60 million years ago, there existed a microcontinent between Madagascar and India that was buried by lava due to continental drift and magma plumes. Scientists are learning that hot magma has more of a role in the break-up of continents than previously understood. About 170 million years ago, the continent known as “Eastern Gondwana” was bombarded on the underside by hot rock which caused it to soften and break up into Antarctica, Australia, India, Madagascar, and India. Mauritia was likely part of that break-up, and it broke up further and was eventually buried by the molten rock that pushed India into Asia.
Scientists have verified that Mauritia was indeed a continent due to the zircons found on the beaches of the various islands of the Seychelles, where Mauritia is though to be buried beneath. Zircons are tiny rock fragments that are extremely resistant to erosion, and thus they can remain relatively unchanged for millions of years. Most rocks on the beaches of the Seychelles islands are no older than 9 million years old, but the zircons found on the beach tested to be much older, revealing that the land was above water millions of years prior. From sci-news:
The sand grains contain semi-precious zircons aged between 660 and 1,970 million years. This is explained by the fact that the zircons were carried by the lava as it pushed through subjacent continental crust of this age. This dating method was supplemented by a recalculation of plate tectonics, which explains exactly how and where the fragments ended up in the Indian Ocean.
Despite the fact that this is not an incredibly rare occurrence, I think it’s incredibly interesting that scientists are able to uncover a mystery about our geography by testing beach sand. The ancient geographical layout of our planet is a topic that has been extensively researched, so much that we are able to paint a picture of our planet’s continents even 500 million years ago. It’s crazy to me that we are still discovering that there were once other continents – albeit small – but ones that we would not have been able to discover by the traditional method of observing modern continents and noticing how they drifted to find their placement millions of years ago. There were many continents that existed for eons and that were buried by the ocean to never be heard of again. I hope that we find more and more instances of continents that were covered with water, especially if we find some rather large ones!
Image and info via Sci-news