Australia: The Land Where Time Began

A biography of the Australian continent 

North Pole, Western Australia                                               

At North Pole, west of Marble Bar in the Pilbara region of Western Australia, 3.5 Billion year old stromatolites have been found. These are the oldest known organisms on Earth. By 3500 million years ago they had already evolved to the stage where they were producing oxygen by photosynthesis using prokaryotic chlorophyll, therefore they must have evolved some time before 3500 million years ago.

When the north pole stromatolites were alive the days were shorter and the tides were higher. One of the requirements for most, if not all stromatolites, is that they need to be submerged for at least part of every day, hence they mostly grow in the intertidal zone, growing to lower heights as the high tide mark is approached. So their maximum height is limited by the depth of water at high tide. At that time the Earth was spinning faster than now and the moon was closer. Since its formation, the Earth has been gradually slowing and the Moon has been slowly moving further away, hence the gravitational pull it exerts on the Earth is less now than it was when the North Pole stromatolites were forming, as a result the present day tides are lower. This is probably why the stromatolite fossils at North Pole, and those also on the banks of the Nullagine River, are much taller than their present-day relatives.

Australian National Parks

Sources & Further reading

Mary E. White, Earth Alive, From Microbes to a Living Planet, Rosenberg Publishing Pty. Ltd., 2003