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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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ScienceShot: Greenland’s Hidden Valley Revealed
29 August 2013 2:00 pm
This vast gorge might rival the Grand Canyon in splendor … if only it weren’t smothered by a couple of kilometers of ice. By stitching together data gathered by ice-penetrating radar equipment suspended from aircraft, researchers have discovered a massive canyon that has likely been hidden for millions of years. This unexpected, yet-to-be-named feature (colored mid- to dark brown in the exaggerated topography above) stretches 750 kilometers—about twice the length the Grand Canyon—from central Greenland (lower center of image) all the way to a fjord along the northwestern coast (top of image). It’s about as wide as the Grand Canyon (10 kilometers) and nearly half as deep at its deepest point (800 meters), the researchers report online today in Science. The proportions of the canyon, as well as its meandering path, suggest that the feature was carved by a great river well before the island was coated with ice, not by glacial action in the years since. Without the ice sheet that is now weighing down Greenland’s terrain, a river in the canyon would, on average, drop about 30 centimeters for every kilometer it flowed seaward, the team estimates. The continually dropping slope helps explain why northern Greenland, unlike Antarctica, has no large subglacial lakes: Meltwater that either forms at the base of Greenland’s ice sheet or ends up there after draining from the ice sheet’s upper surface flows away uninterrupted. This massive flow may also help explain the gargantuan channels on the underside of the floating ice shelf attached to the coast where this canyon meets the sea, the researchers contend. Previous studies have attributed those undersea channels—which measure between 1 and 2 km wide and extend up into the ice shelf as much as 400 meters—solely to the melting action of seawater.
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