Impact of rainfall reaches to roots of mountains

Apr 20, 2006

The erosion caused by rainfall directly affects the movement of continental plates beneath mountain ranges, says a University of Toronto geophysicist — the first time science has raised the possibility that human-induced climate change could affect the deep workings of the planet.

“In geology, we have this idea that erosion’s going to affect merely the surface,” says Russell Pysklywec, a professor of geology who creates computer models where he can control how a range of natural processes can create and modify mountains over millions of years. Pysklywec conducts field research in the Southern Alps of New Zealand, where the mountains are high and geologically “young.”

He found that when mountains are exposed to New Zealand-type rainfall (which causes one centimetre of erosion per year) compared to southern California-type rainfall (which erodes one-tenth of a centimetre or less), it profoundly changes the behaviour of the tectonic plates beneath the mountains.

“These are tiny, tiny changes on the surface, but integrating them over geologic time scales affects the roots of the mountains, as opposed to just the top of them,” says Pysklywec. “It goes right down to the mantle thermal engine — the thing that’s actually driving plate tectonics. It’s fairly surprising — it hasn’t been shown before.”

It takes a supercomputer several days to run one of Pysklywec’s models, which reveal the inner workings of the Earth to hundreds of kilometres below the surface, where the temperature can reach 1,500 degrees Celsius. In extreme conditions, he says, the erosion effect can even cause the underlying plate to reverse direction. “As a concept, imagine blanketing the European Alps with a huge network of ordinary garden sprinklers. The results suggest that the subtle surface weathering caused by the light watering have the potential to shift the tectonic plates, although you would have to keep the water on for several million years.” In the long run, says Pysklywec, it raises the question of whether human activity, which is affecting climate, could ultimately influence deep Earth processes. “That’s what these findings suggest,” he says. “We’re talking millions of years, but it’s one more example of how all these natural systems are interrelated.”

The study appears on the cover of the April issue of Geology and was funded by the Natural Sciences and Engineering Research Council of Canada and Lithoprobe.

Source: University of Toronto

Explore further: NASA's space station Robonaut finally getting legs

add to favorites email to friend print save as pdf

Related Stories

Quest for extraterrestrial life not over, experts say

2 hours ago

The discovery of an Earth-sized planet in the "habitable" zone of a distant star, though exciting, is still a long way from pointing to the existence of extraterrestrial life, experts said Friday. ...

Recommended for you

NASA's space station Robonaut finally getting legs

57 minutes ago

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Quest for extraterrestrial life not over, experts say

Apr 18, 2014

The discovery of an Earth-sized planet in the "habitable" zone of a distant star, though exciting, is still a long way from pointing to the existence of extraterrestrial life, experts said Friday. ...

Sun emits a mid-level solar flare

Apr 18, 2014

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

Impact glass stores biodata for millions of years

Apr 18, 2014

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

The importance of plumes

Apr 18, 2014

The Hubble Space Telescope is famous for finding black holes. It can pick out thousands of galaxies in a patch of sky the size of a thumbprint. The most powerful space telescope ever built, the Hubble provided ...

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...