Kulp, M. A., Miner, M. D. and Fitzgerald, D. M., 2007. Subsurface Controls on Transgressive Tidal Inlet Retreat Pathways, Mississippi River Delta Plain. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 816 – 820. Gold Coast, Australia, ISSN 0749.0208

Tidal inlets and associated barriers along the Mississippi River delta plain are migrating landward in response to rapid relative sea-level rise, backbarrier land loss, and tidal prism increases. Bathymetric data, vibracores, and high-resolution subbottom profiles are used to construct a stratigraphic model of the modern Timbalier Islands including Little Pass Timbalier and Raccoon Pass tidal inlets as well as the relict, landward Terrebonne barrier island trend. Large sand deposits comprising relict ebb deltas are associated with the Terrebonne paleo-barrier trend. Modern inlets are aligned with relict inlets. Moreover, modern inlets have migrated approximately 3 km in a landward direction during the past 100 years with little lateral migration, indicating a tendency of retreating inlets to remain fixed in former inlet channels. Cores from Little Pass Timbalier show that tidal currents are presently scouring into underlying relict Terrebonne ebb tidal delta deposits and introducing this sand into the modern littoral system. Stratigraphic data from modern inlet systems show that tidal inlet retreat paths may also coincide with former distributary channels. Finally, during periods of delta reoccupation and progradation, it appears that relict tidal inlet channels may control the pathway of advancing distributaries. Collectively, these processes lead to an amalgamation of deltaic coastal sand deposits.