Oolitic limestone, a common building material used around the world in various constructions, has been traced to microbes that even predate dinosaurs. The mineralised microbial material, which is made of millimetre-sized spheres of carbonate called ooids, has been used in the construction of the Pentagon and the Empire State Building among others.

Research conducted by The Australian National University (ANU) reveals that these microbes lived up to 340 million years ago. Co-researcher Dr Bob Burne from the ANU Research School of Earth Sciences explains that ooids are made of concentric layers of mineralised microbes, which explains their definitive features.

Oolitic limestones are found across the world with different types formed in various geological periods. Humans, according to Dr Burne, have been using oolitic limestone in building since ancient times for their strength and light weight. Parts of the Pentagon and the Empire State Building in the USA feature Mississippian oolite found in Indiana.

Even Buckingham Palace, the City of Bath, the British Museum and St Paul's Cathedral in England have been built with Jurassic oolite.

The study was led by Professor Murray Batchelor from the Research School of Physics and Engineering and the Mathematical Sciences Institute at ANU.

Professor Batchelor says that their mathematical model explained the concentric accumulation of layers. He added that the findings could help better understand the effects of past climate change.