Effects of Sea Level Rise on the Mississippi River Delta Plain

by Shea Penland, Louisiana State Univ, Baton Rouge, United States,
Randolph A. McBride, Louisiana State Univ, Baton Rouge, United States,
S. Jeffress Williams, Louisiana State Univ, Baton Rouge, United States,
Ron Boyd, Louisiana State Univ, Baton Rouge, United States,
John R. Suter, Louisiana State Univ, Baton Rouge, United States,



Document Type: Proceeding Paper

Part of: Coastal Sediments

Abstract:

Geologic studies of the Mississippi River delta plain and continental shelf reveal the occurrence of several relative sea level stillstands during the last stages of the Holocene transgression. Three shelf-phase delta plains have been identified to date, each separated by a regional transgressive surface of erosion produced by a rise in relative sea level. Sequence stratigraphic relationships suggest that whenever relative sea level rise rates exceed 2 cm/yr for several centuries, the delta cycle process of the Mississippi River stops, and wetlands, estuarine bays, and barrier islands disappear. In contrast, it appears that whenever relative sea level rise rates drop below 2 cm/yr, the delta cycle process builds new wetland, estuarine bays, and barrier islands. The implication of this pattern of coastal landscape evolution, in light of future sea level rise scenarios, is if the rate of eustatic sea level rise approaches 1-3 cm/yr over the next century, as predicted, and this eustatic rate is compounded with the current subsidence rate of about 0.5-1 cm/yr, an acceleration in the drastic landscape changes currently taking place in coastal Louisiana is expected to occur.

Subject Headings: Sea level | Wetlands (coastal) | Rivers and streams | Geology | Estuaries | Landscaping | Islands | Mississippi River | Louisiana | United States

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