What does supergene mean in geology ?

Supergene : definition

This term designates all the physical and chemical phenomena (erosion, dissolution, recrystallization, etc...) that occur in the area close to the surface, following the action of agents in the biosphere (air, water, living beings...).

Many secondary minerals, called supergenes, are formed in this zone by dissolution of primary minerals, combination and precipitation of the elements in solution : these are essentially carbonates, sulphates, phosphates and arsenates. These supergene phenomena are at the origin of mineral concentrations which can become mining deposits (placers, bauxites, laterites...).