Erosional structures

Most areas of present-day sediment accumulation reflect complex interactions between erosion, transport and deposition. Even in areas of net long-term accumulation, deposition may be interrupted by periods of erosion. Similarly, most ancient successions are not the products of steady, continuous deposition but result from alternating periods of deposition, non-deposition and erosion. This chapter deals with features that indicate that erosion has taken place. As with most depositional structures (Chs. 5–7), the chances of an erosional structure being preserved in the rock record are very small. For erosional structures to be preserved the eroded sediment has to be sufficiently cohesive