Magmatic signature of the closure of the north ern branch of the Neo-Tethys: upper paleocene-middle eocene magmatism at the boundary of the TavêanlÏ Sakarya Zone (Turkey)

Nu mer ous plutons com posed of gran ite, granodiorite, diorite-por phyry, monzonite, granodiorite-por phyry and diorite/microdiorite-por phyry oc cur at the bound ary of the TavêanlÏ-Sakarya Zone, in the east ern part of the north west ern Ana to lian mag matic belt, Tur key. These rocks be long to two dif fer ent types: A me dium-K calc-al ka line granodiorite se ries (with as so ci ated dykes and sub-vol ca nic rocks) and a shoshonitic se ries of gran ites. The rocks of the shoshonitic se ries have SiO2 from 67.5 to 75.6 wt.% with Mg# from 35.1 to 59.5, whereas the me dium-K calc-al ka line se ries rocks have SiO2 be tween 54.6 and 67.7 wt.% with Mg# from 43.5 to 60.8. There is a clear en rich ment of LILE with re spect to the HFSE in all mag matic units of the re gion. These mag matic rocks re flect prop er ties of col li sion-re lated arc magmatism in the var i ous geo chem i cal dis crim i na tion di a grams. The ini tial 87Sr/86Sr and 143Nd/144Nd istopic ra tios of the mag matic units range from 0.705506 to 0.710902 and 0.512178 to 0.512594, re spec tively. Col li sion-re lated granitoids yielded a 40Ar/39Ar cool ing age age of 59.13 ±1.87 Ma, and arc-re lated granitoids and as so ci ated sub-vol ca nic units 44.3 ±0.47 and 44.11 ±0.89 Ma. The data ob tained re vealed that con ti nent-con ti nent col li sion in the Paleocene to gether with the ini ti a tion of the clo sure of the Neo-Tethys took place be tween the Anatolide-Tauride Plat form and Sakarya Plate from the end of the Cre ta ceous. The shoshonotic gran ite may cooled in the Mid dle Paleocene, as re gards the subduction-ac cre tion zone in which subduction im pacts have been observed. The me dium-K calc-al ka line mag matic prod ucts in the re gion were formed by par tial melt ing of the con ti nen tallithospheric man tle caused by the upwelling of asthenospheric man tle af ter the subducted slab was de lami nated

Fingerprint of magma mixture in the leucogranites: Spectroscopic and petrochemical approach, Kalebalta-Central Anatolia, Türkiye

Leucogranites of Kalebalta in Central Anatolia are composed of plagioclase, quartz, orthoclase, and biotite and contains mafic microgranular enclaves (MME) in sizes ranging from few cm to 70 cm. In the total alkali-silica diagram, they fall typically in the granite field and show a calc-alkaline nature in the alkalis-iron-magnesium diagram whereas enclaves are Medium K series calc-alkaline, which represents the transition from tholeiitic to calc-alkaline. Leucogranites which have A/CNK(mol%) > 1 are strong peraluminous and seen as the products of magma derived from a metasedimentary source. Signs of magma mixing expressing the mantle inputs are also observed in many bivariation diagrams. Zircon and apatite saturation temperatures calculated on the basis of whole rock chemistry are 744–829°C for leucogranites and 761–832°C for their enclaves. According to the Raman spectra, biotite and plagioclase minerals in leucogranites and their enclaves show similar Raman spectrums. The biotite minerals have Mg–O and/or Fe–O translational (transformation) bonds between 182 and 552 cm−1, Si–O–Si bending between 552 and 1,100 cm−1 and Si–O–Si vibrational bonds between 1,100 and 1,200 cm−1. The results of this study suggest that the leucogranites and enclaves are most probably derived from different magmas. In addition, according to geochemical and spectroscopic data, they may also have fractional crystallization, which is effective after the mixing process

Nature and crystallization stages of spherulites within the obsidian: Acıgöl (Cappadocia-Nevşehir, Turkey)

The study area comprises a part of the Central Anatolian Cenozoic volcanism within the Cappadocia Volcanic Province (CVP). Obsidian, perlite rhyolite flows, and volcanic ashes are observed in the study area and the spherulites within the obsidian are the objects of this study. The spherulites occupied within the obsidian in the form of round nodules 0.5–10 cm in diameter. The confocal Raman spectra of feldspar minerals within the spherulites are characterized by T-O-T and M-O lattice modes in the range of 100–250 cm–1, O-T-O deformation and T-O-T lattice modes in the range of 250–350 cm–1, and O-T-O stretch and O-T-O deformation modes in the range of 400–600 cm–1 and cristobalite minerals are remarkable with their weak peaks at the 296.5 cm–1 and 411.1 cm–1 Raman shifts. The geothermometer studies in the plagioclase minerals which are oligoclase and andesine in composition suggest that the spherulites may have 600–650 °C crystallization temperature. The temperature range shows that the spherulites start the first crystallization at the glass transition (Tg) levels and then continue to grow up to below Tg levels and brown rings are associated with Fe-oxidation development at the last stage

Use of tourmaline as a potential petrogenetic indicator in the determination of host magma: CRS, XRD and PED-XRF methods

WOS: 000403130900010PubMed: 28437687Tourmaline defines a group of complex borosilicate forms as accessory mineral in igneous and metamorphic rocks and they act an important role in the interpretation of the chemical composition changes of the composition of the host fluid of the magma. The variety of tourmaline can be identified by using optical microscopy, X-Ray Diffraction (XRD) and by determining its chemical composition through Polarized Energy Dispersive X-Ray Fluorescence (PED-XRF) methods. However, microscopic investigations and XRD analyses are not quite adequate for detailed determination of tourmaline sub-groups. In addition, the use of chemical composition of tourmaline as a strict indicator of geochemical processes might be a misleading method. In this study, variable tourmaline crystals were collected from three different pegmatitic occurrences in Behrekdag, Yozgat and Karakaya granitic bodies of Central Anatolia to identify their chemical properties through Confocal Raman Spectroscopy (CRS), PED-XRF and XRD analyses. The confocal Raman spectrometry of collected tourmalines from the Behrekdag, Yozgat and Karakaya granites are in the compositions of schorl, schorl and elbaite respectively. The dominant compositional groups of these tourmalines are in the form of schorl. Raman shift values of tourmalines revealed four bands centered at almost 1050, 750, 400 and 300 cm(-1). The first group of the band arises from SiO stretching, the second from B-O stretching and the other two belong to bending modes of O-B-O and B-O-Al with symmetrical deformation of Si-O-Si. The strongest spectra near 360 cm(-1) should belong to the bonding of Al-O. As a result, the confocal Raman studies are more sensitive for identification of tourmaline subgroup compositions and have a quite important in the explaining source of the magma.Ankara University [DPT 2012-K-120-440, BAP 09-B-4343-016]The authors would like to thank Ankara University for supporting the projects, project no: DPT 2012-K-120-440 and BAP 09-B-4343-016

The Petro-chemical properties of Meke and Acigol (Karapinar-Konya) volcanites

WOS: 000472967800010The Craters of Meke Lake and Acigol are located in the district of Konya Province border and 6 km southeast of Karapinar. Compared with petrographical signatures, craters formed during the final stage of volcanism that effective in Plio-Quaternary comprise basalt-andesite and andesitic rocks and are found around the Meke crater, whilst the andesite and trachyandesite lithologies have been observed in Acigol. Volcanics formed by the main mineralogical composition plagioclases (Meke An56-80; Acigol An46-68), pyroxene (Meke Wo37-51, Acigol Wo40-48), amphibole and biotite are observed as mafic components. In Meke volcanics, these mafic components are accompanied by olivines (Fo70-85). The major element oxides of the rocks outcropping in the region show values the values of 51.32-64.88% SiO2, 1.16-3.09 K2O%, 2.39-3.92% Na2O, MgO 1.2-3.39%, 14.24-17.85% Al2O3, 0.18-0.35% P2O5, 5.59-9.46 % CaO, 0.09 to 0.15 % MnO and the 5.17 to 10.21 % Fe2O3. The Harker-type variation diagrams suggested that more basic characters of major oxides are observed in the rocks cropping out around the Meke Lake. MORB-normalized trace element patterns reflect strongly LILE enrichment and slightly HFSE depletion. The petrographic and geochemical studies indicate that the volcanic rocks of Meke and Acigol are characterized by the continental arc setting and the calc-alkaline to alkaline in nature. The petrographic, geochemical and geothermobarometric studies indicate that Acigol and Meke volcanics crystallized under respectively 1093-1107 degrees C-0.9-1 kb and 1133-1141 degrees C -4.7-5.3 kb conditions. Meke and Acigol are characterized by the continental arc setting and the calc-alkaline in nature

Comparison of the collision and extensional related mafic intrusive rocks within central anatolia, Turkey

*Güllü, Bhattin ( Aksaray, Yazar )The closure of Neotethys induced collision and extension related basic magmatism within the Central Anatolia during the late Cretaceous and Early Paleogene. The products of the basic magmatism are alkaline and tholeiitic in character. The temporal and spatial evolution of the basic magma within the Central Anatolia has a great role in the interpretation of magmato–tectonic evolution of the region. The lack of radiometric age for the mafic magmatic rocks let to discussion in the explanation of the nature of these magmatism. The recent study deal with detail mineralogical and petrographic studies with spectroscopically methods. The evaluation of plagioclase, amphibole, pyroxene and biotite by using the Raman confocal spectroscopy and Electron microprobe methods. Mafic magmatic rocks have a wide exposure with different colour and textures in the Central Anatolia. In this study, Hacıibrahimuşağı, Gömük, Akçakent and Hamit gabbros are selected for the purpose of the investigation of this research. Hacıibrahimuşağı and Gömük gabbros are mainly composed of plagioclase, amphibole, pyroxene with lack amount of biotite. The plagioclase compositions range from oligoclase to bytownite. The amphiboles are mainly hornblende and the pyroxenes are diopside in compositions. Akçakent and Hamit gabbros are mainly composed of plagioclase, nepheline, and pyroxene with lack amount of amphibole and cancrinite. Thermobarometry calculations from amphiboles of Hacıibrahimuşağı gabbros are ranging from 798 up to 944°C and 4.2–1.1 kbar with 15.9–4.3 km emplacement depth. Furthermore, the formation of the pyroxene minerals of these rocks are 1388-1464°C and 19.9-25.6 kbar with 91-98 km emplacement depth. Thermobarometry calculations from pyroxene of Akçakent and Hamit gabbros are ranging from 1083 up to 1270°C and 1.8-20.7 kbar with 7-80 km emplacement depth of these pyroxenes. All the detail mineralogical, petrographical and thermobarometry studies reveal that the Hacıibrahimuşağı and Gömük gabbros are tholeiitic in nature and formed due to the Inner Tauride Ocean collision in the Central Anatolia. However, the Akçakent and Hamit gabbros are alkaline in nature and formed due to the extensional of the Anatolian Plate after the collision during Late Cretaceous and Early Paleogene in the region...

Nature of the gabbro in central anatolia: Geological observation and spectroscopic applications, Turkey

*Güllü, Bahattin ( Aksaray, Yazar )Central Anatolia is bounded by the Izmir Ankara Erzincan (IAE) Suture Zone dipping northward beneath the Pontides at the north and the Inner Tauride (IT) Suture Zone with NE-dipping Central part of Turkey with triangular shaped structure. The Paleozoic metamorphic rocks are formed the basement of the Central Anatolia and obducted by the remnant of Inner Tauride ophiolitic products. Both of the units injected by Late Cretaceous age of the felsic and mafic intrusive unit. The mafic products mainly composed of gabbroic rocks and formed the less exposure crystalline magmatic rocks in comparison to the felsic crystalline magmatic rocks. The gabbroic rocks have a wide range in the exposure and mainly exposed at the eastern and far eastern part of Central Anatolia. They are ranging from a few meters up to kilometer square in dimension. The largest outcrops mostly accumulated with felsic intrusion in Central Anatolia. Different geographical distribution, colour, texture and mineral chemistry led to evaluate different source and nature in the region. MORB normalized elemental pattern of most of the gabbroic rocks of the Central Anatolian are enriched with the LIL elements with respect to HFS elements. Whole rock, trace and rare earth element results reveal that most of these mafic rocks are almost reveal almost similar geochemical behavior and patterns. The Raman spectra of the ophiolitic, intrusive and alkaline gabbroic rocks pyroxene mainly composed of augite, augite-diopside and augite- hedenbergite in composition respectively. The Electron Probe Micro Analysis (EPMA) results reveal that the pyroxene of the ophiolitic gabbro, intrusive gabbro and alkaline gabbro may crystalized at 178, 77 and 80 km depth with 46, 20 and 19 kilo bar pressure. Although the mineralogical, whole rock geochemical compositions are not able to differentiate between these gabbro the crystallization conditions of the pyroxene may be used in the classification of the gabbro types in Central Anatolia...

Raman characteristics of gucunkaya (Aksaray) gabbroic rocks, central Anatolia-Turkey

*Güllü, Bahattin ( Aksaray, Yazar )The Central Anatolia Basement Units (CABU) have several mafic and felsic characterized magmatic systems which are associated with the closure of the Neotethys during the Late Mesozoic. Gucunkaya gabbro is located to the southern part of Ağaçören Intrusive to the North East of Aksaray in Central Anatolia. Field and petrographic studies show that the mafic products of the area are mainly composed of two main units as a gabro and diorite. The gabbro and the diorite cut by fine crystalline gabbro, diorite porphyry, fine crystalline diorite and diabase dykes. The plagioclases (An51-An93) + hornblende + augite ± quartz ± epidotite ± calcite ± titanite and opaque minerals form the main compositions of the Gucunkaya gabbro, and they are ranging from pyroxene-hornblende gabbro to diorite in composition. The MORB normalized elemental patterns of the gabbro and mafic dykes reveal enrichment in LIL element and depletion in HFS elements. Confocal Raman Spectroscopy (CRS) was investigated from amphibole and plagioclase minerals in the Gucunkaya gabbroic rocks. The CRS studies, was determined that the amphiboles are in the composition of actinolite and the plagioclases are in the composition of labradorite and anorthite. The CRS studies show that actinolites have a Raman shift value of 218.6, 385.76, 531.81, 677.46 and 1046.5 cm-1. The 156.06, 174.02, 221.69, 389.48, 525.06, 668.70, 926.26, and 1055.04 cm-1 values of Raman shift observed in the pyroxene minerals reflected the augite composition. On the bases of petrological, geochemical and spectroscopic data of the research area, the products of the Gucunkaya Gabbroic rocks are derived from the mantle products with depletion of the continental crust...

Mineral chemistry of ophiolitic gabbros within central anatolia: Hirfanli dam gabbros

*Güllü, Bahattin ( Aksaray, Yazar )The tectonic evolution of the magmatic rocks the Central Anatolia (CA) began at the late Mesozoic with closure of Neotethys in the region. The Central Anatolia has experienced several magmatic events including felsic and mafic intrusions originated from collisional and/or extensional tectonic events. The felsic magmatism of the CA are well reported and studied, whereas the origin and temporal distributions of the mafic magmatism are still controversial. This study includes the preliminary results of the TÜBİTAK project (116Y240) which aims to determine the mineralogical-petrographical, mineral chemistry and whole rock geochemistry of the Hirfanlı Dam gabbroic rocks in CA. The gabbroic rocks has dark to light green in color and fine-to-coarse grained crystal size. They are highly fractured, cracked and usually cut by fine crystalline gabbro and diabase dikes. According to the microscopic investigations, Hirfanlı Dam gabbroic rocks have holocrystalline granular and/or cumulate textures and mainly consist of plagioclase + pyroxene + amphibole + Fe-Ti oxides + chlorite + epidotite in composition. In addition, various alteration products such as uralitization, chloritization, epidotization, and carbonatization can be observed. These results are also supported by the Confocal Raman Spectrometry (CRS). Whole rock geochemistry of gabbroic rocks are characterized by relatively high Mg# (36.1±8.94) with remarkably low (Na2O+K2O) (1.56±0.92 wt.%), Zr (4.36±2.85 ppm), Th (0.64±0.64 ppm) contents. Moreover they have high TiO2 (1.13±0.75 wt.%), Fe2O3 (13.73±4.67 wt.%), CaO (12.27±0.74 wt.%) and V (867±801 ppm) contents. The gabbroic rocks are low-K tholeiite and show N-MORB in character. They display enrichment in LILE with relative to HFSE in MORB normalized multi-element diagrams. In this diagram, they exhibit depletions in Sr, Nb, Zr, TiO2 and Y as characteristics of subduction-related magmas. As a result, the petrographic and geochemical results suggest that gabbroic rocks of Hirfanlı Dam are the most probably products of supra-subduction ophiolite and may derived from N-MORB magma sources...