CoachA detrital rock (or clastic rock) is a sedimentary rock made of fragments, the clasts, of older rocks and minerals. Diagenesis is the set of changes that turn a buried sediment into rock at low temperature: compaction, as the weight of the layers above squeezes out water and air, then cementation, as minerals that crystallise from the water in the pores (calcite, quartz, hematite, clay minerals) glue the grains together.
