Spinel composition as a petrogenetic indicator of the mantle section in the Neoproterozoic Bou Azzer ophiolite, Anti-Atlas, Morocco

Origin of magnetite veins in serpentinite from the Late Proterozoic Bou-Azzer ophiolite, Anti-Atlas, Morocco: An implication for mobility of iron during serpentinization

“…The high Ni, Cr and Co of the bulk serpentinites combined with the high Cr# (up to 0.8) of the intact spinels suggest high degrees of partial melting (e.g. Gü lacar and Delaloye, 1976;Dick and Bullen, 1984;Arai, 1994;Ishiwatari et al, 2003;Ahmed et al, 2005). The highly depleted harzburgite with high Cr# (P0.7) of spinel is very common to the Precambrian ophiolites (e.g.…”

Platinum-group elements distribution and spinel composition in podiform chromitites and associated rocks from the upper mantle section of the Neoproterozoic Bou Azzer ophiolite, Anti-Atlas, Morocco

“…Chromian spinel, both in chromitites and/or in peridotites, occasionally survives alteration and can be used as a reliable petrogenetic indicator to determine the primary mantle lithology even in highly serpentinized ultramafic rocks (e.g. Liipo et al, 1995;Ahmed et al, 2005a). Platinum-group elements (PGEs), on the other hand, are a potential geochemical monitor of the deep-seated processes taking place in the mantle (e.g.…”

Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences

“…3f) in the Fawakhir serpentinites occurs as disseminated subhedral and anhedral crystals of reddish brown color. Studies on ultramafic rocks have confirmed that Cr-spinel can serve as a potential petrogenetic and tectonic indicator (Ahmed et al 2005(Ahmed et al , 2006Hellebrand et al 2001). The chemistry of spinel in peridotites is influenced by serpentinization and higher grades of metamorphism (Abzalov 1998;Barnes 2000); the core composition of a large spinel may be favorable.…”