The evolution and mechanics of modern intertidal and subtidal bedforms: their relevance to geological structures

Abstract

Standard levelling techniques, carried out daily for 13 days during a semi-lunar tidal cycle, were used to obtain cross sectional profiles perpendicular to sandwave crestlines on a drying bank. The results were used to study bedform movement and to infer internal structure ( Langhorne 1982 ). Sedimentary evidence of such structures, or master bedding, was verified by box coring. The conclusions, compared with those obtained on previous occasions at a subtidal site, indicate the difficulties of distinguishing the apparently contrasting hydrodynamic regimes using structural criteria. This has important implications for the interpretation of palaeo-environments from ancient sediment-tary structures.