There are many conditions that create sediments or
particles. Physical breaking of rocks can occur in several ways. The
rushing power of a river or waterfall causes small pieces of the rock to
break and travel within the stream. When the water slows down it will deposit
its load. Wind can be strong enough to act as a natural "sand
blast" to slowly chip away at soft rocks. Glaciers, are so
powerful that they can grind the rocks into very small particles. Cold
and warm weather cycles also help to break rock. If water gets into a
crack and then freezes, it expands. This weakens the rock and will cause
it to break with time.
Chemical break up of the rocks also occurs. As
water travels upon rocks or other substances, it can cause the elements
within the substance to break down and dissolve in the water. It will
later precipitate out and help cement particles together.
Jim Jim Falls in Australia