What are some common characteristics of sedimentary rocks?
Sedimentary rocks are composed of layers of material formed through millions of years of being exposed to pressure generated deep beneath the Earth's crust.
The material is forced deeper underground, and a new layer of material is deposited on top of the current layer. This builds up over millions of years, and this process is known as lithification.
Lithification can occur in many ways, such as:
drying and compacting
oxidation of iron and aluminium
precipitation of calcium and silica
Examples of sedimentary rocks can include gravel, sand, silt and clay.