nodule

nodule

[noj-ool]
nodule: see concretion.

In geology, a rounded mineral concretion that is distinct from, and may be separated from, the formation in which it occurs. Nodules usually are elongated and have a knobby irregular surface; they are generally oriented parallel to the bedding. Chert and flint, clay ironstone, and phosphorites commonly occur as nodules. Manganese-rich nodules are found on the ocean floor.

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Nodule may refer to:

  • Nodule (geology), a small knobbly rock or mineral cluster, such as a manganese nodule
  • Nodule (medicine), a small aggregation of cells
  • Root nodule, an outgrowth formed on the roots of legumes that house symbiotic bacteria that fix atmospheric nitrogen and provide it to the plant in exchange for carbon

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