Lithification
Topic: Minerals, Rocks and the Rock Cycle · NCERT: Beyond NCERT
Meaning
Lithification is the process that turns loose sediment (sand, mud or shell bits) into solid sedimentary rock. It happens in two steps. First, in compaction, the weight of new layers above squeezes the sediment and pushes out water. Second, in cementation, minerals such as silica or calcite, carried by groundwater, settle between the grains and glue them together. Lithification is the step in the rock cycle that turns sediment into sedimentary rock.
Example
Sand laid down long ago in the Vindhyan basin was compacted and cemented into the hard red Vindhyan sandstone, which stretches from Sasaram in Bihar to Chittorgarh in Rajasthan.
Don't confuse with
- Metamorphism: lithification only packs and glues grains together at fairly low heat and pressure. Metamorphism uses much greater heat and pressure to change the minerals and texture themselves, for example turning sandstone into quartzite.