Reef-Front Zone: This zone extends from the surf zone to an indeterminate depth, commonly less than 100 m. The zone is characterized by “spur and groove” structure that forms ridges that are perpendicular to the reef crest. The spurs are formed by biota constructional processes and the grooves are floored by sand being transported into deeper water. The associated rocks types are framestones and bindstones with lesser bafflestones.

Reef-front zone of the Belize barrier reef showing the spur-and-groove” structure that forms ridges that are perpendicular to the reef crest. The spurs (black) can be meters high and are covered by dense coral growth, whereas the grooves (blue) are floored by sand.