What is a Gravity hole?

About Gravity hole:

 

• The gravity hole is a region of the ocean where the effects of gravity are less than usual.
• It occurs at the bottom of the ocean where there are gravitational anomalies.
• Why it occurs? These anomalies are caused by variations in the gravitational pull of the Earth due to differences in the density of the materials that make up the Earth’s crust.
• The Indian Ocean is home to one of the most profound gravitational anomalies on Earth known as the Indian Ocean Geoid Low (IOGL).
• It was discovered in 1948 during a ship-based gravity survey by Dutch geophysicist Felix Andries Vening Meinesz.
• It is found in a large section of over three million sq. km in the Indian Ocean seafloor, located around 1,200 km southwest of India’s southern tip.
• It is estimated to have formed approximately 20 million years ago.
• Researchers said that the IOGL comprises slabs from the Tethys Ocean, a long-lost sea that plunged into the depths of the planet millions of years ago. 
• The Tethys Ocean, which once separated the supercontinents of Gondwana and Laurasia is believed to have perturbed the African Large Low Shear Velocity province

 

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Q1) What is Tethys Sea?

The Tethys Sea was a vast ancient ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era, specifically from the late Paleozoic to the early Cenozoic era. It played a crucial role in the geological and tectonic history of Earth.

Source: What is causing the mysterious ‘gravity hole’ in the Indian Ocean?