THE ORIGIN OF CHARNOCKITE-ENDERBITE COMPL EXES BY MAGMATIC REPLACEMENT - GEOCHEMICAL EVIDENCE

Variations in the contents of trace and rare-earth elements in the cha rnockite-enderbite rocks of the Sharyzhalgai granulite complex cannot be accounted for by only metasomatic processes, which produce these ra cks by the replacement of their metamorphic protolith. Use of the magm atic replacement model for the fractionation of trace elements enabled us to calculate a series of model compositions that realistically app roximate the REE patterns observed in natural enderbites and charnocki tes. As our data indicate, enderbite is a metasomatic rock, which is p roduced by the interaction between migmatizing fluid and metamorphic p rotolith. Charnockite is the product of enderbite melting in columns o f magmatic replacement. As geochemical modeling indicates, rocks betwe en enderbite and the melting front are produced by various stages of t he partial melting. Throughout all of the magmatic replacement stages, the contents of trace elements in the phases were controlled by the c hemistry of the percolating migmatizing fluid.