`Antarctic mountains date back to dinosaur age`

Last Updated: Monday, November 21, 2011 - 21:53

Washington: The root of the mysterious range
of Antarctic mountains completely hidden under the continent`s
massive ice sheet may be over 200 million years old dating
back to the dinosaur age, scientists have claimed.

Researchers on a project to understand the Gamburtsev
Subglacial Mountains in East Antarctica better, said the
mountains rise up to 10,000 feet above the planet`s surface,
but are covered by up to 15,750 feet of ice.

"This icy coat makes them the least understood mountain
range on Earth," researcher Fausto Ferraccioli, a geophysicist
at the British Antarctic Survey, said.

"It is very fitting that the initial results of
Antarctica`s Gamburtsev Province project are coming out 100
years after the great explorers raced to the South Pole," said
Alexandra Isern at the National Science Foundation.

"The scientific explorers of the Antarctica`s Gamburtsev
Province project worked in harsh conditions to collect the
data and detailed images of this major mountain range under
the East Antarctic Ice Sheet. The results of their work will
guide research in this region for many years to come."

What details scientists have gathered about the mountains
provide conflicting evidence about how they got there and how
old they are. For instance, nearby rocks suggest they are very
ancient, but their steep, rugged shapes, which resemble the
Alps, are what one would expect of young mountains.

To learn more about their origins, the team collected new
data from the Gamburtsev region by flying about 120,000km with
two aircraft equipped with ice-penetrating radars, lasers and
magnetic and gravity meters.

Magnetic anomalies seen throughout the Gamburtsevs match
those of about one-billion-year-old rocks seen to the north
that predate the evolution of animals and plants on Earth.

This suggests the root of this mountain range was born
around that time from collisions of several continents or
microcontinents, findings corroborated by gravity and other
data, the team reported in journal Nature.

The research then suggested that rifting events between
250 and 100 million years ago, back when dinosaurs roamed the
Earth, triggered the uplift of these mountains. Specifically,
the rise of rock along the flanks of these rifts and the
buoyant root of these mountains forced the land upward.

Rivers and glaciers then cut deep valleys, giving these
mountains their rugged shapes. The East Antarctic Ice Sheet,
which currently covers one-tenth of Earth`s crust, then
entombed the range, preserving them as they are today, the
researchers said.

"Explorers that set foot on the moon for the first time
were confronted with many unknowns and challenges -- the same
holds true for the Gamburtsevs, in my view," Ferraccioli said.

"Unravelling the mystery of how the mountains formed by
analysing the new data and putting together bits and pieces of
a billion-year history of the region was really exciting."

The new geophysical images and models will help guide
future research on geological evolution and mountain-building
in this remote region for years to come, he added.

PTI



First Published: Monday, November 21, 2011 - 21:53

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