litifikaatio

Litifikaatio, or lithification in geology, is the process by which loose sediment is transformed into solid sedimentary rock. It occurs after deposition during diagenesis and includes mechanical compaction, chemical cementation, and, in some cases, chemical precipitation of minerals within pore fluids. Lithification reduces porosity and increases cohesion, helping to preserve fossils and produce rocks with measurable strength.

Mechanical lithification refers to compaction and rearrangement of grains under overburden pressure, squeezing out water and reducing pore space. Chemical lithification, or cementation, occurs when minerals such as calcite, quartz, or iron oxides precipitate from groundwater and bind grains together. Authigenic clays can also act as cements. Some lithification involves dissolution and re-precipitation that seals the sediment’s fabric.

Common products of lithification include sandstone, siltstone, and shale formed from compacted sands and muds; limestone from cemented carbonate grains and mud; and dolostone formed by dolomitization. The rate and outcome depend on sediment composition, pore-water chemistry, burial depth, temperature, and fluid flow. Lithification is a central part of the rock cycle: it converts loose sediments into sedimentary rocks and influences porosity, permeability, and fossil preservation.