Geologists have long been captivated by the Indian Ocean's "gravity hole," where the Earth's gravitational pull weakens, its mass falls, and sea levels drop by about 328 feet (100 meters). After years of perplexity, Indian Institute of Science researchers in Bengaluru have devised a convincing explanation to explain this enigma.
The team's findings, published in Geophysical Findings Letters, suggest that this gravitational anomaly was caused by lava plumes from the planet's core, like volcanoes.
The concept was developed via supercomputer modeling of millions-year-old settings. Their models were based on an extinct ocean from the distant past. In an attempt to understand what caused the gravity hole, they painstakingly calculated 19 possible tectonic plate motions over the last 140 million years, per Business Insider.
What's Behind The Gravity Hole Mystery?
According to their research, only a few possibilities may explain the gravity anomaly, and none of these models directly attribute the low gravity to what is underneath it. Unexpectedly, the scientists discovered that the crater was probably formed by jets of low-density magma.
The "African blob," a disturbance 600 miles (1,000 km) west beneath Africa, is thought to be the source of these magma plumes. This continent-sized, 100 times higher than Mount Everest thick bubble of crystalline material in Africa's mantle spews forth spurts of mantle rock, according to Live Science. The ocean between these continents, known as Tethys, was squeezed between the tectonic plates when India split from Africa and clashed with the European plate.
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Gondwana, the supercontinent that gave birth to Africa, Australia, and India some 120 million years ago, was split apart due to this geological occurrence. Consequently, the ocean's surface was forced downward, creating a sizable region of decreased gravity. The gravity hole was formed when the low-density magma plumes produced as a result of the melting away of the dense mantle amplified the effect.
Not Enough Explanation
Professor of Geology at the University of Florida, Dr. Alessandro Forte, applauded the work for considering both heated ascending mantle plumes and the sinking of cool material throughout the mantle. However, he noted that the simulation had missed a powerful mantle dynamic plume that had erupted 65 million years ago under the present-day site of Réunion Island, creating one of Earth's most prominent volcanic features-the Deccan Traps, as per a CNN report.
Forte also raised concerns about the discrepancy between the computer simulation's geoid and the real geoid. The Pacific Ocean, Africa, and Eurasia show these disparities. The research acknowledges a modest correlation of 80% between anticipated and observed geoids but does not give a more accurate numerical assessment of their alignment. This discrepancy suggests computer simulation errors.
Future ocean studies will be necessary to prove the occurrence of these plumes in actual settings, which will help further corroborate the results to further uncover the mystery of the gravity hole in the Indian Ocean.
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