Application of sequence stratigraphy to modern sediments

The concept of sequence stratigraphy provides a genetically linked depositional history of sea level and sedimentary processes which has been effectively used to interpret ancient deposits. Few efforts have been made to apply sequence stratigraphy to modern sediments, primarily due to differences in scale and the million(s)-year time span required to develop the lower-order depositional sequences upon which the concept is based. An extensive high-resolution seismic and vibracore database compiled over the last six years on the Louisiana continental shelf, coupled with published information, allows an application of sequence stratigraphy to the Mississippi River delta (MRD) system. Each of the major elements of the model has a counterpart in the MRD sequence. Eustatic fall beginning some 27,000 years ago resulted in fluvial downcutting and subaerial exposure of the continental shelf, creating incised valley, a Type 1 unconformity, and a lowstand wedge. The incised valleys filled as sea level began rising some 18,000 years ago, until a series of backstepping shelf-phase deltas were deposited during relative stillstands, onlapping the Type 1 unconformity as a transgressive systems tract. Once sea level reached its current position about 3,000 years ago, continuing deltaic deposition initiated the highstand systems tract, which has reached the shelfmore » margin in the form of the Balize delta complex.« less