A vast geological jigsaw puzzle has given scientists a new look at one of Earth’s most important ancient landmasses. Researchers have analyzed more than 25,000 rocks from continental fragments around the world and used their chemical signatures to reconstruct the extent of Gondwana, the enormous landmass that dominated much of Earth’s continental surface hundreds of millions of years ago.
The findings, published in Science Advances, suggest that Gondwana accounted for roughly 80 percent of Earth’s land area around 550 million to 500 million years ago, larger than earlier estimates that generally placed it at about two-thirds of the planet’s land.
The research also offers clues about how geological changes deep inside Earth may have helped create environmental conditions linked to the emergence of complex life.
What was Gondwana?
Gondwana was an ancient supercontinent that brought together enormous portions of what are now South America, Africa, Antarctica, Australia, India and other continental fragments.
Its assembly began hundreds of millions of years ago, with the landmass taking shape in the Southern Hemisphere before eventually breaking apart through plate tectonics.
What makes reconstructing Gondwana difficult is that much of the original continent no longer exists as one continuous landmass. Its fragments were separated, collided with other continents and were carried across the planet by the slow movement of tectonic plates.
The new study attempts to reconstruct that lost geography by looking beyond today’s continental boundaries.
How did scientists find Gondwana’s fingerprints?
The researchers examined more than 25,000 rocks collected from ancient continental fragments and analyzed their geological and isotopic characteristics.
One especially useful clue came from isotopes of samarium and neodymium. These isotopic signatures can preserve information about the age and origin of the crust from which rocks formed.
Even when an ancient continental block has been transported, buried or incorporated into a much younger geological structure, those signatures can remain detectable.
William Collins, a geosciences professor at Curtin University and one of the study’s authors, described the samarium-neodymium isotope maps as functioning like a geological “time machine” because their spatial patterns can help identify ancient continental domains.
How AI helped reconstruct the ancient supercontinent
The study forms part of the broader Deep-Time Digital Earth effort, which aims to organize and analyze enormous quantities of geological information about Earth’s past.
Rather than examining each rock in isolation, researchers can combine geochemical measurements, ages and geographic information into large datasets and use computational methods to identify patterns.
That approach makes it possible to connect rocks that are now separated by thousands of miles but may once have belonged to the same ancient crustal system.
The result is a much broader picture of Earth than can be obtained by studying modern maps alone.
Gondwana was bigger than previously estimated
One of the study’s most striking conclusions concerns Gondwana’s size.
Scientists have long recognized Gondwana as one of Earth’s largest ancient continental assemblies, but estimates of how much land it occupied have varied.
The new reconstruction indicates that Gondwana represented about 80 percent of Earth’s continental landmass around 550 million to 500 million years ago. That would make the supercontinent considerably more dominant than earlier reconstructions suggested.
That does not mean Gondwana covered 80 percent of Earth’s entire surface. The figure refers to Earth’s landmass, with oceans making up most of the planet’s surface.
Did Gondwana help trigger the Cambrian explosion?
The study also points toward a possible connection between tectonic activity and one of the biggest biological transformations in Earth’s history.
The Cambrian explosion began roughly 538 million years ago and saw the relatively rapid appearance and diversification of many complex animal groups.
Researchers argue that the geological processes associated with Gondwana’s formation may have contributed to major changes in Earth’s climate and chemistry. The assembly of the supercontinent was accompanied by extensive tectonic activity, including subduction and volcanic processes.
According to the research team’s interpretation, a broad belt of subduction surrounding Gondwana helped drive volcanic activity that released gases into the atmosphere. Such changes may have contributed to warming following extremely cold intervals and altered conditions in ways that were favorable to biological diversification.
From Snowball Earth to a more complex planet
The period preceding the Cambrian was marked by some of Earth’s most severe glaciations, often described through the “Snowball Earth” hypothesis.
Against that backdrop, changes in tectonics, volcanism and atmospheric composition could have had profound consequences.
The new study does not suggest that the formation of Gondwana single-handedly caused the Cambrian explosion. Instead, it adds geological evidence to the growing picture that Earth’s deep interior, tectonic movements, climate and evolution were closely intertwined.
In other words, the story of complex life was not unfolding independently of the planet’s geology. The changing architecture of continents may have been part of the backdrop that shaped when and where life diversified.
Why these ancient rocks matter today
Gondwana itself disappeared as a unified landmass, but its geological fingerprints remain embedded across modern continents.
Those remnants allow researchers to reconstruct how Earth’s surface looked before today’s familiar continents emerged.
The research team plans to expand its database and refine maps of Gondwana and other ancient continental configurations. Such work could help scientists investigate questions ranging from the evolution of continents to the relationship between tectonics, climate and life.
The rocks may look ordinary today. Their chemistry, however, carries a record of a planet that existed hundreds of millions of years before humans appeared.
