LIthification of sediment into sedimentary rocks takes place after the sediment has been deposited and buried. The processes by which the sediment becomes lithified into a hard sedimentary rock is called diagenesis and includes all physical, chemical and biological processes that act on the sediment.

What kind of rocks is formed by the process of lithification?

Lithification includes all the processes which convert unconsolidated sediments into sedimentary rocks. Petrifaction, though often used as a synonym, is more specifically used to describe the replacement of organic material by silica in the formation of fossils.

Where are sedimentary rocks found?

You're most likely to find sedimentary rocks near sources of water, which is where a lot of erosion takes place. You can find different types in riverbeds, ponds and coasts and throughout the oceans.