In East Antarctica, a vast mountain range is hidden beneath thousands of meters of ice where it’s been trapped for millions of years. Soviet scientists first discovered this geological wonder back in the 1950s, but new research is continuing show that this subglacial landscape is truly bizarre.
The frozen titans beneath the ice are known as the Gamburtsev Subglacial Mountains, located up to 3.1 kilometers (just under 2 miles) beneath the surface of the East Antarctic Ice Sheet, the largest ice sheet on this planet.
This vast network of rocky peaks and ridges stretches for around 1,200 kilometers (745 miles) and reaches heights of 3,400 meters (11,155 feet), meaning it rivals many of the great mountains that exist on Earth’s surface without a shield of ice.
Its size and stature are something of a head-scratcher. After millions of years of erosion, why hasn’t it been tamed into a smoother, more subtle mountain range? How have the peaks and valleys managed to be so pristinely preserved within the depths of the continent?
In a new study, geologists from the University of Tasmania and Macquarie University look back at its potential origins to understand why. It’s not possible to dig through the ice to grab samples directly from the rocks, the team had to rely on more inventive methods.
A radar image showing the Gamburtsev mountain range under layers of ice.
They turned to tiny crystals of zircon found in sandstone deposits located hundreds of kilometers away within sediment carried by ancient rivers that once flowed from the now-buried mountains over 250 million years ago. Because zircon contains uranium, which decays into lead at a predictable rate, researchers can use these crystals as natural clocks to reconstruct the timeline of ancient geological events.
Their work revealed evidence that the Gamburtsev Subglacial Mountains were created around 500 million years ago when the supercontinent Gondwana was formed by tectonic plates crashing together.
Just like the formation of more “normal” mountains, the tectonic plates pushed up against each other, causing the edges to push upwards and crinkle. However, the rest of the story isn’t so typical.
As the mountains rose and the crust grew thicker and hotter, the entire system became unstable and too heavy to support itself. Eventually, it began to give way under its own weight.
Deep beneath the surface, heated rocks softened and started to ooze outward. This sideways flow, known as gravitational spreading, caused parts of the mountain range to sag and collapse. Yet despite this surface collapse, a massive root of thickened crust remained anchored deep in the Earth, reaching down into the mantle below.
A whole continent made of solid ground is beneath Antarctica’s ice sheet. Scientists are constantly mapping its topology with the latest imaging techniques, but as this latest study shows, this colossal hidden landscape is full of surprises.
The study is published in the journal Earth and Planetary Science Letters.
Source Link: A Giant Mountain Range Has Been Hidden Under Antarctica's Ice For Millions Of Years
