SCIENTIST PROVIDES Earth experiences “heartbeat” every 27.5 million years

Recent research published in GeoScience Frontiers suggests that Earth’s geologic activity follows a 27.5-million-year cycle. Most scientists believed that geological events occurred randomly. Michael Rampino, a geologist and professor at New York University, said that their study provides statistical evidence for a common cycle, suggesting that these geological events are correlated and not random. Researchers have proposed cycles of major geological events over the last five decades, ranging from roughly 26 to 36 million years, including volcanic activity and mass extinctions on land and sea. However, early work on these correlations in the geological record was hampered by limitations in the age-dating of geological events, which prevented scientists from conducting quantitative investigations.

Recently, there have been significant improvements in radio-isotopic dating techniques and changes in the geological timescale, leading to new data on the timing of past events. Using the latest age-dating data available, Rampino and his colleagues compiled updated records of major geological events over the last 260 million years and conducted new analyses.

The team analyzed the ages of 89 well-dated major geological events of the last 260 million years. These events include marine and land extinctions, major volcanic outpourings of lava called flood-basalt eruptions, events when oceans were depleted of oxygen, sea-level fluctuations, and changes or reorganization in the Earth’s tectonic plates.

They found that these global geological events are generally clustered at 10 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, suggesting that the next pulse of major geological activity is more than 20 million years in the future.

The researchers posit that these pulses may be a function of cycles of activity in the Earth’s interior—geophysical processes related to the dynamics of plate tectonics and climate. However, similar cycles in the Earth’s orbit in space might also be pacing these events. “Whatever the origins of these cyclical episodes, our findings support the case for a largely periodic, coordinated, and intermittently catastrophic geological record,” said Rampino.

Hits: 18