Scientists have reconstructed the long-lost supercontinent Gondwana, revealing it was significantly larger than previously understood and may have played a crucial role in a pivotal period of evolutionary history. The study, published in Science Advances, suggests that Gondwana encompassed approximately 80 percent of Earth's landmass.
Previously, scientists recognized Gondwana as a vast continent that included present-day South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica. However, this new research, led by Tao Wang of the Chinese Academy of Geological Sciences, utilized data from 25,346 igneous rocks to identify previously hidden fragments. These fragments were found in southeastern Asia, central Europe, and southeastern North America, areas now deeply embedded within younger geological formations.
These newly identified components increase Gondwana's estimated landmass coverage to around 80 percent, surpassing the 64 percent previously estimated and falling comfortably above the 75 percent threshold generally accepted for supercontinent status. "This study provides robust evidence that Gondwana fully qualifies as 'Greater Gondwana,' a supercontinent," the researchers stated.
The extensive size of Gondwana, as now understood, has implications for understanding the Cambrian Explosion, a period around 541 million years ago when most of the basic body plans of modern animals emerged. Scientists have long theorized that geological events and atmospheric changes associated with supercontinent cycles influenced this evolutionary burst. The research suggests that Gondwana, at this newly defined size, would have been substantial enough to drive such cycles, impacting sea level, mantle convection, and atmospheric gases, thereby potentially fueling the rapid diversification of life.
"The metazoan radiation that took place at the Ediacaran–Cambrian transition 550 to 500 million years ago is thought to have been driven by supercontinent cycles that impacted sea level, mantle convection, and levels of atmospheric volatile gases," the team explained. "Gondwana, the major landmass at the time, was previously considered too small to create these types of cycles."
While Earth currently consists of seven distinct continents, they were once joined together in supercontinents like Gondwana. The researchers noted that their 80 percent estimate remains conservative, with potential for further components to be identified. The findings challenge previous assumptions about Gondwana's scale and its capacity to influence major global geological and biological events.