Studies have found that mass extinction events always occur at the same time as catastrophic asteroid impact events and volcanic eruption events.
Recently paleontologists have discovered a pattern in which Earth’s terrestrial life, including amphibians, reptiles, mammals and birds, experiences a mass extinction event about every 27 million years.
Coincidentally, this coincides with the extinction cycle of marine life found in previous studies – occurring about every 26 million years, these mass extinction events lead to the extinction of up to 90 percent of marine species.
The study also found that mass extinction events also always occur at the same time as catastrophic asteroid impact events and volcanic eruptions.
Lead author of this study, Michael Rampino of New York University, said, “Global extinction events appear to be contemporaneous with widespread catastrophic asteroid impact, mass volcanic eruption events, that are contemporaneous.”
The researchers were surprised by the patterns they saw in these data, and why this is so. Don’t asteroid and comet impact events happen randomly? How could there be a cycle?
Looking at the fossil record, scientists see at least five major extinction events on Earth.
One was 443 million years ago, at the end of the Ordovician period. The Ordovician is the second epoch of the Phanerozoic Paleozoic Era of geological time, which began about 485 million years ago. The Phanerozoic, also known as the Phanerozoic, is the period when a large number of organisms appeared 541 million years ago.
Once was 360 million years ago, the end of the Devonian. The Devonian is the fourth epoch in the Paleozoic Era, which began about 419 million years ago.
Once was 250 million years ago, the end of the Permian (Permian). The Permian is the last geological epoch of the Paleozoic, and the time is between the Carboniferous and Triassic.
Once was 201 million years ago, the end of the Triassic (Triassic). The Triassic was the first epoch of the Mesozoic, beginning 251 million years ago and ending 201 million years ago, between the Permian and Jurassic periods.
Once was the end of the Cretaceous, 65 million years ago. The Cretaceous is the last epoch of the Mesozoic, 80 million years long, and is the longest phase of the Phanerozoic.
Between these epochs, extinction events of smaller magnitude also occurred. Analysis of statistical data shows that terrestrial extinction events occur almost every 27.5 million years.
This study speculates that this may be related to the solar system’s cycle of orbiting the Milky Way every 30 million years, contributing to the periodicity of these mass catastrophes.
“It appears that impacts of large celestial bodies, along with the pulsations within the Earth that cause volcanic eruptions, occur every 27 million years or so, as do mass extinction events. This may be related to our orbit around the galaxy.” Lempino said.
The study was recently published in the journal Historical Biology.
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