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Distribution of quaternary deformation along the coasts of Cyprus, inferences from marine terraces
Cyprus is located on the subduction zone between African and Eurasia Plates. The topography of the island is a result of distributed deformation associated with the subduction related processes in the south of the Eurasia Plate. Trodos and Kyrenia mountains are major morphotectonic units that integrally tied to plate boundary deformations. The presence of uplifted marine terraces is piece of evidence of subduction related active deformation in the part of the island. To understand rate and pattern of deformation, I conducted geomorphic mapping of marine terraces by ArcGIS and analyzing of paleo-cliffs by TerraceM Matlab based program. As a result of these analyzes I calculated the uplift rates with reference to MIS 5. Here will present morphotectonic implications from temporal and spatial distribution of marine terraces along the Cyprus.
Determination of last glacial equilibrium line altitudes of Turkey by glacial mass balance model
Turkey is located in the Eastern part of Mediterranean region between 36°N and 42°N latitude and 26°E and 45°E longitude. Turkey's climatic and topographic features have strong contrasts which indicate a characteristic feature for Turkey. As a general view, Turkey has a varied topography for its all geographical regions. Turkey is a mid-latitude country located with a relatively high topography. In the current climate of Turkey, glaciers do not occupy large areas but it is known that paleo-glaciers covered larger areas during the Last Glacial stage based on earlier studies. There is a close relationship between climate and equilibrium line altitude (ELA) of a glacier. Glaciers are the most commonly used indicators for climate change. The purpose of this study is to calculate Turkey's ELA by glacial mass balance model during the Last Glacial Maximum (LGM) and compare with previous studies. For this purpose, monthly present day temperature and precipitation were used to make paleo-climatic estimations. The Last Glacial stage ELA were determined by a glacier mass balance model and compared with previous studies. In total, 25 glacial areas have been studied. Using the monthly temperature and precipitation data obtained from WorldClim, annual ablation was calculated by positive degree day model and annual accumulation were calculated assuming that precipitation falls as snow at 0°C. Calculations made by an in-house Matlab program. Annual mass balances were found with the difference between the accumulation and ablation values. The simulations for the last glacial period were firstly done with the precipitation was kept the same as the present conditions, and the temperature depressions was changed between -8°C and -12°C. In the second case, the temperature was kept constant (-10°C lower than today), the precipitation was changed from drier (%25 drier) to humid (%25 wetter) conditions than today. Accordingly, the last glacial paleo-equilibrium line altitudes in Turkey were calculated and spatially compared with earlier studies. When temperature is 10°C cooler than today and precipitation is in the present day condition (Precipitation=1), ELA decreasing from south of Turkey to the north. It is almost between 2400- 2500 m a.s.l. in the Southeast Taurus. In Akdağ and Beydağ, ELA is more than 2200 m a.s.l in Sandıras, Davraz, Dedegöl, Geyikdağ, Aladağlar and Bolkar, ELA is about 2200 m. It has a decreasing pattern toward to north. Erciyes and Soğanlı Mountains have ELA 2000-2200 m. In Uludağ which is situated in the north part of the Turkey it is in between 1600-1800 m. In the eastern part of Turkey, ELA is higher when it compared with western Turkey. In Buzul and İkiyaka Mountains, ELA is in between 2600-2700 m. Southeast part of Turkey has the highest ELA value. For –10°C temperature decrease and same as today's precipitation values (from south to north) there is a decreasing pattern. It shows that there is clear latitude effect in Turkey's ELA. From west to east ELA is increasing as elevation 'increasing from west to east. It also shows that elevation affects the ELA in Turkey because elevation is increasing from west to east. The places where elevation is high have higher ELA compared to other places in the Turkey. According to the study of Messerli (1967), ELA is 2300 m in the Black Sea region. When the temperature -8 °C below today and present day precipitation condition, ELA estimates of 2000- 2100 m in the Black Sea close the Messerli's estimates. In the Mediterranean ELA is around 2500 m. For Mediterranean, all results that I have are higher than 2000 m. This can indicate ELA is almost same values in the Mediterranean in LGM. In the south east region that have most of the glaciers, ELA is between 2700-2800 m in the study of Messerli (1967). It is more than 2400-2500 m in southeast region for all the cases applied. That also shows that there is a match between these values. In the west part of Turkey, ELA is around 2300 m in Messerli (1967) study but in this part, I got lower ELA values when it compares to Messerli (1967)'s study.
Tokat masifi kuzeyinin (Taşova-Ladik) metamorfik evrimi
TOKAT MASİFİ KUZEYİNİN (TAŞOVA-LADİK) METAMORFİK EVRİMİ Bu tezin amacı, Tokat Masifinin en kuzeyinde yer alan Liyas-önecesi yaşlı kayaçların evrimini ortaya koymaktır. Bu amaç için başlıca Taşova ve Ladik bölgeleri seçilmiştir. Taşova bölgesinde Liyas öncesi birimler düşük dereceli metamorfitler ve Orta Permiyen yaşlı kireçtaşlarından oluşurken, Ladik bölgesinde ise yalnızca Orta Permiyen yaşlı kireçtaşlarından oluşmaktadır. Tokat Masifi, Taşova ilçesinde, başlıca metabazit, fillit, mermer, kalkfillit ve bu metamorfik kayaçların içerisinde ~2 km2'lik bir alanı kapsayan ve metamorfik olmayan kireçtaşı kitlesi tarafından temsil edilmektedir. Bu birlikteki metamorfik birimleryeşilşist-mavişist geçişli koşullarda başkalaşıma uğramıştır. Metamorfitler içindeki metabazitler okyanus adası bazalt-zenginleşmiş okyanus ortası sırtı bazalt niteliği sunmakta olup, olasılıkla okyanus içi deniz dağlarının (semount) eklenmiş parçalarını temsil etmektedir. Kayaç birlikteliği bakımından, Taşova kuzeyindeki metamorfik kayaçlar bir yığışım karmaşası niteliğindedir. Bu verilere göre, Tokat Masifi, Lavrasya kıtasının Permo-Triyas döneminde aktif güney kenarı boyunca bulunan Tetis Okyanusunun kapanması ile ilişkilidir. Bu özelliği ile Sakarya Zonu'ndaki, Karakaya Karmaşasının Nilüfer birimi ile deneştirilebir. Dolayısıyla Taşova yöresinde metamorfitler, daha doğuda bulunan Ağvanis metamorfitleri ve Pulur masifinin tabanındaki düşük dereceli birimin batıya doğru devamı niteliğindedir. Liyas önceki birimler arasındaki kireçtaşlarının her iki bölgede tabanı direk olarak gözlenmemektedir. Bu kireçtaşları bol miktarda Orta-Üst Permiyen (Vordiyen-Kapitaniyen) çağını karakterize eden Foraminifer fosili içermektedir. Yer bilimleri literaturunde genel itibarıyla bu kireçtaşlarının daha güneyde bulunan Gondvana kıtasından türemiş olduğu görüşü savunulmaktadır.
Paleoenvironmental interpretations for Kizilirmak delta plain using sedimentological records, multiproxy analysis and palynology
The Kızılırmak Delta is the delta of the Kızılırmak River and it's located near the province of Samsun, Central Black Sea Region of northern Turkey (41◦30 to 41◦45' N, 35◦43' to 36◦08' E). The latest major transgression of the Black Sea is related to the glacial melting accompanied with a worldwide sea level rise. The eastern Kızılırmak Delta platform is thought to be a part of a post-glacially filled canyon system, which has been incised into the former delta platform during the last glacial. The sediment fill of canyon were supplied by the Kızılırmak River. A sediment core was obtained from possible location of filled canyon system in the eastern wetlands of Kızılırmak Delta Plain. High sedimentation rate of the Kızılırmak River provide a perfect archive and continious records of the environmental and climatic conditions for Quaternary. Lithological properties, multi proxy analysis and palynological analysis were carried out from recovered sediment core and age model executed using radiocarbon analysis. By combining several techniques together, a broader data was determined and cross-correlations are made to ensure an accurate paleoenvironment reconstruction of the Kızılırmak Delta. This thesis was carried out in the context of Anatolian pLateau climatE and Tectonic hazards (ALErT) project, funded and supported by the European Commission as part of the Marie-Curie-Initial Training Networks (ITN). Observations and multiproxy analysis are carried out at Istanbul Technical University (ITU), Eurasia Institute of Earth Sciences (EIES) and Eastern Mediterranean Centre for Oceanography and Limnology (EMCOL) laboratories. Palynological analysis is carried out in Faculty of Natural Sciences Department of Geology and Paleontology, Comenius University in Bratislava, Slovakia. The age model was constructed using AMS radiocarbon analysis in Beta Analytic Inc. North American Facilities. Four major lithostratigraphic units have been identified in the BW-1 core section, along with a number of sub-units. This study provides around 7300 year high-resolution sedimentological record of using a multi-proxy approach of a sediment core from the Kızılırmak Delta Plain. Despite the limitations of a single core our results obtained from several methodologies (sedimentology, geochemistry and palynology) provide insights in the paleoenvironmental conditions.
Labranda antik kenti yer radarı araştırması
Bu çalışmada, arkeolojik bir sit alanı olan Labranda Antik Kenti'nde kazı çalışmalarına yardımcı olmak ve daha sonra yapılacak kazı çalışmalarını yönlendirmek amacıyla jeofizik bir yöntem olan Yer radarı çalışması yapılmıştır. Çalışma yapılacak alanlar önceden belirlenmiş, koordinatları alınmış ve Yer radarı çalışmasının yapılması için uygun hale getirilmiştir. Çalışma alanı 2 alana ayrılmış ve her iki alanda da yer radarı ölçümleri yapılmıştır. 1. Alanda profil aralıkları 0,25 metre, 2. Alanda profil aralıkları 0,5 metre olarak uygulanmıştır. Çalışmada GSSI SIR-3000 kontrol ünitesi ve 400 Mhz merkez frekanslı anten kullanılmıştır. 400 Mhz merkez frekanslı anten ile araştırma derinliği 3,5 metre olmuştur. Arazi çalışmaları sonucunda elde edilen hem veriler bilgisayar ortamına aktarılarak işlenmiştir. Veri işlem aşamaları için ReflexW programı kullanılmıştır. Program üzerinde dewow, muting, statik düzeltme, enerji geri kazanımı, arkaplan gürültüsünün süzgeçlenmesi, bant geçişli süzgeçleme, f-k süzgeçleme aşamaları uygulanmıştır. İşlenmiş veriler yine ReflexW programı ile kat haritaları oluşturmak için düzenlenmiştir. Kat haritaları üzerinde derinliklere bağlı olarak, yeraltındaki muhtemel yapılar incelenmiştir. Kat haritalarının değerlendirilmesi sonucunda elde edilen bulgular yorumlanmıştır. Yeraltında olası yapı kalıntılarına ve yıkılmış yapılara ait olabilecek yığıntılara rastlanılmıştır. Çalışmanın sonunda yapı kalıntıları ve yığıntılar harita üzerinde gösterilmiştir.
Reconstruction of the paleoclimate on Dedegol Mountain with paleoglacial records and numerical ice flow models
The current glaciers in Anatolia have been gradually disappearing with the ongoing climate changes. There are geological proxies left behind from the ice, which is an indication of paleoclimate changes. It is known that the glaciers carry large amounts of sediments in their life cycles. After they retreat, these sediments remain where they were. They are called as moraine, which has been well preserved in some Anatolia mountains. In this study, the paleoglaciers that existed in the Late Quaternary period on the Dedegöl Mountain were reconstructed under the prescribed paleoclimatic conditions. The main idea is to recreate paleoglaciers under different climatic conditions; it is the recreation of the paleoclimate. This approach, in a sense, is aimed at understanding the past-term climate. Thus the proxies left behind by the glaciers have been used as an important proxy to estimate the paleoclimate conditions. Dedegöl Mountain is located within the boundaries of Konya and Isparta provinces. The maximum elevation of the mountain is 2997 m above the sea level. Beys ̧ehir Lake is located about 15 km to the east of the study area. 30 m × 30 m resolution digital elevation model of Dedegöl Mountain was used. The model domain is covering 37.5670 - 37.7237 North latitudes and 31.2100 - 31.3667 East longitudes. The model area is about 16.92 km × 16.92 km = 286 km2. Glacial mass balance was calculated with today's climatic conditions. Then the paleoclimate was modeled. A two-dimensional numerical glacier flow model was written in MATLAB to reconstruct the flow of glaciers under different paleoclimatic conditions. An open source glacier flow model software named Parallel Ice Sheet Model (PISM) was also used. The glacier valleys in the area are identified during two field studies in the summer months of 2015 and 2016. The Sayacak Glacial Valley on the north, the Elmadere Glacial Valley on the east, the Muslu and Karagöl and the Karçukuru Glacier Valleys in the south and the Kisbe Glacial Valley in the north-west were studied. The moraine crests positions were identified and paleoglacier boundaries were determined. Then, paleoclimatic conditions of that fit the modeled glacier extent were determined. Positive Degree Days approach was used to calculate the ablation of a glacial. This approach is briefly based on the idea that there is a correlation between the sum of all the temperatures above the melting point and melting of snow (or ice) at the same location over a year. A decrease in glacial mass occurs for days with a temperature higher than 2°C. In the calculation of the accumulation mass, the amount of precipitation in the area is used. If the precipitation occurs at a temperature higher than 0°C degrees, all precipitation occurs as rain. The accumulation linearly increases between 2 and 0°C and it contributes to the annual mass balance. The precipitation is considered to be entirely snow below 0°C air temperature. Therefore, glacier's annual budget is based on the difference between accumulation and ablation. It is thus possible to establish a direct relationship between the amount of ice in a particular area and climate conditions. In these calculations, factors such as surface energy mass, the cloudiness, and the wind effect can be also used, but these factors are not included in this study. Previous studies in the region have indicated that paleoclimate was cooler and wetter than present-day climate during the Last Glacial Maximum period. It is stated that the temperatures were 8 to 11°C lower than today, with the precipitation being 20% higher. In this study, temperatures in the model of paleoglaciers were decreased by 8, 9, and 10°C. Precipitation values were increased by 0%, 25% and 50% than today. The best way as a glacial flow model is to solve the Full Stokes equations. However, the solution of these equations is not efficient in terms of processor requirements and time. Different models have been developed for the flow of glaciers moving. In this work, open source software named Parallel Ice Sheet Model (PISM) was used. However, a two-dimensional time-dependent glacial flow model has also been developed. The results obtained in these two models were discussed. PISM uses the netCDF file type as input. In this file, data such as temperature, precipitation, glacial thickness were stored. Within the scope of the thesis, a code was developed to provide appropriate data input for PISM. This code calculates the glacial mass balance under the paleoclimatic conditions and then transforms this data into an input for PISM. The results obtained from the study include: (1) although the Parallel Ice Sheet Model (PISM) has been developed for modeling larger-scale ice sheets, it is proved it can be also used as a model for valley glaciers, such as Dedegöl Glacier Valleys (2) a temperature depression between 10°C with an increase in precipitation of 25%, and 9°C with 25% for LGM and Early Holocene respectively, (3) existing digital elevation data used in the models may cause some degradation of glacier reconstruction because they contain moraine deposits of different glacial periods, (4) the results obtained from the models indicate that the moraine deposits formed at different times should be evaluated with different climatic conditions. There are various sources of uncertainty in the model. Firstly, the resolution of the climate models is 570 m. The digital elevation model resolution is 30 m, so this dismatching can create some uncertainty. However, sudden elevation changes in the digital elevation model can lead to high slopes. From the past, it can be assumed that the boundaries of the changing structure with erosional processes created uncertainty. Moreover, seasonal fluctuations in climate data can create uncertainty in the model. In further studies, the removal of the moraine deposits to reconstruct the digital elevation model will positively affect the ice flow. This is because these obstacles prevent the glaciers to advance to the past moraines. The glacier flow and climate models applied in this study can be used in other paleoglacial areas in the region which can increase the proxy data about Turkey's paleoclimatic conditions.
Late quaternary glaciations and cosmogenic 36Cl geochronology of mount Dedegöl
Recent years experienced a significant advance in the glacial geochronology of the Turkish mountains. These studies suggested that major glacial advances were occurred in the Late Pleistocene and partly in Holocene. Maximum extent of MIS-2 (Marine Isotope Stage) glaciers happened during the Last Glacial Maximum (LGM, i.e. 21 ka ago). Glaciers were as large as 6 km in length in some mountains. The extend and timing of paleoglaciers on the northern side of the Dedegöl Mountain (37.64oN, 31.27oE, 2992 m), on the western Taurus Range, was not known. Zahno et al (2009) used cosmogenic surface exposure dating method with cosmogenic 10Be and 26Al to date a glacier expansion out of the Muslu Valley, located on the eastern part of the Mount Dedegöl. They dated to maximum extent of paleo-glaciers to 24.3±1.8 ka ago and gave evidence for pronounced glacier advances prior to the global Last Glacial Maximum (LGM). According to Zahno et al (2009), the glacier retreated which driven by climatically was no later than 17.7±1.4 ka ago. Çılğın (2015) used OSL (Optically stimulated Luminescence) dating method to date the moraines in Mount Dedegöl. OSL age results revealed that at least two glacial stages occurred during late Pleistocene in the Mount Dedegöl. In this study, I focused on geomorphological evidence of the Quaternary glaciers on the northern valleys of Mount Dedegöl. The main goal of this study was to determine the glacial geomorphology and obtain the landform ages of glacial deposits of northern Mount Dedegöl. Therefore, to achieve these goals geomorphological maps of the study area were first prepared. Later, rock samples from moraines were taken for cosmogenic surface exposure dating. Main glacial valleys and moraine borders were positioned using the GPS. Both erosional and accumulation landforms such as lateral moraines and cirques formed by glaciers were determined. These landforms were sketched with direct observation to analyze the surface morphologies. The height, length and width properties of the moraines and sample locations noted during the field studies. After the field studies, the data obtained from the field and from the GIS database structure were compared and produced the final glacial geomorphological maps in GIS software (ArcMap 10.3). Based on digital cartographic symbols, sample locations, all moraine types, cirques, and other glacial landforms were drawn for each glacial valley. The cosmogenic 36Cl dating method was used in the Mount Dedegöl in order to determine the surface exposure ages of moraines. In this way, the length of time that any rock has been exposed to the cosmic radiation can be estimated. Samples for cosmogenic 36Cl dating were collected from the top of the boulders on the crest of the moraines. A hammer and chisel were used to take samples from upper few centimeters of the boulders. The boulders were selected according to their positions. Boulders were sampled based on their appearance, size, preservation and position on the crest. Stable boulders with strong roots in the moraine matrix were preferred. The sample preparation of collected rock samples was done in order to measure minute amount of cosmogenic 36Cl in rocks by AMS (Accelerated Mass Spectrometer). The laboratory methods consist of four preparation stages: (1) crushing, grinding and sieving, (2) leaching and digestion, (3) chemical separation and (4) target preparation. Final target samples prepared at ITU/Kozmo-Lab in İstanbul were taken to ASTER AMS lab, France (The French National Facility, CEREGE, Aix en Provence). Surface exposure of the samples were measured by the 36Cl Exposure Age Calculator v2.0 (http://cronus.cosmogenicnuclides.rocks/2.0/html/cl/). Rock samples were collected from a total of 20 boulders in the Mount Dedegöl. There were eight samples in Sayacak Valley, five samples in the Kisbe Valley and seven samples in Karagöl Valley in total. Cosmogenic 36Cl ages obtained from the moraines on Mount Dedegöl have contributed new information to glacial geochronology of Turkey. Twenty boulders from moraines in three glacial valleys of the Mount Dedegöl were dated by 36Cl surface exposure dating. Moraine ages from the Mount Dedegöl indicates that there are three glacial stages identified by dating of 20 samples. Pre-LGM moraines; 29.1 ± 1.7 ka and Early Holocene moraines 10.9 ± 0.8 ka were deposited in Sayacak Valley. In Karagöl Valley, LG (Late Glacial); 13.5 ± 0.7 ka and 16.4 ± 1.1 ka were deposited. There are only Early Holocene moraines; 11.6 ± 0.7 ka were identified in Kisbe Valleys. Surface exposure ages with cosmogenic 36Cl reveal that there is no glacier retreat earlier than 32.4 ± 3.3 ka ago in the Mount Dedegöl. The oldest age obtained from hummocky moraines in the Sayacak Valley give substantial evidence about ice accumulation prior to the global LGM (21 ± 2 ka). Pre-LGM ages from hummocky moraines in the Sayacak Valley are 24.6 ± 2.3 ka, 32.4 ± 3.3 and 30.3 ± 3.2 ka ago. Consequently, the timing of maximum glaciation on Mount Dedegöl can be considered as the average of both ages which is 29.1 ± 1.7 ka. The youngest glacial stage occured during the Early Holocene in the mount Dedegöl. There are only Early Holocene moraines were identified in Kisbe Valleys with ages 11.6 ± 0.7 ka. In Sayacak Early Holocene ages are obtained from right lateral moraine (10.9 ± 0.8 ka). Late Glacial moraines in the Karagöl Valley are well preserved. In Karagöl Valley, a terminal moraine was dated to 15.6 ± 1.4 ka to 17.2 ± 1.7 ka ago. Thus, it can be considered that Late Glacial glaciation in Karagöl valley occured 16.4 ± 1.1 ka ago, which is the avarage age of the terminal moraine ages.
Yer radarı ile karstik boşluk araştırmaları
Bu çalışmada karbonatlı kayaçların hakim olduğu Konya ilinin Ilgın ilçesinde karstik boşlukların araştırılmasına yönelik yer radarı ölçümleri yapılmıştır. Yer radarı yöntemi, yüksek frekanslı elektromanyetik prensip ile çalışan sığ jeofizik araştırma yöntemlerinden biridir. Teknolojik gelişmelerle birlikte kullanım alanı da genişleyen yer radarı, jeolojik, arkeolojik ve diğer birçok araştırma alanında kullanılmaya başlanmıştır. Karstik bölgelerde insan sağlığı ve jeoteknik açıdan tehlike barındıran bu boşlukların tespiti ile söz konusu alanlara yapılacak mühendislik yapılarının planlaması daha doğru olarak yapılabilmektedir. Bu alanlarda oluşturulacak yapılar yer altında bulunan boşluklarda gerçekleşebilecek çökmeler neticesinde ciddi hasar alma ihtimaline sahiptir. Bu nedenle karstik boşlukların oluşum şekillerinin ve yer altındaki uzanımlarının dikkatle araştırılması gerekmektedir. Yer radarının kolay uygulanabilen bir yöntem olması ve kısa zamanda geniş alanlar tarayabilmesi, bu gibi araştırmalarda yoğun olarak kullanılmasını sağlamaktadır. Çalışma sahasında 100 MHz'lik merkez frekansa sahip anten kullanarak toplamda uzunluğu 7.3 km'yi derinliği 5 m'yi bulan profil verisi elde edilmiştir. Daha önceki çalışmalar dikkate alınarak, çeşitli aşamalardan oluşan veri işlem sonuçları karşılaştırılmalı olarak değerlendirilerek en uygun veri işlem yöntemi belirlenmiştir. Elde edilen radargramlardan toplam uzunluğu 350 metreyi bulan dört tanesi seçilerek yorumlanmış ve boşluklu, çatlaklı ve deformasyonlu bölgeler belirlenmiştir. Yorumlanan verilerde detaylı olarak polarizasyon analizi ve genlik analizi yapılmıştır. Boşluk olan yapılar belirlenerek empedans değerleri üzerinden birbirleriyle olan ilişkileri ortaya konmuştur. Elde edilen sonuçlar bölgede mevcut sondaj ve jeoloji verilerinin ışığı altında değerlendirilerek karstik yapıların modellemesi yapılmıştır. Radargramlarda yorumlanan anomalilerin parametreleri hesaplanarak önce basit modelleme ardından da karmaşık modelleme yapılmıştır. Modelleme sonuçları da radargramlarda yapılan analizleri desteklemektedir. Bu tez çalışması ile karstik bölgelerde yer radarı verilerinin işlenmesinde izlenilecek yaklaşımların belirlenmesi, elde edilen radargramların yorumlanması ve modellenmesi konusunda bilgiler sunan bir kaynak ortaya konulmuştur.