Knowra Diagenesis Diagenesis Diagenesis is the physical, chemical, and biological alteration of sediments after deposition and during their conversion into sedimentary rock. It occurs at relatively low temperatures and pressures, before metamorphism.
Compaction : The reduction of sediment volume as grains rearrange and pore spaces shrink under pressure. Burial pressure squeezes sediment, reducing porosity and expelling pore water.
Sediment : Loose mineral or organic particles deposited by water, wind, ice, or gravity. Diagenesis begins with deposited particles and organic matter.
Petroleum geology : The study of how petroleum forms, moves, accumulates, and is extracted from Earth’s crust. Diagenesis can create, preserve, or destroy the pore networks that store hydrocarbons.
Metamorphism : The mineralogical and textural alteration of rock under elevated temperature, pressure, or chemically active fluids, without melting. It follows diagenesis at greater temperatures and pressures and may erase earlier sedimentary features.
Cementation : The precipitation of minerals in pore spaces, binding sediment grains into rock. Minerals carried by pore fluids glue grains together during lithification.
Pore water : Water occupying the spaces between sediment grains or within rock pores. It transports dissolved substances that drive mineral reactions and cement formation.
Reservoir rock : A porous and permeable rock that can store and transmit fluids such as water, oil, or gas. Its storage and flow properties often reflect its diagenetic history.
Weathering : The breakdown and alteration of rock and minerals at or near Earth’s surface. Weathering commonly produces sediment before deposition; diagenesis alters it afterward.
Pressure solution : The dissolution of minerals at stressed grain contacts and their reprecipitation in less-stressed spaces. It transfers material between grain contacts and pore spaces during burial.
Burial diagenesis : Diagenetic alteration that occurs as sediment is buried and experiences increasing pressure and temperature. Burial changes temperature, pressure, and fluid conditions as sediment matures.
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