Abstract
We described petrological and geochemical characteristics of bottom peridotites of Oman ophiolite overlying metamorphic sole, garnet amphibolite, in northwestern Fizh block as an analogue of slab-mantle interface in mantle wedge. The bottom peridotites are slightly serpentinized lherzolite and harzburgite, and commonly include amphiboles (hornblende and tremolite). Modal proportions of amphiboles systematically decrease with increase of the distance from the garnet amphibolite-peridotite boundary. Clinopyroxene and hornblendes in peridotites close to the boundary have LREE-enriched characters, and the degree of LREE enrichment decrease with increase of the distance from the boundary. In addition, hornblendes in the peridotite close to the boundary are extremely rich in Rb and Ba (20 times higher than chondrite). The bottom peridotites are surely hydrated, and LREE and some LILE are added to them during the hydration.
