Dinosaurs Were Smoked Out Following Asteroid Impact

That fateful asteroid may have ejected soot into the atmosphere, setting off a chain reaction of events that ultimately killed off the dinosaurs.

AsianScientist (Jul. 15, 2016) – The mass extinction of the dinosaurs approximately 66 million years ago may have been caused by the ejection of soot into the atmosphere following an asteroid impact, according to a Japanese study published in Scientific Reports.

It has been suggested that the Chicxulub asteroid impact was responsible for the extinction of the dinosaurs by causing the formation of condensed sulfuric acid aerosols in the stratosphere. The aerosols produced acid rain and reflected sunlight, causing global darkness, which then led to a reduction in photosynthesis and near-freezing conditions.

However, under this scenario, crocodilians whose modern day descendants include alligators and crocodiles would have been made extinct as well. Experiments have also concluded that condensed sulfuric acid aerosols cannot form and persist over long periods following asteroid impacts.

Professor Kunio Kaiho and colleagues from Tohoku University examined sediments from Haiti and Spain that dated back to the boundary of the Cretaceous and Paleogene periods approximately 66 million years ago. By analyzing the hydrocarbons found in these samples, the authors suggest that the asteroid impact into an oil-rich area of Mexico launched a cloud of smoke into the atmosphere, which spread globally.

Based on the hydrocarbons found in their samples and climate models, they suggest that a soot ejection of approximately 1,500 teragrams (x1012 grams) would have been sufficient to cause the mass extinction of dinosaurs, while allowing animals such as crocodilians to survive.

The authors argue that soot in the atmosphere produced colder climates at mid-high latitudes, leading to the extinction of most species in these regions. However, droughts accompanied by mild cooling at lower latitudes led to the extinction of the dinosaurs, but allowed crocodilians to survive.


The article can be found at: Kaiho et al. (2016) Global Climate Change Driven by Soot at the K-Pg Boundary as the Cause of the Mass Extinction.

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Source: Scientific Reports; Photo: David Kryzaniak/Flickr/CC.
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