It’d probably be a shock discovering your favorite young-looking rock star is actually a centenarian, so imagine how these scientists felt discovering the stars of the show were at least ten times times older than that.
The researchers scaled eight supposedly “young and fresh” peaks in northwest Svalbard supposedly formed rapidly – geologically speaking – by severe erosion from glaciers about 10,000 years ago. But in a study published this month in the journal Nature Geoscience, they assert the mountains are actually at least one million years ago and the ice frequently preserved rather than reshaped the rocks.
“The findings turn upside down the established lessons about how the alpine landscape formed,” said Endre Før Gjermundsen, a geologist at The University Centre in Svalbard and lead author of the study, in a prepared statement.
The general assumption is alpine peaks were generally formed from repeated glaciations during the past ice age because “before this time, landscapes had much less relief,” according to the study. But after studying the exposure and burial histories of rock samples on Svalbard peaks between 800 and 1,500 meters high, it appears that’s wildly inaccurate.
“The antiquity of Svalbard’s alpine landscape is supported by the preservation of sediments older than one million years along a fjord valley, which suggests that both mountain summits and low-elevation landscapes experienced very low erosion rates over the past million years,” an abstract of the study notes.
As for the ice age 10,000 years ago, “glacial erosion in the Arctic became inefficient and confined to ice streams, and high-relief alpine landscapes were preserved by minimally erosive glacier armor.”
Still, that finding isn’t a rock-solid assumption for how the entire landscape formed.
“Our research shows that the glacial erosion processes are much more complex than we thought,” Gjermundsen said. “It seems that the glaciers have exhibited a ‘bipolar’ behavior, both as an erosive agent, but also as a conserving agent; even in alpine areas we thought were most prone to erosion.”
As moving rivers of ice, glaciers can have a “buzz saw” affect in shaping mountains and valleys, according to Gjermundsen. The difference with the mountains studied in Svalbard is the drier and colder Arctic climate kept many of the glaciers relatively steady.
The age of the rocks was determined by the amount of cosmic radiation they contained. The radiation initiates a reaction in the rock that formed isotopes, which become increasingly prevalent over time.