manganese nodule

noun

1. geology a small irregular concretion found on deep ocean floors having high concentrations of certain metals, esp manganese

Example Sentences

Hydrothermal vents and manganese nodule fields in the deep oceans contain more biodiversity than expected.

From Science Daily

Interest in manganese nodule exploitation may have subsided since the 1970s but it never quite disappeared.

From New York Times

The prospect of mining asteroids was a sci-fi dream of the 1970s, just around the time of the manganese nodule craze.

From New York Times

The lure of the manganese nodule faded from public consciousness.

From New York Times

A sediment core from the bottom of the ocean with a well-preserved sediment-water interface and a manganese nodule sitting on the sediment surface.

From New York Times