Whole Rock Geochemistry and Tectonic Setting of Jurassic Aged Lisar Granite, Talesh Mountains, North Iran

Abstract

The Late Jurassic aged Lisar granite in North Iran is in tectonic contact of the form of thrust and strike slip faults with Upper Cretaceous sandy limestone and is covered by Paleogene polygenetic conglomerate in the Talesh Mountain at the western continuation of the Alborz range. The rock samples of the granite are pink coloured and coarse-gained with K-feldspar, quartz, plagioclase, biotite and amphibole. The Lisar granite is more likely emplaced in an extensional environment indicated with numerous space fi lling silica-rich aplitic veins in the rocks. The granite samples are moderately altered and feldspars are changed to sericite and clay minerals and biotite is partially converted to chlorite. The Lisar granite has derived from a high K magma and is A-type in nature, belonging to A 2 subgroup. The rock samples of granite are characterized by distinct negative Eu anomaly and a decrease from LREE to HREE contents. The parental melts of the granite were generated from partial melting of a lower continental crustal source with possible contribution from the mantle materials. The Lisar granite represents Cimmerian post-collision magmatism in north Iran following closure of Palaeotethys Ocean and subsequent collision. IntroductionPalaeomagnetic studies show that Iran was a part of Gondwana up to Early Carboniferous (Alavi, 1991;Majidi, 1991;Mirnejad et al., 2013; Shafaii Moghdam et al., 2015), Gorgan schists (Ghavidel et al., 2007;Delaloy et al., 1981), metamorphic rocks of the Gasht and Masuleh area (Clark et al., 1975) and Shanderman eclogites (Zanchetta et al., 2009;Omrani et al., 2013). The Palaeotethys suture can be traced to the east to Afghanistan and China and towards the west into Turkey . The Palaeotethys ocean closed 225 Ma ago which followed by uplifting of the Turan plate and emplacement of allochtonous nappes on the Iranian plate (Stampfl i, 1993). Magmatic activities, especially granitoid magmatism, related to the Palaeotethys subduction are well documented along the suture in China. The magmatic arc at Yunnan area (southwestern Yunnan, China), with basaltic-andesitic to granodiorite composition has an age of 292-282 Ma (Hennig et al., 2009). I-type and S-type granitoids of Hindu Kush in Afghanistan have ages of 210, 112 and 193 Ma, respectively (Debon et al., 1987). These granites with roughly Triassic age are traced westward into east of Iran, where the Binalud granites and granodiorites, dated 256 to 211 Ma (Majidi, 1978;Berberian and Berberian, 1981), are intruded into * Corresponding author: Mohssen MOAZZEN moazzen@tabrizu.ac.ir

A Jurassic volcanic passive margin in Iran and Turkey

“…5%-30% partial melting in an extensional tectonic regime with minor involvement of continental crust is suggested for the sources of tholeiitic to alkalic basaltic magma. We suggest two main scenarios for the SW Eurasian Jurassic extensional regime F I G U R E 4 Harker bivariant diagrams for Jurassic mafic samples (Bozorg Seghinsara et al, 2017;Çimen, 2020;Doaee et al, 2020;Dokuz et al, 2010;Dokuz & Sünnetçi, 2019;Eyuboglu et al, 2016;Galoyan et al, 2018;Genç et al, 2010;Günay et al, 2019;Lechmann et al, 2018;Şen, 2007) and mafic parts of the Early Jurassic ophiolites (Sarifakioğlu et al, 2009;Topuz, Göçmengil, et al, 2013;Uysal, Ersoy, et al, 2015) with SiO 2 contents between 45 and 52 wt%. F I G U R E 5 Mafic samples with higher contents of Fe 2 O 3 (t), TiO 2 and Y (Bozorg Seghinsara et al, 2017;Çimen, 2020;Doaee et al, 2020;Dokuz et al, 2010;Dokuz & Sünnetçi, 2019;Eyuboglu et al, 2016;Galoyan et al, 2018;Genç et al, 2010;Günay et al, 2019;Lechmann et al, 2018;Şen, 2007) and mafic parts of the Early Jurassic ophiolite (Sarifakioğlu et al, 2009;Topuz, Göçmengil, et al, 2013;Uysal, Ersoy, et al, 2015) (a and b) mainly plot in the tholeiitic and calc-alkaline field (Irvine & Baragar, 1971) Island arc, MORB and oceanic island basalts (Mullen, 1983) and (c) extensional tectonic regimes such as continental rift (Cabanis & Lecolle, 1989).…”

“…Due to the time progression of Jurassic intrusions in the central SaSZ and bimodal magmatism, a propagating continental rift was suggested for the C-SaSZ . In this discussion, we (Bozorg Seghinsara et al, 2017;Çimen, 2020;Doaee et al, 2020;Dokuz et al, 2010;Dokuz & Sünnetçi, 2019;Eyuboglu et al, 2016;Galoyan et al, 2018;Genç et al, 2010;Günay et al, 2019;Lechmann et al, 2018;Şen, 2007) and mafic parts of the Early Jurassic ophiolites (Sarifakioğlu et al, 2009;Topuz, Göçmengil, et al, 2013;Uysal, Ersoy, et al, 2015) Eurasia (Alavi, 1991;Zanchi et al, 2009;Karimpour et al, 2010;Hassanpour, 2021;Okay and Şahintürk, 1997). Others consider southward subduction of Palaeotethys beneath northern Turkey continued into Jurassic time to form a back-arc basin in the Sakarya Zone (Dokuz et al, 2010;Genç et al, 2010;Kandemir & Yilmaz, 2009;Karsli et al, 2017;Maffione & van Hinsbergen, 2018;Sengör & Yilmaz, 1981).…”

“…Chemistry of Jurassic volcanic and intrusive rocks (Bozorg Seghinsara et al, 2017; Çimen, 2020; Doaee et al, 2020; Dokuz et al, 2010; Dokuz & Sünnetçi, 2019; Eyuboglu et al, 2016; Galoyan et al, 2018; Genç et al, 2010; Günay et al, 2019; Lechmann et al, 2018; Şen, 2007) and mafic parts of the Early Jurassic ophiolites (Sarifakioğlu et al, 2009; Topuz, Göçmengil, et al, 2013; Uysal, Ersoy, et al, 2015). Chemical compositions range from mafic to felsic in the Na 2 O + K 2 O versus SiO 2 (Le Bas et al, 1986) and are dominated by basaltic and acidic groups with subordinate intermediate rocks (a).…”

“…We correlated Jurassic members units and compiled whole-rock chemical and Sr-Nd isotopic data for 216 Early to Middle Jurassic igneous rocks in Turkey, Armenia and Iran from the literature (Bozorg Seghinsara et al, 2017;Çimen, 2020;Doaee et al, 2020;Dokuz et al, 2010;Dokuz & Sünnetçi, 2019;Eyuboglu et al, 2016;Galoyan et al, 2018;Genç et al, 2010;Günay et al, 2019;Lechmann et al, 2018;Şen, 2007). We also compiled geochemical data for ophiolite mafic members with 184-176 Ma (Sarifakioğlu et al, 2009;Topuz, Göçmengil, et al, 2013;Uysal, Ersoy, et al, 2015); these are presented in Table S2 (whole rocks) and Table S3 (Sr-Nd isotopes).…”

“…[Colour figure can be viewed at wileyonlinelibrary.com] F I G U R E 6 Mafic samples (Bozorg Seghinsara et al, 2017;Çimen, 2020;Doaee et al, 2020;Dokuz et al, 2010;Dokuz & Sünnetçi, 2019;Eyuboglu et al, 2016;Galoyan et al, 2018;Genç et al, 2010;Günay et al, 2019;Lechmann et al, 2018;Şen, 2007) and mafic parts of the Early Jurassic ophiolite (Sarifakioğlu et al, 2009;Topuz, Göçmengil, et al, 2013;Uysal, Ersoy, et al, in some petrogenetic variation diagrams (a) Zr versus Y contents (MacLean & Barrett, 1993), (b) Nb/Th versus Nb (Pearce, 2014), (c) Ti-Vi (Shervais, 1982), (d) Ta/Hf versus Th/Hf ratios (Yunliang et al, 2001), (e) Th/Yb versus Nb/Yb ratios (Pearce, 2008), (f) Nb/La versus Nb/Th ratios in some areas (Zhang et al, 2014) show the relation of these rocks to normal mid-oceanic ridge basalt (N-MORB) and oceanic island basalt (OIB) with minor crustal assimilation. (g-i) Yb versus La/Yb and La/Sm and also Sm versus Sm/Yb ratios (Aldanmaz et al, 2000) consistent with the interpretation that these magmas were produced from partial melting of spinel-garnet peridotite and minor garnet lherzolite.…”