Diagenesis is the sum of physical and chemical changes that alter sediment after deposition, driven by water-rock interaction, microbial activity and compaction as burial proceeds. It carries loose sediment toward sedimentary rock, most visibly through lithification, and excludes both surface weathering and the higher-temperature, higher-pressure regime of true metamorphism, with which it grades gradually rather than sharply.
Facts
TimescaleBegins immediately after deposition and continues through progressively deeper burial, typically over thousands to millions of years, with no sharp boundary where it gives way to metamorphism at greater heat and pressure. 1 Driving ForceCompaction under the weight of overlying sediment and chemical reactions with pore fluids, at temperatures and pressures too low to be classified as metamorphism. 1 Resulting FeatureConverts loose sediment into solid sedimentary rock through compaction, cementation and mineral recrystallization. 1 SignificanceDiagenesis determines the porosity and permeability of sedimentary rock, which controls its capacity to store oil, gas and groundwater. 1 Driving Force
Driving Force (category) Timescale
Timescale (category) Connections
Causes
Source Calcite (Wikipedia)
Lithification, the compaction and cementation of sediment into rock, is one outcome of the broader diagenetic process.
Source Pyrite (Wikipedia)
In Discipline
Sources
1. Diagenesis (Wikipedia)
Wikimedia FoundationLead section
Diagenesis () is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition.
Scope
There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures
Porosity
Porosity usually decreases during diagenesis, except in rare cases such as dissolution of minerals and dolomitization.
View the Source Pyrite (Wikipedia)
Causes: Pyrite, OccurrenceQuote, Causes: Pyrite, Occurrence
Pyrite occurs both as a primary mineral, present in the original sediments, and as a secondary mineral, deposited during diagenesis.
Calcite (Wikipedia)
Causes: Calcite, Natural occurrenceQuote, Causes: Calcite, Natural occurrence
Bedding parallel veins of fibrous calcite, often referred to in quarrying parlance as beef, occur in dark organic rich mudstones and shales, these veins are formed by increasing fluid pressure during diagenesis.
Talc (Wikipedia)
Wikimedia FoundationCauses: Talc, FormationQuote, Causes: Talc, Formation
Talc is also found as a diagenetic mineral in sedimentary rocks
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