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Nodular texture
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A rock with a nodular texture consists of nodules, rounded lumps of crystalline or amorphous solid material, surrounded by a matrix. Nodules are concretions and aggregates produced by chemical precipitation of minerals within a rock.
References
Jenkyns, H. C. (1974). Origin of red nodular limestones (Ammonitico Rosso, Knollenkalke) in the Mediterranean Jurassic: a diagenetic model. Pelagic sediments: on land and under the sea, 1, 249-271.
Maliva, R. G., & Siever, R. (1989). Nodular chert formation in carbonate rocks. The Journal of Geology, 97(4), 421-433.
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