4M, Budapest, H-1088, Hungary 2. Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 USA 3. Amphibole is present as an interstitial phase in a few porphyroclastic lherzolites and as a vein component in a composite xenolith.
Phlogopite occurs only in one equigranular lherzolite and in a second composite xenolith.
There is a correlation between deformation and bulk-rock compositions and most of the mineral compositions. In contrast, secondary recrystallized harzburgites are strongly depleted in basaltic components and their clinopyroxenes display LREE-enriched patterns. It is suggested that these different styles of metasomatism have been produced by metasomatizing fluids similar in composition to the host basanitic magma during early upwelling of mantle from deeper asthenospheric levels and accretion to the lithosphere. Infiltration of the metasomatic fluids resulted in LREE - enrichment of clinopyroxene in the deeper and hotter mantle above amphibole stability. Due to the chromatographic nature of metasomatism, fluids far from their source reached equilibrium with the cooler and shallower peridotitic mantle and were consumed through crystallization of LREE-depleted amphiboles.