Indian Ocean gravity hole was caused by extinct ancient sea, scientists say

By Ben Turner published about 21 hours ago

Scientists have puzzled over the origins of a gravity hole in the Indian Ocean for years. Now, researchers think the sunken floor of an extinct ocean could be the cause.



A rendering of the Earth's gravity as seen by the European Space Agency' Goce satellite. Yellow and orange regions are those with more gravity and the blue, marked over the Indian Ocean, shows where gravity is less pronounced. (Image credit: ESA via Getty Images)


Scientists may have finally identified the origins of a deep "gravity hole" in the Indian Ocean — a mysterious region where Earth's gravitational pull is weaker than at other parts of our planet.

The Indian Ocean geoid low (IOGL) is a 1.2 million-square-mile (3 million square kilometers) depression found 746 miles (1,200 kilometers) southwest of India. Compared with its surroundings, the low's gravity is so weak that a layer of its water has been snatched away — making the sea level over the hole 348 feet (106 meters) lower than the global average.

The low is a consequence of our surprisingly squidgy planet, which flattens at the poles, bulges at the equator and undulates between lumps and bumps across its surface. But ever since its discovery in 1948, the origin of this Indian Ocean abyss has puzzled scientists.

Now, a study published May 5 in the journal Geophysical Research Letters suggests the IOGL was caused by low-density magma that was pushed into the Indian Ocean by the sinking slabs of an ancient ocean.

More:
https://www.space.com/gravity-hole-indian-ocean-caused-by-extinct-sea