The Gabbro-dolerite magmatism of the Foum Zguid region: relation to deep structure of Morocco and possible potential for cobalt, nickel and platinum-group metals

Abstract

The territory of Morocco has been used to test a model of block structure of the lithosphere, in which block boundaries guide magmatism and predetermine the most favorable places for the concentration of metals. The examination of Van den Bosch's (1971, 1981) isostatic gravity anomaly map has revealed such a block structure, with boundaries trending N-S and E-W. In Triassic and Jurassic time, these boundaries controlled, to some degree, the shape of a subsiding depression or trough, which is now reflected in the course of the High Atlas Mts. and in the changes in strike of the South Atlas fault zone. Observations indicate that magmatic differentiation in the SW parts of the Foum Zguid region has reached a stage in which separation and concentration of nickel and cobalt was possible. It is suggested that a differentiated body of gabbroic rocks with more substantial concentrations of Ni, Co and possibly Pt-group metals may occur beneath the "screen' of dolerites in the SW-parts of the Foum Zguid region. -from Authors