Research by two scientists hints at asteroid strike 800 million to 550 million years ago, creating a crater

Was southern peninsular India hit by an asteroid larger than the one that wiped out dinosaurs? Is the land between present day Nilgiris and Kodaikanal located on a crater formed by the impact? Two earth scientists think so. They make this claim in a scientific paper and have named the area ‘Kaveri Crater’, possibly the fourth largest in the world.

The investigations included megascopic (done with the unaided eye) and microscopic studies of rocks along with analyses of chemical signatures. The study was carried out by K.R. Subrahmanya, a former professor of Marine Geology, Mangalore University, and K.N. Prakash Narasimha, Professor of the Department of Earth Science, Centre for Advanced Studies in Precambrian Geology, University of Mysore.

Their findings were published in the Journal of the Geological Society of India and the study won the Radhakrishna Prize 2018 for best paper. The scientists told The Hindu that the Kaveri Crater is between Nilgiris and Kodaikanal. Both the Palghat Gap (a mountain pass) and Dhimbam Ghats are a part of the Kaveri Crater, with the geological evidence stretching up to Belakavadi and Shivanasamudra in Karnataka, they said. The coordinates are 10º20’ to 11º30’N latitude and 76º50’ to 78ºE longitude, and the centre of the crater is close to 11ºN and 77º30’E.

The study, which was funded by the Union Ministry of Earth Sciences, suggests that the crater has a diameter of 120 km.

The asteroid hit may have taken place 800 million to 550 million years ago. Unlike the impact event that led to the extinction of the dinosaurs about 65 million years ago, this one took place when there were very primitive life forms. Based on crater size and impact angle, the geologists conclude that the extra-terrestrial object was at least five km in diameter. Unlike smaller craters, Kaveri Crater can be visualised only through satellite images.