Geologists are on the verge of what could be a great discovery:  They’re mapping what could be the remains of a previously unknown continent beneath the floor of the Indian Ocean.

There’s not much of a chance of this being the fabled “Atlantis”, because all of the evidence suggests this pre-Cambrian landscape was pulled apart by plate tectonics between 50 and 100 million years ago.

But how would anyone even know that an ancient continent (may have) existed beneath the ocean floor? 

The first hint is gravity.  It’s already known that the earth’s gravitational force is slightly stronger in a number of places in the Indian Ocean: Around Madagascar, Mauritius and the Seychelles, Maldives, and Lakshadweep islands.

The second is sand.  Beach sand.  Most oceanic islands are made of volcanic rock.  But the sand on Mauritius contains an unusually high concentration of Zircons, which occur in continental landscapes.  That suggests undersea volcanoes blasted through a continental crust before rising up through the ocean floor, releasing the continental Zircon into the sea.

Geologists backtracked the earth’s continental drift and determined that if there was another continent, it was attached to India perhaps 90 million years ago.