A recent study published in the Proceedings of the National Academy of Sciences examines how movements throughout the 36-million-year cycle of Earth’s tectonic plates have caused biodiversity explosions in marine life from changes in sea levels that date back as far as 250 million years. This study was conducted by an international team of researchers and holds the potential to help scientists better understand how plate tectonics helped shape life on Earth throughout the planet’s history.
“In terms of tectonics, the 36-million-year cycle marks alterations between faster and slower seafloor spreading, leading to cyclical depth changes in ocean basins and in the tectonic transfer of water into the deep Earth,” said Dr. Dietmar Müller, who is a professor of geophysics at the University of Sydney, and a co-author on the study. “These in turn have led to fluctuations in the flooding and drying up of continents, with periods of extensive shallow seas fostering biodiversity.”
Plate tectonics is an ongoing geologic process involving the recycling of Earth’s materials that begins deep inside the planet, which reshapes the planet’s surface over the course of hundreds of millions of years. As a result, studying geologic records from billions of years ago is both incredibly rare and extremely difficult. But scientists can still study geologic records of past floods, which help reveal past diversity of life across the planet.
For the study, the researchers examined fossil records from the Cretaceous Winton Formation in Queensland, which is well-known for its myriad of dinosaur fossils and water-based silica, also known as opal, and offers a rare geologic window into Australia’s flooded history. The team found that the cyclical rising and falling of sea levels resulted in periods of distinctive environments for a variety of marine species, which contributed to periods of rich biodiversity all over the Earth.
“The Cretaceous Winton Formation stands as a testament to the profound impact of these sea-level changes, capturing a snapshot of a time when Australia's landscape was transformed and fascinating creatures roamed the land,” Dr. Müller explains.
What new discoveries will scientists make about how plate tectonics shaped the course of life on ancient Earth in the coming years and decades? Only time will tell, and this is why we science!
Sources: Proceedings of the National Academy of Sciences, EurekAlert!, National Geographic, The University of Queensland
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