Geochemical evolution of rocks during ultrametamorphism in the amphibolite-granulite facies transition zone, central part of the Aldan shield

The processes of ultrametamorphism that take place in the zone of the amphibolite-granulite facies transition, which occur rarely in nature, provide insight into a weakly studied problem of the similarities and differences in geochemical evolution of these processes under the conditions of these facies. This transition can be exemplified by the section in the upper reaches of the Aldan River (from the Ungra River mouth to Yuetepneekha Creek), which exposes the basement rocks of the Kurumkan (Upper Aldan) Formation.