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Glaciers Protect Alpine Peaks From Erosion
Hugh Pickens DOT Com writes "BBC reports that French scientists studying erosion on Mont Blanc have discovered that glaciers shield summits from erosion, acting as a protective lid and playing little part in erosion. In contrast, water and rain eroded glacier-free areas 10 times faster than areas protected by the glacier. These results may explain the high altitude of the Alps. Driven by the tectonic collision of Europe with Africa, the high alpine bedrock is rising about one millimeter each year. Glacier-free areas of the Alps erode at a similar rate but where the mountains are protected by ice, the peaks wear away at one tenth that rate. A long-term effect of this might be a rise in the maximum altitude of the Alps. 'However, mountains don't grow to infinity, so there must be another mechanism which has lowered the summit of Europe,' says Fritz Schlunegger. 'According to (Dr) Godon's findings, this erosion is not related to glaciers, so we still have to think about other possibilities.' Around the globe, mountain glaciers — especially those at low latitudes — are retreating in response to climate change. The glaciers around Mount Everest have lost more than one-eighth of their area in the past 50 years, and the snowline had retreated 180 meters up the mountain sides. The results suggest that changes like these could change the shapes of the world's highest mountains, and that climate and mountain landscape are intimately linked."
I have always been told the jaggy, sawtooth peaks in glacier areas were caused by the continual cutting action of glaciers sliding downhill. (Then again, maybe that is still true, just 10x slower than being exposed to the elements).
We will need more govt grant money to study the effects of this.
Most of the area of these glaciers is less than 13,000 years old. On the level of erosion of mountains, not significant. The glacier cover is quite new on this scale of time.
Help stamp out iliturcy.
FTFA - "Glacier-free areas of the Alps erode at a similar rate but where the mountains are protected by ice, the peaks wear away at one tenth that rate."
"Protected by ice" != "glacier"
Former glacial valleys, like in the UK looking down the A5 from Llyn Ogwen north-west towards Bethesda, are clearly far more eroded than the adjacent ridges. The valley is a huge U-shaped gouge, straight through the surrounding mountains,.
A shot of brandy in the formula works well.
" there must be another mechanism which has lowered the summit of Europe,"
A couple of possibilities: During an ice age, when ice cover is in kilometres, the glacier could be wearing down the mountain tops if there is lateral movement of the ice. During a warm age there could be no ice but heavy rains that wear away the mountain tops.
Disclaimer: I am not a geologist. :)
News at eleven...
Really? This is news?
Cause the Alps to crumble away? Are humans to blame for destroying them?
I'd mod, but I want to reply.
One of the things that I love about the book of Genesis and Adam and Eve, is that it describes a unique geologic situation: A single river, in the mountains, that splits into four rivers while still in the mountains.
To me, that means that there had to have been significant glacial melting. That, in turn, means that there had to be significant temperature moderation. Looking at the region of Turkey [the four rivers seem to go around the Republic of Georgia, and kush -- not Ethiopia, but Western Turkey where there also was a Cush and a city kushdar -- and the Tigris and Euphrates], we see that Ararat has glaciers. But the "significant moderation of temperatures" would have occurred when the Black Sea filled. That, then, date stamps the story to be around, say, 5600 BC.
So glaciers form, and glaciers melt, and while they are there, they protect the surface. When they melt, they gouge the surface. Moreover, they don't have to melt entirely.
So, then, this just means that erosion of glaciated mountains is sporadic, not continuous.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
Sounds like the glaciers are behaving as they were designed: to eventually melt.
Sorry to rain on your parade, but the mountains are way older than 13000 years. Maybe you are referring to the ice that's on them? There has been ice on them much longer as well. It's just the current layer of ice that isn't that old, due to the fact that it erodes and slides down the mountain. I doubt the age of the current bits of frozen water is relevant to how much it protects the mountain side from wind and sun erosion, it will be the fact that it's covered that matters.
I was promised a flying car. Where is my flying car?
OMG OMG those mountains will be gone in 30 million years now !!!!
Remember that glaciers also carve out valleys in their flowdown the mountainsides. Slow but a great deal of force.
To hear Catastrophists like Prof. Richard Alley go on and on and on and on about the 'Glacier Buzzsaw' makes many in his audience emit buzzing sounds of snoring.
But a simple observation will endure.
Take the Himalaya-Karakorim and the St. Elias Mountains for example. Each occur along active tectonic plate boundaries. Subduction processes rule for the Himalaya-Karakorim Mountains and transpression-transtension processes for the the St. Elias Mountains. Both are geologically young, a few million years (we humans and forebears have existed for only much less than one millionth of time by comparison). And we find the Himalaya-Karakorim and St. Elias Mountains, the highest elevations on Earth are capped by perennial snow fields and glaciers. Where is Alley's 'Buzz Saw'? Answer: No where to be found! Alley is WRONG! The AGU and IPCC should stop listening to Prof. Alley and just look out their windows to witness reality. Else, people will say they are ... "Queer".