From Discovery News:
Off the west coast of India, there is a suspicious basin called Shiva. It forms a rough ring over 500 kilometers (311 miles) in diameter and has a central underwater peak the size of Mt. McKinley. Where it sweeps on shore, the land appears shattered and riddled with faults and geothermal hot springs.
If Sankar Chatterjee of Texas Tech University is right, Shiva is the largest impact crater on the planet, the scar leftover from a cataclysm that had a hand in killing the dinosaurs.
The basin is a bonanza of oil and gas resources, and energy companies have been drilling in it for decades. Information on its rocks has trickled out slowly from company vaults, but Chatterjee has kept close tabs, suspecting for years that the region has a dramatic story to tell about a long-lost cosmic catastrophe.
So far the evidence he has assembled is mostly circumstantial. The bedrock that lines Shiva is rife with mantle rocks, as though Earth’s crust was simply obliterated across a huge area. And the areas dating to the moment of the suspected impact 65 million years ago are rich in iridium — a typical fingerprint of impacts. More