A study done by researchers from New York University suggests that the earth has a pulse. According to the survey, geological activity on earth tends to occur in a 27.5 million year cycle. The scientists examined major geological events that occurred in about 260 million years to come to this conclusion. They then noticed that some events occurred every 27.5 million years.
Michael Rampino, a lead study author, a professor at New York University’s Department of Biology and a geologist, notes that most geologists believe these events occur randomly. However, this study gives statistical evidence to show that these geological events occur in cycles.
In the last 50 years, more scientists have come to support the theory that the earth has cycles of major geological events such as land or sea extinctions and volcanic eruptions. The timeframes of these cycles are still under debate, with estimates ranging from 26-36 million years.
Progress made in dating major geological events
Dating a geological event can be difficult with the technological limitations we have. However, there have been improvements in radio-isotopic dating techniques and changes in the geologic timescale. Because of this, the researchers were able to obtain an accurate and updated record of major geological events.
The researchers looked at the ages of 89 correctly dated major geological events in the last 260 million years. These events included sea or landmass extinction, flood-base eruptions, events that depleted oxygen in the ocean, changes in the earth’s tectonic plates and sea-level fluctuations. They concluded that these events had occurred at ten distinct points in the last 260 million years. The most recent occurred 7 million years ago, so humans won’t have to worry about major geological events recurring for another 20 million years.
What causes these cycles?
Scientists have come up with a few theories to try and explain these pulses. One theory explains that the earth’s orbit may be responsible for it. Another is that there may be a function of other activities cycle within the earth’s interior.
According to Rampino, while a reason for the cycles is still not known, their results prove that they are, in fact, real and thus contradict the view of geologists that believe otherwise.
