Depositional structures of sands and sandstones

Structures developed in siliciclastic or carbonate sands and in sandstones and calcarenites reflect a variety of transport and depositional processes and they are our clearest indicators of the types and strengths of currents that move and deposit sediment. The transporting medium may be water or air. In this chapter, structures that results from aqueous transport and deposition are considered first, followed by an account of structures due to aeolian processes. Deposition of sand by aqueous currents generally occurs through accumulation from bedload transport during steady or waning flow with excess sediment supply, or by fallout from suspension from powerful, decelerating