The Odivelas gabbro complex (Alentejo, Portugal): a Hercynian synorogenic layered intrusion

The ultramafic-mafic zone of the Hercynian Beja Massif includes 1) the Quintos amphibolite-diorite-serpentinite Complex, 2) the Odivelas layered gabbro Complex, and 3) the Peroguarda (meta) basalt-andesite Complex. The rhythmic and cryptic zoning of the Odivelas Complex is described, as well as its sedimentary structures and cumulate textures. The gabbros are of the high-alumina type; they have tholeiitic affinities at lower levels and alkalic affinities (due to a Nametasomatism) at upper levels. The Odivelas Complex has probably crystallized under conditions of the granulite facies.