Fluids and melts in the upper mantle

This paper presents a direct study of the fluids and melts in the upper man tle by examining the fluid inclusions, melt inclusions and glasses trapped in the mantle Iherzolite xenoliths entrained by Cenozoic alkali basalts (ba sanite, olivine-nephelinite and alkali-olivine basalt) from eastern China T he study indicates that the volatile components, which are dissolved in hig h-pressure solid mineral phases of mantle peridotite at depths, may be exso lved under decompressive conditions of mantle plume upwelling to produce th e initial free fluid phases in the upper mantle. The free fluid phases migr ating in the upper mantle may result in lowering of the mantle solidus (and liquidus), thereby initiating partial melting of the upper mantle, and in the meantime, producing metasomatic effects on the latter.