In the past 260 million years, dinosaurs have come and gone, Pangea split into the continents and islands we see today, and humans have rapidly and irrevocably changed the world we live in.
But through it all, the Earth seemed to be keeping time. Research into ancient geological events suggests that our planet has a slow, steady “heartbeat” of geological activity every 27 million years or so.
This pulse of clustered geological events – including volcanic activity, mass extinctions, plate realignment, and sea level rise – is an incredibly slow, 27.5-million-year cycle of catastrophic tides. But fortunately for us, researchers believe we have another 20 million years before the next “pulse.”
“Many geologists believe that geological events are random over time,” said Michael Rampino, a geoscientist at New York University and lead author of the studyin a 2021 statement.
“But our study provides statistical evidence for a common cycle, suggesting that these geological events are interconnected rather than random.”
The team analyzed the ages of 89 well-understood geological events from the past 260 million years.
As you can see from the chart below, some of those times were tough – more than eight of these world-changing events came together over small geological timescales, forming the catastrophic “pulse.”
“These events include times of marine and non-marine extinctions, major ocean anoxic events, continental flood basalt eruptions, sea level fluctuations, global pulsations of magma within plates, and times of changes in rates of seafloor spreading and plate reorganization.” the team wrote in their paper.
“Our results suggest that global geological events are generally interconnected, and appear to occur in pulses with a basic cycle of about 27.5 million years.”
Geologists have been studying the possible cycle of geological events for a long time. Going back to the 1920s and 1930s, scientists of that era suggested that the geological record had a 30-million-year cycle, while researchers in the 1980s and 1990s used the best-dated geological events of the time to give them a range of lengths between “pulses” of 26.2 to 30.6 million years.
Now, all seems well, 27.5 million years is exactly what we expected. a Study published in late 2020 The same authors suggested that this 27.5 million year mark is when mass extinctions also occur.
“This paper is very good, but I actually think it was a better paper on this phenomenon [a 2018 paper by] Müller and Dutkiewicz,” tectonic geologist Alan Collins of the University of Adelaide, who was not involved in this research, told ScienceAlert in 2021.
Which 2018 paperTwo researchers at the University of Sydney studied the Earth’s carbon cycle and plate tectonics, and also came to the conclusion that the cycle is about 26 million years long.
Collins explained that in this latest study, many of the events the team looked at are causal events, meaning one directly causes the other, and so some of the 89 events are linked to each other: for example, hypoxic events that cause marine extinctions.
He added: “Having said that, this 26-30 million year periodicity appears to be real and over a longer period of time – and it is also not clear what the reason behind it is!”
There is other research conducted by Rampino and his team Proposed comet strikes It could be the reason, and one space researcher even suggested that Planet Nine is the reason.
But if Earth truly has a geological “heartbeat,” it may be due to something a little closer to Earth.
“These periodic pulses of tectonics and climate change may be the result of geophysical processes linked to the dynamics of tectonic plates and mantle plumes, or they may instead be rhythmic by astronomical cycles linked to Earth’s motions in the solar system and the galaxy.” The team wrote In their studies.
The research was published in Frontiers of Earth Sciences.
A previous version of this article was published in June 2021.
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