Geomorphic Responses to Relative Sea Level Change Above a Developing Salt Dome Resolved with Seismic Stratal Slices

Richard H. Fillon¹ and Hongliu Zeng^2
1Earth Studies Group, New Orleans, LA
²Bureau of Economic Geology, Austin, TX

Seismic geomorphologic analysis of the Rabbit Island salt dome area, located on the Louisiana Shelf, employs closely spaced stratal slices to examine key stratal features, e.g., sequence boundaries, flooding and ravinement surfaces. Our work reveals a rich tapestry of coastal paleo-landforms that provide insights into the evolution of sequence architecture in response to early Pliocene salt tectonics and sea level change. We observe that imaged drainage channels appear to transect the geographic center of the salt dome during periods of transgression and maximum flooding. This could be in response to the regional effects of eustatic sea level rise and/or to local cessation of salt-induced uplift. In contrast, during periods of lower relative sea level related either to eustacy or accelerated upward salt movement, drainage channels are strongly deflected away from the geographic center of the dome. This approach which resolves radical changes in depositional environment is particularly useful in evaluating onlap/offlap cycles in reservoirs surrounding salt domes.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas