caliche

• A layer near the surface, more or less cemented by secondary carbonates of calcium or magnesium precipitated from the soil solution. It may be a soft thin soil horizon, a hard thick bed just beneath the solum, or a surface layer exposed by erosion. It is not a geologic deposit.
• Alluvium cemented with sodium nitrate, sodium chloride, or other soluble salts in the nitrate deposits of Chile and Peru.

caliche Source: Research Branch, 1976
Contact: Peter Schut