Since its discovery in 1948 by Dutch geophysicist Felix Andries Vening Meinesz, the Indian Ocean Geoid Low (IOGL), also known as the “gravity hole,” has remained a perplexing phenomenon. Situated nearly 600 miles beneath the Earth’s crust and spanning an area of approximately 3 million square miles, this colossal depression exhibits significantly lower gravity than the surrounding region. Decades of scientific investigation have left researchers puzzled about the origins of this massive gravity anomaly.
However, a recent study published in the journal Geophysical Research Letters has brought us closer to understanding the secrets of the giant gravity hole. Researchers Debanjan Pal and Attreyee Ghosh from the Indian Institute of Science (IISc) in Bengaluru have put forth a plausible explanation for this enigmatic feature.
Professor Ghosh, an Assistant Professor at the Centre for Earth Science, remarked, “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.”
Using computer-simulated models spanning 140 million years, the scientists made a fascinating discovery: the remnants of an ancient ocean located approximately 965 kilometers below the Earth’s crust, just beneath Africa. According to their findings, the gravity hole may have formed when the Tethyan slabs, tectonic plates in the region, perturbed the African Large Low Shear Velocity province, also known as the “African blob.” This disturbance potentially generated plumes beneath the Indian Ocean.
The study states, “Here we assimilate plate reconstruction in global mantle convection models starting from 140 Ma and show that sinking Tethyan slabs perturbed the African Large Low Shear Velocity province and generated plumes beneath the Indian Ocean, which led to the formation of this negative geoid anomaly.”
Despite these promising findings, the researchers note that the simulations do not provide definitive seismographic evidence of the plumes’ presence beneath the Indian Ocean. They also acknowledge that other factors might contribute to the formation of the gravity hole. Therefore, a conclusive explanation remains elusive at this time.
The study’s insights, however, mark a significant step forward in unraveling the mystery surrounding the Indian Ocean Geoid Low. By shedding light on the possible mechanisms underlying this immense gravity anomaly, scientists inch closer to comprehending the complex dynamics of our planet’s geology. Further research and exploration will undoubtedly be necessary to validate these findings and provide a definitive explanation for this awe-inspiring feature lurking deep beneath the Indian Ocean’s depths.