Determining what killed the dinosaurs 66 million years ago at the end of the Cretaceous Period has long been a source of discussion, as scientists try to figure out what caused the five big extinction events that changed life on Earth in a geological second.
Some experts believed that comets or asteroids colliding with Earth were the most likely agents of mass devastation, while others believed that enormous volcanic eruptions were to blame.
What killed dinosaurs and other life on Earth?
(Photo : JEREMIE RICHARD/AFP via Getty Images)
The findings gave the most convincing quantitative evidence to date that the relationship between significant volcanic eruptions and widespread species turnover is not just coincidental, as per ScienceDaily.
According to the researchers, four of the five major extinctions occurred concurrently with a form of volcanic outpouring known as a flood basalt.
In the blink of a geological eye, a million years, these eruptions flooded large areas, even an entire continent, with lava.
They left behind massive fingerprints in the form of step-like igneous rock (solidified from erupting lava) that geologists refer to as "large igneous provinces."
According to the experts, the majority of the volcanoes featured in the study spewed a million times more lava than that.
The researchers examined the temporal relationship between mass extinction and big igneous provinces using three well-established datasets on the geologic time scale, paleobiology, and large igneous provinces.
According to lead author Theodore Green, who conducted this research as part of the Senior Fellowship program at Dartmouth and is now a graduate student at Princeton, the large step-like areas of igneous rock from these large volcanic eruptions appear to line up in time with mass extinctions and other significant climatic and environmental events.
In reality, approximately 252 million years ago, a sequence of eruptions in present-day Siberia sparked the most severe of the mass extinctions, unleashing a massive pulse of carbon dioxide into the atmosphere and virtually killing off all life.
The Siberian Traps, a huge expanse of volcanic rock nearly the size of Australia, bear witness.
Volcanic eruptions also shook the Indian subcontinent during the period of the great dinosaur extinction, forming the Deccan plateau.
This, like the asteroid hit, would have had worldwide consequences, blanketing the atmosphere in dust and poisonous gases, asphyxiating dinosaurs and other species, and changing the temperature on a long-time scale.
The hypotheses in support of asteroid destruction, on the other hand, rely on the Chicxulub impactor, a space rock that crashed-landed onto Mexico's Yucatan Peninsula about the same time as dinosaurs went extinct, according to the experts.
All previous ideas, including volcanism, that sought to explain what killed the dinosaurs were demolished when the Chicxulub impact crater was discovered, according to co-author Brenhin Keller, an associate professor of earth sciences at Dartmouth.
Despite decades of research, however, he noted that there is very little evidence of similar impact events that correlate with the other great extinctions.
Green used the Dartmouth Discovery Cluster supercomputers to crunch the statistics with Keller and co-author Paul Renne, professor-in-residence of earth and planetary science at the University of California, Berkeley, and head of the Berkeley Geochronology Center.
The researchers contrasted the best-known estimates of flood basalt eruptions with geological timescales of catastrophic species extinctions, including but not limited to the five major extinctions.
To demonstrate that the timing was not just coincidental, scientists tested whether the eruptions would line up just as well with a randomly created pattern and repeated the experiment with 100 million such designs.
The agreement with extinction times was found to be significantly greater than random chance.
Also Read: What Happened During the Earth's Very First Mass Extinction?
Volcanoes paved the path for dinosaurs
The end-Triassic extinction took off almost three-fourths of the world's marine and terrestrial species about 200 million years ago, as per Big Think.
This was the end of trilobites, ammonoids, and massive crocodile-like creatures known as phytosaurs - fearsome predators that could grow to be 12 meters long.
Following the loss of phytosaurs, a niche was left available for dinosaurs, who survived and ascended to supremacy.
The end-Triassic extinction is supposed to have been caused by a massive eruption of the Central Atlantic Magmatic Province.
This vast volcanic zone formed the rift that divided Pangea in half, separating the modern-day Amazon from Western Africa and North America's Atlantic coast from Europe.
Kunio Kaiho from Japan's Tohoku University's team collected limestone and mudstone samples from end-Triassic layers in present-day England and Austria to better understand how broad volcanic activity affects the climate.
They heated the stone in the lab to temperatures ranging from 350 to 1100 degrees Celsius, trying to figure out what occurs when hot magma collided with sedimentary rocks containing hydrocarbons and sulfur.
The first 300,000 years of the end-of-Triassic extinction were distinguished by four main surges of volcanism.
The temperature of magma may be monitored in some ways using coronene, a polycyclic aromatic hydrocarbon (PAH).
Because this PAH requires high temperatures to develop, its presence may be used to track magma temperatures.
The researchers were able to assess coronene abundance and how it varied during volcanic activity spikes by analyzing their samples.
Related article: Scientists Find Increasing Tell-Tale Signs of an Upcoming Mass Extinction
© 2024 NatureWorldNews.com All rights reserved. Do not reproduce without permission.
