The emplacement history of the Zaer pluton was studied, using structural data and field relationships. The pluton is one of the Hercynian granitoid bodies that crops out in the Central Paleozoic Massif of Morocco. The principal granitoid rocks are relatively mafic at the margins of the pluton and change inward with or without discontinuities to a more felsic facies, thus defining a concentrically zoned structure.
The emplacement of the pluton was by forceful intrusion of the magma. The elements of granite tectonics observed in the enclosing metasedimentary rocks include deflection of regional trend around the pluton and abundant faulting with a predominantly radial pattern with respect to the granite contact.
The emplacement of the pluton is conceived as a polyphase diapiric process that, in part, obliterated the gradation from biotite granodiorite to two-mica monzogranite. The margins of the plutonic body solidified first and were subjected to deformation during diapiric rise and expansion, resulting in a preferred orientation of mineral grains in the granitic rocks.