for National Geographic News
The existence of a massive Antarctic mountain range buried under miles of ice has become an even deeper mystery, a new study says.
The little-researched Gamburtsev Mountains seem to challenge geologic patterns seen in other mountain ranges on Earth.
For one, the range is situated in the middle of the continent instead of on the edge—at the plate-tectonic boundaries—like most other mountains. (See a high-resolution map of Antarctica.)
The range's high peaks reach an elevation of about 10,000 feet (more than 3,000 meters)—heights typical of relatively young mountain ranges, such as the spiky Rockies and the European Alps.
New findings based on river sediments, which suggest the range is more than 500 million years old, are intriguing, experts say.
Older mountains, such as the Appalachian range in the eastern U.S., are thought to be shorter and less rugged after hundreds of millions of years of erosion.
Because the Gamburtsev range is tall, some scientists have argued it must have formed relatively recently—within the last 60 million years or so.
And because it's not near a tectonic boundary, some have suggested the range rose up as the result of magma buildup around a theoretical volcanic hot spot.
(Related: "Under-Ice Volcano Eruption Spewed Ash Over Antarctica" [January 21, 2008].)
"The hypothesis that the mountains are derived from young volcanic activity is hard to reconcile with our data," said study lead author Tina van de Flierdt of the Imperial College London.
Hard to Reconcile
Scientists examined sediments collected from a coastal area that would have been a vast delta about 35 million years ago, when Antarctica's rivers carried flowing water instead of glacier ice.
SOURCES AND RELATED WEB SITES