The problems of reforming of the International Stratigraphic Chart in terms of evolution of ecosystems (by the example of the Lower Paleozoic)

The hierarchial structure and conceptual bases of the International Stratigraphic Chart (ISC) were created during the first eight sessions of the International Geological Congress (IGC) (1878–1900) by the systematization and unification of mainly the West European regional stratigraphic references, except the Permian and, partly, Carboniferous systems with stratotypes in the Russian territory. In the next stage, the structure was refined and supplemented by on the basis of the same principles. Since the middle 1980s, a radical ISC reforming has been performed in the framework of the International Commission on Stratigraphy (ICS), which revealed the contradictory tendencies in the development of modern stratigraphy. They are expressed first of all in the principal difference between the new methodology of the “rational” substantiation of global stratigraphic references adopted by the ICS and the real practice of the development of their regional equivalents based not on the choice of chronometric markers for global correlations but on the revealing of natural geohistorical stages in the evolution of ecosystems, using the total set of paleontological, sedimentological, and isotope-chronometric data. The new approach is based mainly on the concept of the self-sufficiency of limiting types, i.e., monotaxon markers for graduating the ISC, which replace the stratotypes of subunits, their integral complex characteristics, reflecting the trends and periodicity of the Earth's evolution. The negative consequences of this “rational” substantiation and revision of the stratigraphic references of the ISC are particularly obvious by the example of innovations in the subdivision of the Cambrian and Ordovician systems on the comparison of the new series and stages adopted by the ICS with the global ecosystem rebuildings in the Early Paleozoic.