Diagenes

Diagenes is not a widely recognized term in mainstream geology or related sciences. It is likely a misspelling or shorthand for diagenesis, the set of processes that affect sediments after deposition and before or during lithification. In some contexts, diagenes may be used informally to refer to diagenetic changes, but it does not have a standard, standalone definition in major reference works.

In geology, diagenesis encompasses physical, chemical, and biological changes that convert loose sediment into sedimentary rock. This occurs at conditions lower than those required for metamorphism and typically involves modifications to porosity and mineralogy without major changes in rock texture. Common diagenetic processes include compaction, cementation by minerals precipitated from pore waters (such as calcite or silica), dissolution, replacement of minerals, and recrystallization. Microbial activity can also influence diagenetic pathways by altering pore-water chemistry and producing authigenic minerals.

Diagenetic changes are governed by burial history, temperature, pressure, pore-water chemistry, fluid flow, and the supply of minerals and ions in solution. They can produce recognizable textures such as cemented zones, stylolites, pore-fillarion, and mineral boundaries that record diagenetic events. The degree of diagenesis affects porosity and permeability, with significant implications for hydrocarbon reservoirs, groundwater systems, and sedimentary rock properties.

A common framework divides diagenesis into stages such as eogenesis (early diagenesis near the surface), mesogenesis (progressive burial during deeper diagenesis), and telogenesis (late diagenesis associated with uplift or deep burial changes). While useful, these terms are not universally employed, and other classifications exist depending on regional or lithological context.