Meaning of Supercritical Fluids in Pegmatite Formation and Critical-Element Redistribution

Abstract

. Abstract This contribution shows that the water for some pegmatites comes from mantle deeps via supercritical fluids. Proofs are silicate melt inclusions with high water concentration. This concentration forms with the temperature solvus curves. In addition to such solvus curves, the distributions of a row of elements display characteristic Lorentzian curves regularly related to the solvus. Along with these characteristics, untypical, mostly spherical indicator minerals from mantle deeps are present in the granites and associated pegmatites in the upper crust regions. Nanodiamonds, graphite, coesite, and reidite belong to such minerals.