A foreset bed is one of the main parts of a
river delta
A river delta is a landform shaped like a triangle, created by deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more ...
. It is the inclined part of a delta that is found at the end of the stream channel as the delta
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, san ...
is deposited along the
arcuate delta front. As the sediments are deposited on a sloping surface the resulting bedding is not horizontal, but
dips in the direction of current flow toward deeper water. A cross-section of a delta shows the
cross bedding in the direction of stream flow into the still water.
The foreset bed is formed when a stream carrying sediment meets still water. When the stream meets the still water, the velocity of the water is decreased enough so that the larger sediment particles can no longer be carried and are therefore deposited. The deposited sediment builds up over time, and a delta is formed.
References
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Sedimentology
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