Calc-alkaline magmatism associated with salt diapirs in the Shurab and Garmsar back-arc areas (Central Basin, Iran): magma genesis and tectonic implications

Abstract

Back-arc basalts (BAB) occur behind the main volcanic arc, where they form a transition from arc to intraplate basalts (e.g., D' orazio et al., 2004; Kay et al., 2004; Stern, 2004; Ramos and Kay, 2006). Different types of magma are recognized in back-arc basins (Tarney et al., 1981; Thompson et al., 1984). Both midocean ridge basalt (MORB) and ocean-island basalt magmas characterize oceanic back-arc basins, whereas shoshonites associated with high-K calc-alkaline and ultrapotassic magmatisms characterize continental back-arc environments. The basalts from oceanic back-arc settings have transitional geochemical characteristics between MORB and islandarc tholeiites, while the basalts from continental back-arc settings exhibit transitional geochemical characteristics between arc and intraplate basalts (