What is the mysterious gravity hole in the Indian Ocean?

Scientists have been baffled by the enigmatic "gravity hole" in the Indian Ocean for decades.It is not the kind of "hole" that would allow the entire ocean to be drained. However, there is a massive anomaly in the Earth's crust that has a much weaker gravitational attraction than usual.It is located about 600 miles below the surface of the Earth.This "gravity hole" is actually the Indian Ocean Geoid Low (IOGL), which spans an area of more than two million square miles (more than two-thirds the size of the lower 48 US states).During a ship-based gravity investigation, Dutch geophysicist Felix Andries Vening Meinesz discovered it in 1948. But research into what triggers this "gravity hole" is still ongoing.Recent studies suggested some potential causes for the large, broad depression at the ocean's bottom.Let’s take a look.Also read: Indian Ocean Dipole: What is it and how can it cause higher rainfall in the country?Tracing the originThe latest study, which was just published in Geophysical Research Letters, used a number of computer models to analyse the gravity dip and determine how the region has changed over the past 140 million years as a result of the shifting of the Earth's tectonic plates. Additionally, they used a variety of variables to mimic the convection of molten material within the mantle.Debanjan Pal and Attreye Ghosh, two geoscientists from the Indian Institute of Science (IISc), conducted the research.According to Scientific American, the study argues that the Indian Ocean Geoid Low (IOGL) is composed of blocks from the long-lost Tethys Ocean, which sunk beneath the surface of the globe millions of years ago."The existence of the Indian Ocean geoid low is one of the most outstanding problems in Earth Sciences. It is the lowest geoid/gravity anomaly on Earth and so far no consensus existed regarding its source," Professor Ghosh, an Assistant Professor at the Centre for Earth Science, said about the research, as published on the IISc website.The African Large Low Shear Velocity Province, commonly known as the "African blob," is thought to have been disturbed by the Tethys Ocean, which originally divided the supercontinents of Gondwana and Laurasia, causing plumes to form beneath the Indian Ocean.Lead authors Pal and Ghosh said in the study, "These plumes, along with the mantle structure in the vicinity of the geoid low, are responsible for the formation of this negative geoid anomaly."“What we’re seeing is that hot, low-density material coming from this LLSVP underneath Africa is sitting underneath the Indian Ocean and creating this geoid low,” Attreyee Ghosh, one of the authors of this study, told Scientific American.Also read: Planet X: Earth’s solar system may be hiding an extra planetIt started forming 20 million years agoThe team estimates that the geoid acquired its present shape about 20 million years ago and will probably keep it as long as mantle material continues to flow.The remnants of a long-gone Tethys Ocean's bottom are thought to have generated this mantle structure beneath the Indian Ocean. Two supercontinents, Laurasia and Gondwana, were split by this ancient ocean approximately 200 million years ago, explained Interesting Engineering.Africa and India were once part of Gondwana, but the Indian Ocean was created behind what is now India as it moved north into the Tethys Ocean around 120 million years ago.The authors emphasise that there might be additional supporting evidence for the IOGL's existence. The "Gravity Hole" nevertheless serves as a reminder that the Earth still conceals a number of mysteries that need to be investigated and understood.With inputs from agenciesRead all the Latest News, Trending News, Cricket News, Bollywood News, India News and Entertainment News here. Follow us on Facebook, Twitter and Instagram.