The 2-Ga Eburnean Orogeny in Gabon and the opening of the Francevillian intracratonic basins: A review

The Eburnean orogeny in Africa results from the continental collision between the San Francisco and Congolian cratons. The different stages of this orogeny in Gabon are described from the initial rifting of the Archean continent with the crustal melting producing pre-Eburnean migmatites at 2450 Ma, the opening of an ocean. The eastward subduction of the oceanic lithosphere produced eclogites at 2120 Ma and intrusion of calc-alkaline plutons between 2083 and 2040 Ma. The blocking of the subduction by continental collision in the south induced strike-slip motion and the opening of the intracratonic Francevillian pull-apart basins. The thrusting of the units of the Ogooué complex is linked to the rapid uplift of the orogenic root (slab break-off?) and is sealed by the intrusion of the Lecoué granite at 2009 Ma. Our interpretation links the main tectono-metamorphic phases registered in the mobile zone of Ogooué with the sedimentary events in the pull-apart Francevillian basins.