Does Contamination shut off lands that produce multiple colors of mana or just non-black mana?

Contamination reads: 'If a land is tapped for mana, it produces {B} instead of any amount and type of mana it would otherwise produce.' This is a replacement effect (CR 614.1b) that completely substitutes the mana-production event, no matter what the land would have generated.

Because the replacement covers 'any amount and type,' a land that would normally produce two or more mana symbols (e.g., a land that taps for {G}{W}) still produces only a single {B}. The original quantity and colors are both discarded by the replacement (CR 614.7).

The effect applies to every land, not just those producing non-black mana. Even a Swamp, which already produces {B}, is technically subject to the replacement — it just happens to produce the same result. The critical point is that lands producing multiple mana are reduced to exactly one {B}.

Example: Your opponent controls a Savannah (normally taps for {G} or {W}) and a Gemstone Mine (normally taps for one mana of any color). With Contamination on the battlefield, tapping Savannah produces {B}, and tapping Gemstone Mine also produces only {B} — not two or three mana, just one {B} each.

This makes Contamination especially powerful against decks relying on multi-color or multi-mana lands, since they lose both color fixing and any mana acceleration those lands provided.