Petrology
Habib Biabangard; Farzad Molazadebravate
Abstract
Kuh-Som, KuhzaBozorg and KuhzaKochak volcanic cones are located in the southeastern of Bam and northwest of Bazman cites. From the perspective geology these cones are belong to the Iranian central zone and south-eastern edge of Lut block. These cones are composed of extrusive igneous rocks such as basalt, ...
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Kuh-Som, KuhzaBozorg and KuhzaKochak volcanic cones are located in the southeastern of Bam and northwest of Bazman cites. From the perspective geology these cones are belong to the Iranian central zone and south-eastern edge of Lut block. These cones are composed of extrusive igneous rocks such as basalt, olivine basalt, andesite and basaltic andesite, and are predominant trachytic texture. Plagioclase, pyroxene and olivine are main minerals. Pyroclastic deposits, lapilli, tuff, ash and volcanic bombs, along with lava flows are main construction volcanic cones. These volcanoes are monogenitic and limited eruption. Based on type material that construction cone of the volcanoes, it seems they are among between Hawaii to Strambolian volcanoes. These rocks shows enrichment to LILE relative to HREE (Ce / Yb= 33-45) , high ratio Zr / Y (33.4), enrichment to LILE and negative anomaly from Ni, Cr and nearly Eu that reveals these rocks related to Calc-alkaline magmatism. In spider diagrams of trace elements and rare earth elements that normalized to Chondrites and primitive mantle show light rare earth elements enriched more than high rare earth elements and show pattern similar to affiliate subduction zones. Geochemical characteristics such as ratio of La / Yb 8/6 to 7/13, low Rb content with the tectonic setting discrimination diagrams indicate that they are related to subduction environments and low tendency to intapalate zone. Source of magma that formed these volcanoes resulted from melting of a garnet Lherzolite at depth of 100 to 110 Km. Tectonomagmatic diagrams shows these rocks dependence on of continental subduction environments to show slightly into the intraplate zone, so that it seems the volcanic cones of them related to the Makran and Oman subduction and related to Makran- Chaghy magmatic arc.
