Have you ever imagined what Antarctica appears to be like like beneath its thick blanket of ice? Hidden under are rugged mountains, valleys, hills and plains.
Some peaks, just like the towering Transantarctic Mountains, rise above the ice. But others, just like the mysterious and historical Gamburtsev Subglacial Mountains within the center of East Antarctica, are utterly buried.
The Gamburtsev Mountains are comparable in scale and form to the European Alps. But we are able to’t see them as a result of the excessive alpine peaks and deep glacial valleys are entombed beneath kilometres of ice.
How did they arrive to be? Typically, a mountain range will rise in locations the place two tectonic plates conflict with one another. But East Antarctica has been tectonically secure for thousands and thousands of years.
Our new examine, revealed in Earth and Planetary Science Letters, reveals how this hidden mountain chain emerged greater than 500 million years ago when the supercontinent Gondwana shaped from colliding tectonic plates.
Our findings provide recent perception into how mountains and continents evolve over geological time. They additionally assist clarify why Antarctica’s inside has remained remarkably secure for tons of of thousands and thousands of years.
A buried secret
The Gamburtsev Mountains are buried beneath the best level of the East Antarctica ice sheet. They have been first found by a Soviet expedition utilizing seismic strategies in 1958.
Because the mountain range is totally coated in ice, it’s one of the least understood tectonic options on Earth. For scientists, it’s deeply puzzling. How might such a large mountain range type and nonetheless be preserved within the coronary heart of an historical, secure continent?
Most main mountain chains mark the websites of tectonic collisions. For instance, the Himalayas are nonetheless rising in the present day because the Indian and Eurasian plates proceed to converge, a course of that started about 50 million years ago.
Plate tectonic fashions counsel the crust now forming East Antarctica got here from at the very least two giant continents greater than 700 million years ago. These continents was once separated by an enormous ocean basin.
The collision of these landmasses was key to the birth of Gondwana, a supercontinent that included what’s now Africa, South America, Australia, India and Antarctica.
Our new examine helps the concept the Gamburtsev Mountains first shaped throughout this historical collision. The colossal conflict of continents triggered the circulate of scorching, partly molten rock deep beneath the mountains.
As the crust thickened and heated throughout mountain constructing, it will definitely turned unstable and commenced to break down underneath its personal weight.
Deep beneath the floor, scorching rocks started to circulate sideways, like toothpaste squeezed from a tube, in a course of often known as gravitational spreading. This brought about the mountains to partially collapse, whereas nonetheless preserving a thick crustal “root”, which extends into Earth’s mantle beneath.
Crystal time capsules
To piece collectively the timing of this dramatic rise and fall, we analysed tiny zircon grains present in sandstones deposited by rivers flowing from the traditional mountains greater than 250 million years ago. These sandstones have been recovered from the Prince Charles Mountains, which poke out of the ice tons of of kilometres away.
Zircons are sometimes known as “time capsules” as a result of they comprise minuscule quantities of uranium of their crystal construction, which decays at a identified charge and permits scientists to find out their age with nice precision.
These zircon grains protect a report of the mountain-building timeline: the Gamburtsev Mountains started to rise round 650 million years ago, reached Himalayan heights by 580 million years ago, and skilled deep crustal melting and circulate that ended round 500 million years ago.
Most mountain ranges shaped by continental collisions are ultimately worn down by erosion or reshaped by later tectonic occasions. Because they’ve been preserved by a deep layer of ice, the Gamburtsev Subglacial Mountains are one of the best-preserved historical mountain belts on Earth.
While it’s at present very difficult and costly to drill by means of the thick ice to pattern the mountains instantly, our mannequin presents new predictions to information future exploration.
For occasion, latest fieldwork close to the Denman Glacier on East Antarctica’s coast uncovered rocks which may be associated to those historical mountains. Further evaluation of these rock samples will assist reconstruct the hidden structure of East Antarctica.
Antarctica stays a continent full of geological surprises, and the secrets and techniques buried beneath its ice are solely starting to be revealed.
Jacqueline Halpin is affiliate professor of geology, University of Tasmania. Nathan R. Daczko is professor of earth science, Macquarie University. This article is republished from The Conversation.
Published – May 13, 2025 09:00 am IST
