Innovative technology, which accurately captures how mountains bend to the raindrops, has helped solve an ancient scientific mystery.
The dramatic impact of precipitation on the evolution of mountain landscapes is widely discussed among geologists, but new research led by the University of Bristol and published today in Scientific achievements, clearly calculates its impact, continuing our understanding of how peaks and valleys have evolved over millions of years.
Its results, which focused on the most powerful mountain ranges ̵1; the Himalayas – also pave the way for predicting the possible impact of climate change on landscapes and, in turn, on human life.
Lead author Dr. Byron Adams, a member of the Royal Society of Dorothy Hodgkin, a member of the Cabot University Institute for the Environment, said: “It may seem intuitive that more rain can form mountains, causing rivers to cut rocks faster. But scientists also believe rain can destroy the landscape fast enough to essentially “suck” rocks out of the Earth, effectively lifting mountains up very quickly.Both of these theories have been debated for decades because the measurements needed to confirm them are so painstakingly complicated. strongly supports the idea that atmospheric and solid terrestrial processes are closely linked “
Although there is no shortage of scientific models to explain how the Earth works, it can be a bigger challenge to make good enough observations to verify the most accurate ones.
The study was based in the central and eastern Himalayas of Bhutan and Nepal, as this region of the world has become one of the most selective landscapes for studying the level of erosion. Dr. Adams, along with staff at the University of Arizona (ASU) and the University of Louisiana, used a space clock in sand grains to measure the speed at which rivers erode rocks beneath them.
“When a space particle from outer space reaches Earth, it is more likely to fall on the grains of sand on the slopes of the hills when they are transported to rivers. When this happens, some atoms in each grain of sand can become a rare element. present in a bag of sand, we can count how long the sand has been there and therefore how quickly the landscape is eroding, ”said Dr. Adams.
“Having obtained erosion rates from the entire mountain range, we can compare them with variations in river steepness and rainfall. However, such a comparison is extremely problematic because each data point is difficult to compile and the statistical interpretation of all data together is difficult.”
Dr. Adams overcame this problem by combining regression techniques with numerical models of how erosions are destroyed.
“We tested a wide range of numerical models to reproduce the observed picture of erosion rates in Bhutan and Nepal. In the end, only one model was able to accurately predict the measured erosion rates,” said Dr. Adams. “This model allows us to quantify, for the first time, how precipitation affects cross-country erosion.”
Researcher Professor Kelin Whipple, a professor of geology at ANU, said: “Our findings show how critical it is to consider rainfall when assessing patterns of tectonic activity using topography, and provide an important step forward in how fast sliding tectonic faults can be controlled. climatic erosion on the surface “.
The study also has important implications for land management, infrastructure maintenance and hazard in the Himalayas.
In the Himalayas, there is a constant risk that high erosion rates could dramatically increase sedimentation behind dams, jeopardizing critical hydropower projects. The results also suggest that more rainfall could blow up hillsides, increasing the risk of debris flows or landslides, some of which could be large enough to dam the river, creating a new danger – flooding from a lake outbreak.
Dr Adams added: “Our data and analysis provide an effective tool for assessing erosion patterns in mountainous landscapes such as the Himalayas and can therefore provide an invaluable insight into the dangers that affect hundreds of millions of people living in and at the foot of these mountains. “.
The research was funded by the Royal Society, the British Council on the Environment (NERC) and the US National Science Foundation (NSF).
Based on this important study, Dr. Adams is now studying the reaction of landscapes after large volcanic eruptions.
“This new milestone in modeling landscape evolution is also shedding new light on volcanic processes. Thanks to our advanced methods of measuring erosion rates and rock properties, we can better understand how rivers and volcanoes have affected each other in the past,” Dr. Adams said. “It will help us more accurately predict what is likely to happen after future volcanic eruptions and how to address the consequences for nearby communities.”
Erosion of the Himalayas is regulated by tectonic movements, limiting the impact of climate change on the formation of the landscape
Climate control of erosion in tectonic active landscapes, Scientific achievements (2020). advances.sciencemag.org/lookup… .1126 / sciadv.aaz3166
Provided by the University of Bristol
Citation: The groundbreaking discovery finally proves that rain can really move mountains (2020, October 16) was obtained on October 17, 2020. From https://phys.org/news/2020-10-groundbreaking-discovery-mountains.html
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