New Evidence Suggests Earth Has A 27.5 Million Year Geological Activity Cycle

A new study has been published by researchers at NYU that investigates geological activity on Earth over massive timescales. Researchers analyzed 260 million years of major geological events and found clusters that recur at an interval of 27.5 million years. The geologists say the earth follows the 27.5 million year cycle giving the planet a type of pulse.

Many geologists believe that geological events are random over time, but the new study suggests evidence for a common cycle. The new evidence, according to geologist and professor in the NYU Department of biology, Michael Rampino, suggests that there is a common cycle and the geologic events are correlated and not random. Over the past five decades, researchers have proposed cycles for major geological events, including volcanic activity and mass extinctions on land and sea that ranged from roughly 26 to 36 million years ago.

However, work on the early correlations in the geological record was hampered by limitations in the ability to age-date geologic events. Significant improvements in radio-isotopic dating techniques and changes in the geologic timescale have led to new data for the timing of past events. Rampino and colleagues compiled the updated records for the major events over the last 260 million years using the latest age-dating records.

Researchers analyzed the ages of 89 well-dated major geological events from the last 260 million years. The events included marine and land extinctions, major volcanic outpourings of lava called flood-basalt eruptions, events where oceans were depleted of oxygen, sea-level fluctuations, and changes or reorganizations in the Earth's tectonic plates.

Researchers found the major geologic events are clustered at ten different time points over 260 million years grouped in peaks or pulses approximately 27.5 million years apart. The most recent cluster of events was 7 million years ago, suggesting the next major pulse of geological activity is more than 20 million years in the future.