The Indian Ocean is home to one of the most intriguing features of our planet: a massive gravitational anomaly that spans an area of more than two million square miles (about the size of Greenland). This anomaly, known as the Indian Ocean Geoid Low (IOGL), means that the sea level over this region is about 106 meters lower than the global average, and the gravitational pull is weaker than elsewhere on Earth.
But what causes this mysterious ‘gravity hole’? Scientists have been puzzled by this question for decades, since it was first discovered in 1948. Now, a new study by researchers from the Indian Institute of Science may have uncovered the possible origin of the IOGL.
A Hidden History of Tectonic Movements
The researchers used computer simulations to reconstruct the history of tectonic movements in the Indian Ocean over the past 140 million years. They found that the IOGL could be linked to the remains of an ancient ocean called the Tethys Sea, which existed before India broke away from the supercontinent Gondwana and collided with Asia.
As India moved northward, the seabed of the Tethys Sea plunged into Earth’s mantle, creating a ‘slab graveyard’ of cold, dense material about 1,000 kilometers below Africa. This slab graveyard stirred up hot plumes of molten rock that rose up beneath the Indian Ocean, causing the seafloor to sink and creating the IOGL.
A New Hypothesis with More Questions
The researchers claim that their hypothesis is consistent with previous studies that detected hot plumes beneath the Indian Ocean using seismometers. They also say that their simulations can explain why the IOGL is asymmetric and elongated along India’s movement direction.
However, their hypothesis is not without challenges. Some experts have pointed out that other factors, such as mantle convection or crustal thinning, could also contribute to the IOGL. They also argue that more data and observations are needed to test and validate the simulations.
Therefore, the mystery of the gravity hole in the Indian Ocean is not yet fully solved. But thanks to new technologies and methods, scientists are getting closer to unraveling its secrets and revealing more about Earth’s dynamic and complex history.
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