Geochemical Processes in Lateritic Weathering Systems

Lateritic weathering systems develop under humid tropical and subtropical climates where intense chemical alteration transforms parent rocks into vertically zoned profiles. Acidic solutions generated by CO₂ dissolution and organic acids attack primary silicates, mobilising silica, alkali and alkaline earth cations. Concurrent redox oscillations govern iron cycling, with Fe(III) oxides dissolving under reducing conditions and reprecipitating as goethite and hematite when oxidised. Aluminium is comparatively immobile and accumulates as gibbsite and kaolinite in upper horizons. The evolution from saprolite through mottled transition zones to hard duricrust reflects progressive mineral breakdown, element leaching and precipitation. Biological agents—root exudates and iron‐reducing bacteria—accelerate mineral dissolution and cementation at the microscale, while hydrological pathways control residence time and element flux. Over geological timescales, these processes concentrate economically vital resources such as bauxite, iron ores and nickel laterites, influence soil fertility and landscape stability, and leave isotopic and geochronological signatures that record past climatic and tectonic events.

Research from Nature Portfolio

Recent studies have revealed a novel mechanism of cave formation in Fe(III)‐rich formations driven by microbial activity. Iron‐reducing microorganisms solubilise Fe(III) phases in anoxic zones at cave margins, producing Fe(III)‐depleted sub muros that collapse outward to enlarge voids. This outward‐in mass separation contrasts with classical inward‐out dissolution and offers a new pathway for Fe(II) mobilisation into groundwater. The process also helps explain rare earth element enrichment in residual duricrusts and highlights the broader role of microbially mediated redox cycling in shaping lateritic landscapes.

Geochemical Processes in Lateritic Weathering Systems publication trend

The graph below shows the total number of articles in geochemical processes in lateritic weathering systems across all publications each year (not limited to Nature Index journals).

Technical terms

Laterite: A highly weathered soil or rock rich in iron and aluminium oxides, formed under tropical climates by intense leaching of silica and bases.

Duricrust: A hardened surface layer in a weathering profile, cemented by minerals such as iron oxides (canga), aluminium hydroxides or silica.

Saprolite: The soft, deeply weathered layer directly above unaltered bedrock, retaining the original rock texture but with altered mineralogy.

Redox cycling: Alternating reduction and oxidation reactions that control the solubility and precipitation of redox‐sensitive elements like iron and manganese.

Reactive transport model: A numerical framework that couples chemical reactions with fluid flow to simulate element mobilization and mineral transformation in porous media.

References

1. Enhanced terrestrial Fe(II) mobilization identified through a novel mechanism of microbially driven cave formation in Fe(III)-rich rocks. Scientific Reports (2022).
2. The role of plants in ironstone evolution: iron and aluminium cycling in the rhizosphere. The Science of The Total Environment (2024).
3. Tropical Weathering History Recorded in the Silicon Isotopes of Lateritic Weathering Profiles. Geophysical Research Letters (2021).
4. (U-Th)/He Geochronology Constraints on Lateritic Duricrust Formation on the Guiana Shield. Frontiers in Earth Science (2022).