1. adj. [Geology]

Pertaining to diagenesis, which is the physical, chemical or biological alteration of sediments into sedimentary rock at relatively low temperatures and pressures that can result in changes to the rock's original mineralogy and texture. After deposition, sediments are compacted as they are buried beneath successive layers of sediment and cemented by minerals that precipitate from solution. Grains of sediment, rock fragments and fossils can be replaced by other minerals during diagenesis. Porosity usually decreases during diagenesis, except in rare cases such as dissolution of minerals and dolomitization. Diagenesis does not include weathering processes. Hydrocarbon generation begins during diagenesis. There is not a clear, accepted distinction between diagenesis and metamorphism, although metamorphism occurs at pressures and temperatures higher than those of the outer crust, where diagenesis occurs

See related terms: authigenic,  cement,  compaction,  diagenetic porosity,  dolostone,  lithification,  secondary porosity,  stylolite