Abstract

The physical sense of carbon isotope composition of coeval organic matter and carbonates in sedimentary rocks, which widely used in geological studies and for stratigraphic correlations, was considered. The isotopic differences of the above parameters were grouped into two types. The first type, termed facial isotopic differences, reflects a variety of photosynthesis conditions in separate locations at the moment. In this scale the parameters are independent on time. The second type, dependant on time, consists of the temporal isotopic differences associated with orogenic cycles and those associated with climatic oscillations appearing after the system reached ecological compensation point. Isotopic differences associated with orogenic cycles take into account only cyclic variations (from cycle to cycle) and irreversible motion of carbon cycle system to the ecological compensation point and change in geological time. Isotopic differences associated with climatic oscillations take into account only cyclic variation around ecological compensation point. The latter have most efficient application in geological and stratigraphic correlations.