Dusting Off the Dinosaurs

Pulverized rock dust kicked up by the Chicxulub meteor 66 million years ago played a more significant role in the extinction of nonavian dinosaurs than previously believed, according to a new study. Previous research has emphasized the role of sulfurous fumes and wildfire soot rather than dust in the catastrophe.

Scientists have debated for decades exactly which mechanisms from the impact near the Yucatan Peninsula killed roughly three-fourths of the world's species. The impact immediately generated lethal megatsunamis, magnitude 11 earthquakes, and meltdowns of the ocean floor (watch overview). Over time, photosynthesis—where plants produce the energy that forms the basis of the food chain—ceased across the globe for up to two years as a result of blocked sunlight.

The new study used micrometer-sized dust pulled from the Tanis fossil site in North Dakota to simulate models of the post-impact climate. The models suggest the dust—which better resists being rained out than soot or sulfur aerosols—lingered in the air for up to 15 years.