Here's why:

* Warm, clear water: This allows for the growth of algae, which is a key ingredient in oolitic formation. The algae produce a sticky mucus that helps bind the ooids together.

* Strong currents: These currents are essential for the movement and rolling of the ooids. As the ooids roll along the seafloor, they are coated in layers of calcium carbonate, creating their distinctive concentric layers.

* Shallow water: Shallow water allows for sufficient sunlight for the algae to thrive and also ensures that the ooids remain in the zone of active wave and current action.

Examples of depositional environments where oolitic limestone is commonly found:

* Tidal flats: These environments experience strong tidal currents and are exposed to sunlight.

* Lagoons: These are relatively shallow, protected water bodies that can provide the necessary conditions for oolitic formation.

* Barrier islands: The areas behind barrier islands can have strong currents and warm, clear water.

It's important to note that oolitic limestone can also form in other environments, like some freshwater lakes, but the marine environment is the most common.