Petrology, mineral chemistry and petrogenetic evolutions of the harzburgites from Abgarm ultramafic complex (South of Kerman province)

Abgarm ultramafic complex in termination of the southeast of Sanandaj- Sirjan is a part of the Haji Abad- Esfandagheh ophiolitic belt. This body consist of three different types of rocks includes of ultramafic rocks, mafic and metamorphic. Most ultramafic rocks are harzburgite, dunite, and lherzolite that harzburgites are more than 85 volume percent of this complex. Microscopic evidence suggests that there are several generations of minerals in these rocks. In addition, mineral chemistry data indicate that the Abgarm harzburgites have been formed in an environment similar to those considered for MORB peridotites and they passed about 15% partial melting. Pyroxene porphyroblasts and Olivin- Spinel thermometry in these harzburgites shows 816- 992 and 708- to 840 0C. Moreover, fO2 calculation gives a redox state that lies within a range of 1.6 log bar units around the Fayalite–Magnetite- Quartz buffer FMQ (log = -0.8 - 0.9 log-bar units) in the range of pressure of 1.2 and 2 GPa. For them and suggest that they have been equilibrated in spinel peridotite field for Abgarm peridotites. Chemical evidence shows that these rocks are similar to abyssal peridotites and probably formed in a back-arc basin environment.