The Moho transition zone above residual peridotites of the Nurali ophiolite is represented by a layered dunite-wehrlite-clinopyroxenite sequence with an enstatite-olivine upper part. The absence of deformational fabric patterns of solid-state flow sets up a problem of the magmatic nature of the Nurali transition zone ultramafics. It is interpreted to be the product of a multistage magmatic crystallisation in narrow chambers at low-pressure (plagioclase-peridotite facies) conditions. Systematic chemical trends across the transition zone show gradual increase of Mg# and depletion in compatible elements in the magma upsection, and the formation of the high-Mg enstatite-olivine cumulates at the top. This model suggests high degree of melting of the mantle source. The crystal fractionation of limited magma portions did not yield any regular chemical trends at the scale of the whole transition zone section, but resulted in rhythmic variations of mineral composition. Such a series of magma injections is thought to occur within a rifting zone. Metasomatic influence of gabbroic magma led to only local compositional variations. The gabbroids (hornblende gabbro to diorite) are the products of a later magmatic process with more significant crystal fractionation.