What is the primary process responsible for the transformation of sediment into sedimentary rock?

The transformation of sediment into sedimentary rock primarily involves both compaction and cementation working together in a process known as lithification. When sediments accumulate in layers, they exert pressure on the layers below due to the weight of overlying material, leading to compaction. This process reduces the volume of the sediment as the grains are squeezed closer together.

At the same time, cementation occurs when minerals precipitate from groundwater and fill the spaces between sediment grains, binding them together. Common minerals responsible for cementation include silica, calcite, and iron oxides, which crystallize as the water percolates through the sediment layers.

This combined effect of compaction and cementation is essential for forming solid sedimentary rock from loose sediment. While weathering is involved in breaking down existing rock into smaller particles, it does not play a direct role in the transformation of sediment into sedimentary rock. Therefore, recognizing that both compaction and cementation are crucial highlights the two-step lithification process in sedimentary rock formation.