A quantitative simulation study of asymmetrical tectonic subsidence control on non-synchronous sequence stacking patterns of Eocene lacustrine sediments in Bohai Bay Basin, China

Compared with large-scale passive margin marine basins, continental basins are susceptive to local or regional tectonic, geomorphologic and climatic influences and can form complicated sequence stratigraphic architectures, configurations and sedimentary facies. We report herein a quantitative simulation study on the influences of asymmetrical tectonic subsidence on sequence stratigraphic stacking patterns in rift basins by varying tectonic subsidence, sediment supply, and intra-rift lake levels. It has been demonstrated that isochronous sequences within a rift basin can exhibit both synchronous and non-synchronous stacking patterns as a result of differential asymmetric tectonic subsidence. In sequence stratigraphy, synchronous stacking patterns refer to isochronous sequences at any parts of a basin, which are either all retrogradational or all progradational. We propose the concept of non-synchronous stacking patterns of isochronous sequence stratigraphy for rift basins. Non-synchronous stacking patterns refer to the fact that, within the same basin, some parts may concomitantly exhibit stacking patterns that are exactly opposite to that of other parts. Non-synchronous stacking patterns can form when the accommodation space increment (∆A) is less than that of sedimentary supply (∆S) in one area, but larger than or equal to that of ∆S in another. Moreover, the duration of non-synchronous stacking patterns is controlled by both ∆A and ∆S. Recognition of non-synchronous stacking patterns within isochronous sequence stratigraphy provides a conceptual model for correlation of sequence stratigraphic units in tectonically asymmetric rift basins in eastern China and similar basins around the world.