What is compaction in the context of lithification?

Compaction is a crucial process in the lithification of sediments, where the weight of overlying materials exerts pressure on sediment layers. This pressure causes the sediment particles to be squeezed together, reducing the volume of the sediment as the spaces between individual grains are diminished. As a result, the sediment transforms from loose, unconsolidated material into a denser, solid rock formation. This process typically occurs beneath sedimentary basins, where layers of sediment accumulate over time, leading to significant changes in porosity and permeability, which are essential factors in the geological features and hydraulic properties of sedimentary rocks.