 Ginsburg (1971) suggested that asymmetric, shallowing-upward parasequences could be produced under conditions of steady subsidence and constant eustatic sea level by landward transport of carbonate sediment from subtidal zones, leading to progradation of inter- and supratidal zones.Continuing progradation reduces the size of the productive subtidal area, thus reducing sediment supply until it cannot keep pace with subsidence.When the area subsides and becomes supratidal once again, the inter- and supratidal areas are re-flooded starting a new cycle.