Ooids are rounded, sand-sized particles of calcium carbonate that typically form by mineral precipitation in warm and shallow coastal waters. Their transport by waves and currents gives rise to spectacular shoals and white sand beaches, for example in the Bahamas1,2 (Fig. 1).
What conditions are needed for ooids to form?
There are several factors that affect ooid growth: supersaturation of the water with respect to calcium carbonate, the availability of nuclei, agitation of the ooids, water depth, and the role of microbes.
How do Oolites originate?
They are usually formed in warm, supersaturated, shallow, highly agitated marine water intertidal environments, though some are formed in inland lakes. The mechanism of formation starts with a small fragment of sediment acting as a 'seed', such as a piece of a shell.
