According to the latest scientific studies, this pulse repeats approximately every 27.5 million years.
If we perhaps exclude meteorology, our planet would seem like a stable and immovable rock, but we have known for a long time that this is not the case. The climate, continents, oceans, and even life on Earth change little by little over time.
What we have observed lately is that these changes have their own rhythm.
The “heartbeat” of the Earth. Over the last few years, different studies have been observing a hidden geological cycle on our planet. A “pulse” of activity that repeats itself in cycles that last several million years.
The pulse is characterized by an alternation of long periods of geological stability separated by brief (in a geological context) periods of great activity in which events of great impact occur. Events such as volcanic eruptions, tectonic movements, changes in sea level or mass extinctions, among others.
27.5 million years. Until now, it was estimated that this “beat” had an approximate frequency of between 26 and 30 million years. One of the most recent studies in this field refined this estimate and calculated an average period of 27.5 million years.
The last 260 million years on our planet. To calculate this average, the team responsible for the study used the most recent dating of nearly a hundred geological events that occurred in the last 260 million years.
More specifically, 89 events including extinctions of terrestrial and maritime species, flood basalt eruptions, disappearances of oceanic oxygen, sea level fluctuations, and others. As the team emphasizes, using the most recent data on the events opened the door to generating their new estimate of their periodicity.
10 peaks. In its analysis of the last eras, the team identified 10 peaks of geological activity around which a good part of the analyzed events were grouped. Details of the work were published in an article in the magazine Geoscience Frontiers.
One of these details is reassuring: the last of the identified peaks occurred about 7 million years ago, which gives us plenty of room until the next one.
Various approaches. The study is one of many that have investigated this question. In statements to Science AlertUniversity of Adelaide geologist Alan Collins highlighted another, published in 2018 in the journal Science Advances.
In that study, the calculated frequency of these peaks was not 27.5 million years but 26 million. This analysis was based on carbon cycles and tectonic movements alone. For Collins, the inclusion of other events does not necessarily add statistical validity to the calculation since some of these events would be linked to each other by cause-effect relationships.
The big question. The mystery that these works do not solve is what causes these cycles on our planet. They do consider some hypotheses, such as the possibility that they are caused by geological movements in the Earth’s mantle and plate tectonics.
Another possibility is that it has to do with something external, such as the orbital movement of our planet and its interaction with other bodies, whether they are other planets or asteroids in our environment.
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Image | POT
