Final answer:
The correct answer is compaction, which is part of the lithification process that transforms sediment into sedimentary rock by reducing pore space as weight from overburden increases.
Step-by-step explanation:
The process by which the weight of overlying sediment reduces the pore space in the buried sediment and leads to the formation of sedimentary rock is called compaction. Compaction is a part of the lithification process, where loose grains of sediment undergo transformation into solid rock. During this process, as sediment accumulates, overburden pressure mounts and reduces porosity, squeezing the sediment particles closer together. A familiar example of this is compressing garbage in a trash can to make more room.
Furthermore, as the sediments are compacted, water is forced out, and this leads to cementation. During cementation, minerals like calcite, quartz, and pyrite precipitate into the vacant pore spaces, effectively acting as a glue that cements sediments into rock. Thus, cementation often accompanies compaction during lithification. Together, these processes transform deposits of sand, silt, and other types of sediments into sedimentary rock. The burial process assists in this transformation by adding layers of sediment, increasing the pressure on underlying layers.