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How a major volcanic eruption paved the way for the rise of the dinosaurs by Staff Writers Tokyo, Japan (SPX) Mar 25, 2022
The supercontinent Pangaea, which was a combination of today's continents, broke apart at the end of the Triassic period due to large-scale volcanic activity. This volcanic activity was thought to be the most likely cause of the fourth mass extinction, but studies were inconclusive and provided no explanation of the environmental changes that occurred at that time. Therefore, the research group first examined sedimentary rocks from this period, collected from strata in Austria and England. They found that, by the time the mass extinction began, there were many hydrocarbons that can only form at low temperatures. Such hydrocarbons are also common in sedimentary rocks from the late Paleozoic Devonian (380-360 million years ago) and the end of the Paleozoic Permian (about 250 million years ago), which are known to have undergone mass extinctions due to volcanic eruptions. These hydrocarbons, which are not found in ordinary strata, indicate that the mass extinction at the end of the Triassic was also caused by volcanic eruptions. Scientists had previously estimated, based on analyses of oyster fossils, that the earth cooled during this mass extinction and warmed afterwards. In an attempt to understand this climate change, the group heated the sedimentary rocks and studied the gases that were produced. A large amount of sulfur dioxide (SO2) was released at relatively low temperatures, whereas a large amount of carbon dioxide (CO2) was released at high temperatures. These results suggest that, at the end of the Triassic, large-scale volcanic activity brought relatively low-temperature magma into contact with sedimentary rocks and released a large amount of SO2. When SO2 enters the stratosphere, it creates sulfuric acid particles that reflect sunlight. These particles prevent plants from photosynthesizing and make the earth colder. Based on these hypotheses and the results of calculations from climate models, the researchers concluded that cold weather caused the mass extinction.
Unveiling climate change at the time At the end of the Triassic, mercury was also produced in large quantities. Though an abundance of mercury can indicate large-scale volcanic events, it can also be sourced from terrestrial plants, making it difficult to chalk up the origin of this mercury as the cause of the mass extinction. Therefore, in addition to mercury, the research group used hydrocarbons as evidence to determine the cause of the extinction event, revealing that temperature changes caused by volcanic activity can alter the earth's climate. During the Triassic period, large crocodiles reigned on land and preyed on dinosaurs, which were small. However, these crocodiles went extinct as a consequence of the cold weather. The dinosaurs, freed from their natural enemies, grew in size from the Jurassic period to the Cretaceous period and prospered greatly. This study was a research collaboration between Tohoku University, Yamaguchi University, the University of Tokyo, Akita Prefectural University, Lund University in Sweden, and Amherst College in the United States. The results were published online in Earth and Planetary Science Letters on January 12, and the results were announced on January 13.
Coronene is the key to understanding the rise and fall of life Scientists agree that five mass extinctions occurred throughout history. In 2017, Professor Emeritus Kaiho and colleagues showed through mercury analyses that the first one, which took place at the end of the Paleozoic Ordovician period about 445-443 million years ago before organisms made full-scale inroads on land, was also caused by a major eruption. Using coronene as evidence, they also showed that the second mass extinction in the late Devonian and the third mass extinction in at the end of the Permian also occurred after major eruptions. The fifth mass extinction, which marked the end of the dinosaurs, was caused by a celestial collision 66 million years ago at the end of the Cretaceous period. Interestingly, coronene has also been found in strata from this period. Volcanic activity seems to largely determine the fate of life on Earth. Immediately after the announcement of these results, an underwater volcano off the coast of Tonga in the South Pacific erupted on January 15, making humanity keenly aware of the seriousness of volcanic disasters and the need to deepen our understanding of our living planet, Earth.
Research Report: "Volcanic temperature changes modulated volatile release and climate fluctuations at the end-Triassic mass extinction"
Researchers find Spinosaurus' dense bones allowed it to hunt underwater Washington DC (UPI) Mar 23, 2021 Spinosaurus, the largest known predatory dinosaur, had bones dense enough to submerge itself to hunt, according to a study released Wednesday. A group of paleontologists analyzed the density of Spinosaurid bones and compared them to animals such as penguins, hippos, and alligators to determine that both the Spinosaurus and close relative Baryonyx could swim and actively pursue prey in the water, they said in a paper published in Nature. Scientists were aware that these dinosaurs, which l ... read more
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