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

Abstract

Geochemical data for 435 samples of the Pliocene to Quaternary (P–Q) volcanic rocks from Iran, distributed mostly along a NW–SE trending belt, were compiled from 28 papers (12 written in Persian). Until now, the rock nomenclature employed has been inconsistent with the recommendations of the International Union of Geological Sciences (IUGS). Moreover, older bivariate and ternary tectonic discrimination diagrams and only traditional qualitative approaches using Nb and Ta anomalies, have been used to understand the origin and evolution of the P–Q magmas. The P–Q magma and rock types were classified by strictly following the IUGS recommendations. Two geochemometric multidimensional models based on 10 and 16 elements, along with two decision procedures, capable of discriminating 29 fine tectonic settings, were used to document the existence of six tectonic settings in Iran during the P–Q. The rare earth elements indicated that the evolved intermediate and silicic rocks had a significant crustal component in their origin. The quantification of Nb and Ta anomalies in multielement diagrams was used to support the tectonic inferences from the multidimensional geochemometric models.

Petrogenesis and geochemical characteristics of Plio-Quaternary alkali basalts from the Qorveh–Bijar volcanic belt, Kurdistan Province, NW Iran

“…Kogarko (2006) has noted that generally alkaline magmatism is most typical of stable regions where it is controlled by rift structures and occurs along zones marked by abruptly decreasing thickness of the continental lithosphere. These compositions have received considerable attention regarding their geochemistry, petrology and geodynamic evolution (Cebria et al 2000; Temel et al 2000, 2010; Thompson et al 2005; Xu et al 2005; Jung et al 2006; Kuritani et al 2008, 2009; Pilet et al 2008; Zeng et al 2011; Ducea et al 2013; Pang et al 2013; Torkian et al 2016; Rostami-Hossouri et al 2020; Salehi et al 2020; Verma & Molaei-Yeganeh, 2022). The alkaline basalts parental magmas were produced by relatively small degrees of melting (<5 wt %) of their heterogeneous mantle source (Fitton & Dunlop, 1985) and, as such, alkali basalts may be taken as deep probes of enriched domains in the upper mantle (Farmer et al 2002).…”