STROMATOLITES : THE OXYGEN PUMPS OF EARLY EARTH

"Western Australia, Stromatolites Sharks Bay" by VladPix is licensed under

At the dawn of life, our planet was almost uninhabitable and lacked a diversity of life forms.

The atmosphere was dense and still loaded with toxic gases that blocked the sunlight. This is known as the "faint sun hypothesis."

There was very little free oxygen gas available at that time.

And the only life on the surface was slimy mats of bacterial colonies known as stromatolites. They occur in varied shapes, from conical to horizontal, often forming reef-like structures.

Fossil evidence suggests they first appeared during the Archaean Eon and are still alive today. What a feat!

These microbes released immense quantities of oxygen into the Earth’s atmosphere, so much so that this event is called the "Great Oxygenation Event."

Around this time, thick beds of jasper and hematite were also being deposited. These are also known as "Banded Iron Formations."

The majority of the iron ore used all around the world comes from this particular time in the history of Earth.

Then fast forward a few billion years, right around 635 to 541 million years ago, from the start of the Ediacaran Period to the culmination of the Cambrian Period, something weird happened that put Earth’s biosphere into a frenzy and produced many kinds of life forms never seen before on the planet’s surface.

In India, stromatolite fossils occur in plenty at the following sites:

• Inside the black chert of Chitradurga, Karnataka

• Inside stromatolite bearing limestones of Bundelkhand, Son river valley & Salkhan Fossil Park in Sonbhadra district

• Bhander, near Panna

• The Devonian Rocks of Spiti