Photographic record of Stromatolites

Hamelin Pool  Shark Bay Marine Park

Hamelin Pool
Shark Bay Marine Park

Stomatolite formation

Stromatolite formation occurs in four phases. Firstly filamentous cyanobacteria trap sand grains in mucous. Then heliotropic bacteria lay down a mucilaginous layer. Next sulphate-reducing bacteria form a layer of aragonite crystals. Lastly spherical cyanobacteria bore into this layer making tunnels into which are deposited reinforced crystals of aragonite.