800 million years old - Scientists discover 'fingerprints' of supercontinent Gondwana in ancient rocks

Scientists have found the remains of the ancient landmass Gondwana, which they have now confirmed was a supercontinent. The discovery has shown that Gondwana was huge and accounted for roughly 80 per cent of Earth’s landmass. It formed between 800 and 500 million years ago in the Southern Hemisphere and played a crucial role in the birth of complex life on Earth.

A study published in Science Advances on Wednesday (Sep 9) stated that over 25,000 ancient rocks were gathered to reconstruct the borders of Gondwana. While till now it was believed to have spread over two-thirds of Earth’s land, it has now been revealed that it occupied nearly 80 per cent of Earth's land.

Emergence of complex life on Earth

The Cambrian explosion, which happened about 538 million years ago and led to complex life sprouting on Earth, happened because of the formation of Gondwana. The study authors stated that this shows that complex processes happening deep inside Earth became the reason for most of the life we see today around us. For billions of years before this, only simple microbial organisms existed on our planet.

The discovery was made by an international collaboration called Deep-time Digital Earth. The group gathered thousands of magmatic rocks from this region and created a database to understand their origins. The team used AI and other modern techniques to identify when and where these rocks formed. This helped them reconstruct other continents that were ever on Earth.

Gondwana rocks were strewn across Earth

After they created the global map, they found that pieces from Gondwana had broken and scattered across the planet because of millions of years of tectonic activity. Isotopes of the elements samarium and neodymium emerged as the "fingerprints" of Gondwana and were found embedded inside younger rocks.

Collins called "the samarium-neodymium isotope maps" a time machine that takes them back in time. Their "spatial character that allows us to recognise an ancient continental landmass that formed 500 million years ago," he said. Earth was cold before the Cambrian explosion. Geological processes that shaped Gondwana formed the Ring of Fire, which releases a huge amount of volcanic gases into the atmosphere that warmed the planet.

The team plans to map out the supercontinent in more detail using the database and hopes to solve other mysteries surrounding Earth.