duricrust

A hard, mineral-cemented layer at or near the surface, formed when dissolved minerals are drawn upward through the soil by evaporation and deposited as a crust. The cementing agent determines the type: calcium carbonate produces calcrete (including caliche), silica produces silcrete, iron oxides produce ferricrete (including laterite). Duricrust is the desert armoring itself — creating a shell that protects the softer material beneath from further erosion.