Rift-related linked depositional systems and their seismic expression

Abstract

Abstract The spatial distribution and temporal evolution of depositional systems in active-fault bounded basins are considered to be significantly influenced by tectonics. Fault movement and stage of basin development control the potential for erosion and the rate of sediment flux. Distinct stages of rift evolution can be recognized, each with characteristic linked depositional systems and distinctive expressions on seismic reflection profiles. A four-fold division relating to rift initiation, rift climax, immediate post-rift and late post-rift stages of basin evolution is proposed to characterize most basin infill stratigraphies. The three-dimensional linked depositional systems (systems tracts) associated with each of these stages will vary according to climate, source rock composition, position relative to sea-level, and eustatic fluctuations; however, a dominant tectonic signature can still be isolated if analysis is undertaken in an appropriate fashion. The general suitability of the application of this new method of describing rift basin stratigraphies in terminal half-graben type basins is demonstrated using case studies and published examples. The introduction of new terminology for use in tectonically active settings is justified on the basis that no other technique sufficiently emphasizes the fundamental link between tectonics and sedimentation.