Magnetic Mineral Diagenesis in Sedimentary Environments

Magnetic mineral diagenesis encompasses the suite of post-depositional chemical, physical and biological transformations that alter the nature, abundance and magnetic properties of minerals in sediments. Under varying redox conditions, detrital iron oxides such as magnetite and hematite may undergo reductive dissolution or recrystallisation, while sulphate reduction and microbial iron reduction foster the authigenic precipitation of iron sulphides (for example greigite and pyrite) and iron carbonates (siderite). These processes commonly occur within distinct geochemical horizons, including the sulphate-methane transition zone, and can redistribute magnetic carriers both vertically and laterally. The resulting assemblage of ferrimagnetic, antiferromagnetic and paramagnetic phases exerts a strong control on rock-magnetic proxies used for palaeoenvironmental reconstruction, sediment provenance studies and hydrocarbon migration mapping. Moreover, diagenetic alteration can overprint primary detrital remanence, complicating magnetostratigraphic interpretations unless the timing and mechanism of mineral growth are carefully constrained. Recent advances in high-resolution magnetic profiling, combined with pore-water geochemistry and microscopic imaging, have refined our understanding of the interplay between microbial activity, fluid flow and mineral stability fields. This knowledge is instrumental for applications ranging from basin modelling in petroleum systems to robust recovery of palaeomagnetic signals for tectonic and climate studies.

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Magnetic Mineral Diagenesis in Sedimentary Environments publication trend

The graph below shows the total number of articles in magnetic mineral diagenesis in sedimentary environments across all publications each year (not limited to Nature Index journals).

Technical terms

Diagenesis: The suite of post-depositional processes (physical, chemical and biological) that alter sedimentary minerals and textures under low-temperature conditions.

Authigenic minerals: Minerals that form in situ within sediments during diagenesis, as opposed to detrital grains derived from pre-existing rocks.

Greigite: A ferrimagnetic iron sulphide (Fe₃S₄) commonly produced during early diagenesis under sulfidic conditions, important for remanence acquisition.

Chemical Remanent Magnetization (CRM): A stable magnetic signature acquired when new magnetic minerals grow or alter in the presence of the Earth’s magnetic field.

Sulphate-methane transition zone (SMTZ): A stratigraphic horizon in marine or lacustrine sediments where downward-diffusing sulphate meets upward-diffusing methane, driving anaerobic oxidation of methane and associated mineral reactions.

References

1. Self‐Reversed Magnetization in Sediments Caused by Greigite Alteration. Geophysical Research Letters (2023).
2. The Effect of Early Diagenesis in Methanic Sediments on Sedimentary Magnetic Properties: Case Study From the SE Mediterranean Continental Shelf. Frontiers in Earth Science (2020).
3. Using magnetic techniques to calibrate hydrocarbon migration in petroleum systems modelling: a case study from the Lower Tertiary, UK Central North Sea. Geophysical Journal International (2021).