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Turkish Journal of Earth Sciences

1998

Articles 1 - 21 of 21

Full-Text Articles in Physical Sciences and Mathematics

Post-Collisional Central Anatolian Alkaline Plutonism, Turkey, Durmuş Boztuğ Jan 1998

Post-Collisional Central Anatolian Alkaline Plutonism, Turkey, Durmuş Boztuğ

Turkish Journal of Earth Sciences

A number of Upper Cretaceous-Palaeogene alkaline plutons intruded into the crustal metamorphic rocks, the pre-Maastrichtian ophiolitic mélange, and the Cretaceous-Lower Tertiary units are located in the Central Anatolia (CA), Turkey. These alkaline plutons constitute an important association in the post-collisional Central Anatolian Granitoids. The Dumluca, Murmana, Karakeban, Kösedağ, Hasançelebi, Karaçayir and Davulalan plutons constitute the eastern; whereas the Egrialan, Baranadağ, Hamit, Çamsarı, Durmuslu and Bayindir units the western part of this alkaline association. These plutons are mainly composed of silica oversaturated syenitic to monzonitic, and undersaturated syenitic felsic rocks. However, the Dumluca, Murmana and Karakeban plutons also include some undersaturated …

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Crystallization Processes And Role Of Compositional Convection In Themacrolayer Formation In A Small Layered Complex, Bernard Plateovet Jan 1998

Crystallization Processes And Role Of Compositional Convection In Themacrolayer Formation In A Small Layered Complex, Bernard Plateovet

Turkish Journal of Earth Sciences

The Peloso complex is a 1000m thick gabbroic body composed of two main layered zones (ZA and ZB) that are made up of cyclic macrolayers of olivine gabbro, leucogabbronorite and anorthosite cumulates, and a third zone of unlayered quartz-gabbro (ZC) which may represent a residual liquid. Within a representative macrolayer, cryptic evolution of minerals can not be neglegted, showing that the crystallizing magma batch had a limited volume and was renewed between the formation of two successive macrolayers. The comparison between calculated parental magma density and densities of successive cumulates shows that the residual liquid was probably extracted by compositional …

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Petrogenesis Of The Çiçekdağ Igneous Complex, N Of Kırşehir, Centralanatolia, Turkey, Sabah Yilmaz Şahi̇n, Durmuş Boztuğ Jan 1998

Petrogenesis Of The Çiçekdağ Igneous Complex, N Of Kırşehir, Centralanatolia, Turkey, Sabah Yilmaz Şahi̇n, Durmuş Boztuğ

Turkish Journal of Earth Sciences

Central Anatolia typically represents well-preserved geological features of a collision zone. This collision zone is characterized by some geological events occurred in the Anatolide passive margin of the Anatolide-Pontide collision along the Ankara Erzincan suture zone. This suture zone is commonly known to be formed by the pre-Maastrichtian northward subduction of the northern branch of Neo-Tethys beneath the Pontides which was constituting the southernmost tip of Eurasiain plate at that time. These geological occurrences are inverted metamorphism; ophiolitic slabs derived from main suture zone; syn-collisional and S/C ST type magmatism; post-collisional, high-K calcalkaline, hybrid and I/H LO type magmatism; post-collisional, …

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Alkaline Rocks And Geodynamics, Bernard Bonin Jan 1998

Alkaline Rocks And Geodynamics, Bernard Bonin

Turkish Journal of Earth Sciences

Origin of A-type alkali feldspar granites is currently the subject of a world-wide debate. Contrasting hypotheses have been proposed, which range from an entirely crustal origin to an almost complete mantle derivation. A-type alkali feldspar granites belong to either unimodal granite (rhyolite)-dominated association, or bimodal gabbro (basalt)-granite (rhyolite) suite. It is argued that (i) the ultimate mantle origin of basic to intermediate rocks is beyond doubt, (ii) highly evolved felsic rocks may be produced by other processes besides crustal involvement through anatexis and (iii) large volumes of felsic rocks are a normal and direct consequence of extensive crystal fractionation processes. …

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Evidence For Damaging Historical Earthquakes At Priene, Western Turkey, Erhan Altunel Jan 1998

Evidence For Damaging Historical Earthquakes At Priene, Western Turkey, Erhan Altunel

Turkish Journal of Earth Sciences

The ancient cilty of Priene was one of the earliest Ionian settlements within the western part of the Büyük Menderes valley (the ancient Maeander River) and was first founded about 8 km in the east of the present site. The old Priene was probably destroyed by a destructive earthquake in the 350s BC and the city was shifted to the existing place in 350 BC. The new city contains an abundance of evidence related to earthquakes. The following evidence indicates that damaging earthquakes, occurred in the Büyük Menderes graben, caused great damage to the new Priene. (1) Part of the …

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Petrology Of The Post-Collisional, Within-Plate Yıldızdağ Gabbroic Pluton, Yıldızeli-Sivas Region, Central Anatolia, Turkey, Durmuş Boztuğ, Mustafa Yağmur, Nazmi Otlu, Sibel Tatar, Akif Yeşi̇ltaş Jan 1998

Petrology Of The Post-Collisional, Within-Plate Yıldızdağ Gabbroic Pluton, Yıldızeli-Sivas Region, Central Anatolia, Turkey, Durmuş Boztuğ, Mustafa Yağmur, Nazmi Otlu, Sibel Tatar, Akif Yeşi̇ltaş

Turkish Journal of Earth Sciences

The Yildizdag gabbroic pluton intrudes the Paleocene-Eocene Yakupoğlan formation which is imbricated with the ophiolitic melange of the northern branch of the Neo-Tethyan ocean, and the crustal metasediments of Kırsehir block or Central Anatolian Crystalline Complex. It is subdivided into some mapable subunits such as gabbroic main body, dioritic marginal facies and microdioritic dykes. Mineralogical-geochemical (major, some trace and REE) data reveal that the magnetite + olivine + augite + calcic plagioclase, and hornblende + biotite + intermediate (or sodic) plagioclase fractionation/accumulation has formed the gabbroic main body and dioritic rocks, respectively, during the solidification of a single mafic magma …

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Geochemistry And Origin Of The Oligocene Binkılıç Manganese Deposit;Thrace Basin, Turkey, Ali Haydar Gülteki̇n Jan 1998

Geochemistry And Origin Of The Oligocene Binkılıç Manganese Deposit;Thrace Basin, Turkey, Ali Haydar Gülteki̇n

Turkish Journal of Earth Sciences

Many Oligocene Manganese deposits are found in the Trace basin, a Tertiary collisional-collapse type basin in the northwestern part of Turkey. All the mineralizations are originally sedimentary type. The most economically important deposits are around Çatalça; of these, the Binkılıç manganese ore occurs conformably within the Oligocene fossiliferous formations, as a stratiform type manganese deposit. The manganese ores at Binkiliç show a continuity along strike and consists of micro-to Cryptocrystalline pyrolusite, psilomelane, radial manganite, cryptomelane, wad, rhodochrosite and dispersed organic matter, calcite, feldspar, clay minerals, and quartz but generally only minor quantities of limonite and goethite. Mn oxides with variable …

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The Origin Of Clay Minerals In Salina Playa-Mudflat Facies,Yeniçubuk Formation (Lower-Middle Miocene), Gemerek, Sivas, Türkiye, İbrahim Türkmen, Cemal Bölücek Jan 1998

The Origin Of Clay Minerals In Salina Playa-Mudflat Facies,Yeniçubuk Formation (Lower-Middle Miocene), Gemerek, Sivas, Türkiye, İbrahim Türkmen, Cemal Bölücek

Turkish Journal of Earth Sciences

The playa-mudflat facies under investigation are found in the Gemerek Basin (Sivas, Türkiye). This Miocene basin is bordered by the Akdağ Metamorphics (Paleozoic) to the N-NW, the Elmalıdağ Volcanic Rocks (Thanetian) to the E and clastic rocks and evaporites of the Cevizcik Formation (Oligocene) to the S-SW. Illite, palygorskite, smectites (montmorillonite, saponite and sauconite), chlorite (clinochlore) and serpentines had been studied using XRD analysis of mudstone samples. Illites and chlorites were found to have originated from marble, schists, granitic rocks, dioritic rocks and syenitic rocks of Akdağ Massif to the north. Palygorskite were formed in evaporitic basins by chemical sedimantation. …

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Orogenic To Non-Orogenic Magmatic Events: Overview Of The Late Variscan Magmatic Evolution Of The Alpine Belt, Bernard Bonin Jan 1998

Orogenic To Non-Orogenic Magmatic Events: Overview Of The Late Variscan Magmatic Evolution Of The Alpine Belt, Bernard Bonin

Turkish Journal of Earth Sciences

The Alpine belt comprises several pieces of Pre-Mesozoic basement, which have received various imprints of the successive Paleozoic orogenic episodes. If Pre-Mesozoic palinspatic reconstructions are taken into account, the Alpine basement can be considered as one single area before Mesozoic continental breakup. Contrasting magma associations were emplaced according to space and time. There exists a controversy about the existence of the Caledonian orogenic episode. The Lower Paleozoic orogenesis was advocated through different lines of evidences in the southern Alpine basement, such as emplacement of Ordovician and Silurian protoliths of calc-alkaline and alkaline orthogneisses. The Variscan orogenic episode ended with the …

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Fractional Crystallization And Magma Mingling/Mixing Processes In The Monzonitic Association In The Sw Part Of The Composite Yozgat Batholith (Şefaatli-Yerköy, Sw Yozgat), Si̇bel Tatar, Durmuş Boztuğ Jan 1998

Fractional Crystallization And Magma Mingling/Mixing Processes In The Monzonitic Association In The Sw Part Of The Composite Yozgat Batholith (Şefaatli-Yerköy, Sw Yozgat), Si̇bel Tatar, Durmuş Boztuğ

Turkish Journal of Earth Sciences

The Yozgat batholith takes place in the passive margin of the Anatolide-Pontide convergence system. It includes; syn-collisional S-type, two-mica granites; post-collisional I-type, calcalkaline monzonitic association, and post-collisional, M-type, tholeiitic gabbroic/dioritic association. Among these associations, the monzonitic association is also subdivided into five mapable units such as Cankılı monzogabbro/monzodiorite, Akçakoyunlu quartz monzodiorite, Adatepe quartz monzonite, Yassiagil monzogranite and Karakaya monzogranite. All these subunits, except the Karakaya monzogranite, include K-feldspar megacrysts. These five subunits represent some evidence of fractional crystallization (FC) and magma mingling/mixing processes by means of field, mineralogical-petrographical and geochemical characteristics. There is a good zonation in the field that …

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Tectono-Magmatic Evolution Of Alkaline Volcanics At Thekırka-Afyon-Isparta Structural Trend, Sw Turkey, M. Yilmaz Savaşcin, Tolga Oyman Jan 1998

Tectono-Magmatic Evolution Of Alkaline Volcanics At Thekırka-Afyon-Isparta Structural Trend, Sw Turkey, M. Yilmaz Savaşcin, Tolga Oyman

Turkish Journal of Earth Sciences

The youngest Alpine magmatism (Miocene to Quaternary) in Western and Central Anatolia is represented by three coeval assemblages from West to East. They are the Western Anatolian Volcanic assemblage (WAV), the N-S trending Kirka-Afyon-Isparta Alkaline Volcanic assemblage (KAIAV) and the Central Anatolian Volcanic Provinces (CAVP). The WAV and CAVP start with calc-alka-line volcanics and continue after Middle Miocene with shoshonitic to alkaline products of graben volcanism, while the KAIAV are all alkaline in character, without any former or later calc-alkaline contributions. The KAIAV are emplaced in three steps of alkaline vol-canic activities which exhibit southward younging along the N-S Kirka-Afyon-Isparta …

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Latest Cr Etaceous Magmatism In The Central Anatolian Crystalline Complex: Review Of Field, Petr Ographic And Geochemical Features, Nurdan S. Aydin, M. Cemal Göncüoğlu, Ayhan Erler Jan 1998

Latest Cr Etaceous Magmatism In The Central Anatolian Crystalline Complex: Review Of Field, Petr Ographic And Geochemical Features, Nurdan S. Aydin, M. Cemal Göncüoğlu, Ayhan Erler

Turkish Journal of Earth Sciences

Magmatic, metamorphic and ophiolitic rock assemblages in Central Anatolia ar e collectively named as the Central Anatolian Crystalline Complex (CACC). Magmatic rocks form significant portion of the CACC and display a range of fabrics, mineralogies and compositions. However , composite granitoid intrusions, such as the Yozgat, Agaçör en, Ekecikdağ and Cefalıkdağ, dominate the geology of the complex. Overall, ther e ar e two main types of Central Anatolian Granitoids (CAG): a) the C-type (crustal) leucog ranites and b) the H-type (hybrid) hornblende ± K-feldspar megacrysts ± mafic micr ogranular enclave bearing granites. The emplacement of granitoid magmatism was followed by …

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Strain Analysis Of The Kapidagi Peninsula Shear Zone In The Ocaklargranitoid, Nw Turkey, Rahmi̇ Aksoy Jan 1998

Strain Analysis Of The Kapidagi Peninsula Shear Zone In The Ocaklargranitoid, Nw Turkey, Rahmi̇ Aksoy

Turkish Journal of Earth Sciences

The Kapidagi Peninsula shear zone is a W-to NW-trending, moderately to steeply dipping, sinistral strike-slip shear zone that runs almost parallel to the northern coast of the peninsula. It is a minimum of 28 km in length and extends from Rikoz Cape in the west to the north of Çakil village in the east. A quantitative strain analysis is presented for the shear zone evolved in the Ocaklar Granitoid by a syn-shear granitod intrusion. Deformed autoliths in the granitoids were used as strain markers. Long, intermediate and short axes of autoliths were measured in 66 subareas across the shear zone. …

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Application Of The Correspondence-Type Geostatistical Analysis On Theco, Ni, As, Ag And Au Concentrations Of The Listwaenites Fromserpentinites In The Divrigi And Kuluncak Ophiolitic Mélanges, Ali̇ Uçurum Jan 1998

Application Of The Correspondence-Type Geostatistical Analysis On Theco, Ni, As, Ag And Au Concentrations Of The Listwaenites Fromserpentinites In The Divrigi And Kuluncak Ophiolitic Mélanges, Ali̇ Uçurum

Turkish Journal of Earth Sciences

The main aim of this research was to find out correlation-if there is any-among Co, Ni, As, Ag and Au concentrations in three different listwaenite sampling sets in Divirigi and Hekimhan areas. The low temperature hydrothermal alteration of serpentinite bodies from the Divrigi and Kuluncak ophiolitic mélanges in the Cürek, Divrigi-Sivas, Güvenç and Karakuz areas, Hekimhan-Malatya, has formed two distinct types of listwaenite. Type I, is silica-carbonate listwaenite, which is dominated by silica+calcite+dolomite+ankerite±magnesite. Type II listwaenite bodies are carbonate listwaenite characterized by calcite+dolomite+ankerite ±magnesite, and lack any significant introduced silica. Correspondence-type geostatistical analysis has been thought to be the best …

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Ree Chemistry Of Arid Zone Calcrete Profiles-A Case Study From The Thar Desert, India, D. Ramakrishnan, Krishna Chandra Tiwari Jan 1998

Ree Chemistry Of Arid Zone Calcrete Profiles-A Case Study From The Thar Desert, India, D. Ramakrishnan, Krishna Chandra Tiwari

Turkish Journal of Earth Sciences

Calcrete is the widely prevalent duricrust associated with the weathering profiles of the Thar desert. The studies on REE behaviour within different weathering horizons of calcrete profiles, have revealed distinct pattern of enrichment and depletion. Fractionation of REE as evidenced through La/Lu, La/Sm, Nd/Dy ratios and removal index, are attributed to pedogenic processes such as breakdown of micas, pyroxenes, amphiboles, feldspars; removal of elements as soluble complexes; selective fixation of elements in neoformed clay minerals like montmorillonite, illite and chlorite. Sesquioxides rich Bir horizon shows enrichment of REE. REE depletion in Palaeo- Bt horizons could be due to their removal …

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Commingling Of Contrasted Magmas In Various Geodynamic Settings, Bernard Plateovet, Jean Bebien, Edilene Gomes Jan 1998

Commingling Of Contrasted Magmas In Various Geodynamic Settings, Bernard Plateovet, Jean Bebien, Edilene Gomes

Turkish Journal of Earth Sciences

Three acid-basic associations taken in various geodynamical settings are studied: the gabbro-granite association of Porto (Corsica), the associations of the Guevgueli (Greek Macedonia), and the associations of the Piracaia complex (Brazil). The diversity of field relations, the degree of mingling, the origins of the melts are debated for each association, using petrological and geochemical tools for each acid-basic association. An origin by hybridization is assumed for the intermediate rocks of the Porto association, it is tested by numerical calculation. Then, we focus on the mixing process between the comagmatic components. Mixing of melts may have happened by thorough mingling and …

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Geochemical And Petrological Characteristics Of The Eastern Pontide Eocene (?) Alkaline Volcanic Province, Ne Turkey, Cüneyt Şen, Mehmet Arslan, Ali̇ Van Jan 1998

Geochemical And Petrological Characteristics Of The Eastern Pontide Eocene (?) Alkaline Volcanic Province, Ne Turkey, Cüneyt Şen, Mehmet Arslan, Ali̇ Van

Turkish Journal of Earth Sciences

The Eastern Pontide Alkaline Volcanic Province is developed by volcanic cycles erupted in Cenozoic era. Petrographical and geochemical data suggest presence of at least two different suits of alkaline rocks (Tonya group and Trabzon group). Petrographically, both groups consist of alkali basalt, tephrite, phonolitic tephrite, basanite, nephelinite, nepheline latite and their pyroclastic rocks. Geochemically, Tonya samples have high MgO and Ni, low LREE contents and LILE/HFSE ratios compare to Trabzon group. Preliminary studies show that these two groups of rocks are related with low level differentiation and derived from a metasomatised mantle source.

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Geochronology And Geochemistry Of Basaltic Rocks In The Karasu Graben Around Kırıkhan (Hatay), S. Turkey, Osman Parlak, Ali̇can Kop, Ulvi̇ Can Ünlügenç, Cavi̇t Demi̇rkol Jan 1998

Geochronology And Geochemistry Of Basaltic Rocks In The Karasu Graben Around Kırıkhan (Hatay), S. Turkey, Osman Parlak, Ali̇can Kop, Ulvi̇ Can Ünlügenç, Cavi̇t Demi̇rkol

Turkish Journal of Earth Sciences

The study area, which is located in the middle sector of the Amanos mountains, covers the north of Kırıkhan (Hatay) in southern Turkey. Tectonostratigraphic rock units from Paleozoic to Cenozoic are exposed within this terrain, which is tectonically active as a result of continent-continent collision between Afro-Arabia and Eurasia. Young basaltic volcanism, located at the N-end of the Dead Sea transform fault in southern Turkey, crops out along the NE-SW trending structural lineaments within the Karasu valley (Hatay). K.Ar age determinations performed on the volcanic rocks give an age range from 0.4 Ma to 2.2 Ma that indicate Plio-Quaternary time …

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Miocene Synvolcanic Alluvial Sedimentation In Lignite-Bearing Soma Basin, Western Turkey, Uğur İnci̇ Jan 1998

Miocene Synvolcanic Alluvial Sedimentation In Lignite-Bearing Soma Basin, Western Turkey, Uğur İnci̇

Turkish Journal of Earth Sciences

Calcalkaline volcanism and volcaniclastic deposition controlled considerable mode of late Miocene sedimentation and basinal development of the lignite-bearing Soma basin in western Turkey. The volcanism-induced Denis Formation, overlying the Soma Formation discordantly, is represented by two rock assemblages: 1) In the depositional axis of the basin, green, fine-grained sandstone dominated alluvial-lacustrine deposits and, 2) In the northern margin of te basin, syn-eruptive volcaniclastic apron deposits which are mainly composed of fine and coarse-grained volcaniclastic/pyroclastic rocks and lavas. The primary volcanic rocks surrounding probably low-relief volcanoes representing near-vent assemblage are composed mainly of andesitic, rhyolitic and basaltic lavas and pyroclastics. These …

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The Coexistence Of The Silica Oversaturated (Alkos) And Undersaturated Alkaline (Alkus) Rocks In The Kortundag And Baranadag Plutons From The Central Anatolian Alkaline Plutonism, E Kaman/Nw Kırşehir, Turkey, Nazmi̇ Otlu, Durmuş Boztuğ Jan 1998

The Coexistence Of The Silica Oversaturated (Alkos) And Undersaturated Alkaline (Alkus) Rocks In The Kortundag And Baranadag Plutons From The Central Anatolian Alkaline Plutonism, E Kaman/Nw Kırşehir, Turkey, Nazmi̇ Otlu, Durmuş Boztuğ

Turkish Journal of Earth Sciences

Baranadağ and Kortundağ plutons, outcropping in the Kaman-Kırşehir region, constitute the important members of the Central Anatolian post-collisional alkaline plutonism. The Baranadağ pluton comprises only one lithodem called Baranadağ quartz monzonite, whereas, the Kortundağ pluton consists of four mapable units such as Hamit quartz syenite, Durmuslu nepheline-nosean-melanite porphyritic syenite, Bayındır nepheline-cancrinite syenite, and Çamsarı quartz syenite. Among these units, the Baranadağ quartz monzonite and Hamit quartz syenite cut the metamorphics of the Kırşehir Block. On the other hand, Durmuslu, Bayindir and Çamsarı are emplaced in both the Hamit quartz syenite and the metamorphics. The Baranadağ quartz monzonite, Hamit quartz syenite …

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Alkali Basalts From The Galatia Volcanic Complex, Nw Central Anatolia, Turkey, Ayla Tankut, Ni̇lgün Güleç, Marjorie Wilson, Vedat Toprak, Yilmaz Savaşçin, Orhan Akiman Jan 1998

Alkali Basalts From The Galatia Volcanic Complex, Nw Central Anatolia, Turkey, Ayla Tankut, Ni̇lgün Güleç, Marjorie Wilson, Vedat Toprak, Yilmaz Savaşçin, Orhan Akiman

Turkish Journal of Earth Sciences

Alkali basalts occur as small lava flows associated with the andesitic lava flows and pyroclastics of Early to Middle Miocene age which are the main constituents of the Galatia volcanic complex. The northern margin of the complex is bordered by the North Anatolian Fault wher eas the southern margin is surrounded by a continental sedimentary sequence which interfingers with the volcanics. New K-Ar age determinations of the basalts reveal that alkali basalts erupted at two differ ent periods of time: Early Miocene and Late Miocene. The Lower Miocene basalts are contemporaneous with the major phase of the andesitic volcanism in …

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