Vast Volcanic Eruptions Did Dinosaurs a Huge Favour
A massive extinction event that paved the way for the propagation and diversification of dinosaurs at the end of the Triassic period was caused by periods of volcanic eruptions.
That is the conclusion of new research in a vast field of igneous rocks on four continents, supporting the hypothesis that global climate change were responsible for the final three-quarters of the species worldwide are 200 million years old.
The study by scientists at Oxford University has supported suspicions that a series of volcanic pulses responsible for the production of a large mass of igneous rock called the Central Atlantic Magmatic Province (CAMP) caused large-scale climate change, As part of a global extinction event.
CAMP is a broad spread of igneous rock covering about 11 million square kilometers (about 4.2 million square miles), established by periods or “pulse” of volcanic activity is about 200 million years.
The rock province has long since disappeared, tectonic plates slid over the surface of the Earth, separated into four continents spanning both hemispheres.
Previous studies had suggested a relationship between volcanic activity triggered the CAMP and 600,000 years of intermittent levels rise and fall of carbon dioxide in the atmosphere.
However, other research has found evidence that carbon dioxide fluctuated. Not only that, other geological processes must also be rejected before concluding that the apparent pulse of CO2 concentrations were undoubtedly caused by periods of volcanic activity.
Scientists worked with the universities of Exeter and Southampton to examine mercury levels in sediment deposits collected in the United Kingdom, Austria, Argentina, Greenland, Canada and Morocco.
Mercury levels are released as trace elements in volcanic gases, thus a fairly reliable indicator of activity, as it enters the atmosphere before being absorbed by the organic process.
Mercury levels in five of the six samples analyzed by the team showed a strong increase of the element coinciding with the start of the Triassic extinction test, with the peaks corresponding to previously established atmospheric carbon dioxide increases.
“These results strongly support the repeated episodes of volcanic activity in the late Triassic, with the emergence of volcanism in the final Triassic extinction,” said Lawrence Percival, principal investigator.
As we know very well today, increased levels of carbon dioxide can have a dramatic impact on terrestrial and marine ecosystems, trapping heat and increasing the acidity of the ocean.
On the other hand, the fine particles released by eruptions can be suspended in the atmosphere, which reflects the light of the sun and causing the fall of temperatures.
No one is sure that the scenario was responsible, although studies like this increase the weight of the hypothesis that carbon dioxide global warming levels were at work.
The extinction event that marked the boundary between the Triassic and Jurassic was one of the most important to shake our biosphere – about 76 percent of the species have been annihilated, including most of a group of dinosaur ancestors called archosaurs .
It is unclear why a number of species of early dinosaurs survived, but along with mammals and a number of species of amphibians, they evolved rapidly to fill in the gaps left behind.