Mozahem stratovolcano and its structural controlling factors in the Cenozoic magmatic arc of Iran

Abstract

The location of volcanoes in magmatic arcs associated with subduction zones often follows the structures present at the time of magma formation in these zones. The Mozahem stratovolcano, which has been caused by the subduction of the oceanic crust of Neotethys under Central Iran, is one of the Neogene volcanoes located in the southeast of the Urumieh-Dokhtar magmatic arc. The magmatic nature of the rocks forming the volcano is potassium-rich calc-alkaline. In this research, we used petrology, satellite images, and aeromagnetic data to understand the relationship between tectonics and magmatism. Mozahem stratovolcano area is limited to the NW-SE-trending Rafsanjan and Shahr-e-Babak fault zones and cut by the N–S-trending Anar fault. During the Neogene, the activity of the dextral Anar fault, especially in its southern termination areas, has caused changes in the local stress field and created deformations in different parts of this region. The displacement of blocks on both sides of the Anar fault has led to the development of compressive structures (folds and thrusts) at the eastern and tensile structures (dikes and subvolcanic masses) at its western half. The location of minor faults in the southern tip of the Anar fault and different mechanisms on both the eastern and western sides of the fault are comparable with the model of synthetic and antithetic splay faults at the tip. At the confluence of the Anar fault, NE-SW-trending Madvar-Riseh fault, and the NW-SE-trending Mozahem fault, lava, and pyroclastic volcanic materials erupted and the stratovolcano was formed. A tectonic evolution model was prepared to show how the area and the stratovolcano were formed and evolved.