Where Do Stromatolites Form?

Stromatolites, also known as layered rocks, form in shallow waters when biofilms of living microorganisms, like cyanobacteria, trap sediment. Most stromatolites grow in extremely salty lagoons or bays, in places like Australia, Brazil, Mexico and the Bahamas.

Where can stromatolites be found?

Modern stromatolites are mostly found in hypersaline lakes and marine lagoons where extreme conditions due to high saline levels prevent animal grazing. One such location where excellent modern specimens can be observed is Hamelin Pool Marine Nature Reserve, Shark Bay in Western Australia.

How do stromatolites form?

Stromatolite, layered deposit, mainly of limestone, formed by the growth of blue-green algae (primitive one-celled organisms). These structures are usually characterized by thin, alternating light and dark layers that may be flat, hummocky, or dome-shaped.