Fig. 9.2. Photographs illustrating some of the larger varieties of carbonate particles. (A) Pisolitic wackestone,
Late Pre-Cambrian. Ella Island, East Greenland. The pisoids show concentric laminae and have diameters of
0.5-1.2 mm. (B) Algal oncoids, Inferior Oolite (Middle Jurassic), Dorset. These particles, up to 15 cm in diameter, have a bioclast or intraclast as a nucleus, and a rind of algal laminae. Algal oncoids typically form in
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Late Pre-Cambrian. Ella Island, East Greenland. The pisoids show concentric laminae and have diameters of
0.5-1.2 mm. (B) Algal oncoids, Inferior Oolite (Middle Jurassic), Dorset. These particles, up to 15 cm in diameter, have a bioclast or intraclast as a nucleus, and a rind of algal laminae. Algal oncoids typically form in
402