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Articles 571 - 600 of 917
Full-Text Articles in Earth Sciences
Coeval Shoshonitic-Ultrapotassic Dyke Emplacements Within The Kestanbol Pluton, Ezine – Biga Peninsula (Nw Anatolia), Cüneyt Akal
Coeval Shoshonitic-Ultrapotassic Dyke Emplacements Within The Kestanbol Pluton, Ezine – Biga Peninsula (Nw Anatolia), Cüneyt Akal
Turkish Journal of Earth Sciences
The Biga Peninsula, in the north-western part of Western Anatolia, is part of the Sakarya Zone of the Western Pontides and the tectonically overlying Ezine group. The basement rocks are intruded by the early Miocene Kestanbol Pluton and early to middle Miocene calc-alkaline to shoshonitic-ultrapotassic volcanic successions related to postcollisional continental extension. The Kestanbol Pluton mainly comprises monzonite and granodiorite and is cut by shoshonitic-ultrapotassic tephriphonolite dykes. ^{40}Ar-^{39}Ar ages of biotite (21.22 ± 0.09 Ma) and leucite (22.21 ± 0.07 Ma) crystals indicate that tephriphonolite dyke emplacement was coeval with the intrusion of the Kestanbol Pluton during the early Miocene …
Tragulidae (Artiodactyla, Ruminantia) From The Middle Miocene Chinji Formation Of Pakistan, Muhammad Akbar Khan, Muhammad Akhtar
Tragulidae (Artiodactyla, Ruminantia) From The Middle Miocene Chinji Formation Of Pakistan, Muhammad Akbar Khan, Muhammad Akhtar
Turkish Journal of Earth Sciences
The fossil record of the Siwalik tragulids remains poorly documented. The study of the tragulid material from the Chinji Formation allows the identification of 3 species: Dorcatherium minus, Dorcatherium majus and Dorcabune anthracotherioides. The tragulid assemblage is quite rich and Dorcatherium is the predominant taxon in the Chinji Formation of Pakistan. The fossils from the Chinji Formation of the Chakwal district, northern Pakistan, may document the first appearance of the 3 tragulid species in the Lower Siwaliks. The selenodonty and palaeoecology of the Siwalik tragulids are also discussed.
The Effects Of Linear Coarse-Grained Slope Channel Bodies On The Orientations Of Fold Developments: A Case Study From The Middle Eocene-Lower Oligocene Kırkgeçit Formation, Elazığ, Eastern Turkey, Hasan Çeli̇k
Turkish Journal of Earth Sciences
A significant magnitude of tectonic feature deflection away from the principal stress direction was investigated. This was caused by oblique spatial orientation of coarse-grained sediment bodies, principally large conglomerate and sand-filled deep-water slope channels, in an otherwise mud-rich sedimentary section. After detailed mapping and field work to find the cause of this localised fold axis deflection, superbly exposed conglomerate and sand filled deep-water slope channel bodies were found both in and/or next to the core of the folds with the same spatial orientation as the folds. It was concluded that the channel bodies are effectively dictating the orientations of the …
Late Holocene Climatic Oscillations Traced By Clay Mineral Assemblages And Other Palaeoceanographic Proxies In Ria De Vigo (Nw Spain), Virginia Martins, Fernando Rocha, Cristina Sequeira, Paula Martins, José Santos, Joao Alveirinho Dias, Olivier Weber, Jean-Marie Jouanneau, Belén Rubio, Daniel Rey, Ana Bernabeu, Eduardo Silva, Lázaro Laut, Rubens Figueira
Late Holocene Climatic Oscillations Traced By Clay Mineral Assemblages And Other Palaeoceanographic Proxies In Ria De Vigo (Nw Spain), Virginia Martins, Fernando Rocha, Cristina Sequeira, Paula Martins, José Santos, Joao Alveirinho Dias, Olivier Weber, Jean-Marie Jouanneau, Belén Rubio, Daniel Rey, Ana Bernabeu, Eduardo Silva, Lázaro Laut, Rubens Figueira
Turkish Journal of Earth Sciences
This work aims to study recent climatic oscillations and their influence on sedimentation in the Ria de Vigo, a coastal embayment in Galicia, NW Spain. It is based on the study of clay mineral assemblages, in conjunction with other proxies (granulometric, geochemical, geochronological and microfaunal), in the core KSGX 24. A Benthic Foraminifera High Productivity (BFHP) proxy was used to determine changes in the flux of organic matter (OM) at the bottom of the study area. Total organic carbon (TOC) content is not a suitable proxy to estimate changes in the past supply of OM due to diagenetic processes. The …
Stress Features In Terra Rossa Soil Under Traditional Olive Cultivation: A Micromorphological And Mineralogical Characterization, Salvatore Madrau, Claudio Zucca, İhsan Akşi̇t, Valeria Fiori
Stress Features In Terra Rossa Soil Under Traditional Olive Cultivation: A Micromorphological And Mineralogical Characterization, Salvatore Madrau, Claudio Zucca, İhsan Akşi̇t, Valeria Fiori
Turkish Journal of Earth Sciences
This study analyzes the micromorphological and mineralogical properties of a Terra Rossa soil under a traditional Mediterranean olive grove. It highlights the microscopic and sub-microscopic features generated by the permanent crop cover. The study area, where the land use has remained unchanged for the last 150 years, is near Sassari (Sardinia, Italy) and is characterized by dominant Terra Rossa developed on Miocene marine limestone. Two soil profiles were opened and described in July 2009, 1 under the canopy of an olive tree and 1 between the trees. Chemical and physical analyses were carried out. Undisturbed aggregates were collected from all …
Multi-Proxy Evidences Of Mid-Pleistocene Dry Climates Observed On Calcretes In Central Turkey, Ceren Küçükuysal, Asuman Günal Türkmenoğlu, Seli̇m Kapur
Multi-Proxy Evidences Of Mid-Pleistocene Dry Climates Observed On Calcretes In Central Turkey, Ceren Küçükuysal, Asuman Günal Türkmenoğlu, Seli̇m Kapur
Turkish Journal of Earth Sciences
Palaeosols are very important in reconstructing palaeoclimate studies, since they are accepted as useful climate markers and as potential providers of proxy data. The study of the palaeosols of the Plio-Pleistocene rock sequences around Ankara revealed evidence for a reconstruction of the Quaternary palaeoclimate of the region. The study area is located in Bala, south-east of Ankara, which contains Middle Pleistocene red palaeosols with powdery to nodular calcrete developments, alternating with channel deposits. During this warm and arid period in the Pleistocene, the limited water available in the soil led to the accumulation of low magnesian carbonates, forming calcretes. The …
Geology And Diagenesis Of A Zeolitic Foça Tuff Unit Deposited In A Miocene Phreatomagmatic Lacustrine Environment (Western Anatolia), Mustafa Albayrak, Abdullah Mete Özgüner
Geology And Diagenesis Of A Zeolitic Foça Tuff Unit Deposited In A Miocene Phreatomagmatic Lacustrine Environment (Western Anatolia), Mustafa Albayrak, Abdullah Mete Özgüner
Turkish Journal of Earth Sciences
This study explains the relations between the depositional environment of a zeolitic tuff unit and its diagenesis. It gives new ideas of the juvenile phreatomagmatic origin of the zeolitic unit with its bentonitic cap rock, and finds that the diagenetic alteration of the volcanic ash deposition in a hot hydrologic system is penecontemporaneous and not epigenetic. A massive, fine-grained zeolitic unit has a sharp contact with the underlying shallow subaqueous rhyolitic dome intrusions and their surrounding volcanoclastic ejecta. Juvenile emanations from the basal subaqueous intrusions activated thorough zeolitic diagenesis within the overlying rhyolitic tuff deposits extending as far as the …
The Mineralogy And Geochemistry Of Neogene Sediments From Eastern Turkey, Southeast Of Arapgir (Malatya), Di̇cle Bal Akkoca, Zeynep Baytaşoğlu
The Mineralogy And Geochemistry Of Neogene Sediments From Eastern Turkey, Southeast Of Arapgir (Malatya), Di̇cle Bal Akkoca, Zeynep Baytaşoğlu
Turkish Journal of Earth Sciences
The mineralogy and geochemistry of volcaniclastic sediments in the southeastern part of the Arapgir area (Malatya) were studied by optical microscopy, XRD, SEM, ICP-AES, and MS techniques. Samples were collected from the marine and lacustrine deposits of the Dibekli and Böğürlüdağ sections that contained calcite, clay minerals, feldspar, quartz, dolomite, and opal. Clay minerals were mixed layer smectite-chlorite, illite, and palygorskite, with Ca-smectite being the dominant clay phase. Smectite was derived from the transformation of volcanic glass and volcanic rock fragments. The fact that Y, Sc, Co and \SigmaREE concentrations and (La/Lu)N, La/Sc, Sc/Th, Co/Th, Th/U, and Zr/Hf ratios of …
Preliminary Geoelectrical Identification Of A Low-Temperature Hydrothermal System In The Anzer Glacial Valley, İkizdere, Rize, Turkey, Abdullah Karaman
Preliminary Geoelectrical Identification Of A Low-Temperature Hydrothermal System In The Anzer Glacial Valley, İkizdere, Rize, Turkey, Abdullah Karaman
Turkish Journal of Earth Sciences
The Anzer glacial valley, at an elevation of over 2300 m in the Eastern Black Sea region of Turkey, exhibits evidence for a low-temperature hydrothermal system (40-100 °C). Low-temperature hydrothermal systems usually do not receive attention since they are not useful for energy production. However, in areas where natural beauty is prominent, as in the Anzer valley, such resources can easily trigger investment for all-season resorts that significantly contribute to the economy. In this study, we examine the site evidence and carry out self-potential and dc-resistivity sounding surveys using a Schlumberger electrode configuration. The resistivity cross-section obtained from the inversion …
Stable Isotope-Based Reconstruction Of Oligo-Miocene Paleoenvironment And Paleohydrology Of Central Anatolian Lake Basins (Turkey), Tina Lüdecke, Tamás Mikes, Fuat Bora Rojay, Michael A. Cosca, Andreas Mulch
Stable Isotope-Based Reconstruction Of Oligo-Miocene Paleoenvironment And Paleohydrology Of Central Anatolian Lake Basins (Turkey), Tina Lüdecke, Tamás Mikes, Fuat Bora Rojay, Michael A. Cosca, Andreas Mulch
Turkish Journal of Earth Sciences
Isotope geochemistry of lacustrine carbonate represents a powerful tool to reconstruct paleoclimatic and paleoenvironmental conditions. Here, we present a comprehensive set of long-term oxygen (delta^{18}O) and carbon (delta^{13}C) stable isotope records from 5 Chattian to Burdigalian lacustrine sequences distributed over the Central Anatolian Plateau. Field relationships combined with stable isotope geochemistry indicate a relatively humid subtropic Late Oligocene climate with an environment characterized by large, temporally open freshwater lakes. Approximately during the middle Aquitanian, a 4%o-5%o increase in lake delta^{18}O values indicates changes in regional climate including more arid conditions and an increasing dominance of closed saline lake conditions in …
Cenozoic Tectonics Of The Tuz Gölü Basin (Central Anatolian Plateau, Turkey), David Fernández-Blanco, Giovanni Bertotti, Tahsi̇n Atti̇la Çi̇ner
Cenozoic Tectonics Of The Tuz Gölü Basin (Central Anatolian Plateau, Turkey), David Fernández-Blanco, Giovanni Bertotti, Tahsi̇n Atti̇la Çi̇ner
Turkish Journal of Earth Sciences
We present a new 3D geologic model for the architecture and Cenozoic tectonic evolution of the Tuz Gölü Basin, a major sedimentary basin in the Central Anatolian orogenic plateau. This model is grounded on 7 depth-converted seismic reflection profiles in combination with the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross-section. Two stages of basin formation are detected during Cenozoic times. During the Palaeogene, around 2 km of basement subsidence led to the development of a sag basin broader than the present basin in the absence of bounding faults. After a period of uplift and erosion, …
Circum-Tethyan Carbonate Platform Evolution During The Palaeogene: The Prebetic Platform As A Test For Climatically Controlled Facies Shifts, Stefan Höntzsch, Christian Scheibner, Johannes P. Brock, Jochen Kuss
Circum-Tethyan Carbonate Platform Evolution During The Palaeogene: The Prebetic Platform As A Test For Climatically Controlled Facies Shifts, Stefan Höntzsch, Christian Scheibner, Johannes P. Brock, Jochen Kuss
Turkish Journal of Earth Sciences
The distribution of selected shallow-benthic biota at circum-Tethyan carbonate platforms demonstrates an excellent proxy for the impact of latitudinally controlled cooling and variations in the trophic resources during the Palaeogene. In this study, we link and compare the spatial distribution and abundance of larger benthic foraminifera and hermatypic corals of Tethyan carbonate successions with new records from the Prebetic platform in SE Spain. The succession of the Prebetic platform is dominated by larger benthic foraminifera and coralline red algae throughout the Eocene, whereas corals were not recorded until the Late Eocene. Similar biotic trends were reported from 10 selected circum-Tethyan …
Impact Of Pb-Zn Mining Activity On Surficial Sediments Of Lake Kalimanci(Fyr Macedonia), Petra Vrhovnik, Nastja Rogan Smuc, Tadej Dolenec, Todor Serafimovski, Matej Dolenec
Impact Of Pb-Zn Mining Activity On Surficial Sediments Of Lake Kalimanci(Fyr Macedonia), Petra Vrhovnik, Nastja Rogan Smuc, Tadej Dolenec, Todor Serafimovski, Matej Dolenec
Turkish Journal of Earth Sciences
The activities of the Sasa mine have led to industrial discharge being released into Lake Kalimanci since the beginning of mining activity in 1954. For this reason, an ecological risk assessment is urgently required. In the present study, surficial lake sediments were analyzed using inductively coupled plasma mass spectrometry (ICP-MS), with all geochemistry data processed using Statistica 8. In order to assess the environmental pollution status, 2 environmental factors were established, while for the determination of chemical fractionation of toxic metals a sequential extraction procedure was carried out. Concentrations of As, Mo, Zn, Ni, Co, Pb, Cd, and Cu in …
Computation Of Grade Values Of Sediment-Hosted Barite Deposits In Northeastern Isparta (Western Turkey), Numan Elmas, Uğur Şahi̇n
Computation Of Grade Values Of Sediment-Hosted Barite Deposits In Northeastern Isparta (Western Turkey), Numan Elmas, Uğur Şahi̇n
Turkish Journal of Earth Sciences
Grade value is a crucial parameter for the mineral industry. Investigation of grade value of mineral resources provides the optimum benefit. In this study, an adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) model were applied for the prediction of grade values. The spatial coordinates X, Y, and Z of the study area along with bore hole geochemical data were used as input variables in the model. In order to illustrate the applicability and capability of these methods, the western part of Turkey, between the latitudes 38°01 45 N and 38°09 52 N and between the longitudes 31°23 …
An Avalanche Hazard Model For Bitlis Province, Turkey, Using Gis Based Multicriteria Decision Analysis, Levent Selçuk
An Avalanche Hazard Model For Bitlis Province, Turkey, Using Gis Based Multicriteria Decision Analysis, Levent Selçuk
Turkish Journal of Earth Sciences
Most avalanche fatalities in Turkey have occurred in Bitlis Province. The scope of this research was to identify the avalanche hazard area of that province, using geographical information system (GIS) based multicriteria decision analysis (MCDA) and to evaluate it by means of sensitivity and accuracy analysis. The model consists of 5 GIS layers: elevation, slope, aspect, vegetation density, and land use. The hazard model is obtained by using a comparison matrix where all identified criteria of GIS layers are compared against each other. The acceptability of the model was determined using historical events. All of these events plotted over the …
Afc-Modeler: A Microsoft® Excel© Workbook Program For Modelling Assimilation Combined With Fractional Crystallization (Afc) Process In Magmatic Systems By Using Equations Of Depaolo (1981), Mehmet Keski̇n
Turkish Journal of Earth Sciences
AFC-Modeler is a user-friendly, interactive Microsoft Excel workbook program which is specifically designed to model up to ten theoretical AFC curves (corresponding to ten different r values; r being the ratio of mass assimilation rate to fractional crystallization rate) for a set of variables that can be interactively and precisely modified by the user (i.e. D, initial element concentration and isotope ratio in magma and element concentration and isotope ratio in wallrock). Being able to model ten curves for ten different 'r' values is an important feature of the program, because results of many studies indicate that the r values …
The Upper Cretaceous Calciclastic Submarine Fan Deposits In The Eastern Pontides, Ne Turkey: Facies Architecture And Controlling Factors, Di̇lek Sofracioğlu, Rai̇f Kandemi̇r
The Upper Cretaceous Calciclastic Submarine Fan Deposits In The Eastern Pontides, Ne Turkey: Facies Architecture And Controlling Factors, Di̇lek Sofracioğlu, Rai̇f Kandemi̇r
Turkish Journal of Earth Sciences
The Tonya Formation, which represents the uppermost part of the Mesozoic sequence in the Eastern Pontides, consists of calciturbidites in Trabzon and its surrounding region. Two stratigraphic sections of the unit were measured in the Hacımehmet and Gürbulak areas to decipher the distribution of rock types, facies architecture, sediment textures and depositional environment. The grain size, channels, suprafan lobes and slump structures of the sediments suggest that calciclastic sequences were deposited in a submarine fan system. Calcarenites/calcirudites and hemipelagic rocks, comprising an alternation of marls and mudstones, are the two dominant lithologies described in the studied calciclastic submarine fan system. …
Silurian Graptolite, Conodont And Cryptospore Biostratigraphy Of The Gülüç Section In Ereğli, Zonguldak Terrane, Nw Anatolia, Turkey, Valeri Sachanski, Mehmet Cemal Göncüoğlu, Iskra Lakova, Ilina Boncheva, Gülnur Saydam-Demi̇ray
Silurian Graptolite, Conodont And Cryptospore Biostratigraphy Of The Gülüç Section In Ereğli, Zonguldak Terrane, Nw Anatolia, Turkey, Valeri Sachanski, Mehmet Cemal Göncüoğlu, Iskra Lakova, Ilina Boncheva, Gülnur Saydam-Demi̇ray
Turkish Journal of Earth Sciences
The studied Gülüç section of the Silurian Fındıklı Formation is situated on the western bank of Gülüç Creek in Ereğli, NW Anatolia, Turkey, in the eastern part of the Zonguldak Terrane. The Gülüç section consists of 3 sedimentary packages: greenish grey limy siltstones, 5-7 m thick (1), overlain by an irregular alternation of black shales and clayey limestones, about 15 m thick (2), and a 6-7 m thick succession of mainly siltstones and sandy limestones (3). A combined biostratigraphy based upon graptolites, cryptospores and conodonts indicates that Package 1 is of Llandovery (Rhuddanian, Aeronian and/or early Telychian) age, Package 2 …
Variability Of Neogene Continental Climates In Northwest Europe - A Detailed Study Based On Microfloras, Torsten Utescher, Abdul Rahman Ashraf, Andreas Dreist, Karen Dybkjaer, Volker Mosbrugger, Jörg Pross, Volker Wilde
Variability Of Neogene Continental Climates In Northwest Europe - A Detailed Study Based On Microfloras, Torsten Utescher, Abdul Rahman Ashraf, Andreas Dreist, Karen Dybkjaer, Volker Mosbrugger, Jörg Pross, Volker Wilde
Turkish Journal of Earth Sciences
This study presents a detailed continental palaeoclimate record for the Neogene of Northwestern Europe. Palynomorph samples from continental to marginal marine deposits in 5 correlated sections from the Lower Rhine Basin (NW Germany) covering the time-span from Burdigalian to Zanclean are analysed. Independent time-control in the sections is provided by sequence stratigraphy. Based on 1470 microfloras 3 temperature (mean annual temperature, warm and cold month mean) and 4 precipitation variables (mean annual precipitation, mean monthly precipitation in the driest, wettest and warmest month) are quantified using the Coexistence Approach, a method employing climate requirements of Nearest Living Relatives of fossil …
Al-In-Hornblende Thermobarometry And Sr-Nd-O-Pb Isotopic Compositions Of The Early Miocene Alaçam Granite In Nw Anatolia (Turkey), Altuğ Hasözbek, Burhan Erdoğan, Muharrem Satir, Wolfgang Siebel, Erhan Akay, Güllü Deni̇z Doğan, Heinrich Taubald
Al-In-Hornblende Thermobarometry And Sr-Nd-O-Pb Isotopic Compositions Of The Early Miocene Alaçam Granite In Nw Anatolia (Turkey), Altuğ Hasözbek, Burhan Erdoğan, Muharrem Satir, Wolfgang Siebel, Erhan Akay, Güllü Deni̇z Doğan, Heinrich Taubald
Turkish Journal of Earth Sciences
During and after the closure of the Neo-Tethyan Ocean and progressive collision of the Tauride-Anatolide Platform with the Sakarya Continent, widespread magmatism occurred in NW Anatolia. This magmatism is manifested in a NW-trending belt along the northern border of the Menderes Massif. Due to the complex geodynamic setting of this region, the exact emplacement depth of the granitoids is still a matter of debate. Here we present Al-in-hornblende barometrical data and Sr-Nd-Pb isotope compositions of the Early Miocene Alaçam granite. The results imply a shallow emplacement depth of this granite (4.7±1.6 km) in contrast to previous studies which suggested emplacement …
Stable Isotope Composition Of Hydrothermally Altered Rocks And Hydrothermal Minerals At The Los Azufres Geothermal Field, Mexico, Ignacio S Torres Alvarado, Muharrem Satir, Daniel Perez Zarate, Peter Birkle
Stable Isotope Composition Of Hydrothermally Altered Rocks And Hydrothermal Minerals At The Los Azufres Geothermal Field, Mexico, Ignacio S Torres Alvarado, Muharrem Satir, Daniel Perez Zarate, Peter Birkle
Turkish Journal of Earth Sciences
The Los Azufres geothermal field is the second most important geothermal field for electricity production in Mexico, with a total installed capacity of 188 MW. Hydrothermal alteration studies have been an important tool for geothermal exploration and development of the field, but little attention has been given to the geochemical and isotopic characterization of hydrothermal minerals. \delta^1^8O, \delta^2H, and \delta^1^3C systematics at Los Azufres geothermal field were investigated using whole rock samples, as well as hydrothermal minerals separates, obtained from different depths in the wells Az-26 and Az-52. Most \delta^1^8O values reproduce well the present in-situ field temperatures and isotopic …
Kinematics And Basin Formation Along The Ezinepazar-Sungurlu Fault Zone, Ne Anatolia, Turkey, Mehmet Korhan Erturaç, Okan Tüysüz
Kinematics And Basin Formation Along The Ezinepazar-Sungurlu Fault Zone, Ne Anatolia, Turkey, Mehmet Korhan Erturaç, Okan Tüysüz
Turkish Journal of Earth Sciences
The Ezinepazar-Sungurlu Fault (EzSF) is a major offshoot of the dextral North Anatolian Fault (NAF) zone, which bifurcates from the main fault strand around the Niksar pull-apart basin (37°E) and strikes through the Central Anatolian Block for 200 km to the west (34°E). The easternmost segment of the EzSF, the Ezinepazar Fault (EzF), which ruptured during the 1939 Erzincan earthquake (Mw= 7.8), has a very remarkable expression as a single-strand fault. Micromammal dating of young sediments along this segment indicate that the EzF was initiated during the Middle Pleistocene (0.7-1 Ma) and propagated westward accumulating 6.5±0.5 km maximum morphological offset. …
Palaeozoic Formations From Dobrogea And Pre-Dobrogea – An Overview, Antoneta Seghedi
Palaeozoic Formations From Dobrogea And Pre-Dobrogea – An Overview, Antoneta Seghedi
Turkish Journal of Earth Sciences
No abstract provided.
Stratigraphy And Some Structural Features Of The İstanbul Paleozoic, Necdet Özgül
Stratigraphy And Some Structural Features Of The İstanbul Paleozoic, Necdet Özgül
Turkish Journal of Earth Sciences
Palaeozoic rocks crop out across large areas in the İstanbul region. The Palaeozoic sequence starts with the Lower Ordovician fluviatile and lacustrine deposits (Kocatöngel and Kurtköy formations). The area was transgressed by the sea during the Late Ordovician-Early Silurian, represented by the feldspathic quartzwacke and quartz-arenites of the Kınalıada and Aydos formations. The basin became progressively deeper and more stable during the Silurian and Devonian. In this period, micaceous siltstones and sandstones of the Yayalar Formation (Upper Ordovician (?)-Lower Silurian), shelf-type carbonates of the Pelitli Formation (Lower Silurian-Lower Devonian), fossil-rich micaceous shales with rare limestone intercalations representing a low-energy open …
Geochemical And Isotopic Constraints On Petrogenesis Of The Beypazarı Granitoid, Nw Ankara, Western Central Anatolia, Turkey, Yeşi̇m Yücel Öztürk, Cahi̇t Helvaci, Muharrem Satir
Geochemical And Isotopic Constraints On Petrogenesis Of The Beypazarı Granitoid, Nw Ankara, Western Central Anatolia, Turkey, Yeşi̇m Yücel Öztürk, Cahi̇t Helvaci, Muharrem Satir
Turkish Journal of Earth Sciences
The Upper Cretaceous Beypazarı granitoid of the western Ankara, Turkey, is composed of two different units, on the basis of petrography and geochemical composition; these are granodiorite and diorite. The granitoid is subalkaline, belonging to the high-K calc-alkaline I-type granite series, which have relatively low initial 87Sr/86Sr ratios (0.7053-0.7070). All these characteristics, combined with major, trace element geochemical data as well as mineralogical and textural evidence, reveal that the Beypazarı granitoid formed in a volcanic arc setting and was derived from a subduction-modified and metasomatized mantle-sourced magma, with its crustal and mantle components contaminated by interaction with the upper crust. …
Archaean Zircon U-Pb Age Paradox In Juvenile Neoproterozoic Granitoids, Central North Sudan, Saharan Metacraton, Shang Cosmas, Morteani Giulio, Muharrem Satir
Archaean Zircon U-Pb Age Paradox In Juvenile Neoproterozoic Granitoids, Central North Sudan, Saharan Metacraton, Shang Cosmas, Morteani Giulio, Muharrem Satir
Turkish Journal of Earth Sciences
It has long been shown that central North Sudan with its heterogeneous isotopic composition, unlike neighbouring Archaean cratons and the Neoproterozoic Arabian-Nubian Shield, is part of the Saharan metacratonic crust that was remobilized in the Neoproterozoic. In this paper, we report an Archaean zircon U-Pb age in the Saharan Metacraton that paradoxically does not indicate the presence of an Archaean crust. The second paradox concerns geochemical data that show Archaean tonalite-trondhjemite-granodiorite (TTG) features and also post-Archaean granitoid features, yet the rocks are Neoproterozoic. The granitoids studied are from north of Delgo in the Halfa terrane. They are calc-alkaline and meta- …
Carbon Isotope And Stomatal Data Of Late Pliocene Betulaceae Leaves From Sw China: Implications For Palaeoatmospheric Co2-Levels, Bainian Sun, Suting Ding, Jingyu Wu, Chong Dong, Sanping Xie, Zhicheng Lin
Carbon Isotope And Stomatal Data Of Late Pliocene Betulaceae Leaves From Sw China: Implications For Palaeoatmospheric Co2-Levels, Bainian Sun, Suting Ding, Jingyu Wu, Chong Dong, Sanping Xie, Zhicheng Lin
Turkish Journal of Earth Sciences
The cuticular \delta^1^3C values and stomatal parameters (stomatal density and stomatal index: SD and SI) of two Betulaceae species, Betula mioluminifera Hu et Chaney and Carpinus miofangiana Nathorst, from a suite of superposed horizons in West Yunnan, southwestern China, were measured in order to recover Late Pliocene CO2 levels. Correlations are given for \delta^1^3C, SD, epidermal cell density (ECD), and SI. \delta^1^3C reveals a positive trend with the SD and SI in the two species, and such a positive correlation can also be observed between the \delta^1^3C and ECD in C. miofangiana. However, \delta^1^3C has a slightly negative correlation with …
Palaeoclimate Evolution In Siberia And The Russian Far East From The Oligocene To Pliocene – Evidence From Fruit And Seed Floras, Svetlana Popova, Torsten Utescher, Dmitry Gromyko, Angela Bruch, Volker Mosbrugger
Palaeoclimate Evolution In Siberia And The Russian Far East From The Oligocene To Pliocene – Evidence From Fruit And Seed Floras, Svetlana Popova, Torsten Utescher, Dmitry Gromyko, Angela Bruch, Volker Mosbrugger
Turkish Journal of Earth Sciences
The Cenozoic continental deposits of Western Siberia, Eastern Siberia and the Russian Far East are best described on the basis of carpological records. The palaeoclimate evolution has been reconstructed quantitatively (Coexistence Approach) providing inferred data on temperature, precipitation and the mean annual range of these parameters. Climate curves document the transition from very warm and humid conditions in the Late Oligocene via the Middle Miocene Climatic Optimum to a cool temperate climate during the Pliocene. Compared with other time intervals the Miocene climate is the most comprehensively reconstructed. For the Middle Miocene the Siberian and Far Eastern data are combined …
Ichnology Of The Miocene Güneyce Formation (Southwest Turkey): Oxygenation And Sedimentation Dynamics, Jan Kresten Nielsen, Muhi̇tti̇n Görmüş, Kubi̇lay Uysal, Süveyla Kanbur
Ichnology Of The Miocene Güneyce Formation (Southwest Turkey): Oxygenation And Sedimentation Dynamics, Jan Kresten Nielsen, Muhi̇tti̇n Görmüş, Kubi̇lay Uysal, Süveyla Kanbur
Turkish Journal of Earth Sciences
The Güneyce Formation is well exposed in the Lake District of southwestern Turkey. It was deposited in the early Miocene in the Neotethys ocean and contains a large variety of trace fossils. The following ichnotaxa were recognized: Chondrites intricatus, C. targionii, ?Cosmorhaphe isp., Helminthopsis isp., Helminthorhaphe flexuosa, Lorenzinia isp., Naviculichnium marginatum, ?Nereites isp., Ophiomorpha rudis, ?Phycosiphon incertum, Planolites beverleyensis, cf. Rhizocorallium isp. and Thalassinoides suevicus. There is a lateral trend from proximal turbiditic successions to distal low-oxygen shaly mudstone. Ophiomorpha rudis ichnosubfacies, Paleodictyon ichnosubfacies of the Nereites ichnofacies and Zoophycos ichnofacies were identified.
A New Late Holocene Eolianite Record From Altınkum Beach, North Cyprus, Ahmet Evren Ergi̇nal, Nafi̇ye Güneç Kiyak, Topçu Ahmet Ertek
A New Late Holocene Eolianite Record From Altınkum Beach, North Cyprus, Ahmet Evren Ergi̇nal, Nafi̇ye Güneç Kiyak, Topçu Ahmet Ertek
Turkish Journal of Earth Sciences
In 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 …