Massive Underwater Gravity Hole Found in the Indian Ocean Finally Has an Explanation After 75 Years

Key Points:

• New research identifies a hidden mass of hot mantle rock, originating from the African superplume, as the cause of the Indian Ocean Geoid Low, a major gravitational anomaly south of India where the ocean surface lies about 106 meters lower than surrounding waters.
• Scientists used time-dependent mantle convection models spanning 140 million years and ran 19 simulations, with seven successfully reproducing the geoid anomaly; the best model showed a mass deficit in the deep mantle caused by hotter, lighter material between 300 km and 900 km depth.
• The hot mantle material travels eastward beneath the Indian Ocean, influenced by the northward movement of the Indian plate, interacting with ancient subducted slabs to create the distinctive gravitational signature observed today.
• Researchers reconstructed Earth's past plate movements and mantle density structures, finding that an influx of hot upper-mantle material about 20 million years ago intensified the anomaly, highlighting the dynamic and uneven nature of Earth's interior.
• Some experts note limitations in the models, such as failure to reproduce certain mantle plumes and discrepancies in geoid patterns elsewhere, but the study's authors maintain confidence that the identified hot mantle mass is the primary cause of the Indian Ocean Geoid Low.