GEOLOGY

Detailed explanation-1: -Barrier reefs are similar to fringing reefs in that they also border a shoreline; however, instead of growing directly out from the shore, they are separated from land by an expanse of water. This creates a lagoon of open, often deep water between the reef and the shore.

Detailed explanation-2: -barrier reef, a coral reef (q.v.) roughly parallel to a shore and separated from it by a lagoon or other body of water. A barrier reef is usually pierced by several channels that give access to the lagoon and the island or continent beyond it.

Detailed explanation-3: -One example of Barrier Reef is the Great Barrier Reef of Australia which is 1200 mile long.

Detailed explanation-4: -A barrier reef is separated from the shore by a lagoon. The reef forms a barrier between the coast and the open ocean or sea. Some barrier reefs consist of chains of smaller reefs separated by narrow waterways. The Great Barrier Reef is constructed this way. An atoll is a reef in the open sea that surrounds a lagoon.

Detailed explanation-5: -Atoll lagoons are very common in the tropical waters of the South Pacific and Indian Oceans. Atoll lagoons form as coral reefs form around volcanic islands. Over millions of years, the island subsides into the ocean.