On the Role of Paleotectonics and Antecedent Topography for Source-to-Sink Analysis in Deep Time

Source-to-sink analysis (S2S) has rapidly become a method by which onshore catchments and their downdip resulting clastic deposits can be analysed in an all-inclusive processes and product manner. The analysis involves sedimentologic transport processes, geomorphological studies, studies of hinterland tectonics, topography and climate, as well as analysis and prediction of the resulting deposits and the stratigraphy formed. The S2S approach facilitates prediction of basin fill in a more complete way than sequence stratigraphy, and provides a unique way of coupling previously disparate fields in geology into a common and coherent method.

Current S2S templates are necessarily simple due to the need to apply the method in ancient and subsurface systems, although it is clear that it is imperative to honor local controls. A particular modification to the generic templates is the inclusion of the role of tectonics and resulting topography. This process is by no means simple, since the impact of tectonics, and the resulting topography is increasingly difficult to assess in deep time. In addition, the effect of tectonics on paleotopography varies from one structural regime to another, and furthermore, inherited structures from previous tectonic episodes are likely to control later structural development and resulting S2S systems significantly. In short, multiphase tectonics and antecedent topography are considered the main controls on the overall spatial distribution of sediments down dip of tectonically influenced catchments.

Several examples from both North and South Atlantic margins, as well as from rift basins, exemplify the control of tectonics on the development of S2S systems over short to even very long (hundreds of millions of years) periods of geological time. Tectonics, of all the processes controlling S2S systems, is considered the primary mechanism that needs to be understood to understand S2S systems in deep time.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California