Metamorphic and magmatic overprint of garnet pyroxenites from the Beni Bousera massif (northern Morocco): Petrography, mineral chemistry and thermobarometry

Fatima El Atrassi (1) , Fabrice Brunet (1, 2) , Gilles Chazot (3) , Mohamed Bouybaouène (4) , Christian Chopin (1)

1 LGENS - Laboratoire de géologie de l'ENS
2 ISTerre - Institut des Sciences de la Terre
3 LDO - Domaines Océaniques
4 Laboratoire d'Océanologie, géodynamique et génie biologique

A detailed mineralogical and textural study of two pyroxenites from the Beni Bousera massif, a garnet clinopyroxenite (GP) and a garnet clinopyroxenite containing graphite pseudomorphs after diamond (GGP), indicates a strong metamorphic overprint associated with the massif exhumation. In both pyroxenites, the primary assemblage [Cpx(I) + Gt(I) ± Opx] originally stable with diamond, records temperatures in excess of 1200 °C. Along the exhumation path, Cpx(I) has decomposed according to the reaction:CpxI=0.55-0.60CpxII+0.30-0.35OpxII+0.03-0.05GtII+0.03-0.5Pl.

Keywords: Pyroxenite; Garnet; REE elements; Thermobarometry; Graphite pseudomorph; Melt percolation

Domains: Mineralogy

Fatima El Atrassi, Fabrice Brunet, Gilles Chazot, Mohamed Bouybaouène, Christian Chopin. Metamorphic and magmatic overprint of garnet pyroxenites from the Beni Bousera massif (northern Morocco): Petrography, mineral chemistry and thermobarometry. Lithos, 2013, 179, pp.231-248. ⟨10.1016/J.LITHOS.2013.08.023⟩. ⟨insu-00933753⟩