THE FOLDING LAYER STRUCTURE AND STRATIGRAPHIC DIVISION IN LOW-GRADE METAMORPHIC TERRANES

As part or most of low-grade metamorphic rocks have undergone solid-and liquid-state deformation, not only relict （primary） structure has been preserved but there also occur late-stage rheomorphic folds （folding layers） and ductile shear deformation as well as readjustment of rock fabrics and transposition of structure. Therefore the authors stress that we should adopt the working method of "taking the lithological division as the foundation and the structural analysis as the dominant factor of the geological work"; in other words, we should follow the tectonostratigraphic criteria in order to ascertain the normal superposition relation of the strata and establish correct stratigraphical units for mapping in low-grade metamorphic terranes. According to the basic structural style——folding structure——in low-grade metamorphic terrane, this paper proposes some fundamental methods for stratigraphical division and correlation.