Figure

The Great Barrier Reef grew in stages. The top picture shows the reef (yellow section on right) underwater as it is today, growing offshore while sediments collect in a shallow sea between the reef and the mainland. The middle picture shows when sea levels were lower, about level with the top of the area where the reef is now, and a swamp had formed between the reef and the mainland. The third picture shows the sea level below the level of the reef as it was before 11 700 years ago; the reef is stranded above water. The bottom right of the picture shows a close-up of the reef in all its colour and glory.