Marine Delta

Marine delta created if the sediment loads from rivers are abundant which caused accumulations of sediments at the river's mouth. 

If the sediments loads from river are low, estuary will be formed. The effect of current, waves and tides keeps sediments form accumulating.

In prograding (growing) delta, it consists of 3 structure: topset, foreset and bottomset.

The topset located nearest to shore consists of heavier and coarser particles. 

If there is a river flowing on the topset, the topset will consists of channels and levee.

if there are no channels at the topset, the topset will consists of shallow bay which contains finer sediments which often shelter abundant plant and animal life.

Finer sediments carried beyond topset will be transported to foreset beds on the steep seaward face delta. In foreset beds, finer sediments (fine sand) will be deposited below the wave base. This is due to wave action that suspends the finer sediments. 

Below the wave base, muddy sand and silt will be deposits at the bottom of foreset beds.

The location of the slope-shelf break are subject to the relative sea level during the deposition of the prograding marine delta. 

If the relative sea level rises during the process, the shelf-slope break will increasingly shallower.

If there are no movement in sea level, the shelf -slope break will be at the same level.

If the the relative sea level low, the shelf-slope break will be lower.