Abstract:In response to external forcings such like eustatic changes, tectonic activities, and sediment supply, the stacking of strata is controlled by both autogenic and allogenic mechanisms. One of the main progresses in recent years is a realization that autogenic ones may take place in a wide variety of spatio- temporal scales during the deposition. Unlike small- scale autogenic mechanisms that happens on local positions of the depositional system, large- scale ones control the formation of strata systematically in regional scale, which might modify and even change the allogenic processes. To check the relationship between strata stacking patterns and external forcings, large- scale autogenic processes must be determined from allogenic ones. Based on the understanding of large- scale autogenesis, autostratigraphy has developed in recent years. Autostratigraphy provides new perspectives in analyzing the relationships between strata stacking patterns and external forcings, based on two pairs of coupled notions, i.e. autogenesis and allogenesis, equilibrium and non- equilibrium responses. Autostratigraphy defines external forcings of constant rates as steady, and those of changing rates as unsteady. Strata stacking patterns or processes controlled by steady external forcings are considered as autogenesis, while by unsteady external forcings are considered as allogenesis. Autostratigraphy also defines steady strata stacking patterns or processes where the ratio of aggradation rate and progradation rate (i.e. R agg/R pro) remains constant during the interested period. Otherwise, the strata stacking patterns or processes are considered as unsteady. Equilibrium response is then defined as a response where steady external forcings form steady strata stacking patterns and thus is autogenic. If steady external forcings form unsteady strata stacking patterns, this response is called non- equilibrium response and is also autogenic. Moreover, unsteady external forcings may also form steady strata stacking patterns, which is also a kind of non- equilibrium response but is allogenic. Under the framework of autostratigraphy, the stacking up of strata generally takes the large- scale autogenic non- equilibrium responses and thus usually exhibits an unsteady pattern. In contrast, steady stacking patterns of strata only takes places under very rare conditions. The acquiescence of equilibrium response between strata stacking patterns and external forcings and its corollary in conventional genetic stratigraphy should be revisited.