According to many geologists, geological activity on Earth is a rare event. Plate tectonic theory implies that episodes of various regional geological events should manifest global patterns of plate dynamics and mantle-plume activity.
But, a new study offers statistical evidence for a common cycle- suggesting that these geological events are correlated. Scientists from New York University and the Carnegie Institution of Science in Washington D.C. analyzed 260 million years of geological feedback. They found that our Earth has a heartbeat- that goes off on a regular schedule, albeit with millions of years in between.
The study suggests that Earth has a pulse- a 27.5-million-year cycle of geological activity. That means a geologic activity on Earth follows a 27.5-million-year cycle, giving the planet a ‘pulse.’
Significant improvements have been made on radio-isotopic dating techniques and changes in the geologic timescale, leading to new data on the timing of past events in Earth’s geological history.
Scientists used the latest age-dating data available: They compiled updated records of major geological events over the last 260 million years and conducted new analyses.
A spectral analysis was performed on the ages of 89 well-dated major geological events of the last 260 Myr. These events include times of marine and non-marine extinctions, major ocean-anoxic events, continental flood-basalt eruptions, sea-level fluctuations, global pulses of intraplate magmatism, and times of changes in seafloor-spreading rates and plate reorganizations.
They found that these global geologic events are generally clustered at ten different time points over the 260 million years, grouped in peaks or pulses of roughly 27.5 million years apart.
The most recent cluster of geological events was approximately 7 million years ago. It means the next pulse of significant geological activity is more than 20 million years in the future.
According to scientists, these cyclic pulses may be the result of geophysical processes related to the dynamics of plate tectonics and mantle plumes. However, similar cycles in the Earth’s orbit in space might also be pacing these events.
Michael Rampino, a geologist and professor in New York University’s Department of Biology, as well as the study’s lead author, said, “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.”
- Michael R.Rampino et al. A pulse of the Earth: A 27.5-Myr underlying cycle in coordinated geological events over the last 260 Myr. DOI: 10.1016/j.gsf.2021.101245