Massive, planet-destroying events are thought to occur at random over time. According to a recent paper published in the journal Geoscience Frontiers, a study of ancient geological events suggests that Earth follows a 27.5-million-year cycle. This suggests that our planet is experiencing a slow and steady “pulse” of catastrophic events.
Surprisingly, this geological activity keeps time, and the geologic events are correlated rather than random. They include, among other things, volcanic activity, mass extinctions, plate reorganizations, and sea level rises.
Because early work was hampered by limitations, this study was made possible by significant advances in radio-isotopic dating methods. A team of scientists led by Michael Rampino, a geologist and professor in the Department of Biology at New York University, collected records of major geological events over the last 260 million years and performed new analyses using the most recent age-dating data available.
The researchers examined the ages of 89 well-dated major geological events that occurred over the previous 260 million years, including times of marine and non-marine extinctions, major ocean-anoxic events, continental flood-basalt eruptions, sea-level fluctuations, global pulses of intraplate magmatism, and changes in seafloor spreading rates and plate reorganizations.
Surprisingly, the researchers discovered that these global occurrences are typically clustered at ten distinct time points, grouped in peaks or pulses approximately 27.5 million years apart. They discovered that the most recent cluster of geological events occurred about 7 million years ago. This implies that the next major geological event will occur within the next 20 million years, which is not a timeframe to be concerned about.
According to the researchers, these pulses could be caused by cycles of activity in the Earth’s interior. Similar cycles in the Earth’s orbit in space, on the other hand, could be timing these occurrences as well.
“Whatever the origins of these cyclical episodes, our findings support the case for a largely periodic, coordinated, and intermittently catastrophic geologic record, which is a departure from the views held by many geologists,” said Michael Rampino in a press release. In a study published late last year, the same authors suggested that this 27.5-million-year mark is also where mass extinctions occur.