There are seven continents that shape our world today, but it wasn’t always that way.
We know that millions of years ago Earth harbored supercontinents. Massive pieces of unbroken land,
far bigger than any of the landmasses on the current world map. These incredible,
natural structures are already fascinating to think back on… but new research has seemingly
uncovered something else, in particular, that was also supersized in our planet’s ancient past:
the mountains. This is Unveiled, and today
we’re answering the extraordinary question; Did scientists just discover supermountains?
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The mountain ranges on Earth today are towering, massive landmarks,
that reach high into the skies above. But they aren’t only impressive because of how tall they
are. The Himalayas, for example, are notable not only for containing the tallest mountains on Earth
(including Mount Everest at 29,000 feet) but also for spanning an incredible 1,500 mile
distance across Asia. The Himalayas aren’t the longest mountain range by any means, either. The
Rocky Mountains in North America stretch for some 3,000 miles, and the Southern Great Escarpment in
southern Africa continues uninterrupted for just slightly further. These colossal features of the
natural world truly do define Earth as we know it. But, according to fresh research, even they’re
overshadowed by hypothesized supermountains that once existed, in the distant past.
The most recent claims relate to a study published in the “Earth and Planetary Science Letters”
journal, in February 2022. Led by one Ziyi Zhu, a student of the Australian National University,
the findings could revolutionize how we think of Earth’s history. The paper proposes that
there were two distinct periods in Earth’s past, both millions of years ago, when there
were supermountains on the surface. These ranges were roughly the same height as our tallest peaks
today, but crucially they were far longer. They snaked across the land for far greater distances
than even the lengthiest mountain ranges in the modern world… and the study suggests that
their existence may have played an essential role in the evolution of life to this point.
But first, how do we know they were there? At the heart of the latest research is a mineral known
as Zircon. It’s special, as it can act as a kind of sponge for other elements that may be present
in Earth’s crust… and because of this, it can function as a sort of time capsule. Researchers
behind the study have, then, analyzed zircons for evidence of elements and natural processes that
are indicative of highly pressurized environments such as those found deep below massive mountains.
The findings are still to be confirmed by wider study, but dedicated zircon analysis has so far
suggested that some were at one time buried beneath ancient mountains that were at least
5,000 miles long - perhaps longer. Or about twice the width of the United States.
Taking up considerably more space than today’s mountains do, then,
it’s no exaggeration to say that these geological marvels once cut the world
in two. In general, a supermoutain forms in much the same way that a regular mountain does,
just on a much larger scale. Tectonic plates below Earth’s surface collide and push the land
above upwards, with supermountains forming when conditions are such that entire supercontinents
meet and rise along an enormous length. At their peak, the mountain ranges addressed in the 2022
study may well rank among the largest, natural, Earth-bound structures ever.
Earlier studies had already theorized the existence of supermountains before,
although the literature has now been significantly added to. One of the mountains is known as
the Transgondwanan Supermountian, which is thought to have existed between 650 and 500
million years ago. It’s named after the Gondwana supercontinent, which at one time dominated Earth,
comprised (as it was) of modern-day Africa, Australia, Antarctica, and South America. But,
when it (and the supermountain that cut across it) eventually broke apart, it helped to
form what would ultimately become the smaller continents and landmasses that we know today.
The more recent research, however, adds to the story of the Transgondwanan mountain,
revealing that another, similar mountain may have also formed before it. Newly dubbed the
Nuna Supermountain, it’s thought to have existed between 2 billion and 1.8 billion years ago,
at a time when Earth itself was around 2.5 billion years
old. The Nuna mountain is named for another one-time supercontinent from Earth’s past,
known as Columbia (or sometimes Nuna). Again, as Nuna eroded away over time,
it’s thought that it became a major contributor to how Earth evolved from that point forward.
At the time that both it and the Transgondwanan Supermountian broke down, research suggests that
there was an explosion of activity on Earth. The declining rock appears to have brought forth a
flurry of biodiversity, as those behind the 2022 study propose that there’s a striking similarity
between the lifespans of both mountains and the occurrence of two of the most important moments
in the evolution of life. First, the Nuna Mountain’s rise and fall (between 2 and 1.8
billion years ago) matches up to when Eukaryotes first formed - a key early organism. Then, the
Transgondwanan mountain (around 650-500 million years ago) lines up to when the first large and
complex animals began appearing on Earth - a time otherwise known as the Cambrian explosion,
when fossil records start becoming much more populated. Finally, and for further context, it’s
said that we should look at when supermountains weren’t around. There’s a length of time sometimes
referred to by scientists as the “boring billion”, about 1.8 billion to 800 million years ago,
when seemingly not much happened in terms of evolution. And, as it turns out, there weren’t
any supermountains around this time, either. So, what’s actually happening here? Well,
the theory is that the key to these post-mountain periods of rapid change is erosion. When the
mountains themselves formed, certain elements from far below the surface of Earth were suddenly
pushed up to the top. And so, as the mountains were eroded away, including into nearby oceans,
a wealth of new nutrients became available for life to feast on. It’s thought the natural world
changed in all manner of ways as a result, but perhaps one of the most crucial was that there
came a burst of oxygen. According to those behind the study, one of the largest ever increases of
oxygen on Earth is synchronized with the erosion of the Transgondwanan mountain. The idea is that
the eroding mountain released all new biological material (including masses of carbon) and early
lifeforms converted it into unparalleled levels of oxygen. And, of course, that oxygen would go
on to become one of our most precious resources. The seeming rate of change is perhaps something of
a surprise. But, while it might seem like massive mountains such as these would stick around for
ages, the opposite is what actually happened. The huge size of the Nuna and Transgondwanan
mountains made them far bigger targets for erosion in all the normal, expected ways… and, ultimately,
they were worn down much quicker than other, regular mountains are. Earth’s raging elements,
including harsh winds and heavy rain, broke them apart and spread the rocks, dust, minerals, and
nutrients within them all over the supercontinents that they dominated, and therefore essentially all
around the planet. These mountains were effective banks for early biological material… and as they
disappeared, they enriched the rest of the world. On an even more fundamental level, the rise and
fall of supermountains is thought to be all part of the supercontinent cycle, which is
the well-known pattern seen throughout Earth’s history wherein supercontinents form and then
splinter off into smaller continents over time. On average, it occurs every 300-800 million years,
which means that supercontinents should form again in the future. And, therefore, it’s likely
that supermountains will form again, too. One current prediction as to what could lie ahead is
that a landmass known as Amasia will take shape sometime in the next few hundred million years,
as many of today’s continents are drifting toward one another. It’s difficult to predict where
precisely another supermountain will emerge, but if (or when) it does it’ll signify the beginning
of another period of massive environmental, geological, and biological change.
Naturally, the ramifications of this research aren’t only confined to Earth,
either. The work unlocks other lines of enquiry regarding how complex life might evolve on other
planets, too. We’ve known for a long time that tectonic activity is important and could be
essential… but now we have another model as to how the movement of a planet’s tectonic plates,
and the rise and fall of mountains, could serve to fuel how things evolve on the surface.
On this world, or on any other. Whether here or elsewhere, however,
it’s a discovery that takes us another step forward in our understanding of the vast and
complex natural processes that have brought us all to this point, right now. And that’s how
scientists have unearthed giant supermountains, and why that’s potentially extremely important.
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