The debate regarding how the dinosaurs went into extinction is ongoing. The common belief is that they were wiped out by the Chicxulub asteroid that hit the Earth, but two new studies reveal how a series of volcanic eruptions called the Deccan Traps may have contributed to the dinosaurs’ mass extinction.
Deccan Traps
Evidence shows that the Earth was already warming long before the asteroid that supposedly killed the dinosaurs hit the planet. In fact, the planet warmed by 5 degrees Celsius about 400,000 years before the asteroid hit and plunged right before the extinction event.
It is believed that this warming was caused by the eruption of massive volcanoes called the Deccan Traps, and some believe that 80 percent of the lava had already erupted before the asteroid even hit. However, two new studies suggest that this may not be the case.
Late Lava Flow
In the first study, researchers went on three trips to India, where some of the thickest lava deposits from the Deccan Traps can be found, and sampled the basaltic rocks from the now-cool lava. Using a method called argon-argon dating, the researchers determined that the eruptions began 400,000 years before the asteroid hit and released 75 percent of the total volume in the 600,000 years following the asteroid strike.
This suggests that the Deccan Traps triggered the global warming because of carbon dioxide emissions even before the lava flow really went into high gear.
Eruption Pulses
Researchers of the second study used a different method by looking at the zircon crystals that were trapped between the basalt layers. Through this, they determined that the Deccan Traps had in fact erupted in four pulses, one of which happened right before the asteroid strike.
This suggests that the asteroid impact did not trigger the volcanic eruptions but that it’s possible that the big volcanic pulse before the asteroid hit played a role in the mass extinction.
Volcanic Eruption
Simply put, the first study did not find a definitive role for the Deccan Traps in the mass extinction since it released 75 percent of its lava after the asteroid hit, but the second study suggests that the eruptions before the impact possibly changed the climate in such a way that stressed out life forms.
That said, despite the differences between the two studies, they do agree on the general timing of when the Deccan Traps erupted. Furthermore, both teams are committed to working together to find the answer.
Both studies are published in the journal Science.
