Australia: The Land Where Time Began

A biography of the Australian continent 

Nullagine River              

By 2.8 Ga stromatolites, and the similar cyanobacterial and bacterial associations that form mats, were flourishing in many similar environments around the world. This was a time when the granite blocks that formed the basis of later continents, as opposed to the denser, heavier basaltic crust that forms the floors of oceans, and upon which the less dense, lighter continental crust floats, were being raised above the ocean surface. The conditions that stromatolites require occur mostly around the margins of the continental crust, so they had many more places suitable for growth. This great increase in the area suitable for photosynthetic cyanobacteria and bacteria led to a big increase in the amount of one of the by-products of their metabolism, oxygen, which changed the direction of future life. They may have been the first organism to use chlorophyll in photosynthesis.

Fossil stromatolites from this period have been found on the banks of the Nullagine River about 80 km south-east of North Pole. 

The stromatolites found in the Pilbara dating from 2.8 bya are enormous compared with those of Shark Bay, the biggest known living stromatolites. Some are nearly 2 m across. These fossils have been excavated by the Nullagine River.

Mary E. White, The Nature of Hidden Worlds, Reed, 1993