The Shelf Revisited: Critical Interface on Continental Margins and in Source-to-Sink Systems

Abstract

In the epic SEPM Special Publication 33, Stanley and Moore (1983) and authors therein focused on the interplay of sedimentary process and stratigraphy of the shelfbreak, the most important physiographic boundary in sedimentary basins. Since then, massive new research has resulted on the topic, also for the definition of segments in Source-to-Sink (S2S) analysis, a morphometric, process-based method that complements sequence stratigraphy as a predictive tool for petroleum exploration in various tectonic settings, particularly at basin and play level.

Recently, new S2S analyses on continental margins and in intracratonic basins has revitalized the importance stressed by Stanley and Moore (1983) of the shelfbreak. Three important points are: (i) The four S2S segments initially proposed by Sømme et al. (2009; Basin Research) can be simplified into two first-order segments divided by the shelfbreak. These two megasegments have upwards concave equilibrium profiles: the onshore-shelf segment where the shelf is a continuation of the onshore, and the slope-basinal segment where the basin floor is a continuation of the slope. These megasegments apply where the shoreline and base-of-slope higher-order segment boundaries are highly dynamic because of processes such as sea-level change and/or high sediment supply; (ii) Many high-resolution studies of latest Pliocene, Pleistocene and Holocene shelf systems illustrate the importance of exceptionally dynamic sediment supply systems in various forms as drivers for S2S systems development; (iii) Lastly, despite widely different tectonic settings, for example passive margins and intracratonic thrust belt-foreland basin S2S systems, share several shelf characteristics at first order level that allow for application and comparisons of S2S concepts. A number of examples will be presented to illustrate first-order principles for prediction of petroleum systems.

New technology such as remote sensing and digitalization of originally analog, qualitative data have facilitated breakthroughs in geological thinking and application in particular for S2S systems. Ongoing global efforts among vendors and energy companies create more efficient and effective interpretation tools, and the prediction is that new breakthroughs in earth science will occur. This will shed new light on earlier established geological concepts such as for the shelf and shelfbreak and improve the ability to predict energy resources.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018