Offshore drilling of dinosaur-killing impact crater yields crucial samples

Science : In April the first offshore drilling of the Chicxulub crater began from a drilling platform off the Yucatán Peninsula in Mexico. The crater was formed some 66 million years ago when a large asteroid struck Earth and probably caused the extinction of the dinosaurs. Now researchers believe they have achieved one of the key goals of the drilling: reaching the peak ring, a circular ridge of rock located inside the crater rim. The peak ring would have formed just minutes after impact, when granite bedrock became liquefied and rose up in a column some 10 km high before collapsing back into the crater. Although peak rings have been seen on the Moon, Mars, and Mercury, none has ever been sampled on Earth before. By analyzing core samples from as deep as 1500 meters, scientists hope to better understand how impact craters form and to discover signs of ancient microbial life that may have appeared after the impact.