MATHEMATICAL MODEL OF SEA-LEVEL CHANGE CURVES IN GEOLOGICAL HISTORY

The stratigraphical sequences are considered as a medium to record sea-level changes. The effective accommodation space (C(t)), an accumulation strata for stratigraphic sequences, is a function of sea-level changes (L(t)), tectonic subsidence (Y(t)) and geological time (t). The research into the Permian-Triassic sequence stratigraphy in the western margin of the Upper Yangtze block, and the summary of previous research methods for the sea-level change curves both have been employed to establish the mathematical model of sea-level change curves, including mathematical geological model and mathematical function model. Firstly, the mathematical geological model of sea-level change curves: C(t)=L(t)+Y(t) is established, then the mathematical function model is proposed. The mathematical model has been used to compile quantitatively the Permian-Triassic seal-level change curves on the western margin of the Upper Yangtze block.