Petrological and source region characteristics of ophiolitic hornblende gabbros from the Aksaray and Kayseri regions, central Anatolian crystalline complex, Turkey

Koçak, Kerim; Işik, Fuat; Arslan, Mehmet; Zedef, Veysel

doi:10.1016/j.jseaes.2004.08.006

Cited by 31 publications

(25 citation statements)

References 46 publications

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“…Such geochemical features are typical for oceanic crust, formed on a back-arc setting with the melting of a shallow asthenospheric source contaminated by slab-derived fluids (Tarney et al 1981;Saunders & Tarney 1984). Such a hypothesis has already been proposed for ophiolitic gabbros from Turkey (Kocak et al 2005), but has to be further evaluated considering isotopic compositions and partial melting rates constraints. † Lower Cretaceous Alkaline lavas of variable thicknesses overlain this ophiolitic sequence.…”

Section: Discussionmentioning

confidence: 94%

The Armenian Ophiolite: insights for Jurassic back-arc formation, Lower Cretaceous hot spot magmatism and Upper Cretaceous obduction over the South Armenian Block

Rolland

Galoyan

Sosson

et al. 2010

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Similar geological, petrological, geochemical and age features are found in various Armenian ophiolitic massifs (Sevan, Stepanavan and Vedi). These data argue for the presence of a single large ophiolite unit obducted on the South Armenian Block (SAB). Lherzolite Ophiolite type rock assemblages evidence a Lower–Middle Jurassic slow-spreading rate. The lavas and gabbros have a hybrid geochemical composition intermediate between arc and Mid Ocean Ridge Basalt (MORB) signatures which suggest they were probably formed in a back-arc basin. This oceanic sequence is overlain by pillowed alkaline lavas emplaced in marine conditions. Their geochemical composition is similar to plateau-lavas. Finally, this thickened oceanic crust is overlain by Upper Cretaceous calc-alkaline lavas likely formed in a supra-subduction zone environment. The age of the ophiolite is constrained by 40Ar/39Ar dating experiments provided a magmatic crystallization age of 178.7±2.6 Ma, and further evidence of greenschist facies crystallization during hydrothermal alteration until c. 155 Ma. Thus, top-to-the-south obduction likely initiated along the margin of the back-arc domain, directly south of the Vedi oceanic crust, and was transported as a whole on the SAB in the Coniacian times (88–87 Ma). Final closure of the basin is Late Cretaceous in age (73–71 Ma) as dated by metamorphic rocks

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Section: Discussionmentioning

confidence: 94%

The Armenian Ophiolite: insights for Jurassic back-arc formation, Lower Cretaceous hot spot magmatism and Upper Cretaceous obduction over the South Armenian Block

Rolland

Galoyan

Sosson

et al. 2010

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“…Furthermore, along the MZT, there are some intrusive bodies in the Aksaray and Kayseri regions in the Anatolian Suture Zone in Turkey. Kocak et al (2005) have reported that these bodies are mainly gabbroic rocks. The results of major trace and rare-earth elemental analyses indicate that they are SSZ-type rocks and were formed from a wet magma by the high-temperature partial melting of peridotite, possibly coupled to contamination with predominantly neighboring-slabderived fluids, within an intra-oceanic back-arc basin (Kocak et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Review of the tectonic setting of Cretaceous to Quaternary volcanism in northwestern Iran

Azizi

Moinevaziri

2009

Journal of Geodynamics

153

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“…These contact relationships together with their identical Ar-Ar ages lead to the interpretation of coeval formation of granitoids and gabbros within the AIA (Kadioglu et al 2003). Other authors, however, (e.g., Göncüoglu et al 1991;Göncüoglu and Türeli 1994;Yaliniz et al 1996Yaliniz et al , 1999Yilmaz and Boztug 1998;Floyd et al 1998Floyd et al , 2000ToksoyKöksal et al 2001;Koçak et al 2005;Ilbeyli 2008) described the gabbros within the central Anatolia as remnants of the ophiolitic units and as roof pendants on the granitic rocks, which we accept as the most likely model.…”

Section: Geological Frameworkmentioning

confidence: 96%

Crustal homogenization revealed by U–Pb zircon ages and Hf isotope evidence from the Late Cretaceous granitoids of the Agaçören intrusive suite (Central Anatolia/Turkey)

Köksal

Möller

Göncüoğlu

et al. 2011

Contrib Mineral Petrol

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Geochemical and isotopic evidence from the Agaçören Igneous Association in central Anatolia-Turkey indicates that this suite of calc-alkaline granitic rocks have undergone crustal homogenization during regional metamorphic and related magmatic events. Whole-rock chemical and Sr-Nd isotopic data of the granitoids reveal crustal affinity with an earlier subduction component. Zircons show inherited cores and subsequent magmatic overgrowths. The laser ablation ICP-MS 206 Pb/ 238 U zircon ages are determined as 84.1 ± 1.0 Ma for the biotite-muscovite granite, 82.3 ? 0.8/-1.1 Ma for the hornblende-biotite granite, 79.1 ? 2.1/-1.5 Ma for the granite porphyry dyke, 75.0 ? 1.0/-1.0 Ma for the alkali feldspar dyke, and 73.6 ± 0.4 Ma for the monzonite. This is interpreted as continuous magma generation, possibly from heterogeneous sources, from ca. 84 to 74 Ma during the closure of the northern branch of the Neotethyan Ocean. The oldest granitoids (84-82 Ma) were probably formed due to crustal thickening after obduction of the MORB-type oceanic crust onto the Tauride-Anatolide microplate. The younger granitoids are interpreted to be related to the subsequent post-collisional extension after lithospheric delamination. Combination of the laser ablation ICP-MS zircon Lu-Hf isotope data with the U-Pb ages of inherited cores suggests that Cretaceous granitoids formed by melting of heterogeneous crustal protoliths, which results in significant variation in eHf (t) data (from -12.9 to ?2.2). These protoliths were probably composed of reworked Early Proterozoic crust, minor juvenile Late Proterozoic magmatic components, and Paleozoic to pre-Late Cretaceous recycled crustal material. Moreover, the Late Cretaceous zircon domains of the different granitoids are characterized by a crustal signature, with a relatively restricted zircon eHf (t) data ranging from -4.1 to -8.8. This variation is only about twice the reproducibility (ca. ±1 eHf) of the data, but Communicated by J. Hoefs. Electronic supplementary materialThe online version of this article (much smaller than the isotope variability of inherited zircons. Our preferred interpretation is effective isotopic homogenization of the heterogeneous central Anatolian crust during the Late Cretaceous high-grade metamorphic and magmatic events, a process that we propose to be relevant for other active continental margins.

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Petrological and source region characteristics of ophiolitic hornblende gabbros from the Aksaray and Kayseri regions, central Anatolian crystalline complex, Turkey

Cited by 31 publications

References 46 publications

The Armenian Ophiolite: insights for Jurassic back-arc formation, Lower Cretaceous hot spot magmatism and Upper Cretaceous obduction over the South Armenian Block

The Armenian Ophiolite: insights for Jurassic back-arc formation, Lower Cretaceous hot spot magmatism and Upper Cretaceous obduction over the South Armenian Block

Review of the tectonic setting of Cretaceous to Quaternary volcanism in northwestern Iran

Crustal homogenization revealed by U–Pb zircon ages and Hf isotope evidence from the Late Cretaceous granitoids of the Agaçören intrusive suite (Central Anatolia/Turkey)

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