Dinosaur-Killing Asteroid Triggered Global Winter 66 Million Years Ago

Explosion that killed dinosaurs blanketed skies with ash and unleashed a global "impact winter."

An asteroid hitting Mexico's Yucatan some 66 million years ago is shown in this computer depiction.


The massive asteroid impact that ended the age of dinosaurs some 66 million years ago triggered a decades-long, deadly, global "impact winter," an analysis of ancient sediment confirmed on Monday. (Related: "What Killed Dinosaurs: New Ideas About the Wipeout.")

Sea temperatures dropped as much as 12.6 degrees Fahrenheit (7 degrees Celsius) after the Chicxulub crater blast blanketed the planet in ashy darkness, halting photosynthesis, concludes the team led Johan Vellekoop of Utrecht University in the Netherlands.

Massive hurricanes also struck during the impact winter, according to a report his team published in the Proceedings of the National Academy of Sciences.

Long suspected and now confirmed, the long-ago global winter has been seen as playing a major role in the mass extinction that followed the asteroid's impact in what is today Mexico's Yucatan. All dinosaurs—with the exception of birds—along with many marine reptiles and plant species, disappeared in the ancient calamity.

Volcanoes, wildfires, and tsunamis also added to the impact's deadly effects, with the catastrophe playing out over a century, according to the analysis.

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