How are sedimentary rocks formed?

Sedimentary rocks form when minerals or organic particles settle and accumulate in rivers, streams and oceans in a process known as sedimentation. More and more sediment is built up and after a few hundred thousand years the sediment is compacted into sedimentary rocks. Almost all sedimentary rocks form underwater at low temperature and low pressure.

Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension.