In the central part of the Sanandaj-Sirjan zone (C-SaSZ) in southern Ghorveh, western Iran two different types of gabbroic rocks in terms of mineralogical characteristics and chemical composition of the same age (late Jurassic) exists in the vicinity of each other including the olivine bearing gabbroic rocks (OGRs) and the amphibole-bearing gabbroic rocks (AGRs). The effective process in magma’s evolution of OGRs is differentiation. In the second category, digestion and/or mixing also occurred in addition to differentiation due to the geochemical positive anomalies of Pb, Rb, Ba, Th, and U. The AGRs have a high content of LIL elements and a low content of HFSEs. In particular, they have low Nb, Ti, and Ta contents. Zr depletion and low Zr/Sm and Zr/Ti ratios in these rocks indicate that their magma formed at a shallow depth (upper parts of the mantle). The melting of the mantle at a shallow depth, which produced the magma of the AGRs as a result of the fluids released from a sub ducting slab (subduction of the Neo-Tethys Ocean under the Iranian Plateau), is a step in the development of OGRs. Ascending magma has created a rift, which has caused the pressure on the underlying rocks to decrease at a steady temperature, melting the mantle. This mechanism leads to the creation of OGRs.