The Qalaylan pluton of Late Jurassic age is composed of intermediate and felsic rocks that crop out in the northern Sanandaj-Sirjan Zone. A body is comprising alkaline, high K, Ferroan A1-type rocks with contrasting aspects; whiles, Nd-Sr primitive isotopic composition consistent with a mantle source. On the other hand, inherited zircon cores (with a range of 230 – 2700 Ma) and elevated Nd model ages (Avg. »670 Ma) indicate that the source of these rocks was not juvenile mantle-derived subduction related magma. Unusually large proportion of inherited zircons demonstrates that fast and non-equilibrium melting of pre-fertile crust with primitive isotopic signatures was the source of these rocks. Zoning and porphyritic texture of the body, oscillatory zoning of plagioclase grains and unusually amount of pre-magmatic zircons all are evidences of non-equilibrium condition as a result of fast cooling rate of parental magma of Qalaylan.