laterite

Laterite is a soil and rock type formed in hot, humid tropical climates through intense chemical weathering, a process known as laterization. It is typically rich in iron and aluminum oxides and often displays a reddish-brown to yellow color. Leaching during heavy rains removes soluble elements such as silica and bases, while insoluble oxides accumulate, sometimes creating a hard, cemented layer that can resist further weathering.

Formation occurs under high rainfall and temperatures with seasonal variation. Prolonged weathering depletes silica and bases and concentrates iron and aluminum oxides, producing a crustal horizon near the surface and a clay-rich layer beneath. Laterites are commonly acidic and nutrient-poor, making them relatively infertile for agriculture unless mechanized management or amendments are applied.

In practice, laterite can refer to either the weathered soil or the consolidated rock that forms when altered material hardens through cementation by oxides. The hard, durable form is widely used as a building material in tropical regions, known as laterite stone or brick. Softer laterite is more prone to crumbling and less suitable for construction.

Nickel laterite refers to deposits formed by the same lateritization processes but enriched in nickel and cobalt; such ores are mined for nickel production. Economically, laterites support construction materials and, in some regions, mining activities for metals.

Distribution: well-developed laterites occur in tropical areas of Africa, South and Southeast Asia, Australia, and parts of South America, where climate and bedrock conditions favor intensive weathering.