Scientists have known about Gondwana for a long time, but it’s the discovery of a microcontinent, a fragment of that larger landmass, which has them excited.
So, where was the continent, how much is left, and how do we know this is true?
Evidence for the continent has been found scattered across the Indian Ocean. The actual fragments of rock left over from the continent are spread between the islands of Mauritius and India. Some researchers are referring to the remaining fragments as “Mauritia.”
About 60 million years ago, after the mass extinction of the dinosaurs, Mauritia broke away from India and Madagascar and spanned much of the space between the landmasses. It was eventually torn apart, and the fragments collapsed into the sea.
In 2013, Lewis Ashwal suggested a missing microcontinent could lie under the sea around the islands. His guess was prompted by the discovery of two-billion-year-old zircon crystals on the beaches of Mauritius.
Then, in 2015 another team of researchers examining volcanic rocks on the island found crystals that were 300 billion years old. The only rocks this old are found on continents, but Mauritius is an island in the middle of the Indian Ocean, and somewhat far from any continents. How did the fragments get there?
Researchers decided to look into the Earth and the surrounding sea floor for clues. They quickly discovered that Ashwal was correct.
Under the sea floor, rests ancient rock, three billion years old, which formed part of Gondwana. When Gondwana broke up, one of the last fragments to break apart was Mauritia. Then, nine million years ago, volcanoes erupted under the sea and pushed magma up though the sunken lost continent, bringing them to the surface as the island of Mauritius was formed.
What this discovery tells us is Earth’s geology is less neat and clean than previously assumed. While we can roughly see how the continents once fit together, there may be many more pieces and fragments that we have never discovered.
Our knowledge of the Earth is extensive but imperfect. We can rest assured that we have solved only a fraction of the mysteries that encompass our planet.