Investigation of alkaline basalts of Joupar block located in south of Kerman

Abstract

In the western part of the Joupar Mountains, a set of Neogene basic rocks cover the felsic rocks. Volcanic rocks suite consisting of basalt- andesite- dacite and rhyolite. Main minerals in basaltic ricks consist of olivine, plagioclase, pyroxen and have microphyric, glomeroprophyric, hyaloprophyric, intergranular textures. The volcanic rocks are enriched in LILE and LREE, and depleted HREE, and display highly fractionated REE patterns. Based on the tectonomagmatic environment diagrams, all alkalibasalt samples from the Joupar plot in the island arc setting of a subduction zone and show active continental setting characteristics. The primary magma of the studied rocks is the melting of 1-5% of a lherzolite garnet mantle source with phlogopite. The post collision convergence between Arabia and Eurasia continental plates, starting in Miocene, resulted in thermal perturbation processes in the underlying lithospheric mantle led to partial melting at a low degree, producing alkali- basalt magmas, with garnet remaining stable in the source region. The ascent of the basaltic magma and its emplacement in the lower crust resulted in the partial melting of the crustal materials and development of acidic magma. These processes led to the ascent and eruption of the felsic magmas prior to the mafic magmas. There are mineralogical as well as geochemical evidences that AFC-type processes were involved in the evolution of the Joupar volcanic rocks in Kerman

Keywords

• alkaline basalts
• lherzolite garnet
• active continental margin
• neogene
• joupar
• central iran