Wednesday, 1 July 2020

It's the Asteroid That Did it!

It's the Asteroid That Did it!

From a twitter feed, a reader of this blog, Anthony Brook, produced THIS PDF file. It concerns a paper which looks at the causes of the K/Pg extinction event. (This was the K/T event in my youth.) Among the authors are two from Bristol's School of Geographical Sciences.

They discuss whether the Chicxulub asteroid or the Deccan traps were the culprit. They use climate modelling of a complexity which I can appreciate, if not understand.

The conclusion they reach is that Deccan volcanism would have led to cooling but have left enough equatorial habitats for dinosaur survival. Indeed the CO₂ produced by the volcanism would have mitigated the effects of solar dimming.

Asteroid impact, however, would be sufficient to remove all dinosaur friendly habitats. They suggest that the Deccan volcanism might have made things rather better! Global warming, due to CO₂, might be a good thing here!

Since the production of the twitter feed the actual publication has now emerged. You can get it HERE. Thanks to Anthony Brook for bringing this to my attention.

Geologic (A) and paleontological (B) records of the K/Pg mass extinction. Paleothermometer (A) showing the Deccan-induced warming with the two main episodes of volcanism highlighted by the black arrows and symbols of volcanoes. The last phase extends beyond the end of the Cretaceous, characterized by the bolide impact in Chicxulub. Fossil remains of non-avian dinosaurs (body fossils, egg fragments, and nesting sites) occur throughout the whole stratigraphic record of prolonged volcanism episodes (dinosaur silhouettes). Numbers represent upper Maastrichtian dinosaur bearing localities, mapped on a late Maastrichtian paleogeography in B. 1, Hell Creek Formation (United States); 2, Lameta Formation (India); 3, Tremp Formation (Spain); 4, Phosphorite beds (Morocco); 5, Marilía Formation (Brazil); 6, Nemegt Formation (Mongolia). Dinosaur silhouette image credit: Phylopic/Jack Mayer Wood, which is licensed under CC BY 3.0.

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