The present study focuses on selected four younger gabbro masses cropping out in Wadi Sa’al (south Sinai), Umm Battat and El-Bakryia (central Eastern Desert) and Korab-Kansi (south Eastern Desert) of the Nubian shield in Egypt. They exhibit intrusive contact against the involved country rocks. Some of them are structurally unaffected by the major folding of the ophiolite but they are affected by the major faulting dominated on the intrusive rocks. Variable petrographic varieties were identified for the present gabbros. They comprise pyroxene–hornblende, hornblende- and leuco-gabbro (Sa’al); troctolite, olivine gabbro, normal gabbro, pyroxene-hornblende gabbro and leucogabbro (Umm Battat); troctolite, olivine gabbro, normal gabbro and altered gabbro (El-Bakryia); metaperidotite, pyroxenite, olivine gabbro, normal gabbro and hornblende gabbro (Korab Kansi). Microprobe data show that all of the masses contain augitic pyroxene, pargasitic amphibole and labradoritic plagioclase. They reveal a transition from tholeiitic (Sa’al, Umm Battat and Korab Kansi) to alkaline (El-Bakryia) basaltic magma. They were derived by variable partial melting of the mantle at various depths. Crystal fractionation processes at moderate to low pressure (7-4.5Kb) and temperature of 1200-600˚C at variable depths create the alkaline magma from tholeiitic one during the change from arc to intraplate setting.