![]() “We are now at the level of coincidence that geologically doesn’t happen without causation,” said co-author Sean Gulick, a research professor at the UT Jackson School of Geosciences who co-led the 2016 expedition with Joanna Morgan of Imperial College London. In the crater, the sediment layer deposited in the days to years after the strike is so thick that scientists were able to precisely date the dust to a mere two decades after impact. In the new study, researchers found a similar spike in a section of rock pulled from the crater. An iridium spike in the geologic layer found all over the world is how the asteroid hypothesis was born. The telltale sign of asteroid dust is the element iridium – which is rare in the Earth’s crust, but present at elevated levels in certain types of asteroids. Research from this mission has helped fill in gaps about the impact, the aftermath and the recovery of life. The study is the latest to come from a 2016 International Ocean Discovery Program mission co-led by The University of Texas at Austin that collected nearly 3,000 feet of rock core from the crater buried under the seafloor. “The circle is now finally complete,” said Steven Goderis, a geochemistry professor at the Vrije Universiteit Brussel, who led the study published in Science Advances on Feb. ![]() The new study seals the deal, researchers said, by finding asteroid dust with a matching chemical fingerprint within that crater at the precise geological location that marks the time of the extinction. In the 1990s, the connection was strengthened with the discovery of a 125-mile-wide Chicxulub impact crater beneath the Gulf of Mexico that is the same age as the rock layer. This discovery painted an apocalyptic picture of dust from the vaporized asteroid and rocks from impact circling the planet, blocking out the sun and bringing about mass death through a dark, sustained global winter – all before drifting back to Earth to form the layer enriched in asteroid material that’s visible today. Credit: The University of Texas at Austin/Jackson School of Geosciences/ Google Map.ĭeath by asteroid rather than by a series of volcanic eruptions or some other global calamity has been the leading hypothesis since the 1980s, when scientists found asteroid dust in the geologic layer that marks the extinction of the dinosaurs. A 2016 mission led by the International Ocean Discovery Program extracted rock cores from the offshore portion of the crater. The crater is buried beneath many layers of rock and sediment. Part of the crater is offshore and part of it is on land. ![]() It is called Chicxulub after a nearby town. The crater left by the asteroid that wiped out the dinosaurs is located in the Yucatán Peninsula. AUSTIN, Texas - Researchers believe they have closed the case of what killed the dinosaurs, definitively linking their extinction with an asteroid that slammed into Earth 66 million years ago by finding a key piece of evidence: asteroid dust inside the impact crater.
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