Ilmenite et pseudobrookite (kennedyite) magnesiennes dans les cumulats ultrabasiques de l'intrusion stratifiee occidentale de Laouni, Hoggar meridional (Algerie)

Two grains of a magnesian pseudobrookite ("kennedyite', MgO approx 11 wt.%) are reported as inclusions in chrome spinel from an ultrabasic orthocumulate in the Western Laouni intrusion, Algeria, where they coexist with a Mg-rich ilmenite (MgO approx 10 wt.%). The crystallization of both oxides is attributed to movements of Ti- rich differentiated liquids that have infiltrated while the liquid remaining in the orthocumulates was still very magnesian. At lower T, pseudobrookite was isolated from the liquid by being trapped within the spinel.-R.A.H. Lab. de Mineralogie du Museum National d'Histoire Naturelle de Paris, 61 rue Buffon, 75005 Paris, France.