Abstract:

Changes in depositional base-level cycle control the development and evolution of sequence stratigraphy.The depositional base-level of continental basin,different from that of marine basin,is neither sea-level nor lake-level but an abstract contact equivalent to river depositional equilibrium profile.Different position with different size of compatible space during depositional base-level cycles resulted in the distribution of sediments in volume within various facies leading to the variation of stratigraphic-accumulation patterns and symmetries of stratigraphic cycles.Therefore,these variations are just markers for correlation of sequence division.According to the principal of distribution of sediments in volume in the depositional base-level cycle,the correct chronostratigraphic correlation of sequence stratigraphy with high resolution shall be that of rocks to rocks,rocks to surfaces,surfaces to surfaces or contacts to contacts instead of the correlation of lithology or isostratigraphy.During the change of depositional base-level cycle,there were very close relations between differences in the variation of compatible space size and the development of source rock,reservoir rock and cap rock in different tracts as well as the unconformity surface and the distribution of litho-pinch out.

Key words: depositional base-level, acceptable space, sequence division, correlation, litho stratigraphic reservoir predication