A forearc (Guleman, Elaziğ) ophiolite: Evidence from peridotite mineral geochemistry

The Guleman ophiolite, one of the most important ophiolitic massifs of the Southeast Anatolian Ophiolitic Belt, consists of a core of serpentinized mantle rocks overlain by an ultramafic sequence, layered and isotropic gabbro, and sheeted dykes. The ophiolite structurally overlies the Lower Miocene Lice Formation and is overlain by young sandstones and shales of the Upper Maashtrichtian‐Lower Eocene Hazar Complex and Middle Eocene Maden Complex. The Guleman ophiolite tectonically overlain by Precambrian to Upper Triassic Bitlis metamorphic massif. The mantle peridotites compose mainly of fresh and in place serpentinized harzburgite tectonite with local bands and lenses of dunites with large‐sized chromitite pods. The Guleman peridotites commonly show porphyroclastic texture, high‐temperature fabrics such as kink‐bands in olivines. According to microprobe analyses, the harzburgite and dunite have low CaO and Al2O3 abundance similar to Mariana forearc, and their average Cr‐ (=Cr/(Cr+Al) atomic) ratio of Cr‐spinelsis surprisingly high (>0.63) besides Fo content of olivine is between 90.9 to 92.3 in peridotites. According to Mg# (Mg/(Mg+Fe2+)) versus Cr# in spinel diagram, the degree of partial melting is higher than 35% and spinel values plot in the forearc peridotites field. The Gulemanharzburgites have low CaO, Al2O3 and TiO2 contents in orthopyroxene and clinopyroxene lammelles, resembling those of depleted harzburgites from modern forearcs and different from moderately depleted abyssal peridotites. Consequently, we propose that the Guleman peridotites form in a forearc setting during the subduction initiation that developed as a result of northward subduction of the southern branch of the Neo‐Tethys in response to the convergence between Arabian and Anatolian plates

Zircon U-Pb age and geochemical constraints on the origin and tectonic implication of Cadomian (Ediacaran-Early Cambrian) magmatism in SE Turkey

The Bitlis-Pütürge Massifs and Derik volcanics that crop out in the Southeast Anatolian Belt are parts of the Cadomian domain in Anatolia where relicts of the oldest continental crust of Turkey are exposed. The Bitlis-Pütürge Massifs contain a Neoproterozoic basement, with overlying Phanerozoic rocks that were imbricated, metamorphosed and thrust over the edge of Arabia during the Alpine orogeny. The basement consists mainly of granitic to tonalitic augen gneisses and metagranites, associated with schists, amphibolites and paragneisses. Based on whole-rock geochemical data, the augen gneisses are interpreted to have protoliths crystallized from subduction zone magmas. This study conducted the first zircon dating on two augen gneisses that gave 206Pb/238U dates of 551 ± 6 and 544 ± 4 Ma, interpreted as the formation ages of the Pütürge Massif, broadly coeval to those of the Bitlis metagranites and the Derik volcanics that occurred from ca. 581 to 529 Ma (the Ediacaran-early Cambrian). The eHf(t) values (+1.2 to 5.3) of the dated zircons, with crustal model ages (TDM C ) from 1.4 to 1.8 Ga, indicate that formation of the Pütürge Massif involves an older, most likely the Mesoproterozoic, continental crust component. Similar to the Bitlis-Pütürge gneisses, coeval basement rocks are widespread in the Tauride-Anatolide platform (e.g., the Menderes Massif). All these dispersed Cadomian basement rocks are interpreted as fragments of the Ediacaran-Early Cambrian continental arcs bordering the active margin of northern Gondwan

Supra-subduction zone magmatism of the Koçali ophiolite, SE Turkey

The Late Cretaceous Koçali ophiolite is an important element within the southeastern Anatolian ophiolite belt and contains all components of a complete ophiolite, including mantle peridotites (harzburgites, and subordinate dunite) gabbros, sheeted dyke complexes, lower volcanic unit (pillowed basalts), and upper volcanic unit (andesite and andesitic pyroclastics) plagiogranite and ultramafic rocks intruded into the gabbros. All components of the Koçali ophiolites show strong suprasubduction-zone affinities, from harzburgitic mantle to basaltic lavas. The radiolarian faunas and geochronological data indicate that there are two different volcanic units: Tarasa volcanics and volcanics of the Koçali ophiolite. While the Tarasa volcanics are of Carnian to Rhaetian age, the Koçali ophiolite is of the Late Cretaceous age. The geochemical features indicate an E-MORB source for the Tarasa volcanics, and a forearc source for the Koçali ophiolite

Mineralogical, petrographical and geochemical characteristics of plutonic rocks in the Çolaklı (Elazığ) region

İnceleme alanı, Çolaklı (ELAZIĞ) çevresinde yaklaşık 130 km2’lik bir alanı kapsamaktadır. Çalışma alanında yaşlıdan gence doğru Üst Kretase yaşlı Elazığ Magmatitleri, Orta Eosen-Üst Oligosen yaşlı Kırkgeçit Formasyonu, Üst Miyosen-Alt Pliyosen yaşlı Karabakır Formasyonu ve Pliyo-Kuvaterner yaşlı Palu Formasyonu yüzeylemektedir. Elazığ Magmatitleri inceleme alanında granit, granodiyorit, tonalit, diyorit ve kuvars diyorit gibi derinlik; mikrodiyorit ve aplit gibi yarı derinlik kayaçlarıyla temsil olunmaktadır. Elazığ Magmatitleri’ni uyumsuz olarak örten Kırkgeçit Formasyonu; kumtaşı ve marnlardan meydana gelmiştir. Kendisinden yaşlı birimleri uyumsuz olarak örten Karabakır Formasyonu, inceleme alanında bazaltlardan oluşmaktadır. Karasal konglomeralardan meydana gelen Palu Formasyonu ise çalışma alanının en genç birimidir. Çalışma alanındaki asidik bileşimli kayaçlarda yapılan analiz sonuçlarına göre; bu kayaçlar magmatik seri olarak subalkalen karakterli ve I-tipi granitoyid özelliğinde olup, tektonik olarak ise, volkanik yay granitoyidleri (VAG) ve çarpışmayla eş yaşlı granitoyidleri (Syn-COLG) alanında yer almaktadır. Elazığ Magmatitleri’ne ait olan Çolaklı (Elazığ) çevresi plütonik kayaçları ada yaylarında oluşmuş yay magmatizması ürünüdürler.Abstract The studied area covers an area about 130 km2 in the Çolaklı (ELAZIĞ) environment. The units of studied area from the oldest to the youngest; Upper Cretaceous Elazığ Magmatics, Middle Eosen-Upper Oligocene Kırkgeçit Formation, Upper Miocene-Lower Pliocene Karabakır Formation and Plio-Quaternary Palu Formation are exposed. In the studied area, the Elazığ Magmatics is represented by plütonic rocks such as granite, granodiorite, tonalite, diorite, quartz diorite; subvolcanic rocks such as microdiorite and aplite. Kırkgeçit Formation covers an angular unconformity Elazığ Magmatics and this formation consists of sandstone and marls. Karabakır Formation comprising basalts overlap on older units with an unconformity. Palu Formation composed of terrestrial conglomerate is the youngest unit in the studied area. According to the geochemical analysis results, it defined that this magmatic rocks have subalkaline characteries and I-type granitoid plotted volcanic arc granitoids (VAG) and syn-collision granitoids (Syn-COLG). The intrusive rocks in studied area belong to Elazığ Magmatics are products of island arc magmatism

Mineralogy and charectarizations of nodular sepiolite (meerschaum) of Türkmentokat-Karatepe district (Eskişehir)

Sepiyolitin; yapısı ile ilişkili olarak özgül yüzey alanları, adsorpsiyon kapasitesi, kimyasal bileşimi, beyaz rengi, gözenekli yapısı, düşük özgül ağırlığı ve katalitik özelliklerinden dolayı en önemli endüstriyel minerallerden birisidir. Tetrahedral ve oktahedral oksit tabakalarının istiflenmesi sonucu oluşan lifsi bir yapısı vardır ve lif boyunca devam eden kanal boşluklarına sahiptir. Sepiyolit, oluşum şartlarına bağlı olarak kristal kimyası, kristallenme derecesi ve dokularında önemli değişiklikler gösterir. Bu çalışmada Türkmentokat-Karatepe köyleri arasında bulunan Sarısu Ocakları (Eskişehir) olarak da bilinen yumrulu sepiyolitlerin (lületaşlarının) jeolojisi, alınan 12 örneğin mineralojisi ve karakterizasyonu incelenmiştir. Örneklerin mineralojik bileşimleri benzerdir. 2 örnek saf yumrulu sepiyolit iken, 2 örnekte ise az oranlarda dolomit vardır. Sepiyolit, (110) yüzeyine ait 12.20Å civarındaki karakteristik pikiyle, sepiyolitin saf olduğunu vermektedir. Manyezit örnekleri için yapılan XRF analiz sonuçları örneklerin XRD sonuçları ile uyumluluk göstermektedir. SEM incelenmesinde, yumrulu sepiyolit örneklerinin farklı uzunluklarda (0,5μm ile 35 μm arasında) liflere sahip olduğu görülmektedir. Spesifik yüzey alanı değerleri (330m2/g -380m2/g) arasındaki farkın fazla olmaması sepiyolitin bileşiminin nisbeten saf veya safa yakın olduğunu belirtmektedir.Sepiolite is one of the most important industrial minerals, due primarily to its surface properties related to its structure. Sepiolite contains alternating 2:1 polysomes that produce tunnels at the inner part of the fibre and channels at the edge of the fibre. Sepiolite is a mineral with notably wide variations in the crystal-chemistry, crystallinity and texture, depending on the formation conditions,which results in highly different characteristics and properties. In this study; the geology, mineralogy and characterization of nodular sepiolite (also known as meerschaum) between the Türkmentokat and Karatepe villages (Eskişehir), which is called as Sarısu deposits, were done. Because of its unique properties, such as adsorption chemical composition, white color, good porosity, low specific gravity and catalytic properties, meerschaum has many industrial applications. The most common usage of Eskişehir’s meerschaum is pipemaking. Small quantities have been used for other purposes, such as decoration (bracelets and necklaces), removing stains, and as thermal insulating material. On the basis of XRD, XRF, SEM, BET and thermal analysis, the raw meerschaums occurred within İmişehir Conglomerates as nodules and pebbles between Türkmentokat and Karatepe villages (known as Sarısu Quarries) can be classified as ‘right meerschaum’ which indicates the best quality meerschaum as well as semi precious stone

A forearc (Guleman, Elaziğ) ophiolite: Evidence from peridotite mineral geochemistry

The Guleman ophiolite, one of the most important ophiolitic massifs of the Southeast Anatolian Ophiolitic Belt, consists of a core of serpentinized mantle rocks overlain by an ultramafic sequence, layered and isotropic gabbro, and sheeted dykes. The ophiolite structurally overlies the Lower Miocene Lice Formation and is overlain by young sandstones and shales of the Upper Maashtrichtian‐Lower Eocene Hazar Complex and Middle Eocene Maden Complex. The Guleman ophiolite tectonically overlain by Precambrian to Upper Triassic Bitlis metamorphic massif. The mantle peridotites compose mainly of fresh and in place serpentinized harzburgite tectonite with local bands and lenses of dunites with large‐sized chromitite pods. The Guleman peridotites commonly show porphyroclastic texture, high‐temperature fabrics such as kink‐bands in olivines. According to microprobe analyses, the harzburgite and dunite have low CaO and Al2O3 abundance similar to Mariana forearc, and their average Cr‐ (=Cr/(Cr+Al) atomic) ratio of Cr‐spinelsis surprisingly high (>0.63) besides Fo content of olivine is between 90.9 to 92.3 in peridotites. According to Mg# (Mg/(Mg+Fe2+)) versus Cr# in spinel diagram, the degree of partial melting is higher than 35% and spinel values plot in the forearc peridotites field. The Gulemanharzburgites have low CaO, Al2O3 and TiO2 contents in orthopyroxene and clinopyroxene lammelles, resembling those of depleted harzburgites from modern forearcs and different from moderately depleted abyssal peridotites. Consequently, we propose that the Guleman peridotites form in a forearc setting during the subduction initiation that developed as a result of northward subduction of the southern branch of the Neo‐Tethys in response to the convergence between Arabian and Anatolian plates

A forearc (Guleman, Elaziğ) ophiolite: Evidence from peridotite mineral geochemistry

The Guleman ophiolite, one of the most important ophiolitic massifs of the Southeast Anatolian Ophiolitic Belt, consists of a core of serpentinized mantle rocks overlain by an ultramafic sequence, layered and isotropic gabbro, and sheeted dykes. The ophiolite structurally overlies the Lower Miocene Lice Formation and is overlain by young sandstones and shales of the Upper Maashtrichtian-Lower Eocene Hazar Complex and Middle Eocene Maden Complex. The Guleman ophiolite tectonically overlain by Precambrian to Upper Triassic Bitlis metamorphic massif. The mantle peridotites compose mainly of fresh and in place serpentinized harzburgite tectonite with local bands and lenses of dunites with large-sized chromitite pods. The Guleman peridotites commonly show porphyroclastic texture, high-temperature fabrics such as kink-bands in olivines. According to microprobe analyses, the harzburgite and dunite have low CaO and Al2O3 abundance similar to Mariana forearc, and their average Cr- (=Cr/(Cr+Al) atomic) ratio of Cr-spinelsis surprisingly high (>0.63) besides Fo content of olivine is between 90.9 to 92.3 in peridotites. According to Mg# (Mg/(Mg+Fe2+)) versus Cr# in spinel diagram, the degree of partial melting is higher than 35% and spinel values plot in the forearc peridotites field. The Gulemanharzburgites have low CaO, Al2O3 and TiO2 contents in orthopyroxene and clinopyroxene lammelles, resembling those of depleted harzburgites from modern forearcs and different from moderately depleted abyssal peridotites. Consequently, we propose that the Guleman peridotites form in a forearc setting during the subduction initiation that developed as a result of northward subduction of the southern branch of the Neo-Tethys in response to the convergence between Arabian and Anatolian plates

Zircon U-Pb age and geochemical constraints on the origin and tectonic implication of Cadomian (Ediacaran-Early Cambrian) magmatism in SE Turkey

The Bitlis-Pütürge Massifs and Derik volcanics that crop out in the Southeast Anatolian Belt are parts of the Cadomian domain in Anatolia where relicts of the oldest continental crust of Turkey are exposed. The Bitlis-Pütürge Massifs contain a Neoproterozoic basement, with overlying Phanerozoic rocks that were imbricated, metamorphosed and thrust over the edge of Arabia during the Alpine orogeny. The basement consists mainly of granitic to tonalitic augen gneisses and metagranites, associated with schists, amphibolites and paragneisses. Based on whole-rock geochemical data, the augen gneisses are interpreted to have protoliths crystallized from subduction zone magmas. This study conducted the first zircon dating on two augen gneisses that gave 206Pb/238U dates of 551 ± 6 and 544 ± 4 Ma, interpreted as the formation ages of the Pütürge Massif, broadly coeval to those of the Bitlis metagranites and the Derik volcanics that occurred from ca. 581 to 529 Ma (the Ediacaran-early Cambrian). The eHf(t) values (+1.2 to 5.3) of the dated zircons, with crustal model ages (TDM C ) from 1.4 to 1.8 Ga, indicate that formation of the Pütürge Massif involves an older, most likely the Mesoproterozoic, continental crust component. Similar to the Bitlis-Pütürge gneisses, coeval basement rocks are widespread in the Tauride-Anatolide platform (e.g., the Menderes Massif). All these dispersed Cadomian basement rocks are interpreted as fragments of the Ediacaran-Early Cambrian continental arcs bordering the active margin of northern Gondwan

Doğu Anadolu fay sistemi boyunca gelişen kuvaterner mafik alkali volkanizmasının petrojenezi ve tektonik konumu, Güneydoğu Anadolu Orojenik Kuşağı (Elazığ)

Bu çalışma ile Elazığ Bölgesinde yüzeyleyen Kuvaterner volkanik kayaçlarının inceleme sonuçları verilmiştir. Sol yönlü doğrultu atımlı Doğu Anadolu Fay Zonu (EAFZ) Türkiye’nin en önemli faylarından birisidir. Elazığ bölgesinde EAFZ boyunca mafik alkali özellikte volkanik kayaçlar yüzeylemektedir. Bu volkanik kayaçlar, yüksek LILE ve HFSE içeriklerine ve düşük LILE/HFSE oranlarına (Ba/Nb=2.28-10.7) ve düşük 87Sr/86Sr (0.703149-0.703915) ve yüksek 143Nd/144Nd (0.512751-0.512895) oranlarına sahiptirler. Kimyasal bileşimleri levha içi magmaların bileşimlerine benzemektedirler. Yüksek Nb (34-76.6 ppm), ve Nb/La oranları (>1.0) gösterirler. Nb/La oranları lavların kirlenmemiş veya çok az kirlenmiş olduğunu belirtmektedir. Pozitif Sr anomalisi ve Eu anomalisinin olmaması plajiyoklasların esas fraksiyonlaşma mineral fazı olmadığını belirtir. Farklı veriler Harput volkanitlerinin spinel lerzolitin düşük derecede kısmi ergimesi (~%0.4-4) ile Doğu Anadolu Fay Zonu’na ait fay sistemlerinin kesişme noktalarında oluşmuştur