Geological term for a small, rounded mineral mass or concretion, such as a manganese nodule on the ocean floor. Also used in other scientific contexts for small lumps or nodes.
See also: 団塊
Deep-sea manganese nodules are attracting attention as a future resource.
この地層からは、石灰質のノジュールが多数見つかる。
Many calcareous nodules are found in this stratum.