Sub-continental lithospheric mantle structure beneath the Adamawan plateau inferred from the petrology of ultramafic xenoliths fromn Ngaoundere (Adamawa plateau, Cameroon, Central Africa)

摘要

Ultramafic xenoliths (lherzolite, harzburgite and olivine websterite) have been discovered in basanites close to Ngaoundere in Adamawa plateau. Xenoliths exhibit protogranular texture (lherzolite and olivine websterite) or porphyroclastic texture (harzburgite). They are composed of olivine Fo89-90, orthopyroxene, clinopyroxene and spinel. According to geothermometers, lherzolites have been equilibrated at 880-1060 degrees C; equilibrium temperatures of harzburgite are rather higher (880-1160 deg