Antarctica is the continent of the superlatives: the coldest (the record: - 94.5o C), the driest (20 mm annually), the remotest and the highest continent, with an average height of 2,450 m or 8,170 ft (the second highest continent, Asia is just 960 m (3,200 ft) high).
The Transantarctic Mountains across the frozen continent split the continent in two. These mountains are connected with alpine chains in South America, that's why they are called the Antarctic Andes.
Transantarctic Mountains form one of the longest mountain chains in the world, stretching over 2,200 mi (3,500 kilometers) and many of their heights go beyond 4,500 m (2.5 mi) in height. The highest of their peaks is "Committee Range", 6096 m (Everest is 8,848 m tall). The geographic South Pole is located at a 2804 m
altitude.
But the origins of these huge mountains have been wrapped in mystery. A new research suggests they are the remains of a gigantic high plateau that collapsed as the earth split off. Usually, Earth's highest mountain ranges (like Himalaya or Andes) typically emerge when massive tectonic plates impact against each other.
The puzzle was triggered by the fact that normally mountains resulted from Earth's crust rifting apart, like the foothills of the Red Sea, are much lower.
"The Transantarctic Mountains are nearly an order of magnitude larger than other mountain ranges formed the same way," said geophysicist Michael Studinger at Columbia University's Lamont-Doherty Earth Observatory.
Now Studinger's team shows this Antarctic mountain range is what was left from the edge of a gigantic plateau the size of France that was over 2 mi (3 km) tall. Thus, these mountains are so high now because the area was already high before their formation.
Studinger's team flew in airplanes over the Antarctica assessing the gravity field of the Earth, which can have different values over the planet's surface determined by how much rock is stored underneath a given point. It appeared that the interior of this tall plateau collapsed somewhat in the manner of a failed souffl.
"This is something that commonly happens because the plateau's interior gets too hot. High, elevated plateaus eventually become unstable. But the edges of such plateaus are probably cooler and thus stiffer, so they remain high." said Studinger.
The rifting process started about 105 million years ago, leaving the peaks along the edge of a great plain and the ruggedness of the mountain chain was further stressed by glaciation that eroded the rocks.
"There's all kinds of information that has been published that has sometimes been known about for decades that support this idea. For instance, we know streams in the Transantarctic Mountains have flowed in the other direction-we think that's because what was once high was low and vice versa."
The Transantarctic Mountains are one shoulder of the rift, but "we think the other shoulder is simply no longer there. Antarctica was part of [the super-continent called] Gondwanaland, and when it broke away during the Mesozoic, we think this rift shoulder simply disappeared and is part of what is now New Zealand," said Studinger.
"To understand the onset of glaciation in Antarctica, it's important to know when the mountains were there and how high they were," he added.
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