REGULAR PERIODICITY OF GLAUCOPHANE SCHIST AND OPHIOLITE FORMATION AS AN INDICATOR OF THE PERIODICITY OF GEOLOGIC PROCESSES

Abstract

The periodicity of geologic processes is one of the main, still unsolved problems of geology. The study of geodynamic and metamorphism now allows this problem to be posed on a new level. The key to such an approach could be the regular periodicity of jadeite-glaucophane metamorphism, discussed here. Jadeite-glaucophane metamorphism is a special type of metamorphism confined to geosutures, the collision zones of lithospheric plates. The periodicity of ophiolite formation has already been examined as well. However, there is more frequent and regular periodicity in the formation of jadeite-glaucophane schists; these peaks also coincide with the end of formation of some ophiolite complexes and with its onset in others. The correspondence between peaks of glaucophane metamorphism and principal tectonic phases on continents cannot be regarded as accidental. These and other aspects of the subject are discussed.