Interlinked barrier chain and delta lobe development, northern Gulf of Mexico

Coastal Habitats of the Gulf of Mexico

“…According to Otvos and Carter (2008) and Otvos and Giardino (2004), the Mississippi Sound barrier islands formed during a deceleration in sea-level rise approximately 5,700 to 5,000 years ago. At that time, the core of Dauphin Island at its eastern end was the only subaerial feature in the location of the modern barrier island system through which predominant west-directed littoral sand transport from the Florida panhandle via Mobile Pass ebb-tidal shoals could transit and deposit as elongate sand spits and barrier islands.…”

“…Beginning approximately 3,500 years ago, the Mississippi River flowed east of New Orleans toward Mississippi Sound, creating the St. Bernard delta complex (Figure 6.85) (Otvos and Giardino 2004). Delta deposition extended over the western end of the Mississippi barrier island system, west of Cat Island.…”

“…By about 2,400 years ago, fluvial sediment from the expanding St. Bernard delta created shoals as far west as Ship Island (Otvos 1979), changing wave propagation patterns and diminishing the supply of west-directed littoral sand to Cat Island. With changing wave patterns and reduced sand supply from the east, the eastern end of Cat Island began to erode, resulting in beach sand transport perpendicular to original island orientation (Rucker and Snowden 1989;Otvos and Giardino 2004). Persistent sand transport from the east has been successful at maintaining island configuration relative to rising sea level for much of the barrier system; however, reduced sand transport toward Ship Island has resulted in increased island erosion and segmentation from tropical cyclones (Rucker and Snowden 1989).…”

The Use of Aerial RGB Imagery and LIDAR in Comparing Ecological Habitats and Geomorphic Features on a Natural versus Man-Made Barrier Island

“…4.5 ka 14 C [14], is located approximately 15 km south of the Mississippi mainland shore (30˝14 1 13"N,´88˝53 1 13"W). The island is composed mostly of quartz sand with finer silts and clays on its lagoonal side.…”

Near-surface stratigraphy and morphology, Mississippi Inner Shelf, northern Gulf of Mexico

“…Sediment supply for the islands was sourced primarily from the Mobile River embayment deposits (Otvos, 1981;Greene and others, 2007). As sea level reached its present position, the St. Bernard Delta complex of the Mississippi River Delta encroached into the western Mississippi-Alabama Shelf, covering the backfilled stratigraphy with muddy prodelta deposits until delta development ceased about 2 kyr BP (Otvos and Giardino, 2005), completing the modern morphologic setting of the inner shelf.…”