Compaction as a Primary Control of Sequence Development on Carbonate Platforms

Dave Hunt, Tim Allsop, Richard Swarbrick

Compaction is typically considered a 'secondary' factor in sequence stratigraphy. This is because compaction is thought to proceed at a relatively low and constant rate compared to that of sequence development. The aim of this paper is to change this view of the compaction process by showing how it can play a dynamic and dominant role in sequence development. In particular, the potential control of compaction-induced differential subsidence on the development of stratal patterns, accommodation space and diagenesis is examined.

The potential for differential compaction exists where wedge-shaped stratal packages are deposited and/or where strata with different compaction 'potentials' are juxtaposed. The timing and degree to which compaction-induced subsidence can influence sequence development is controlled by the relative rates of deposition, compaction and sea-level change. When rates of deposition match or exceed those of compaction, any induced topography is subdued. Accordingly, the generation of compaction-induced relief is most important when compaction rates exceed those of deposition. On carbonate platforms, sediment production varies with changes in sea-level, and reduced production rates are associated with the lowstand and transgressive systems tracts. Sea-level changes can also increase or retard compaction. Therefore it is suggested that compaction 'catch-up' can occur during lowstand and transgressive systems tracts to develop 'enhanced' unconformities. This process is most important following times of rapid progradation. Well-documented examples illustrate the variety of scales and frequencies at which compaction processes can opera e within a sequence stratigraphic framework.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995