sciencenewsThe work bolsters the counterintuitive notion that glaciers, rather than just carving down young peaks into eroded hills like a buzzsaw, could sometimes protect high jagged terrain.
“It’s feasible for topography to be preserved,” says Stephen Cox, a graduate student at Caltech and coauthor of a paper scheduled to appear in Geophysical Research Letters. A supercold cap of ice could have allowed the ancient Gamburtsevs to look like the Alps instead of the highly eroded Appalachians.
Russian scientists first identified the Gamburtsevs in 1958 as part of a survey during the International Geophysical Year, and geologists have been puzzled ever since about how the range came to be. The mountains are in a stable part of the continent that hasn’t seen much tectonic activity — usually the way mountains are born — in more than 500 million years. “The Gamburtsevs are either really old, or some big part of the tectonic puzzle is missing,” says Cox.
His team tackled the question by looking at how quickly the mountains eroded over time. Because the range is buried, researchers have to study it indirectly — in this case by probing mineral grains at the bottom of Prydz Bay in East Antarctica, where pieces of rock washing off the Gamburtsevs ended up.
Grains of the mineral apatite preserve a record, known as a cooling age, of how fast the mountains were eroded. Cox’s team analyzed the apatite in two ways — the amounts of uranium, thorium and helium it contained, and the number of “fission tracks” left by decaying uranium — to build a cooling history of the Gamburtsevs.
Read more at Wired
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