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The granitic masses of the Homr Akarem area are classified as tonalite, trondhjemite and granite. The tonalite and trondhjemite have compositions consistent with subduction-related magmatism, whereas the pink and muscovite granites are correlated with collision-related magmatism. The change from early tonalite, to intermediate trondhjemite, and finally to peraluminous pink and muscovite granites can be modelled successfully as a result of three magma generations. The early mafic magma produced tonalite in the early stage of underplating. As a result of crustal thickening, the deeper parts of the overlying metasediments were raised above their solidus temperatures and contributed melt to the early mafic magma. The resultant magma producing trondhjemite would be intermediate between the early and the final magma. Later on, during the collision stage, the metasediments underwent anatexis which led to final magma producing pink and muscovite granites by progressive chemical fractionation. The relatively high values of U, Th and K in the pink and muscovite granites are consistent with the derivation from pre-existent crustal materials. In pink and muscovite granites, as well as in tonalite, most of the U is located around grains, while Th is a constituent of the major mineral phases. In the trondhjemite, however both elements are preferentially hosted in the accessory minerals.