Many recent studies have sought to understand the response of barrier islands and their attendant marshes to sea level rise. The Mississippi River delta plain, specifically the Chandeleur Islands and associated interior wetlands in eastern Louisiana, serves as an excellent natural laboratory for studying these responses. This region is presently undergoing the highest rates of shoreline erosion (> 15 m yr -1) in North America as wetlands are converted to open water in a regime of subsidence-driven rapid relative sea-level rise (~1 cm yr-1). Three conceptual models were developed based on the geomorphic relationships observed in the marsh that describe and predict shoreline processes as the Chandeleur Islands continue to disintegrate and submerge. These models indicate that shells are the dominant shoreline-forming material in the marsh due to the lack of sand-rich strata in the subsurface of the marsh.

During the last half century researchers have suggested that active deformation driven by neotectonic activity has locally influenced areas of southeastern Louisiana in the form of wetland loss and coastal erosion. This study, within the Pearl River Delta Area of Louisiana, applied geomorphologic and stratigraphic methods of analysis to assess whether evidence of recent fault motion is present within the shallow, unconsolidated Holocene strata of the study area. Geomorphological historical change analyses focused on meander patterns, elongated water bodies and spatial changes in vegetation identify areas where fault motion may have recently occurred. The shallow stratigraphy was then investigated in these locations using vibracores and seismic reflection profiling. Facies relationships coupled with radiocarbon ages of select stratigraphic intervals led to the development of a detailed stratigraphic framework. Based on these relationships, data suggest that subsurface deformation, resultant of neotectonic activity, has recently occurred within the shallow, unconsolidated Holocene strata.