Death of the dinosaurs has always been an intriguing subject. From theories of a massive super-volcano eruption to a deadly disease that wiped all dino-species, a lot hasbeen proposed. One theory that keeps popping over and over again is that an asteroid impact killed all the non-avian dinosaurs. While there has been enough circumstantial evidence to suggest this theory, a group of scientists in Texas may have just found some actual proof of the act. They found the evidence in the form of asteroid dust inside the impact crater (of the supposed asteroid that killed the giant reptiles).
Picture this — it is 66 million years ago. A bright sunny day (or rainy, one can’t be sure). Herbivores are grazing the grasslands, predators are hunting vulnerable prey. A baby dino follows the mama dino to a lake to drink some water. Then suddenly — chaos. A massive impact shakes the Earth, dust clouds cover the sky, there’s no sunlight for weeks and followed by global winter. This is what happened when the asteroid hit the 125-mile-wide Chicxulub impact crater beneath the Gulf of Mexico.
This theory was recently tested by doing a full chemical ‘fingerprinting’ of the asteroid dust found within the crater. Nearly 3,000 feet of rock core from the crater buried under the seafloor was collected for the study. The comprehensive study analyses the impact, aftermath, and recovery of life after the collision.
It was the element iridium that helped solve the mystery. Rare on Earth, but found abundantly in most asteroids. A spike in iridium in geological layers is one of the reasons behind the asteroid-impact theory.
They believe the dust kicked up by the impact circulated the atmosphere for nearly two decades — this is how long the extinction of nearly 75% of Earth species (including non-avian dinosaurs) took.Highest iridium concentration was within 5-centimeter section of the rock core retrieved from the top of the crater’s peak ring.
Additionally, they found other chemical evidences to confirm asteroid-impact theory. The full study can be found in Science Advances.