Scientists Found the Missing 16% of Earth’s Lost Supercontinent Hiding in the Himalayas: A continental mash-up some 750 to 550 million years ago was likely essential for complex life to emerge during the Cambrian Explosion

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Here’s what you’ll learn when you read this story:

• Gondwana, Earth's second-youngest supercontinent, formed just as complex animal life emerged.
• A new study argues that Gondwana accounted for roughly 80 percent of the Earth’s continental mass (14 percent more that previously believed) and caused the creation of a volcanic chain, similar to today’s Ring of Fire, that released water vapor and carbon dioxide, making the planet more hospitable for life.
• Scientists made this breakthrough after collecting granite samples in the Himalayas and finding evidence that the rocks originated from a common block—Gondwana.

When viewed from the microscopic temporal lengths of the average human lifespan, Earth’s continents appear like immutable giants—a geologic constant that makes terrestrial life possible. Of course, we now know this is far from the truth. Over the course of 80 years, these massive landmasses might only move a handful of feet, but apply that movement across Earth’s vast 4.5-billion-year lifespan, and Earth’s land surfaces change drastically across geologic eras.

Most people are familiar with Pangea, a supercontinent that formed roughly 300 million years ago, but that’s only Earth’s latest continental smash-up. At least three other, similarly large landmasses have formed in the planet’s past, including Columbia, Rodinia, and the second-youngest, Gondwana. The latter is especially interesting to scientists, because it formed at the same time that complex life arose. It’s widely believed that Gondwana began forming around 750 million years ago and finished assembling roughly 200 million years later—right at the threshold of a geologic period of immense speciation known as the Cambrian Explosion.

Now, a new study published in the journal Science Advances says that the two events are intrinsically linked and that the history of life on Earth might’ve looked much different if Gondwana never formed. But to truly understand its impact, the study needed to first solve a lingering question about Gondwana: Was it even a supercontinent at all?

“The supercontinent status of Gondwana has been questioned in the 21st century,” Curtin University’s Bill Collins, a co-author of the study, wrote in The Conversation. “This was because an arbitrary value of 75% of continental landmass was considered necessary to attain supercontinent status and Gondwana was initially measured at 64%.” So while a continent with 64% of Earth’s total landmass sounds pretty big, apparently it’s not enough to be super.

However, Collins and his team made a surprising discovery while building a global dataset of granite samples to understand how geologic processes form minerals. While the analysis found that granite samples in the Himalayas were roughly 20 to 50 million years old, they came from a common continental block—Gondwana. By including this new chunk of continental mass, the study estimated that Gondwana’s share of Earth’s total land surface was more like 80 percent.

“We have traced the original Gondwanan fragments from India and southeast Asia, through most of China into Kazakhstan,” Collins writes. “Previously, much of this region was thought to be ancient ocean floor containing volcanic island chains like in the Pacific Ocean today.”

So how much can a 16 percent difference really impact the Earth’s biological history? Quite a lot, as it turns out. When supercontinents form, they also cause climactic and geological changes. In this case, the formation of a larger supercontinent forced the Earth to reconfigure its plate tectonics, and formed a volcanic arc chain—a precursor to today’s Ring of Fire, according to Collins. Once formed, this volcanic chain did what it did best: It belched plumes of volcanic gasses, water vapor, and carbon dioxide that slowly transformed the planet from a cold, desolate slab of rock into a warming greenhouse that nourished the nascent seeds of a complex animal life.

“Our results identify a ‘Greater Gondwana’ encompassing at least 80% of Earth’s continental landmass, thereby confirming its supercontinent status,” the authors write. “This finding has profound implications for understanding the Ediacaran-Cambrian Earth system, invoking a planetary-scale subduction girdle that initiated Gondwana breakup and helped drive the transformative environmental change.”