The two important processes involved in lithification of sedimentary rocks are compaction and cementation.
Fresh sediment is usually loose material filled with open spaces or pores filled with air or water. Lithification serves to reduce this pore space and replace it with solid mineral material. The main processes involved in lithification are compaction and cementation.
Compaction compresses the sediment to a smaller volume by packing the sediment particles more tightly, removing water from the pore spaces, or by reducing the pressure at the sediment particle contact points. Cementation involves filling the pore spaces with solid minerals that are either deposited from solution or allow particles of existing sediment to grow into the pores.
A convergent boundary is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction.
