Geochemical Characteristics of Sabalan Volcanic Rocks in Northwestern Iran​

Abstract

Sabalan is a voluminous stratovolcano situated in the northwestern part of Alborz-Azerbaijan zone, 25 km from Meshkinshahr. It is separated by a fault creating a tectonic boundary from Sarab plain and Meshkinshahr. The composition of Sabalan volcanic rocks ranges from andesite, trachyandesite to dacite. The rocks have hypocrystalline porphyritic texture with a glassy matrix and microlite. Plagioclase, amphibole, pyroxene, biotite, and oxides are the main phenocryst phase of the rocks. Some plagioclases show disequilibrium textures (sieve texture and oscillatory zoning). The sieve texture and oscillatory zoning in the plagioclases may be indicative of magma mixing processes in the genesis of the Sabalan volcanic rocks. Geochemical data reveal that the Sabalan lavas exhibit calk-alkaline major-oxide trends with a sodic character and they range in composition from andesite to dacite. Pre-caldera and post-caldera volcanic rocks have similar geochemical features with enrichments in LILE and LREE relative to HFSE and HREE, respectively, and have negative Ti, Nb, and Ta anomalies. Ba/Ta ratios higher than 450 and La/Nb ratios ranging between 2 and 3 indicate a volcanic arc setting for the studied rocks. Based on fi eld and geochemical studies, Sabalan is a subduction-related volcano, occurred as a result of subduction of Neo-Tethyan oceanic crust beneath the Iranian microplate.

Estimation of Co-Seismic Land Deformation Due to Mw 7.3 2017 Earthquake in Iran (12 Nov 2017) using Sentinel-1 DInSAR

“…Zagros Mountains is the result of mountain range between two plates (Şengör and Kidd, 1979;Dewey et al, 1986;Dilek et al, 2009;Ghalamghash et al, 2016;Fahim Guilany et al, 2019). The plates' motions create high earthquake activitiy and remarkable surface topography.…”

“…1909 and recent events sourced from the Zagros fold belt in the Zagros vicinity that has the most of the active faults of Iran. The reason for the seismic activities in this region is the continental collision between the African-Arabian and Eurasian plates (Şengör and Kidd, 1979;Dewey et al, 1986;Dilek et al, 2009;Ghalamghash et al, 2016;Fahim Guilany et al, 2019) (Figure 1). Moreover, the Zagros fold belt is characterized by a folded 12-14 km thick sedimentary cover deposited on the northeastern continental border of the Arabian plate (Falcon, 1974;Colman-Sadd, 1978).…”

Tectonic settings of the Plio–Quaternary volcanism in Iran from multidimensional and multielement solutions

“…The 10 Pliocene to Quaternary ages varied from 3.782 ± 0.061 Ma to 0.396 ± 0.040 Ma. Based on the age data from the literature (K–Ar by Alberti et al, 1976; Mousavi, Darvishzadeh, Ghalamghash, & VosoughiAbedini, 2014; U–Pb zircon by Ghalamghash, Mousavi, Hassanzadeh, & Schmitt, 2016), Fahim Guilany et al (2019) affirmed that the Sabalan volcano erupted during the late Miocene to Quaternary.…”

“…Most authors (Ahmadzadeh, Jahangiri, Lentz, & Mojtahedi, 2010; Amel & Akbarzadeh Laleh, 2017; Amel et al, 2009; Amel, Moayyed, Ameri, Abedini, & Moazzen, 2008; Biabangard, Shahraki, & Boomari, 2015; Fahim Guilany, Darvishzadeh, Sheikhzakariaee, & VosoughiAbedini, 2019; Jalili, Amel, Hajaliogli, & Moayyed, 2015; Khezerlou, Amel, Gregoire, Moayyed, & Jahangiri, 2017; Khodami, Noghreyan, & Davoudian, 2009; Khosroshahi, 2015; Mahmoudi & Khajehei, 2019; Mojarrad & Souri, 2019; Noghreyan, Khodami, Davoudian, & Shabanian, 2011; Pirmohammadi et al, 2011; Pirooj, Jahangiri, Amel, & Kamali, 2014; Salehi, Torkian, & Furman, 2019; ShahbaziShiran & Shafaei Moghadam, 2014; Sherafat, Yavuz, Noorbehesht, & Yýldýrým, 2012) used the total alkalis vs. silica (TAS) classification diagram, but, in none of the papers, the rock classification was achieved by strictly following the International Union of Geological Sciences (IUGS) recommendations (Le Bas, 2000; Le Bas, Le Maitre, Streckeisen, & Zanettin, 1986; Le Maitre et al, 2002). According to the IUGS, unless both Fe oxidation varieties were measured, the total Fe must first be split into FeO and Fe 2 O 3 and then all major oxides be adjusted to sum up to 100% on an anhydrous basis, which can be easily achieved through a suitable computer program, such as IgRoCS (Verma & Rivera‐Gómez, 2013).…”

“…For tectonic inferences, none of the authors, except Amel and Akbarzadeh Laleh (2017) who employed the multidimensional diagrams of Agrawal, Guevara, and Verma (2008), used the recent developments of multidimensional techniques that have been available for about 15 years (Verma, 2020a, 2020b; Verma, Guevara, & Agrawal, 2006; Verma, Pandarinath, Verma, & Agrawal, 2013). Conventional bivariate (Gorton & Schandl, 2000; Muller, Rock, & Groves, 1992; Pearce, 1982; Pearce & Cann, 1973) and ternary (Muller & Groves, 1997; Pearce & Norry, 1979) diagrams were used by most researchers for deciphering the tectonic setting of the areas they studied (Ahmadzadeh et al, 2010; Alishahi et al, 2013; Amel et al, 2008, 2009; Biabangard et al, 2015; Fahim Guilany et al, 2019; Fazelihagh, Amel, & Jahangiri, 2017; Mojarrad & Souri, 2019; Pirooj et al, 2014; Salehi et al, 2019; Taheri et al, 2017). Other workers (Khezerlou et al, 2017) did not provide any constraints on the possible tectonic setting of their study area.…”