500-Million-Year-Old Mountains Beneath Antarctic Ice Could Hold Secrets To Earth’s Past
A 5-mile-long stretch draped across the South Pole recently caught the attention of scientists. Accommodating nearly 30 million cubic kilometers of ice and almost 60% of Earth’s fresh water, this white-flecked stretch is the familiar guy called Antarctica. From the space, it appears to be an ordinary icy white landscape. Zoom in further, and it reveals that it is, in fact, a gigantic dome of ice that encapsulates bizarre mysteries entombed beneath its layers. In a recent study published in Earth and Planetary Science Letters, a team of scientists has uncovered a mysterious mountain range that has been hidden beneath the Antarctic ice for the past 500 million years. The name is Gamburtsev Subglacial Mountains.
The story of Gamburtsev began about 700 million years ago. Earth’s crust, which is composed of several tectonic plates, like puzzle pieces, began to jiggle. Provoked and stimulated by the torrent of elemental forces churning within the mantle, some larger plates started moving towards each other, ultimately heading for a massive collision. Before the collision, the plates were separated by huge expanses of the vast ocean. But as they collided, enormous heaps of the hot crustal material rose in towering masses, blazing with the ooze of scorching magma and lava bursting from the mantle’s mouth. The heap of accumulating tectonic material ballooned into the mountainous supercontinent Gondwana.
Triggered by the colossal clash of tectonic plates, the crust thickened and eventually became unstable. About 180 million years ago, the supercontinent started experiencing a breakup, burdened by its own weight. In a process called “gravitational spreading,” these hot rock fragments, mixed with magmatic material, began to flow sideways in the same way as “toothpaste is squeezed out of the tube,” researchers described. As Gondwana collapsed, the present-day Antarctica piece escaped to the South Pole, where it remained isolated for millions of years.
By 34 million years ago, this isolated piece was already covered in a thick cloak of ice, which has persisted to date. In the latest study, scientists discovered that the Gamburtsev mountain range likely emerged during this collision and then got buried under the East Antarctic Ice sheet. Ever since, this mountain chain has been sitting, untouched, under this ice sheet. While erosions, sparked by winds, water, and soils, often destroy mountain belts, Gamburtsev has remained perfectly preserved. A black-and-white radar image shared by the researchers shows the mountains enshrined beneath a thick blanket of ice.
For the latest study, scientists were interested in investigating the collage of Gamburtsev’s architecture to map out the geological time trail of its metamorphosis. Mountain chains often hide clues to the past tectonic collisions. Their ridges, bumps, crevasses, and deformations hold fascinating stories of Earth’s geological history. The Great Himalayas, for instance, emerged about 50 million years ago, triggered by the crashing of the Indian and Eurasian plates. As the plates continue to dance with each other, the mountains continue to rise, per The Conversation.
To unfurl the stories trapped inside Gamburtsev’s gouging valleys and undulating curves, scientists extracted rock samples. In the laboratory, they crushed the rocks to extract zircon crystals. For a scientist, a zircon crystal is a precious “time capsule” that locks within it the tales of geological history that cannot be found anywhere else. Scientists used high-resolution back-scattered electron images, powerful lasers, and mass spectrometers to estimate the chronology of Gamburtsev from these crystals.
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