Abstarct: The Majerad mextamorphic-igneous complex (MMIC) with NE-SW trend cropped out in the 150 km southeast of the Shahrood and northern edge of the Central Iran structural zone. This complex includes a wide variety of mextamorphic and igneous rocks. mextamorphic rocks of this complex include mextacarbonate, mextabasite (greenschist, amphibolite and garnet amphibolite), mextapelite (micaschist, garnet micaschist and garnet gneiss), mextapsammite and mextarhyolite and igneous rocks include of granites and leucogranites. The protolith of the mextabasites has been small-scale intrusions, submarine basaltic lava flows which erupted within the Late Neoproterozoic intracontinental extensional basins. baxsed on the termobarometery performed on the selected rock samples from the mextabasites and mextapelites of the Majerad complex, the obtained P-T range (for stopping of the geochemical exchanges and final equilibrium of the minerals phases) is: 454 to 662 °C and 4 to 13 kbar (equivalent to greenschist up to upper amphibolite facies). By providing P-T conditions for the starting of partial melting, in some regions such as north of the Majerad pass, the mextapelites are partially melted and crystallization of the produced melt resulted in the formation of small scale granitic intrusions. These granites cropped out in the form of thin aplitic veins, packet and pegmatite veins, small apophyse, and small-scale intrusions. Performed U-Pb age dating on zircon extracted from different rock groups show that they have the following age ranges (in terms of millions years): 1- mextabasites (2350, 1900 and 1200), 2- micaschists (2350, 1900 and 1200), 3-gneisses (524 and 513) 4-mextapasamites (2350, 1900 and 1200), 4- granites (553, 515 and 506) and 6- mextarhyolites (521 and 494). By considering the obtained youngest ages and age of the neighboring similar associated rock complexes, the age range of the evolution of MMIC is between 540-520 Ma (Late Neoproterozoic, Ediacaran-Cambrian), the older ages are mainly inherited ages. With respect to all of the field evidence, geochemical results and isotopic age dating, at the end of Neoproterozoic, intracontinental extensional basins formed, and the early sedimentary sequences of the protolith of the MMIC deposited in them. These mentioned basins often didn’t experience of the formation and extension stage of the producing oceanic lithosphere, and then due to the dominance of the compressional tectonic regime, rapidly closed and the contributed rocks in these processes, obducted in the form of accretion prisms and emplaced on the continental plates and probably progressed up to the continental-continental collision. In the north of Majerad pass, the MMIC crosscut by several small-scale gabbrodioritic intrusions and numerous diabasic dikes. Field evidence of fractionation from gabbro to tonalite are observed in these intrusions. In respectively, baxsed on the termobarometery results, the calculated P-T condition are from 1181 to 800 °C and the 7 to 5 kbar. The U-Pb age dating carried out on zircons extracted from the mentioned gabbrodiorites, represented an average age 167 million years (equivalent to middle Jurassic, Bajocian - Bathonian boundary) for their formation. Geochemical studies indicate that magma forming of gabbrodiorites originated from partial melting of the mextasomatized subcontinental lithospheric mantle source with spinel - peridotite nature in an extensional intracontinental (or back-arc basin) tectonic setting which located above the Neothetyan subducted oceanic slab, on the northern edge of the Central Iran structural zone in the middle Jurassic.