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Preliminary Assessment of Recent Deposition Related to a Crevasse Splay on the Mississippi River Delta: Implications for Coastal Restoration

N. F. Ferina1, J. G. Flocks1, J. L. Kindinger1, M. D. Miner2, J. P. Motti2, P. C. Chadwick3, and J. B. Johnston3
1U.S. Geological Survey, Center for Coastal and Watershed Studies, St. Petersburg, Florida 33713
2University of New Orleans, Coastal Research Laboratory, New Orleans, Louisiana 70148
3U.S. Geological Survey, National Wetlands Research Center, Lafayette, Louisiana 70506

Historically, the Mississippi River has replenished sediment across the lower deltaic plain, abating land loss. However, flood-control structures along the river now restrict this natural process and divert sediment from the modern delta offshore to the shelf break, thereby removing it from the coastal system. Localized crevasse splays, however, can deposit significant amounts of sediment in a short span of time.

Satellite imagery and field investigations, including eight sediment vibracores, have identified a recent crevasse splay originating from Brant Bayou within the Delta National Wildlife Refuge on the lower Mississippi River delta. The splay deposits are estimated to be as much as 3 m thick and are located stratigraphically above shallow interdistributary-bay deposits. In addition, the deposits exhibit physical characteristics similar to those of large scale prograded deltas. The Bayou Brant crevasse splay began forming in 1978 and has built approximately 3.7 km2 of land. Coastal planners hope to utilize on this natural process of sediment dispersion to create new land within the deltaic plain.

 

AAPG Search and Discovery Article #90080©2005 GCAGS 55th Annual Convention, New Orleans, Louisiana