Abstract
Primary sedimentary structures revealed in epoxy peels of box cores from the upper 0.5 m of sediment in a perennial, straight, wave-formed marine bar provide indices of the patterns of sediment transport. The bar crest is located 3–400 m from the beach face and approximately 2 m below mean water level. A high degree of locational stability is exhibited by the bar and it is suggested from structural evidence that this results from a balance of sediment movements in two opposite directions: (1) landward over the whole of the seaward slope, bar crest and landward slope through migrating bedforms under near-symmetric and highly asymmetric wave-induced oscillatory flows; (2) obliquely seaward across the trough, landward slope and bar crest in narrowly defined zones of dunes and/or lunate megaripples formed under wave-induced longshore and rip-type currents. No distinct channels or longshore periodicity indicate the location of the latter, however; their limited areal extent compared with the landward flows is thought to be compensated for in the overall sediment balance by the higher rates of transport associated with uni-directional flow.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call