Where Do Ooids Form?

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 Bahamas^1,2 (Fig. 1).

How is Ooids formed?

An ooid is a small spherical grain that forms when a particle of sand or other nucleus is coated with concentric layers of calcite or other minerals. Ooids most often form in shallow, wave-agitated marine water.

What environment are Ooids formed?

Ooids usually form on the sea floor, most commonly in shallow tropical seas (around the Bahamas, for example, or in the Persian Gulf). After being buried under additional sediment, these ooid grains can be cemented together to form a sedimentary rock called an oolite.