Mountain Range Hiding Beneath Antarctica’s Ice Frozen in Time, Study Finds

Have you ever imagined what Antarctica looks as if underneath its thick blanket of ice? Hidden under are rugged mountains, valleys, hills and plains.

Some peaks, just like the towering Transantarctic Mountains, upward thrust above the ice. But others, just like the mysterious and historical Gamburtsev Subglacial Mountains in the course of East Antarctica, are totally buried.

The Gamburtsev Mountains are an identical in scale and form to the European Alps. But we will be able to’t see them since the prime alpine peaks and deep glacial valleys are entombed underneath kilometres of ice.

How did they arrive to be? Typically, a mountain vary will upward thrust in puts the place two tectonic plates conflict with every different. But East Antarctica has been tectonically strong for hundreds of thousands of years.

Our new find out about, printed in Earth and Planetary Science Letters, finds how this hidden mountain chain emerged greater than 500 million years in the past when the supercontinent Gondwana shaped from colliding tectonic plates.

Our findings be offering recent perception into how mountains and continents evolve over geological time. They additionally lend a hand give an explanation for why Antarctica’s inner has remained remarkably strong for masses of hundreds of thousands of years.

A buried secret

The Gamburtsev Mountains are buried underneath the perfect level of the East Antarctica ice sheet. They have been first found out via a Soviet expedition the use of seismic tactics in 1958.

Because the mountain vary is totally coated in ice, it is one of the vital least understood tectonic options on Earth. For scientists, it is deeply puzzling. How may just the sort of large mountain vary shape and nonetheless be preserved within the center of an historical, strong continent?

Most primary mountain chains mark the websites of tectonic collisions. For instance, the Himalayas are nonetheless emerging lately because the Indian and Eurasian plates proceed to converge, a procedure that started about 50 million years in the past.

Plate tectonic fashions counsel the crust now forming East Antarctica got here from no less than two massive continents greater than 700 million years in the past. These continents was once separated via an infinite ocean basin.

The collision of those landmasses used to be key to the start of Gondwana, a supercontinent that incorporated what’s now Africa, South America, Australia, India and Antarctica.

Our new find out about helps the concept the Gamburtsev Mountains first shaped all through this historical collision. The colossal conflict of continents brought on the drift of sizzling, partially molten rock deep underneath the mountains.

As the crust thickened and heated all through mountain constructing, it ultimately was volatile and started to cave in below its personal weight.

Deep underneath the skin, sizzling rocks started to drift sideways, like toothpaste squeezed from a tube, in a procedure referred to as gravitational spreading. This brought about the mountains to partly cave in, whilst nonetheless retaining a thick crustal “root”, which extends into Earth’s mantle underneath.

Crystal time drugs

To piece in combination the timing of this dramatic upward thrust and fall, we analysed tiny zircon grains present in sandstones deposited via rivers flowing from the traditional mountains greater than 250 million years in the past. These sandstones have been recovered from the Prince Charles Mountains, which poke out of the ice masses of kilometres away.

Zircons are incessantly known as “time capsules” as a result of they include minuscule quantities of uranium of their crystal construction, which decays at a recognized charge and permits scientists to resolve their age with nice precision.

These zircon grains maintain a report of the mountain-building timeline: the Gamburtsev Mountains started to upward thrust round 650 million years in the past, reached Himalayan heights via 580 million years in the past, and skilled deep crustal melting and drift that ended round 500 million years in the past.

Most mountain levels shaped via continental collisions are ultimately worn down via erosion or reshaped via later tectonic occasions. Because they have been preserved via a deep layer of ice, the Gamburtsev Subglacial Mountains are one of the vital best-preserved historical mountain belts on Earth.

While it is these days very difficult and costly to drill during the thick ice to pattern the mountains immediately, our style provides new predictions to lead long term exploration.

For example, contemporary fieldwork close to the Denman Glacier on East Antarctica’s coast exposed rocks that can be comparable to those historical mountains. Further research of those rock samples will lend a hand reconstruct the hidden structure of East Antarctica.

Antarctica stays a continent filled with geological surprises, and the secrets and techniques buried underneath its ice are handiest starting to be published.

Jacqueline Halpin, Associate Professor of Geology, University of Tasmania and Nathan R. Daczko, Professor of Earth Science, Macquarie University

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