Enviado por Do utilizador6624

At the base

- At the base: an erosion surface representing the base of the channel. This will be overlain by
a basal lag of coarse clasts deposited on the channel floor.
- A sandy bar composed of stacked sets of subaqueous dune deposits will form a succession of
cross-bedded sands.
- As the flow is stronger in the lower part of the channel the subaqueous dunes, and hence the
cross-beds, tend to be larger at the bottom of the bar, decreasing in set size upwards.
- Finer sands or silts on the top of a bar deposit represent the abandonment of the bar when it
is no longer actively moving. There is therefore an overall finingup of this channel-fill