Supergene enrichment

Supergene enrichment is the near-surface redistribution of metals by weathering and groundwater, concentrating them into secondary ore zones above or within primary deposits.

Oxidation zone: The near-surface part of an ore deposit where oxygen-rich water oxidizes primary minerals. Oxidation releases metals that groundwater can carry downward.
Hypogene mineralization: Ore formation by processes operating at depth, commonly involving hot hydrothermal fluids. It supplies the primary minerals that near-surface weathering later modifies.
Porphyry copper deposit: A large, low- to moderate-grade copper deposit associated with intrusive igneous rocks. Supergene enrichment can raise its near-surface copper grades substantially.
Laterite: A soil or rock layer rich in iron and aluminum oxides formed by intense tropical weathering. Lateritization concentrates residual elements, unlike the downward metal transfer defining enrichment blankets.
Leaching: The removal of soluble substances from rock or soil by percolating fluid. Weathering water dissolves metals from the upper part of a deposit.
Sulfide minerals: Minerals composed of sulfur combined with one or more metallic elements. Many primary copper deposits contain sulfides that release metals during oxidation.
Copper mining: The extraction of copper ores and their processing into usable metal. Enrichment blankets have historically supplied high-grade copper ore.
Oxidation: A chemical process involving electron loss, often accompanied by oxygen gain. Oxidation drives supergene reactions but does not itself mean metals become concentrated.
Groundwater: Water held beneath Earth's surface in pores and fractures. It transports dissolved metals from leached zones toward places where they precipitate.
Chalcocite: A copper sulfide mineral with the formula Cu₂S. It commonly forms as a secondary copper mineral in enriched zones.

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