Beaches and Dunes

Marine Discovery Centre

Beaches and Dunes

The sand on Australia’s eastern beaches originates from a long belt of granite stretching from Stanthorpe to Armidale. It formed about 240 million years ago when magma deep below the Earth’s crust rose and slowly cooled. Over time, the granite weathered into smaller particles as it flowed through waterways to the ocean.

The sand dunes that stretch up from the beach form a barrier that protects the ecosystems behind it from the ravages of the ocean and salt air. Spinifex and pigface plants colonise these dunes, trapping the sand. They are the pioneers, which establish the right conditions for larger plants such as she-oaks (casuarinas) and paperbarks (melaleucas).