METHODIC PRINCIPLES OF THE RIPHEAN STRATIGRAPHY

Riphean stratigraphy, which was born 50 years ago when this stratigrap hic subdivision was discriminated by using data of comparative tectoni cs (historical geology), now utilizes a series of the methods applied in biostratigraphy, isotopic geochronology, chemostratigraphy, paleocl imatology, and paleomagnetic studies. This paper considers the methodi c possibilities of four indicated scientific branches for solving chro nostratigraphic problems of the Riphean. It also presents a synopsis o f data on taxonomic changes in the microfossil and stromatolite assemb lages, and on large-scale variations in the C- and Sr-isotope composit ion of carbonate rocks depicting unique features of successive interva ls of the Late Precambrian, each decreasing upward in duration in the section. Specific bio- and chemostratigraphic characteristics of three Riphean erathems and their subdivisions, in combination with data of isotopic geochronology and climatostratigraphy, not only provide the p ossibility to distinguish and correlate these subdivisions in remote r egions, but also create a real and promising perspective to identify t hem as chronostratigraphic units (to formally determine their lower bo undary) by using a paleontological and chemostratigraphic framework.