Abstract

Traditional shallow-water sequence stratigraphy acknowledges that deepwater systems are linked to shallow water processes, and suggests a framework to tie deepwater deposition into the shallow-water glacio-eustatic cycle. This connection is via sediment supply rate, rather than water depth. This model is of general use but lacks predictive power for localization of deepwater reservoirs in time and space. In addition, the model is devalued if the correlative shallow-water sequence is unavailable for study due to political, commercial, or geological reasons.

We offer instead a different way to view deepwater deposition – as an independent process occurring on the slope and dominated by a sequence stratigraphic framework which is driven by equilibrium slope, rather than eustatic base level. This framework maintains the tectonic and compactional subsidence component of traditional sequence stratigraphy and also utilizes sediment input. Collectively, these controls define deepwater accommodation space by changes of the balance of subsidence, sediment supply, and slope.

The stacking patterns of deepwater progrades and channel fills are significant for understanding deepwater tectonostratigraphy in a similar way that shallow water stacking patterns illustrate eustatic sea level history:- retrogradational stacking reflects basin shallowing or landwards tilt, progradational stacking reflects basin deepening or seawards tilt, and aggradational stacking reflects uniform conditions.

Examples are presented of deepwater sedimentary systems, as viewed in this paradigm, with predictions for areas of enhanced reservoir presence and quality.