The landform created by the slow movement of water and deposition of silt is a delta.

Here's why:

* Slow Movement: As a river slows down near its mouth, it loses energy. This causes the sediment (silt, sand, clay) it has been carrying to settle out of the water.

* Deposition: This process of sediment settling is called deposition.

* Delta Formation: Over time, the deposited sediment builds up, creating a fan-shaped landform at the river's mouth called a delta.

Let me know if you'd like to know more about deltas!