Pyritisaatio

Pyritisaatio is a geological process where iron sulfides, primarily pyrite (FeS2), are formed within sediments or rocks. This process is often associated with environments that are rich in organic matter and have low oxygen levels, such as swamps, bogs, and the seafloor. In these conditions, sulfate-reducing bacteria play a crucial role. They metabolize organic matter and reduce sulfate ions (SO42-) from water into sulfide ions (S2-). These sulfide ions then react with dissolved iron (Fe2+) in the pore water to form iron monosulfide (FeS). With further reaction, often involving elemental sulfur, this iron monosulfide is transformed into pyrite. Pyrite can form as individual crystals, nodules, or as replacements for other minerals and organic structures. The presence of pyritisaatio can significantly impact the chemical and physical properties of sedimentary rocks, influencing their color, porosity, and potential for hosting hydrocarbons or mineral deposits. It is a common diagenetic alteration that occurs during the burial and lithification of sediments.