Persistence of depositional features in a strongly seasonal, tide-dominated delta

The Ganges-Brahmaputra-Meghna (GBM) Delta is one of the largest deltas in world, covering more than 100,000 km 2 . GBM River system transports over billion tons sediment annually and delivers ∼750 million to Bay Bengal, ∼25% which advected by tides into fluvially abandoned western delta plain. Fluvial water discharge are controlled southwest Asian monsoon, with wet season rates exceeding those dry a factor five. Sundarbans National Forest (SNF) located within and, 10,000 , world's continuous mangrove stand. present rate delivery allows SNF platform elevation keep pace regional sea level rise, but India's Linking Project (NRLP) could decrease suspended loads Ganges Brahmaputra Rivers 39–75% 9–25% respectively, thus may change future sedimentation. In this study, we examine whether stored tidal channels serve as an additional source for nourishment, if resuspended delivered throughout year. Over two field seasons, 70 shallow (<50 cm) cores were collected from channel banks, imaged using x-radiography observe fine scale changes depositional characteristics on subsampled textural geochemical analyses. half examined there no style laminations, suggesting that processes controlling deposition remain constant year, despite seasonal external supply. Cores where depth laminations decreases demonstrate being eroded banks elsewhere, likely sink. 70% showed surface (0–2 grain sizes coarsening season, be product winnowing sediments overall supply material lower bulk density preferentially taken away. findings analysis further supported total organic carbon (TOC) profiles, also indicate reworking • Sediment varies across remains constant. Deep, physical consistent Fine during season. Resuspended available nourish Channel erosion important contributor