Eocene Granitic Magmatism in NW Anatolia (Turkey) revisited: New implications from comparative zircon SHRIMP U–Pb and 40Ar–39Ar geochronology and isotope geochemistry on magma genesis and emplacement

Altunkaynak, Şafak; Sunal, Gürsel; Aldanmaz, Ercan; Genç, Can; Dilek, Yıldırım; Furnes, Harald; Foland, K. A.; Yang, Jingsui; Yıldız, Merve

doi:10.1016/j.lithos.2012.09.008

Cited by 97 publications

(67 citation statements)

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“…For the determination of other trace Figure 2. The geological map of the Biga Peninsula (slightly modified from Altunkaynak et al (2012) and the references therein). elements including rare earth elements, the solutions were aspirated into an ICP mass spectrometer (PerkinElmer Elan 6000).…”

Section: Whole-rock Analysesmentioning

confidence: 99%

Devonian magmatism in the western Sakarya Zone, Karacabey region, NW Turkey

Sunal

2012

Geodinamica Acta

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The Karacabey Pluton is a large magmatic body in the northwestern Turkey overthrust by the probable Triassic metamorphic rocks of the Lower Karakaya Complex. Both the metamorphic rocks and the Karacabey Pluton are unconformably overlain by a Lower Jurassic and younger sedimentary sequence. The Karacabey Pluton was regarded as a Carboniferous intrusion based on the previous K-Ar biotite geochronological data. Here, we provide new geological, geochemical and geochronological data from the Karacabey Pluton. Zircon U-Pb results from two samples yielded ages of 393.8 +/−2.7 to 395.9 +/−4.09 Ma, suggesting that the granitoids intruded in the crust throughout the Early to Middle Devonian. The Karacabey Pluton consists mainly of biotite and locally hornblende bearing granitoid with lesser amounts of S-type leucocratic granodiorite, all of which are cut by pegmatitic bodies. It belongs to the high-K calc-alkaline series with distinct Nb and Ta anomalies in multi-element spider diagram. Sr and Nd isotopes' initial values are 0.709-0.712 and 0.511-0.512, respectively. εNd(i) values range between −7.8 and −9.4. The isotopic characteristics of the rocks indicate lower crustal sources of both metapelitic and metaigneous origin. Geochemical features of the rocks suggest that they developed in an arc-related environment, along with the other Devonian granitoids described from the Biga Peninsula in northwest Turkey. The granitoid shows a low-temperature alteration/metamorphism marked by recrystallization of quartz, sericitization of the feldspar and formation of late chlorite, epidote and muscovite. Possibly because of these, the Ar-Ar biotite ages are scattered with a possible concentration at around Permo-Carboniferous boundary. Zircon (U-Th)/He geochronology suggests that after the granitoid was reburied during Early Jurassic to Early Cretaceous sedimentation, there was renewed uplift and erosion during the Late Cretaceous (Turonian), which is possibly related to the closure of the Intra-Pontide Ocean in the north.Keywords: Karacabey Pluton; Sakarya Zone; geochemistry; zircon U-Pb, biotite Ar-Ar and zircon (U-Th)/He ages IntroductionThe Sakarya Zone of the Pontides is an E-W trending belt bounded by Istanbul Zone in the north and by the Izmir-Ankara Suture in the south (Figures 1 and 2). It consists of a complex basement overlain by Jurassic and younger sedimentary sequence. The basement rocks of the Sakarya Zone can be divided into two separate parts: 1. Paleozoic plutonic and metamorphic rocks possibly related to the Variscan orogeny and 2. Triassic accretionary complexes with blueschists and eclogites, called as the Karakaya Complex (Okay & Göncüoğlu, 2004;Okay & Tüysüz, 1999;Okay, Satır & Siebel, 2006).Most of the plutonic rocks in the basement of the Sakarya Zone are of Carboniferous age (350-320 Ma, Figure 1). These can traced from the Kazdağ Massif in the Biga peninsula (308-329 Ma, Okay et al., 1996, through west of Ankara (~290 Ma, Okay et al., 2006, 319-327 Ma;Robertson, 2012) and Central Pontides (275-295 Ma, Nzeg...

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Section: Whole-rock Analysesmentioning

confidence: 99%

Devonian magmatism in the western Sakarya Zone, Karacabey region, NW Turkey

Sunal

2012

Geodinamica Acta

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“…The vanishing of the northern branch of the Neo-Tethyan ocean during the Cretaceous and subsequent collision of the Pontides and Anatolide-Tauride microcontinents with the CACC in the Paleocene gave rise to a long and narrow ophiolitic mélange belt called the IAESZ at the northern part of the Anatolian Plate (Şengör and Yılmaz, 1981;Okay and Tüysüz, 1999) (Figure 1a). Around both sides and along this suture zone, postcollisional Eocene magmatism (particularly Middle Eocene) developed through the western to eastern part of the Anatolian Plate and is represented by granitoids (Harris et al, 1994;Genç and Yılmaz, 1997;Topuz et al, 2005;Arslan and Aslan, 2006;Okay and Satır, 2006;Karslı et al, 2007Karslı et al, , 2011Boztuğ, 2008;Karacık et al, 2008;Ustaömer et al, 2009;Altunkaynak et al, 2012;Gülmez et al, 2013;Öztürk, 2015, Özdamar et al 2017), gabbroic intrusions (Boztuğ et al, 1998;Temizel et al, 2014;Eyuboglu et al, 2016), and calcalkaline, mildly alkaline, and potassic/shoshonitic volcanic products (Figure 1b;Peccerillo and Taylor, 1976;Keskin et al, 2008 and references therein; Karslı et al, 2011, Kaygusuz et al, 2011Arslan et al, 2013 and references therein; Aydınçakır and Şen, 2013;Dokuz et al, 2013;Gülmez et al, 2013;Aslan et al, 2014;Aydınçakır, 2014, Sipahi et al, 2014Yücel et al, 2014;Kasapoğlu et al, 2016;Temizel et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

40Ar-39Ar geochronology and petrogenesis of postcollisional trachytic volcanism along the İzmir-Ankara-Erzincan Suture Zone (NE, Turkey)*

Göçmengil¹,

Karacık²,

Genç³

et al. 2018

Turkish J Earth Sci

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The obliteration of the Neo-Tethyan Ocean and collision of the microplates along the northern part of Turkey led to the development of the İzmir-Ankara-Erzincan suture zone (IAESZ). After the collision of Pontides with the Central-Anatolian Crystalline Complex (CACC) in the Paleocene, a new phase of extension and volcanism concomitantly developed along the northern (Almus; Pontides) and southern (Yıldızeli; CACC) sides and along the IAESZ during the Middle Eocene time interval. The first products of the Middle Eocene volcanism in these areas are represented by calc-alkaline to alkaline (basic-intermediate) volcanic and volcanoclastic units together with late-stage trachytic dikes, plugs, and stocks. The mantle source area of both volcanic units displays a metasomatized character, which was dominantly fluxed by sediment-sourced melts. The partial melting of the metasomatized source area gave rise to first-stage basic-intermediate volcanism in the crustal levels. Simultaneously with the generation of the first-stage volcanism, basaltic trachyandesitic shallow-seated magma mushes were also developed. The reactivation of these shallow-seated mushes by latestage extensional tectonics gave rise to the development of trachytic volcanism in both regions, which have a high-K to shoshonitic character. Almus trachytic lavas are phenocryst-poor and have differentiated Mg# numbers (avg. 26). On the other hand, Yıldızeli trachytic lavas have a broad compositional range (benmoreite to latite); they are phenocryst-rich and show more basic character (Mg# avg. 40). Trachytic volcanism in both areas is largely controlled by fractional crystallization of similar basaltic trachyandesitic parental magma with minor assimilation of the upper crustal lithologies. 40 Ar-39 Ar ages from sanidine phenocrysts from both areas also confirm that trachytic volcanism in both regions developed nearly coevally in different tectonic blocks (~41-40 Ma). Generation of similar volcanism on the different tectonic blocks during the postcollisional stage was probably governed by a regional-scale delamination and/ or lithospheric removal-related tectonomagmatic processes.

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“…The Eocene granitic and volcanic rocks are rare and restricted to NW Anatolia. The following magmatic phase occurred during the late Oligocene and middle Miocene and is known to have produced the widespread granitic plutons (i.e., Kozak, Evciler, Cataldag, Kestanbol, Ilica, Eybek, Egrigoz, Çamlık, Uludağ) and volcanic rocks in western Anatolia (Yilmaz, 1989;Altunkaynak et al, 2012b;Yilmaz, et al, 2001;Ozgenc and Ilbeyli, 2008;Akay 2009). They are represented mostly by medium to high-K calc-alkaline to shoshonitic I-type granitic plutons emplaced into the continental blocks on both side of the IASZ.…”

Section: Geological Settingmentioning

confidence: 99%