petrographic and geochemical characteristics, and optically-stimulated luminescence ages of buried quartz grains were studied. The seaward-inclined (~5-10°) parallel-stratified beds are composed mostly of sandstone alternating with conglomerate. Ooids, benthic and planktic foraminifera, bioclasts of red algae, echinoid spines and gastropods make up a significant proportion of the cemented beds. With CaCO3 content ranging between 37% and 65%, poorly-sorted grains are bonded by four distinct cements: circumgranular micritic coatings, sparry calcite infillings, pore fills, and meniscus bridges. This consecutive nature of cementation is typical of a marine phreatic and meteoric vadose environment when the sea level was lower than present but had a tendency to increase during middle to late Holocene. OSL ages ranging from 5.4 ka to 0.38 ka indicate that the deposition and ensuing cementation of the quartz grains occurred during two main stages; younger beds dated between 2.3 ka and 0.38 ka and older beds from 2.3 ka to 5.4 ka. A period devoid of beachrock formation was attested between 3.5 ka and 2.3 ka.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 RegCM4.3.5 İklim modeli benzetimleri kullanılarak Türkiye'nin gelecek hava sıcaklığı ve yağış klimatolojilerindeki değişikliklerin çözümlenmesi(Ege Üniversitesi, 2011-06-01) Öztürk, Tuğba; Türkeş, Murat; Kurnaz, Mehmet LeventBu çalışmada 1970-2000 dönemi günümüz iklimine göre 2070-2100 dönemi için Türkiye’nin ortalama hava sıcaklığı ve yağış klimatolojilerindeki değişikler, bölgesel iklim modeli simülasyonları (benzetim) kullanılarak öngörüldü. Günümüz ve gelecek iklim koşullarının model kestirimlerinin yapılması için, International Centre for Theoretical Physics (ICTP) bölgesel iklim modeli RegCM4.3.5 kullanıldı. Met Office Hadley Merkezi’nin HadGEM2 küresel iklim modeli, Türkiye ve çevresi için alt ölçeklendirme yöntemi ile çalışıldı. Gelecekte Türkiye’nin iklim değişkenlerinde oluşacak değişimleri incelemek için, küresel iklim modelinin RCP4.5 ve RCP8.5 salım senaryoları çıktıları kullanıldı. Model çıktılarına göre, Türkiye’de ortalama hava sıcaklıklarında 3 °C ile 7 °C arasında değişen artışlar olacaktır. Sıcaklık artışı, sıcak mevsimlerde soğuk mevsimlere göre daha fazla olacaktır. Bölgesel iklim modeli sonuçlarına göre, Türkiye’nin yağış klimatolojisinde ise, –0.8 mm/gün ile 1.2 mm/gün arasında değişen değişimler beklenmektedir.Yayın Projections of climate change in the Mediterranean Basin by using downscaled global climate model outputs(Wiley-Blackwell, 2015-11-30) Öztürk, Tuğba; Ceber, Zeynep Pelin; Türkeş, Murat; Kurnaz, Mehmet LeventThe Mediterranean Basin is one of the regions that shall be affected most by the impacts of the future climate changes on hydrology and water resources. In this study, projected future changes in mean air temperature and precipitation climatology and inter-annual variability over the Mediterranean region were studied. For performing this aim, the future changes in annual and seasonal averages for the future period of 2070-2100 with respect to the period from 1970 to 2000 were investigated. Global climate model outputs of the World Climate Research Program's Coupled Model Intercomparison Project Phase 3 multi-model dataset were used in this work. Intergovernmental Panel on Climate Change SRES A2, A1B and B1 emission scenarios' outputs were used in future climate model projections. Future surface mean air temperatures of the larger Mediterranean basin increase mostly in summer and least in winter, and precipitation amounts decrease in all seasons at almost all parts of the basin. Future climate signals for air temperature and total precipitation values are much larger than the inter-model standard deviation. Inter-annual temperature variability increases evidently in summer season and decreases in the northern part of the domain in the winter season, while precipitation variability increases in almost all parts of domain. Probability distribution functions are found to be shifted and flattened for future period compared to the reference period. This indicates that the occurrence of frequency and intensity of high temperatures and heavy precipitation events will likely increase in the future period.Yayın Eolianite and coquinite as evidence of MIS 6 and 5, NW Black Sea coast, Turkey(Elsevier B.V., 2017-04) Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Selim, Hamit Haluk; Bozcu, Mustafa; Öztürk, Muhammed Zeynel; Ekinci, Yunus Levent; Demirci, Alper; Elmas, Elmas Kırcı; Öztürk, Tuğba; Çakır, Çağlar; Karabıyıkoğlu, MustafaThis paper discusses the implications of a lowstand carbonate eolianite and overlying transgressive sequence of coquinite at Şile on the Turkish Black Sea coast based on composition, depositional characteristics and optical age estimations. The cross-bedded eolianite is a mixed ooid quartz grainstone in composition, yielding a depositional age matching MIS 6. It formed at the backshore of the paleobeach with the supply of sediment the from the beach face and offering insights into the drift of mixed shallow marine carbonates and siliciclastics together with radial ooids by onshore winds from a subaerially exposed high- to low-energy ooid shoals and oolitic sand complexes which developed parallel to the shoreline on the shallow shelf margin. During this lowstand, a low-relief dune retaining a record of opposing paleowind directions than that of prevalent northeasterly winds of today appears to have been lithified to form dune rock (aeolinite) under drier conditions compared to the present. Coinciding with MIS 5e, shallow marine coquina beds resting unconformably on the eolianite indicate the occurrence of the Mediterranean transgression during the last interglacial, as confirmed by benthic foraminifera within the high-salinity tolerant coquina shells.Yayın On the origin and age of the Ariburnu Beachrock, Gelibolu Peninsula, Turkey(Scientific Technical Research Council Turkey-TUBITAK, 2008-03-13) Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Bozcu, Mustafa; Ertek, Topçu Ahmet; Güngüneş, Hakan; Sungur, Ali; Türker, GülenThe 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 CaCO(3) 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.Yayın Impact of climate change on natural snow reliability, snowmaking capacities, and wind conditions of ski Resorts in Northeast Turkey: a dynamical downscaling approach(Mdpi Ag, 2016-04) Demiroğlu, Osman Cenk; Turp, Mustafa Tufan; Öztürk, Tuğba; Kurnaz, Mehmet LeventMany ski resorts worldwide are going through deteriorating snow cover conditions due to anthropogenic warming trends. As the natural and the artificially supported, i.e., technical, snow reliability of ski resorts diminish, the industry approaches a deadlock. For this reason, impact assessment studies have become vital for understanding vulnerability of ski tourism. This study considers three resorts at one of the rapidly emerging ski destinations, Northeast Turkey, for snow reliability analyses. Initially one global circulation model is dynamically downscaled by using the regional climate model RegCM4.4 for 1971-2000 and 2021-2050 periods along the RCP4.5 greenhouse gas concentration pathway. Next, the projected climate outputs are converted into indicators of natural snow reliability, snowmaking capacity, and wind conditions. The results show an overall decline in the frequencies of naturally snow reliable days and snowmaking capacities between the two periods. Despite the decrease, only the lower altitudes of one ski resort would face the risk of losing natural snow reliability and snowmaking could still compensate for forming the base layer before the critical New Year's week. On the other hand, adverse high wind conditions improve as to reduce the number of lift closure days at all resorts. Overall, this particular region seems to be relatively resilient against climate change.Yayın First note on marine-like cementation of Late Holocene beachrock, Iznik Lake (Turkey)(Versita, 2012-03) Erginal, Ahmet Evren; Güneç Kıyak, Nafiye; Öztürk, Muhammed Zeynel; Yiğitbaş, Erdinç; Bozcu, Mustafa; Avcıoğlu, Mustafa; Öztürk, BeyhanMicro-fabric characteristics and optically stimulated luminescence (OSL) dating results are presented to discuss the controlling agents and timing of beachrock cementation on the fresh-water Iznik Lake shoreline. The beachrocks are made up of grain-supported polygenic conglomerate containing 20.42% carbonate with encrusted grains, basically as micrite coatings, isopachous aragonite rims, cryptocrystalline void fills and meniscus bridges. The optical ages of twelve samples yielded ages that range from 4.226 +/- 0.569 ka on the lowermost beds to 0.706 +/- 0.081 on the uppermost. This is the first report of precipitation of marine-like cements in Iznik Lake. The abundant aragonite-dominated cement is likely indicative of precipitation-prone dry evaporative conditions from the climatic optimum to the last millennia.
