On October 30, a study published in Nature Geoscience showed that “dust clouds” from asteroid impacts may be to blame for the extinction of the dinosaurs.
Chicxulub crater formed by impact Credit: Mark Garlick/Science Photo Library
Cem Berk Senel and others at the Royal Observatory of Belgium re-examined the Chicxulub asteroid impact and found that the impact caused the extinction of dinosaurs and most species on Earth at the time.
Researchers studied well-preserved rock samples that formed in what is now North Dakota, USA, at the time of the dinosaur extinction event. This rock contains traces that geologists have used to mark changes in the Earth’s history from the Cretaceous to the Paleogene. They tested the samples for sulphur, soot and silicate and found that the samples contained more small particles of silicate dust than expected, ranging from 0.8 to 8 microns in diameter.
The team believes that tiny particles from the asteroid impact form “dust clouds” that obscure the sun and may cause plants to fail to photosynthesize for up to two years, causing vegetation to die and starvation of many herbivorous species, including some dinosaurs, leading to a catastrophic mass extinction event.
Models show that dust can remain in the atmosphere for up to 15 years, during which time global temperatures drop by as much as 15°C.
“We need to gain a deeper understanding of the causes of global cooling or loss of photosynthesis to advance our understanding of the exact extinction mechanisms following the impact of the Chicxulub asteroid,” Senel said. This is the first time that paleoclimate modelling has shown that photosynthesis activity has been suppressed for 2 years, and that dust-induced shock winters have lasted for 15-20 years. (Source: China Science News Wang Zhaoyu)
Related Paper Information:https://doi.org/10.1038/d41586-023-03406-7
