Petrological analysis at the monogenetic volcanoes around Bazman has indicated porphyritic basalts containing clinopyroxene, hornblende, olivine and plagioclase, and titanite and zircon as accessories. The rocks have medium K content, lower than that of Taftan and Koh-i-Sultan. This may reflect differences in the subduction beneath Bazman and the other two volcanoes. Composition data are typical of volcanic island arc rocks, with some samples have element ratios more akin to ocean island basalts. Lithosphere modified by the subduction may be the origin of the magmas that formed the monogenetic cones. On the basis of its composition, the environmental conditions under which one of the samples formed have been estimated, the temperature being c. and a minimum depth of about . The magmas ultimately originate through partial melting from a stable heat source.