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Articles 691 - 720 of 917
Full-Text Articles in Earth Sciences
Testing Miocene Remagnetization Of Bey Dağları: Timing And Amount Of Neogene Rotations In Sw Turkey, Douwe J.J. Van Hinsbergen, Mark J. Dekkers, Ayten Koç
Testing Miocene Remagnetization Of Bey Dağları: Timing And Amount Of Neogene Rotations In Sw Turkey, Douwe J.J. Van Hinsbergen, Mark J. Dekkers, Ayten Koç
Turkish Journal of Earth Sciences
Here we reassess the timing and amount of rotation of the eastern limb of the Aegean orocline, located in SW Turkey. The current model for this orocline involves a 25-30° counterclockwise (CCW) rotation of the Bey Dağları region, which exposes upper Cretaceous to Eocene platform carbonates and lower Miocene flysch deposits. In this model the rotation has to postdate a Miocene remagnetization, which would not exclude non-synchroneity between rotations of the western and eastern limbs of the Aegean orocline. To test this model a detailed palaeomagnetic study was conducted on lower Miocene strata in the Bey Dağları area. Two (composite) …
Petrography And Geochemistry Of The Jajarm Bauxite Ore Deposit, Northeast Iran: Implications For Source Rock Material And Ore Genesis, Dariush Esmaeily, Hosein Rahimpour-Bonab, Amir Esna-Ashari, Ali Kananian
Petrography And Geochemistry Of The Jajarm Bauxite Ore Deposit, Northeast Iran: Implications For Source Rock Material And Ore Genesis, Dariush Esmaeily, Hosein Rahimpour-Bonab, Amir Esna-Ashari, Ali Kananian
Turkish Journal of Earth Sciences
The Jajarm bauxite deposit, northeast Iran, is the largest such deposit in Iran. The deposit is sandwiched between the Triassic Elika formation and the Jurassic Shemshak formation, housed within karstic features developed within the former unit. The deposit generally shows an internal layering defined by the following four distinct horizons (from bottom to top): (a) a lower argillaceous horizon, approximately 50-80 cm thick, is mainly composed of clay minerals that directly overlies the carbonate footwall (Elika formation); (b) a bauxitic clay layer approximately 2-3 m thick that consists mainly of hematite, kaolinite, anatase, and diaspore; (c) a red bauxite layer …
Sensitivity Analysis On Relations Between Earthquake Source Rupture Parameters And Far-Field Tsunami Waves: Case Studies In The Eastern Mediterranean Region, Seda Yolsal, Tuncay Taymaz
Sensitivity Analysis On Relations Between Earthquake Source Rupture Parameters And Far-Field Tsunami Waves: Case Studies In The Eastern Mediterranean Region, Seda Yolsal, Tuncay Taymaz
Turkish Journal of Earth Sciences
We present several sensitivity tests, that were applied to exhibit the effects of earthquake source rupture characteristics on amplitudes, frequency contents and arrival times of earthquake generated tsunami waves in the far field, as case studies in the eastern Mediterranean. The investigated earthquake parameters are principally epicentral location, focal mechanism parameters (strike, dip and rake angles), faulting area dimensions, maximum displacement and focal (centroid) depth. We have implemented a numerical method of TUNAMI-N2 based on non-linear shallow-water theory to obtain synthetic water surface fluctuations at selected pseudo tide gauge locations in the eastern Mediterranean. It has been observed that the …
Tsunami Hazard Assessment On The Southern Coast Of Spain, Mauricio González, Raul Medina, Maitane Olabarrieta, Luis Otero
Tsunami Hazard Assessment On The Southern Coast Of Spain, Mauricio González, Raul Medina, Maitane Olabarrieta, Luis Otero
Turkish Journal of Earth Sciences
In this study an indirect statistical method has been proposed to estimate the tsunami hazard assessment along the Alborán Sea Coast (Southeastern Spanish Coast). This method can be summarized as: (1) analysis of the global neotectonic setting, including geodynamic processes as well as seismicity of the region; (2) tsunami source model; (3) generation of a numerical data base of tsunami events using a numerical model; (4) probabilistic model based on Monte-Carlo simulations in order to generate a synthetic tsunami catalogue; and (5) a multidimensional interpolation method applied to combine the numerical data base with the synthetic catalogue to produce inundation …
Geochronological Evidence Of Pan-African Eclogites From The Central Menderes Massif, Turkey, Oberhaensli Roland, Osman Candan, Franziska Wilke
Geochronological Evidence Of Pan-African Eclogites From The Central Menderes Massif, Turkey, Oberhaensli Roland, Osman Candan, Franziska Wilke
Turkish Journal of Earth Sciences
The Menderes Massif in western Anatolia documents a complex geodynamic history from Precambrian to recent. Eclogitic relics found in metagabbros in the Precambrian basement were dated by the U/Pb method. The zircon age data from granulitic (coronitic) and eclogitic metagabbros is consistent with geological constraints as well as relative and radiometric ages of the host granulitic gneisses and augen gneisses. A Pan-African intrusion age (540 Ma) of the metagabbros and a shortly later eclogite facies event (530 Ma) are inferred. This scenario fits with the geodynamic evolution deduced form the acidic country rocks of the eclogitic metagabbros. Direct links between …
Oligocene History Of The Çardak - Dazkırı Subbasin (Denizli, Sw Turkey): Integrated Molluscan And Planktonic Foraminiferal Biostratigraphy, Yeşi̇m İslamoğlu, Aynur Hakyemez
Oligocene History Of The Çardak - Dazkırı Subbasin (Denizli, Sw Turkey): Integrated Molluscan And Planktonic Foraminiferal Biostratigraphy, Yeşi̇m İslamoğlu, Aynur Hakyemez
Turkish Journal of Earth Sciences
The detailed analysis of molluscan and planktonic foraminiferal fauna in the Oligocene Çardak-Dazkırı sub-basin, in northeastern Denizli provin ce (western Turkey) allowed accurate dating of the deposits, together with interpretation of their depositional environments. Gastropod, bivalve, scaphopod and planktonic foraminiferal assemblages identified in ten sections reveal a succession which was deposited between the Late Rupelian and Early Chattian. Planktonic foraminifera, documented for the first time in the basin, indicate the P19 Zone (Turborotalia ampliapertura Zone) of the Late Rupelian at the base of the succession whereas Molluscan fauna, determined for the first time in this study, assign the whole succession, …
Debrunia Occitanica Nov. Sp. (Monopleuridae) From The Early Aptian Of Se France, Mükerrem Fenerci̇-Masse, Jean-Pierre Masse
Debrunia Occitanica Nov. Sp. (Monopleuridae) From The Early Aptian Of Se France, Mükerrem Fenerci̇-Masse, Jean-Pierre Masse
Turkish Journal of Earth Sciences
Debrunia occitanica nov. sp., described from the early Aptian platform limestones of SE France, is characterized by: a moderately convex left valve, inconspicuous radial bands and a ligament groove in a depression flanked by two longitudinal rounded edges. Debrunia occitanica nov. sp. is considered as a chronospecies belonging to a single lineage rooted in the Barremian, and including Debrunia bruni and Debrunia mutabilis. Evolutionary trends in the three species include flattening of the left valve, development of the corresponding myophores, and reduction of the radial bands. This new species has the potential to be a stratigraphic marker for the early …
Blending Rudists With Technology; Non-Destructive Examination Of The Internal And External Structures Of Rudists Using High Quality Scanning And Digital Imagery, Ann Molineux, Robert W. Scott, Jessie Maisano, Richard Ketcham, Louis Zachos
Blending Rudists With Technology; Non-Destructive Examination Of The Internal And External Structures Of Rudists Using High Quality Scanning And Digital Imagery, Ann Molineux, Robert W. Scott, Jessie Maisano, Richard Ketcham, Louis Zachos
Turkish Journal of Earth Sciences
Certain formations within the Cretaceous of Texas include zones of silicified rudists. Such diagenetic alteration, combined with the timing of alteration, has preserved many structural features of the rudist suitable for computed tomography (CT scanning). The excellent density differences between those skeletal structures (silica) and the internal sediment (calcitic mud) or later crystallization (calcite), fulfill a fundamental requirement for such analysis. The Jackson School of Geosciences at The University of Texas provides access to a high resolution computed tomography scanning system. This equipment, not identical to medical scanners, provides higher resolution and sophisticated software to analyze the imagery. Several rudist …
Bala (Ankara) Earthquakes: Implications For Shallow Crustal Deformation In Central Anatolian Section Of The Anatolian Platelet (Turkey), Onur Tan, Mustafa Cengi̇z Tapirdamaz, Semi̇h Ergi̇ntav, Sedat İnan, Yildiz İravul, Ruhi̇ Saatçilar, Beki̇r Tüzel, Adi̇l Tarancioğlu, Sali̇h Karakisa, Recai̇ Feyi̇z Kartal, Sami̇ Zünbül, Kenan Yanik, Mehmet Kaplan, Fuat Şaroğlu, Ali̇ Koçyi̇ği̇t
Bala (Ankara) Earthquakes: Implications For Shallow Crustal Deformation In Central Anatolian Section Of The Anatolian Platelet (Turkey), Onur Tan, Mustafa Cengi̇z Tapirdamaz, Semi̇h Ergi̇ntav, Sedat İnan, Yildiz İravul, Ruhi̇ Saatçilar, Beki̇r Tüzel, Adi̇l Tarancioğlu, Sali̇h Karakisa, Recai̇ Feyi̇z Kartal, Sami̇ Zünbül, Kenan Yanik, Mehmet Kaplan, Fuat Şaroğlu, Ali̇ Koçyi̇ği̇t
Turkish Journal of Earth Sciences
Central Anatolia is quiet in terms of seismic activity, and rarely earthquakes up to magnitude 5.6 occur in the inner part of the Anatolian block or Anatolian platelet. Southeast of Ankara, the capital city of Turkey, two earthquake sequences with maximum magnitude of 5.6 occurred in 2005 and 2007. We discuss these shallow crustal deformation in the Anatolian platelet, in the light of seismological data from these earthquakes (M_L= 5.6) and their aftershocks. Following the earthquake of December 20, 2007 near Bala town, Ankara, we installed seven temporary stations in the first 24 hours to observe the aftershock activity and …
Displacements And Kinematics Of The February 1, 1944 Gerede Earthquake (North Anatolian Fault System, Turkey): Geodetic And Geological Constraints, Mehmet Emi̇n Ayhan, Ali̇ Koçyi̇ği̇t
Displacements And Kinematics Of The February 1, 1944 Gerede Earthquake (North Anatolian Fault System, Turkey): Geodetic And Geological Constraints, Mehmet Emi̇n Ayhan, Ali̇ Koçyi̇ği̇t
Turkish Journal of Earth Sciences
The North Anatolian Fault System (NAFS) is an approximately 2-110-km-wide, 1600-km-long right-lateral intra-continental transform fault boundary between the Anatolian platelet and the Eurasian plate. The Gerede fault zone is one of the major active structures in the western section of the NAFS. It is a 1-9-km-wide, 325-km-long and ENE-trending dextral strike-slip fault zone, with a total accumulated offset since its initiation (Late Pliocene) of about 43 km. This offset indicates an average geological slip rate of 16.5 mm/yr. The 1 February 1944 Gerede earthquake occurred within the Gerede fault zone. Based on recent field geological mapping of the rupture traces …
Whole Rock And Mineral Chemistry Of Ultramafic-Mafic Cumulates From The Orhaneli (Bursa) Ophiolite, Nw Anatolia, Ender Sarifakioğlu, Hayretti̇n Özen, John A. Winchester
Whole Rock And Mineral Chemistry Of Ultramafic-Mafic Cumulates From The Orhaneli (Bursa) Ophiolite, Nw Anatolia, Ender Sarifakioğlu, Hayretti̇n Özen, John A. Winchester
Turkish Journal of Earth Sciences
The Orhaneli ophiolite, situated in the western part of the İzmir-Ankara-Erzincan Suture Zone (İAESZ) and south of Bursa, exposes cumulates belonging to the mantle-crust transition zone. The Orhaneli ophiolite consists mainly of ultramafic cumulates and subordinate mafic cumulates. The basal cumulate sequence comprises dunites locally interlayered with chromitite levels. Above, dunitic cumulates, commonly interbanded with cumulate wehrlites, grade up into two pyroxene peridotites (cumulate lherzolites showing some transition to cumulate harzburgites in places). The observation of cumulate gabbroic thin layers intercalated with ultramafic cumulates at least three times suggests that the magma chamber was periodically replenished by basaltic liquids. Petrographic …
^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Fission-Track Geothermochronology Quantifying Cooling And Exhumation History Of The Kaman-Kırşehir Region Intrusions, Central Anatolia, Turkey, Durmuş Boztuğ, Özlem Güney, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa, Nazmi̇ Otlu
^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Fission-Track Geothermochronology Quantifying Cooling And Exhumation History Of The Kaman-Kırşehir Region Intrusions, Central Anatolia, Turkey, Durmuş Boztuğ, Özlem Güney, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa, Nazmi̇ Otlu
Turkish Journal of Earth Sciences
The Kaman-Kırşehir region intrusions were generated in a post-collisional extensional setting following Cenomanian-Turonian docking of an oceanic island arc, comprising the supra-subduction zone (SSZ) Central Anatolian ophiolite (CAO), onto the Tauride-Anatolide Platform (TAP). These granitoids have been named, from N to S, the Çamsarı quartz syenite, Hamit quartz syenite, Bayındır nepheline-cancrinite syenite, Durmuşlu nepheline-nosean-melanite syenite porphyry and Baranadağ quartz monzonite. They intrude the crustal metasediments of the Central Anatolian Crystalline Complex (CACC) and CAO and are unconformably overlain by Upper Paleocene to Lower-Middle Eocene sediments. The single-zircon ^{207}Pb-^{206}Pb evaporation age of the Çamsarı unit is 95.7±5.1 Ma; those of the …
Bedrock Depth Mapping Of The Coast South Of İstanbul: Comparison Of Analytical And Experimental Analyses, Gülüm Bi̇rgören, Oğuz Özel, Bi̇lge Si̇yahi̇
Bedrock Depth Mapping Of The Coast South Of İstanbul: Comparison Of Analytical And Experimental Analyses, Gülüm Bi̇rgören, Oğuz Özel, Bi̇lge Si̇yahi̇
Turkish Journal of Earth Sciences
Local S-wave velocity-depth profiles and bedrock depth distribution are key factors in assessing seismic hazard and earthquake ground motion characteristics since they allow determination of the amplification potential of geological formations overlying bedrock. In this study, an empirical relationship between the thickness of Tertiary-Quaternary sediments (hereafter referred as cover) overlying Palaeozoic bedrock and their resonance frequencies was calculated for the İstanbul region and the bedrock depth distribution beneath the city was presented. The relationship was investigated by comparing transfer functions obtained from single station microtremor analyses and one-dimensional (1D) S-wave velocity profiles at sites where shallow velocity structure is known. …
Cross-Basin Faulting And Extinction Of Pull-Apart Basins In The Sea Of Marmara, Nw Turkey, İsmai̇l Kuşçu
Cross-Basin Faulting And Extinction Of Pull-Apart Basins In The Sea Of Marmara, Nw Turkey, İsmai̇l Kuşçu
Turkish Journal of Earth Sciences
Although offshore multi-channel seismic reflection and multi-beam bathymetric studies were intensively carried out in the Sea of Marmara especially after the August 17, 1999 İzmit earthquake (Mw 7.4), some basic problems remain unsolved, for example whether the seafloor was cut by a double fault system or just by a single fault. The researchers advocating the double fault system assumed that most of the deformation occurred along the margins of the basins and concluded that the classical model of pull-apart basin formation along releasing bends or stepovers within an east−west-trending dextral strike-slip system prevails. An alternative and completely different proposition proposed …
Crustal Thermal Properties Of The Central Pontides (Northern Turkey) Deduced From Spectral Analysis Of Magnetic Data, Nafi̇z Maden
Crustal Thermal Properties Of The Central Pontides (Northern Turkey) Deduced From Spectral Analysis Of Magnetic Data, Nafi̇z Maden
Turkish Journal of Earth Sciences
The Pontides can be divided tectonically into three main sectors: Eastern, Central, and Western Pontides. Each of these represents an amalgamated tectonic mosaic consisting of remnants of oceanic, continental, and island arc segments. The Eastern and the Western Pontides meet in the Central Pontides, where they are structurally mixed and form a tectonic knot. The Central Pontides of northern Turkey is one of the best exposed segments of the southern margin of Eurasia adjacent to the Tethys Ocean. The study area also extends to parts of the Sakarya and Kırşehir continents. Magnetic spectral analysis, which has been used to estimate …
Permian Trilobites From Antalya Province, Turkey, And Enrollment In Late Palaeozoic Trilobites, Rudy Lerosey Aubril, Lucia Angiolini
Permian Trilobites From Antalya Province, Turkey, And Enrollment In Late Palaeozoic Trilobites, Rudy Lerosey Aubril, Lucia Angiolini
Turkish Journal of Earth Sciences
Trilobites are a minor component of Permian benthic marine faunas, which explains why they remain poorly known. For example, only two specimens have been found in the highly fossiliferous and extensively studied Middle-Upper Permian Pamucak Formation (Antalya Province, Turkey). These two complete enrolled trilobites of Wordian age are described herein. The diagnosis of the subgenus Pseudophillipsia (Nodiphillipsia) Kobayashi & Hamada 1984a is emended and its occurrence outside of eastern Asia is reported for the first time. The second specimen represents a new species, Pseudophillipsia (Carniphillipsia) kemerensis sp. nov. Its discovery in the Wordian of Turkey suggests that Pseudophillipsia (Carniphillipsia) is …
Geochemical And Mineralogical Characteristics Of Fe-Ni Laterite Ore Of Sarıçimen (Çaldıran-Van) Area In Eastern Anatolia, Turkey, Ali̇ Riza Çolakoğlu
Geochemical And Mineralogical Characteristics Of Fe-Ni Laterite Ore Of Sarıçimen (Çaldıran-Van) Area In Eastern Anatolia, Turkey, Ali̇ Riza Çolakoğlu
Turkish Journal of Earth Sciences
The Sarıçimen Fe-Ni laterite ore is located 15 km east of Çaldıran County, northeast of Lake Van. This area is situated in the eastern Anatolia accretionary complex of Turkey, close to the Iran boundary. It is the first transported Fe-Ni rich laterite to be described from this area. This paper concentrates on the mineralogical and textural features of the ore minerals and the transported Fe-Ni laterite zone. These transported laterites are very inhomogeneous and contain very abundant zoned chromite grains, which have been altered to magnetite. SEM/probe investigations indicate that Fe-Ni is depleted in the core chromite and increases in …
Optically Stimulated Luminescence To Date Coastal Dunes And A Possible Tsunami Layer On The Kavak Delta (Saros Gulf, Nw Turkey), Ahmet Evren Ergi̇nal, Nafi̇ye Kiyak Güneç, Hasan Özcan
Optically Stimulated Luminescence To Date Coastal Dunes And A Possible Tsunami Layer On The Kavak Delta (Saros Gulf, Nw Turkey), Ahmet Evren Ergi̇nal, Nafi̇ye Kiyak Güneç, Hasan Özcan
Turkish Journal of Earth Sciences
Optically stimulated luminescence (OSL) dating was used to determine the timing of initial dune formation and reconstruct the evolution of coastal dunes that developed on the Kavak Delta, Saros Gulf, Turkey. Along a 500-m-long representative transect, dune sands were extracted from foredune, semistable (grey) dune, stable (dark) dune and dune-swamp boundary defined by a scarp 50-75 cm high. The data obtained showed that dune drift initiated 670 years ago. A pumice layer 15-20-cm-thick interbedded with marine clay and sand showed an OSL age of 340 years coinciding with underlying dune sand. XRF analysis showed that pumices were of similar composition …
First Record Of Crassostrea Cyathula Lamarck 1806 From �The Rupelian-Lower Chattian Of Sarıbuğday-Kovancılar� (Ne Palu) Eastern Taurids, E Turkey, İzzet Hoşgör, Yavuz Okan
First Record Of Crassostrea Cyathula Lamarck 1806 From �The Rupelian-Lower Chattian Of Sarıbuğday-Kovancılar� (Ne Palu) Eastern Taurids, E Turkey, İzzet Hoşgör, Yavuz Okan
Turkish Journal of Earth Sciences
Crassostrea cyathula (Lamarck 1806), a valuable biostratigraphic marker, was found for the first time in eastern Turkey (Eastern Mediterranean), in the Rupelian-Lower Chattian sedimentary sequences of northeastern Palu, Elazığ region, and its palaeoecological characters, palaeobiogeographic and stratigraphic distribution are discussed. These oyster specimens are also the first abundant macrofossils from the Oligocene sediments of the Sarıbuğday-Kovancılar section, which were formerly only recorded by micropalaeontological data.
Minerals From Macedonia. Xx. Geological Setting, Lithologies, And Identification Of The Minerals From Rzanovo Fe-Ni Deposit, Blazo Boev, Gligor Jovanovski, Petre Makreski
Minerals From Macedonia. Xx. Geological Setting, Lithologies, And Identification Of The Minerals From Rzanovo Fe-Ni Deposit, Blazo Boev, Gligor Jovanovski, Petre Makreski
Turkish Journal of Earth Sciences
The Rzanovo deposit lies within the western ophiolite belt of the Vardar zone. Its main geological units are discussed in terms of their mineralogy, petrology and petrological evolution. Minerals observed include: magnetite, hematite, clinochlore, talc, sepiolite, magnesioriebeckite, lizardite, dolomite, phlogopite, stilpnomelane, quartz, albite, pyrite, maghemite, pyrrhotine, digenite and millerite. Some minerals had non-distinct morphologies and ambiguous characteristics, preventing identification on the basis of physical properties alone. Thus, some of the minerals (magnetite, hematite, talc, dolomite, olivine, calcite, aragonite and brucite) as well as some serpentine minerals (antigorite and chrysotile) were identified by vibrational spectroscopy. Difficulties in identification by IR spectroscopy …
Alteration Mineralogy And Geochemistry Of The Hydrothermally Altered Rocks Of The Kutlular (Sürmene) Massive Sulfide Deposit, Ne Turkey, Emel Abdi̇oğlu, Mehmet Arslan
Alteration Mineralogy And Geochemistry Of The Hydrothermally Altered Rocks Of The Kutlular (Sürmene) Massive Sulfide Deposit, Ne Turkey, Emel Abdi̇oğlu, Mehmet Arslan
Turkish Journal of Earth Sciences
Volcanogenic massive sulfide deposits accompanying the Upper Cretaceous felsic rocks in the intra-arc rift zone of the Pontide palaeo-arc are common in the NE Turkey. One of them, the Kutlular (Sürmene, Trabzon) deposit, is an abandoned mine within the Upper Cretaceous mafic, felsic volcanics and subvolcanic rocks. Detailed mineralogical and geochemical studies indicate the presence of hydrothermal alteration zones around the Kutlular deposit; these alteration zones are represented by silicification-pyrite-illite zone, illite-silicification zone, illite/smectite-silicification zone, smectite zone accompanying kaolinite and halloysite in the dacitic pyroclastics, and additionally chlorite zone in the mafic volcanics. Lithogeochemical data indicate that the footwall dacitic …
Lead And Sulfur Isotope Studies Of The Koru (Çanakkale, Turkey) Lead-Zinc Deposits, Gülcan Bozkaya, Ahmet Gökçe
Lead And Sulfur Isotope Studies Of The Koru (Çanakkale, Turkey) Lead-Zinc Deposits, Gülcan Bozkaya, Ahmet Gökçe
Turkish Journal of Earth Sciences
Koru (Çanakkale) barite-bearing lead-zinc deposits are typical examples of the lead-zinc deposits occurring in the Tertiary volcanic rocks which crop out in the Biga Peninsula. Volcanic rocks around the investigated deposits are distinguished as Eocene Akçaalan andesite, Oligocene Adadağı pyroclastics, Miocene Dededağ dacite and Plio-Quaternary Karaömerler basalt. The investigated deposits are hosted by Adadağı pyroclastics and show two different mineralization styles such as stockwork ore veinlets in the upper parts and ore veins along the fault zones in WNW-ESE direction, in the lower parts. Sphalerite, galena, pyrite, chalcopyrite, quartz, barite and calcite are the main minerals and they are accompanied …
^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Apatite Fission-Track Geothermochronology Revealing The Emplacement, Cooling And Exhumation History Of The Karaçayır Syenite (N Sivas), East-Central Anatolia, Turkey, Durmuş Boztuğ, Esra Türksever, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa
^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Apatite Fission-Track Geothermochronology Revealing The Emplacement, Cooling And Exhumation History Of The Karaçayır Syenite (N Sivas), East-Central Anatolia, Turkey, Durmuş Boztuğ, Esra Türksever, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa
Turkish Journal of Earth Sciences
The Karaçayır syenite, intruding the Palaeozoic crustal metamorphics and unconformably overlain by Upper Paleocene to Eocene Tokuş formation in the north of Sivas (east-central Anatolia), has been studied with respect to ^{207}Pb-^{206}Pb single zircon evaporation, biotite ^{40}Ar-^{39}Ar, and apatite fission-track geothermochronology. ^{207}Pb-^{206}Pb single zircon evaporation dating yields an age of 99.0±11.0 Ma (Cenomanian-Turonian) which is considered to be the intrusion age. Biotite ^{40}Ar-^{39}Ar age determination gives a cooling age of ca. 65 Ma. Apatite fission-track dating, combined with T-t modeling based on track-length distribution data, determines a fast tectonic exhumation with an uplift rate of > 1 mm/a which occurred 58-61 …
Mineral Chemistry And Petrochemistry Of Post-Collisional Tertiary Mafic To Felsic Cogenetic Volcanics In The Ulubey (Ordu) Area, Eastern Pontides, Ne Turkey, İrfan Temi̇zel, Mehmet Arslan
Mineral Chemistry And Petrochemistry Of Post-Collisional Tertiary Mafic To Felsic Cogenetic Volcanics In The Ulubey (Ordu) Area, Eastern Pontides, Ne Turkey, İrfan Temi̇zel, Mehmet Arslan
Turkish Journal of Earth Sciences
Post-collisional Tertiary volcanic rocks in the Ulubey (Ordu) area at the western edge of the eastern Pontides palaeo-arc are divided into four suites. The Yenisayaca basalt (TB) contains plagioclase (An_{61-83}), clinopyroxene (Wo_{42-44}En_{39-41}Fs_{15-18}) and olivine phenocrysts and titanomagnetite microphenocrysts, whereas the Çatal Tepe and Elekçioğlu Tepe suite (ÇES), Işık Tepe suite (ITS) and andesite/ trachyandesite suite (ATS) rocks include plagioclase (An_{23-78}), clinopyroxene (Wo_{27-48}En_{37-55}Fs_{11-26}), hornblende (Mg#= 0.63-0.76), biotite (Mg#= 0.63-0.82), sanidine phenocrysts and titanomagnetite and apatite microphenocrysts. Petrochemically, the volcanic rocks show tholeiitic-alkaline to the calc-alkaline affinities, and have medium to high-K contents. Most samples have low Mg#, Cr, and Ni, which …
Geochemical Characteristics Of Mafic And Intermediate Volcanic Rocks From The Hasandağ And Erciyes Volcanoes (Central Anatolia, Turkey), Aykut Güçteki̇n, Nezi̇hi̇ Köprübaşi
Geochemical Characteristics Of Mafic And Intermediate Volcanic Rocks From The Hasandağ And Erciyes Volcanoes (Central Anatolia, Turkey), Aykut Güçteki̇n, Nezi̇hi̇ Köprübaşi
Turkish Journal of Earth Sciences
Hasandağ and Erciyes stratovolcanoes, which are the two important stratovolcanoes in Central Anatolia, erupted volcanic products with both calc-alkaline and alkaline compositions, although the calc-alkaline activity is more widespread. There are three stages of geochemical evolution in the history of the Hasandağ stratovolcanic complex: (1) Keçikalesi tholeiitic volcanism, (2) Hasandağ calc-alkaline volcanism, and (3) Hasandağ alkaline volcanism. The geochemical evolution of Erciyes volcanic complex also exhibits three distinct evolutionary stages: (1) Koçdağ alkaline volcanism, (2) Koçdağ calc-alkaline volcanism and (3) Erciyes calc-alkaline volcanism. The volcanic rocks from both suites show enrichments in LREE relative to HREE. The rocks as a …
Compositional Variations, Zoning Types And Petrogenetic Implications Of Low-Pressure Clinopyroxenes In The Neogene Alkaline Volcanic Rocks Of Northeastern Turkey, Faruk Aydi̇n, Orhan Karsli, M. Burhan Sadiklar
Compositional Variations, Zoning Types And Petrogenetic Implications Of Low-Pressure Clinopyroxenes In The Neogene Alkaline Volcanic Rocks Of Northeastern Turkey, Faruk Aydi̇n, Orhan Karsli, M. Burhan Sadiklar
Turkish Journal of Earth Sciences
Clinopyroxene phenocrysts and microphenocrysts in different series of the Neogene alkaline volcanic rocks from the eastern Pontides (NE Turkey) record various stages in the crystallization conditions and evolution history of the alkaline melt as well as its origin. Crystal chemical studies reveal that the clinopyroxenes in each rock series show strong textural and compositional similarities, which all reflect a common petrogenetic affinity. They have relatively high Mg-numbers (0.68-0.95), variable Al_2O_3 (1.3-9.6 wt%), low TiO_2 (
Petrogenesis Of The Refahiye Ophiolite And Its Tectonic Significance For Neotethyan Ophiolites Along The İzmir-Ankara-Erzincan Suture Zone, Ender Sarifakioğlu, Hayretti̇n Özen, John A. Winchester
Petrogenesis Of The Refahiye Ophiolite And Its Tectonic Significance For Neotethyan Ophiolites Along The İzmir-Ankara-Erzincan Suture Zone, Ender Sarifakioğlu, Hayretti̇n Özen, John A. Winchester
Turkish Journal of Earth Sciences
The Refahiye ophiolite, situated near Erzincan in the eastern part of the İzmir-Ankara-Erzincan Suture Zone (İAESZ), is one of the best exposures of oceanic lithosphere in the northern branch of the Neotethyan Ocean. The ophiolite, mainly thrust southwards, transported on an ophiolitic mélange, over the Early Triassic-Campanian Munzur Limestone of the Anatolide-Tauride Platform, was also emplaced by north-directed backthrusting onto the Pontides in the Late Cretaceous. It displays an almost complete ophiolite series unconformably overlain by Tertiary volcano-sedimentary units. The mantle peridotites are dominated by harzburgites, with dunite bands and lenses locally cut by isolated diabase dykes, whereas the mafic-ultramafic …
The Relationship Between The Tectonic Setting Of The Lake İznik Basin And The Middle Strand Of The North Anatolian Fault, Kurultay Öztürk, Cenk Yaltirak, Bedri̇ Alpar
The Relationship Between The Tectonic Setting Of The Lake İznik Basin And The Middle Strand Of The North Anatolian Fault, Kurultay Öztürk, Cenk Yaltirak, Bedri̇ Alpar
Turkish Journal of Earth Sciences
The İznik Basin is an active depression created by a series of faults developed in relation to the Middle Strand of the North Anatolian Fault (NAFMS). The most important of these faults is the oblique Sölöz fault, which runs parallel to the NAFMS. It is interpreted as a releasing bend, and plays a crucial role in the evolution of the 75-m-deep ellipsoid-shaped depression in the southern part of the lake. The faults that limit the coastal alluvial plain on land, some of which developed during the early evolution of the NAFMS, are equally important in the development of the İznik …
Two-And-Three-Dimensional Crustal Thickness Of The Eastern Pontides (Ne Turkey), Nafiz Maden, Kenan Geli̇şli̇, Yener Eyüboğlu, Osman Bektaş
Two-And-Three-Dimensional Crustal Thickness Of The Eastern Pontides (Ne Turkey), Nafiz Maden, Kenan Geli̇şli̇, Yener Eyüboğlu, Osman Bektaş
Turkish Journal of Earth Sciences
The Eastern Pontide orogenic belt is divided into three subzones (northern, southern and axial zones) based on present lithologies and facies associations. NE-SW-, NW-SE- and E-W-trending fault systems, which play an important role in palaeotectonics and neotectonics of the Eastern Pontides, separate these zones. Three different methods were used to estimate the Moho depth from observed gravity value, namely (i) empirical relationship between Moho depth and Bouguer anomaly; (ii) spectral analysis of the radial wave number and; (iii) by the gravity inversion method. Power spectrum, a statistical approach, is a widely used technique to determine the depth of geological sources …
Anomalous Strong Reflections On High Resolution Seismic Data From The Turkish Shelf Of The Eastern Black Sea: Possible Indicators Of Shallow Hydrogen Sulphide-Rich Gas Hydrate Layers, Derman Dondurur, Günay Çi̇fçi̇
Anomalous Strong Reflections On High Resolution Seismic Data From The Turkish Shelf Of The Eastern Black Sea: Possible Indicators Of Shallow Hydrogen Sulphide-Rich Gas Hydrate Layers, Derman Dondurur, Günay Çi̇fçi̇
Turkish Journal of Earth Sciences
Some strong reflections about 3 to 5 m thick were observed at depths of 25-60 metres below the sea floor using deep-towed, 5 kHz subbottom profiler data in the Turkish shelf and upper slope of the Eastern Black Sea at water depths of 250 to 700 m. Strong reflections of this kind are generally attributed to shallow and localized gas accumulations. We, however, observed that the reflection polarity of these strong reflections was positive, suggesting that they do not correspond to reflections from the upper boundary of a possible gas front. In this study, we evaluate these reflections to determine …