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Articles 811 - 840 of 917
Full-Text Articles in Earth Sciences
Shape And Size Characteristics Of Bedload Transported During Winter Storm Events In The Cwm Treweryn Stream, Brecon Beacons, South Wales, Tuncer Demi̇r, R. P. D. Walsh
Shape And Size Characteristics Of Bedload Transported During Winter Storm Events In The Cwm Treweryn Stream, Brecon Beacons, South Wales, Tuncer Demi̇r, R. P. D. Walsh
Turkish Journal of Earth Sciences
Bedload transport in the Cwm Treweryn stream, a tributary of the Usk in the Brecon Beacons, South Wales, was investigated during a wet winter period in early 1995 using basket-type bedload traps and the tracing of painted clasts. The Cwm Treweryn is a typical mountain stream of the region with its gravel-bedload, flashy regime, high gradient and pool-riffle sequences. In particular, the study explored - for a range of categories of clast size - the nature of any influence of clast shape on bedload movement. Competent flows ranging from 2.5 to 19.5 m^3 s^{-1} (the latter close to bankfull flow) …
Genetic Relations Between Skarn Mineralization And Petrogenesis Of The Evciler Granitoid, Kazdağ, Çanakkale, Turkey And Comparison With World Skarn Granitoids, Yeşi̇m Yücel Öztürk, Cahi̇t Helvaci, Muharrem Satir
Genetic Relations Between Skarn Mineralization And Petrogenesis Of The Evciler Granitoid, Kazdağ, Çanakkale, Turkey And Comparison With World Skarn Granitoids, Yeşi̇m Yücel Öztürk, Cahi̇t Helvaci, Muharrem Satir
Turkish Journal of Earth Sciences
Most skarn deposits are directly related to magmatic activity, and there is a systematic correlation between the composition of causative plutons and the metal contents of the related skarns. This paper documents the composition of facies within the Evciler pluton and correlations between intrusion composition and the metal contents of associated skarns. There have been previous studies of mines (e.g., Cu mines) in the Evciler district, however, there have been no detailed geological investigations of such ore deposits or associated skarn mineralization. In the Evciler district both calcic exoskarn (garnet-pyroxene) and endoskarn (pyroxene-epidote) occur along the contacts between granitoid and …
Stratigraphy And Geochronology Of The Early Miocene Volcanic Units In The Bigadiç Borate Basin, Western Turkey, Fuat Erkül, Cahi̇t Helvaci, Hasan Sözbi̇li̇r
Stratigraphy And Geochronology Of The Early Miocene Volcanic Units In The Bigadiç Borate Basin, Western Turkey, Fuat Erkül, Cahi̇t Helvaci, Hasan Sözbi̇li̇r
Turkish Journal of Earth Sciences
Western Turkey has undergone an intense deformation which has given rise to two types of basins since the Late Oligocene: NE-trending and E-W-trending basins situated on the basement rocks of the Menderes Massif, the Sakarya Zone, the Lycian nappes and the Bornova Flysch Zone. One of the NE-trending basins, the Bigadiç borate basin, is located in the Bornova Flysch Zone - a 50-90-km-wide zone between the Sakarya Zone and the Menderes Massif. Lower Miocene successions are dominated by lacustrine, fluvial, evaporitic sedimentary rocks and numerous NE-trending volcanic centres which produced considerable amounts of lava and volcaniclastic detritus in the Bigadiç …
Stratigraphy Of The Volcanic Products Around Nemrut Caldera: Implications For Reconstruction Of The Caldera Formation, Özgür Karaoğlu, Yavuz Özdemi̇r, A. Ümi̇t Tolluoğlu, Mustafa Karabiyikoğlu, Onur Köse, Jean-Luc Froger
Stratigraphy Of The Volcanic Products Around Nemrut Caldera: Implications For Reconstruction Of The Caldera Formation, Özgür Karaoğlu, Yavuz Özdemi̇r, A. Ümi̇t Tolluoğlu, Mustafa Karabiyikoğlu, Onur Köse, Jean-Luc Froger
Turkish Journal of Earth Sciences
The volcanological development of the Nemrut stratovolcano, located near the southwestern tip of Lake Van in eastern Turkey, is subdivided into three stages: pre-caldera, post-caldera and late stages. Two ignimbrite flows have been recognized in the pre-caldera stage. The earlier of the two occurred after basaltic lavas formed along extensional fissures. The latter, which forms the main subject of this paper, was a major flow associated with the development of the Nemrut caldera. The pyroclastic deposits of the Nemrut volcano in the pre-caldera stage are divided into three phases on the basis of palaeosols that separate them. The first phase …
Alpine Metamorphism And Granitoid Magmatism In The Strandja Zone: New Data From The Sakar Unit, Se Bulgaria, Ianko Gerdjikov
Alpine Metamorphism And Granitoid Magmatism In The Strandja Zone: New Data From The Sakar Unit, Se Bulgaria, Ianko Gerdjikov
Turkish Journal of Earth Sciences
The Strandja Zone is a pre-Cenomanian orogen consisting of three tectonic units: the Veleka, Strandja and Sakar units. The first two units display very low-grade Alpine metamorphism, whereas in the Sakar unit the Triassic sediments are metamorphosed to the amphibolite facies. For years this high-grade metamorphism was enigmatic and most of the metamorphic rocks were interpreted as a reworked Precambrian crust of the Rhodope. This contribution begins with a review of the recent data about the structure and evolution of the Sakar unit. Probably the most important recent finding was the demonstration of the lack of a structural break between …
Petrography And Petrology Of The Calc-Alkaline Sarıhan Granitoid (Ne Turkey): An Example Of Magma Mingling And Mixing, Zafer Arslan
Petrography And Petrology Of The Calc-Alkaline Sarıhan Granitoid (Ne Turkey): An Example Of Magma Mingling And Mixing, Zafer Arslan
Turkish Journal of Earth Sciences
There are many acidic intrusions of varying age in the northern and southern zones of the eastern Pontides, NE Turkey, and the Sarıhan Granitoid is one of these. The Maastrichtian Sarıhan Granitoid was emplaced into the pre-Permo-Carboniferous Pulur Massif, generally comprising medium-grade metamorphic rocks; the Liassic Hamurkesen Formation, that begins with the Dikmetaş conglomerate and continues upward into volcano-sedimentary rocks; and the Malm-Lower Cretaceous Hozbirikyayla Formation, comprising limestone and sandy limestones. The Sarıhan Granitoid crops out in an area of approximately 40 km2, has an ellipsoidal shape, and comprises mainly quartz monzodiorite, granodiorite and lesser quartz diorite. The pluton contains …
Investigation Of Safe And Sustainable Yields For The Sandy Complex Aquifer System In The Ergene River Basin, Thrace Region, Turkey, Şebnem Ökten, Hasan Yazicigi̇l
Investigation Of Safe And Sustainable Yields For The Sandy Complex Aquifer System In The Ergene River Basin, Thrace Region, Turkey, Şebnem Ökten, Hasan Yazicigi̇l
Turkish Journal of Earth Sciences
This study aims to determine the safe and sustainable yields for the Sandy Complex aquifer system in Ergene River basin in northwestern Turkey. A numerical ground-water flow model was developed for the Sandy Complex aquifer, which is the most productive and the most widespread aquifer in the basin. The finite difference ground-water model was used to simulate steady and unsteady flow in the aquifer. The model was calibrated in two steps: a steady-state calibration, by using the observed ground-water levels of January 1970; then a transient calibration, by using the observed ground-water levels for the period of January 1970 and …
Geotectonic Setting And Origin Of The Youngest Kula Volcanics (Western Anatolia), With A New Emplacement Model, Murat Tokçaer, Samuele Agostini, Mehmet Yilmaz Savaşçin
Geotectonic Setting And Origin Of The Youngest Kula Volcanics (Western Anatolia), With A New Emplacement Model, Murat Tokçaer, Samuele Agostini, Mehmet Yilmaz Savaşçin
Turkish Journal of Earth Sciences
The Quaternary Kula volcanics are Na-dominant in character while all the older volcanic rocks of western Anatolia are generally definitive K-dominant rocks. As a unique example in western Anatolia, the existence of a huge amount of plateau basalts at Kula indicates rapid uplift of mantle material, as confirmed by new geochemical data. Based on our field observations, the oldest Kula volcanics are the plateau basalts with more than one main lava flow. At the beginning of volcanic activity (first-period plateau basalts), this plateau was vast. Subsequently, parts of the first-period plateau basalts were uplifted and partly eroded while other parts …
Evolution Of And Factors Controlling Eocene Sedimentation In The Darende-Balaban Basin, Malatya (Eastern Turkey), Kemal Gürbüz, Murat Gül
Evolution Of And Factors Controlling Eocene Sedimentation In The Darende-Balaban Basin, Malatya (Eastern Turkey), Kemal Gürbüz, Murat Gül
Turkish Journal of Earth Sciences
Collision of the Arabian and Anatolian plates affected evolution of basins located along the southern flank of the Anatolian Plate. The Darende-Balaban foreland basin is one such basin a basin filled with Upper Cretaceous and Eocene sediments, accumulated unconformably and transgressively above ophiolitic and carbonate basement rocks. This basin is locally surrounded, to the north and south, by Late JurassicEarly Cretaceous structural highs created by tectonic elements during the collision of Arabia and Anatolia. This paper aims to describe the factors controlling and evolution of the Eocene sedimentation in the Darende-Balaban basin. The basin fill comprises two distinct sequences …
Water-Level Changes In Shallow Wells Before And After The 1999 İzmit And Düzce Earthquakes And Comparison With Long-Term Water-Level Observations (1999–2004), Nw Turkey, Cenk Yaltirak, Tolga Yalçin, Erkan Bozkurtoğlu, Gali̇p Yüce
Water-Level Changes In Shallow Wells Before And After The 1999 İzmit And Düzce Earthquakes And Comparison With Long-Term Water-Level Observations (1999–2004), Nw Turkey, Cenk Yaltirak, Tolga Yalçin, Erkan Bozkurtoğlu, Gali̇p Yüce
Turkish Journal of Earth Sciences
It is well known that earthquakes cause hydrological changes, such as drying or flooding of water wells, fluctuations in ground-water levels in wells, changes in water quality, and formation of new springs. Significant drops in ground-water levels in wells were recorded during recent earthquakes in NW Turkey on August 17, 1999 in İzmit and on November 12, 1999 in Düzce. The İzmit earthquake (Ms 7.4) caused pre-seismic water-level changes in wells at Eskişehir, located 118-216 km away from the epicentre. Well-level changes in the Eskişehir, Sakarya, Bursa, Yalova, Yenişehir and İnegöl basins were recorded prior to and after the Düzce …
Areal Distribution And Bulk Rock Density Variations Of The Welded İncesu Ignimbrite, Central Anatolia, Turkey, Ulrike Mues-Schumcher, Rolf Schumacher, Lothar Georg Viereck-Götte, Petra Lepetit
Areal Distribution And Bulk Rock Density Variations Of The Welded İncesu Ignimbrite, Central Anatolia, Turkey, Ulrike Mues-Schumcher, Rolf Schumacher, Lothar Georg Viereck-Götte, Petra Lepetit
Turkish Journal of Earth Sciences
The 2.8 Ma İncesu ignimbrite is one of the most densely welded ignimbrites of the Cappadocian Volcanic Province. Estimates of areal extent and volume reveal at least 7,760 km^2 and 38 km^3 of erupted magma. The source area can be located beneath the northeastern flanks of the Erciyes Dağ-Koçdağ stratovolcano. Today, the ignimbrite typically forms relatively small plateaus or isolated remnants and caps on hill tops. Field characteristics of the deposit include a local dark-brown or black basal vitrophyre and horizontally zoned changes in colour which correspond to changes in modal composition. Upwardly increasing amounts of lithic fragments and pumice …
The Karakaya Complex: A Review Of Data And Concepts, Aral İ. Okay, M. Cemal Göncüoğlu
The Karakaya Complex: A Review Of Data And Concepts, Aral İ. Okay, M. Cemal Göncüoğlu
Turkish Journal of Earth Sciences
The Karakaya Complex in the Pontides consists of highly deformed and partly metamorphosed clastic and volcanic series of Permian and Triassic age. It is generally subdivided into two parts: The structurally lower part, called the Lower Karakaya Complex, consists of a mafic lava-mafic pyroclastite-shale-limestone succession metamorphosed in the greenschist and blueschist facies during the Late Palaeozoic or Triassic. The structurally upper part is made up of highly deformed Permian and Triassic clastic, volcaniclastic and volcanic rocks with exotic limestone blocks. There are currently two different models for the depositional setting and tectonic evolution of the Karakaya Complex. The rift model …
Significance Of The Volcanogenic Nilüfer Unit And Related Components Of The Triassic Karakaya Complex For Tethyan Subduction/Accretion Processes In Nw Turkey, Elizabeth A. Pickett, Alastair H. F. Robertson
Significance Of The Volcanogenic Nilüfer Unit And Related Components Of The Triassic Karakaya Complex For Tethyan Subduction/Accretion Processes In Nw Turkey, Elizabeth A. Pickett, Alastair H. F. Robertson
Turkish Journal of Earth Sciences
The Tethyan Karakaya Complex extends east-west across northern Turkey from the Aegean coast to Iran (c. 1100 km), and is interpreted as a Mid-Late Triassic subduction/accretion complex. It comprises strongly deformed fragments of Triassic oceanic seamounts, mid-ocean ridge-type oceanic crust, trench-type sedimentary rocks (Ortaoba Unit) and Permian-Triassic continental fragments (Çal Unit). We focus on the Triassic Nilüfer Unit, which comprises altered basic volcanic and volcaniclastic rocks, volcanogenic sedimentary rocks, heterogeneous debris flow deposits, calciturbidites, siliceous pelagic sedimentary rocks and, in places, Triassic shallow-water limestones. The predominant lithologies are massive basalt and reworked basic pyroclastic deposits. Additional detrital lithologies include volcanogenic …
Geology And Correlation Of The Ezine Zone: A Rhodope Fragment In Nw Turkey?, Laurent Beccaletto, Catherine Jenny
Geology And Correlation Of The Ezine Zone: A Rhodope Fragment In Nw Turkey?, Laurent Beccaletto, Catherine Jenny
Turkish Journal of Earth Sciences
In northwestern Turkey, the Denizgören ophiolite and its sedimentary substratum, the Ezine Group, are enigmatic geological objects whose evolution remains problematic. Based on long-term fieldwork, we here propose a solution for their genesis and correlation. The whole of the Ezine Group, more than three km thick, is characterised by the systematic occurrence of carbonate rocks in the greenschist facies. It has been subdivided into three conformable formations: the Geyikli Formation, with a slight terrigeneous detrital nature, (Middle)-Late Permian in age; the Karadağ Formation, with platform-type sedimentation with local detrital input, Late Permian (Djulfian) in age; the Çamköy Formation, with a …
New Results On The Lithostratigraphy Of The Kazdağ Massif In Northwest Turkey, Mehmet Duru, Şükrü Pehli̇van, Yalçin Şentürk, Fatma Yavaş, Hüseyi̇n Kar
New Results On The Lithostratigraphy Of The Kazdağ Massif In Northwest Turkey, Mehmet Duru, Şükrü Pehli̇van, Yalçin Şentürk, Fatma Yavaş, Hüseyi̇n Kar
Turkish Journal of Earth Sciences
The high-grade metamorphic rocks of the Kazdağ mountain range, termed the Kazdağ Group, crop out as a tectonic window under the Karakaya Complex in northwestern Turkey. The Kazdağ Group forms a doubly plunging, NE-SW-trending anticliniorium. During our regional geological mapping of the Kazdağ Group, we have subdivided the metamorphic rocks into four formations. The lowermost unit is the Fındıklı formation, which comprises amphibole-gneiss, marble and minor amphibolite. It crops out mainly in the southern part of the Kazdağ Massif. The marble horizons within the Fındıklı formation have been named the Altınoluk and Babadağ marble members. The overlying unit, comprising metadunite …
Uppermost Triassic Limestone In The Karakaya Complex- Stratigraphic And Tectonic Significance, Aral İ. Okay, Demi̇r Altiner
Uppermost Triassic Limestone In The Karakaya Complex- Stratigraphic And Tectonic Significance, Aral İ. Okay, Demi̇r Altiner
Turkish Journal of Earth Sciences
Two important tectonostratigraphic units of the Karakaya Complex in northwest Turkey are: a lower metamorphic sequence of metabasite, phyllite and marble, called the Nilüfer Unit; and an upper clastic sequence with Permian and Carboniferous limestone olistoliths called the Hodul Unit. In northwestern Turkey, the Hodul Unit consists of arkosic sandstones, which pass upward into greywacke and siltstone with Permian and Carboniferous limestone blocks. A scarce macrofauna in the sandstones indicates a Norian age for the Hodul Unit. We report for the first time Norian-Rhaetian limestones, here named the Kaşal Limestone Member, from the Hodul Unit to the southwest of Balıkesir. …
Upper Permian (Changxingian) Radiolarian Cherts Within The Clastic Successions Of The "Karakaya Complex" In Nw Anatolia, M. Cemal Göncüoğlu, Kiyoko Kuwahara, U. Kağan Teki̇n, Necati̇ Turhan
Upper Permian (Changxingian) Radiolarian Cherts Within The Clastic Successions Of The "Karakaya Complex" In Nw Anatolia, M. Cemal Göncüoğlu, Kiyoko Kuwahara, U. Kağan Teki̇n, Necati̇ Turhan
Turkish Journal of Earth Sciences
The arkosic sandstones with olistostromes within the "Karakaya Complex" in NW Anatolia to the south of Geyve include a thin layer of green chert with radiolaria. Based on the composition of Albaillellids, the radiolarian assemblage corresponds to the Neoalbaillella ornithoformis assemblage, and its age is assigned to the Changxingian (Late Permian). This is the first finding of synsedimentary radiolarian cherts within the Karakaya units and the indication of latest Permian rifting of the Karakaya basin within the Midian carbonate platform and its pre-Permian basement in the Sakarya Composite Terrane.
Autochthonous Upper Permian (Midian) Carbonates In The Western Sakarya Composite Terrane, Geyve Area, Turkey: Preliminary Data, Necati̇ Turhan, Cengi̇z Okuyucu, M. Cemal Göncüoğlu
Autochthonous Upper Permian (Midian) Carbonates In The Western Sakarya Composite Terrane, Geyve Area, Turkey: Preliminary Data, Necati̇ Turhan, Cengi̇z Okuyucu, M. Cemal Göncüoğlu
Turkish Journal of Earth Sciences
Permian limestones occur widely within the clastic units of the "Karakaya Complex" and are interpreted as allochthonous bodies or olistoliths. In the Kadirler area to the south of Geyve, however, Upper Permian (Midian) quartz sandstones and carbonates with a rich foraminifer fauna disconformably overlie a crystalline basement complex. This basement complex comprises metaclastic rocks, recrystallised limestones, metacherts, and metadiabases, and is intruded by granodiorites. The overlying basal conglomerates and quartzitic sandstones are dominated by pebbles from the basement complex and are followed upward by medium- to thick-bedded dolomites, dolomitic limestones and limestones. The foraminiferal assemblage with Neoschwagerina haydeni Dutkevitch and …
Geology And Structural Evolution Of The Tokat Massif (Eastern Pontides, Turkey), Ali̇ Yilmaz, Hüseyi̇n Yilmaz
Geology And Structural Evolution Of The Tokat Massif (Eastern Pontides, Turkey), Ali̇ Yilmaz, Hüseyi̇n Yilmaz
Turkish Journal of Earth Sciences
The Tokat Massif consists of a pre-Jurassic metamorphic complex that crops out widely between Amasya and Reşadiye in the western part of eastern Pontides, and which can be correlated with the Karakaya Complex of the western Pontides. This complex is named the Tokat Group, and is divided into two main units, namely, the Turhal Metamorphics and Devecidağ Mélange. The Turhal Metamorphics form a volcano-sedimentary sequence in the northern part of the Tokat Massif. The lower level of the formation is made up of gneiss, amphibolite and mica schists, whereas the upper part is represented by an alternation of mica schist, …
Field, Petrographic And Geochemical Characteristics Of The Hamit Alkaline Intrusion In The Central Anatolian Crystalline Complex, Turkey, Nurdane İlbeyli̇
Field, Petrographic And Geochemical Characteristics Of The Hamit Alkaline Intrusion In The Central Anatolian Crystalline Complex, Turkey, Nurdane İlbeyli̇
Turkish Journal of Earth Sciences
The Hamit pluton is one of the alkaline intrusions in the Central Anatolian Crystalline Complex (CACC). The pluton consists of nepheline syenite, pseudoleucite syenite, alkali-feldspar syenite and quartz syenite. The nepheline syenite and pseudoleucite syenite are cut by foid-bearing microsyenitic dykes, whereas the alkali-feldspar syenite and quartz syenite are cut by aplitic and silicic dykes. The predominantly peralkaline Hamit intrusive rocks possess field, petrographic and geochemical characteristics comparable to A-type granites. All intrusive rocks of this pluton show enrichment in LILE and LREE relative to HFSE. The Th/Yb versus Ta/Yb plot suggests that the intrusive rocks formed from an enriched …
Magma Interaction Recorded In Plagioclase Zoning In Granitoid Systems, Zigana Granitoid, Eastern Pontides, Turkey, Orhan Karsli, Faruk Aydin, M. Burhan Sadiklar
Magma Interaction Recorded In Plagioclase Zoning In Granitoid Systems, Zigana Granitoid, Eastern Pontides, Turkey, Orhan Karsli, Faruk Aydin, M. Burhan Sadiklar
Turkish Journal of Earth Sciences
Plagioclase crystals characterized by compositional zoning are typical of the Zigana Granitoid (ZG), NE Turkey. The zoned crystals, which show textural equilibrium with the assemblage quartz + plagioclase + K-feldspar + hornblende + biotite + pyroxene + magnetite + ilmenite, exhibit oscillatory zoning. The zoned plagioclase crystals, ranging in size from 3 to 6 mm, are oval and larger than normal lath-shaped crystals. The zoned crystals are divided petrographically into two main types: (i) crystals zones only at their rims, with spongy cores; and (ii) completely zoned ones. Composition of the zoned crystals ranges from An_{23} (oligoclase) to An_{70} (labradorite). …
Halitpaşa Transpressive Zone: Implications For An Early Pliocene Compressional Phase In Central Western Anatolia, Turkey, Orhan Kaya, Engi̇n Ünay, Gerçek Saraç, Silke Eichhorn, Sabine Hassenrück, Andrea Knappe, Asaf Pekdeğer, Serdar Mayda
Halitpaşa Transpressive Zone: Implications For An Early Pliocene Compressional Phase In Central Western Anatolia, Turkey, Orhan Kaya, Engi̇n Ünay, Gerçek Saraç, Silke Eichhorn, Sabine Hassenrück, Andrea Knappe, Asaf Pekdeğer, Serdar Mayda
Turkish Journal of Earth Sciences
The Late Cenozoic evolution of the eastern Aegean is dominated by widespread continental extension. The most prominent structures are E-W- and NE-SW-trending grabens and intervening horsts, while NW-SE- and N-S-trending faults form the other less important structures. This paper documents the results of recent geological mapping and structural and stratigraphical analysis from the Halitpaşa half graben, which forms the northwestern continuation of the Gediz Graben. Field evidence for a new NW-SE-trending dextral wrench-dominated fault zone (here named the Halitpaşa transpression zone), which involved the thrusting of pre-Palaeogene basement onto Upper Miocene-Lower Pliocene sediments, is presented. The fault zone is correlated …
The Problem Of The Core-Cover Boundary Of The Menderes Massif And An Emplacement Mechanism For Regionally Extensive Gneissic Granites, Western Anatolia (Turkey), Burhan Erdoğan, Tali̇p Güngör
The Problem Of The Core-Cover Boundary Of The Menderes Massif And An Emplacement Mechanism For Regionally Extensive Gneissic Granites, Western Anatolia (Turkey), Burhan Erdoğan, Tali̇p Güngör
Turkish Journal of Earth Sciences
In previous studies, the stratigraphy of the Menderes Massif was divided into a Precambrian core and Mesozoic cover associations, the core consisting of gneissic granites and high-grade schists and the cover of mica schists and platform-type marbles. It has also been proposed that the two associations are separated by an unconformity although nowhere is this relation clearly observed. In this study, the Bafa and Kavaklıdere areas in the southern part of the massif have been examined. In the Bafa area, Mesozoic mica schists with marble lenses occur in the lowermost parts of the sequence and are overlain, along a gradational …
Trace- And Rare-Earth Element Geochemistry Of The Karalar (Gazipaşa-Antalya) Barite-Galena Deposits, Southern Turkey, Gülcan Bozkaya, Ahmet Gökçe
Trace- And Rare-Earth Element Geochemistry Of The Karalar (Gazipaşa-Antalya) Barite-Galena Deposits, Southern Turkey, Gülcan Bozkaya, Ahmet Gökçe
Turkish Journal of Earth Sciences
The Karalar barite-galena deposits are typical examples of carbonate-hosted barite-galena deposits that occur widely in the central Taurides. Recent mining activity has been concentrated in the Büyük and Boyalık mine areas. The mineralisation occurs as ore veins along fault zones and as ore-filled breccia zones along the strongly deformed lower walls of limestone blocks in the Permian limestones of the Bıçkıcı Formation. These veins contain mainly barite (80-85%) and galena (10-15%), and lesser amounts of sphalerite, pyrite, fahlore, limonite, quartz and calcite as gangue minerals. Barite developed during an early episode of mineralisation and was mylonitised before the precipitation of …
Geochemistry And Geochronology Of Orthogneisses In The Derbent (Alaşehir) Area, Eastern Part Of The Ödemiş-Kiraz Submassif, Menderes Massif: Pan-African Magmatic Activity, Ersi̇n Koralay, O. Özcan Dora, Fukun Chen, Muharrem Satir, Osman Candan
Geochemistry And Geochronology Of Orthogneisses In The Derbent (Alaşehir) Area, Eastern Part Of The Ödemiş-Kiraz Submassif, Menderes Massif: Pan-African Magmatic Activity, Ersi̇n Koralay, O. Özcan Dora, Fukun Chen, Muharrem Satir, Osman Candan
Turkish Journal of Earth Sciences
Pan-African basement rocks and the Palaeozoic cover series of the Menderes Massif are exposed around Derbent (Alaşehir) in the eastern part of the Ödemiş-Kiraz submassif. Garnet-mica schists of the Pan-African basement are intruded by the protoliths of orthogneisses and Triassic leucocratic orthogneisses. This study focuses on the geochronology and geochemistry of orthogneisses related to the Pan-African evolution of the Menderes Massif in latest Proterozoic time. Geochemical data suggest that the orthogneisses were derived from S-type, peraluminous, syn- to post-collisional granitoids of calc-alkaline affinity. Zircon grains from the orthogneisses, which are euhedral with typical igneous morphologies, were dated by the Pb-Pb …
First Records Of Conodonts From "The Permo-Carboniferous Of Demirözü" (Bayburt), Eastern Pontides, Ne Turkey, Şenol Çapkinoğlu
First Records Of Conodonts From "The Permo-Carboniferous Of Demirözü" (Bayburt), Eastern Pontides, Ne Turkey, Şenol Çapkinoğlu
Turkish Journal of Earth Sciences
Permo-Carboniferous sedimentary rocks, which belong to the pre-Jurassic basement of the Eastern Pontides, occur in the Cebre relative autochthon and the Hamurkesen thrust sheet in the Demirözü area, Bayburt, NE Turkey, and consist of the Çatalçeşme and Hardişi formations, respectively. Some limestone beds of the Çatalçeşme Formation in the village of Çatalçeşme produced the first conodont faunas encountered in Palaeozoic sediments of the Eastern Pontides. A rich conodont fauna with abundant Neognathodus bassleri (HARRIS & HOLLINGSWORTH), less Idiognathodus sp. and Streptognathodus elegantulus STAUFFER & PLUMMER, and rare Gondolella sp. were obtained from a densely-packed bioclastic packstone bed on the west …
Extensional Neotectonic Regime Through The Ne Edge Of The Outer Isparta Angle, Sw Turkey: New Field And Seismic Data, Ali̇ Koçyi̇ği̇t, A. Arda Özacar
Extensional Neotectonic Regime Through The Ne Edge Of The Outer Isparta Angle, Sw Turkey: New Field And Seismic Data, Ali̇ Koçyi̇ği̇t, A. Arda Özacar
Turkish Journal of Earth Sciences
The Akşehir-Afyon Graben (AAG) is a 4-20-km-wide, 130-km-long NW-trending depression that separates central Anatolia in the NE and the Isparta Angle (IA) in the SW. Its southwestern margin-bounding fault determines the northeast edge of the outer IA that was previously interpreted as a compressional neotectonic structure, whereas our field evidence and recent seismic data substantiated that it is an oblique-slip normal fault characterising an extensional neotectonic regime. The AAG has an episodic and asymmetrical evolutionary history. This is indicated by two superimposed graben infills and structures. The older infill is folded, thrust-faulted and Early-early Middle Miocene in age. The younger …
Coulomb Stress Interactions And The 1999 Marmara Earthquakes, Zi̇yadi̇n Çakir, A. Aykut Barka, Emre Evren
Coulomb Stress Interactions And The 1999 Marmara Earthquakes, Zi̇yadi̇n Çakir, A. Aykut Barka, Emre Evren
Turkish Journal of Earth Sciences
The effects of previous earthquakes on the 1999 İzmit and Düzce earthquakes, the influence of the İzmit earthquake on the Düzce earthquake, and the seismic hazard in the Marmara region are investigated using Coulomb failure stress. Calculation of the Coulomb stress changes using the fault parameters deduced from the modelling of the coseismic Synthetic Aperture Radar Interferometry (InSAR) and GPS data shows that the İzmit earthquake occurred where the Coulomb stress was increased by the previous events. Despite the stress decrease on the Düzce Fault due to the events before 1999, the Düzce earthquake appears to have been triggered by …
Kinematics Of The November 12, 1999 (Mw=7.2) Düzce Earthquake Deduced From Sar Interferometry, Zi̇yadi̇n Çakir, A. Aykut Barka, Jean Bernard De Chabalier, Rolando Armijo, Bertrand Meyer
Kinematics Of The November 12, 1999 (Mw=7.2) Düzce Earthquake Deduced From Sar Interferometry, Zi̇yadi̇n Çakir, A. Aykut Barka, Jean Bernard De Chabalier, Rolando Armijo, Bertrand Meyer
Turkish Journal of Earth Sciences
On November 12 1999, a destructive earthquake struck the Düzce area, following the 17 August 1999 İzmit earthquake that had occurred to the west about 3 months earlier. The Mw=7.2 Düzce earthquake was somewhat interesting in several ways. The most surprising feature of this earthquake is related to its rupture geometry, which appears to contradict what is commonly observed in strike-slip earthquakes. First, compared to its magnitude, the length of the surface rupture mapped in the field was rather short (~35 km). Second, according to seismic and some geodetic observations, the fault plane dips to the north at a very …
Timing Of Late Holocene Earthquakes On The Eastern Düzce Fault And Implications For Slip Transfer Between The Southern And Northern Strands Of The North Anatolian Fault System, Bolu, Turkey, Christopher Hitchcock, Erhan Altunel, A. Aykut Barka, Jeffrey Bachhuber, William Lettis, John Helms, Scott Lindvall
Timing Of Late Holocene Earthquakes On The Eastern Düzce Fault And Implications For Slip Transfer Between The Southern And Northern Strands Of The North Anatolian Fault System, Bolu, Turkey, Christopher Hitchcock, Erhan Altunel, A. Aykut Barka, Jeffrey Bachhuber, William Lettis, John Helms, Scott Lindvall
Turkish Journal of Earth Sciences
Results of trenching across the eastern Düzce Fault document that surface rupture has occurred repeatedly on the fault prior to the 1999 Düzce earthquake, and that offset during previous earthquakes occurred at the same location and with similar amounts and type of slip as that of the 1999 earthquake. The most recent pre-1999 earthquake on the fault occurred about 300 years ago. At least four and possibly five earthquakes (including 1999) have occurred in the past 2100 years. The earthquake recurrence interval ranges from 300 to 800 years. Estimates of cumulative slip on the northern and southern branches of the …