The role of backbarrier infilling in the formation of barrier island systems

Barrier islands develop through a variety of processes, including spit accretion, barrier elongation, and inlet filling. New geophysical and sedimentological data provide a means of documenting the presence of a paleoinlet within a barrier lithosome in the western Gulf of Maine, illuminating the process of backbarrier infilling and its effect on barrier and tidal inlet morphodynamics. The transport of sediment into the backbarrier through tidal inlets as well as sediment contribution from nearby rivers led to bay infilling, formation of tidal flats and marshes, and a vast reduction in the bay tidal prism. Using existing marsh stratigraphy and high resolution imaging of a paleo inlet, this study investigates the effects of this diminishing tidal prism and inlet closure process. Chronostratigraphic reconstructions and digital backstripping of the backbarrier explain rates and timing of infilling and eventual conversion of an open water lagoon to the modern high marsh and tidal creek system.