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Mountains rise because glaciers

27 Sep

mountainsIrregularity and roughness of the mountain peaks, most scientists attribute the action of glaciers. Always been assumed that the ice, advancing and retreating, and destroys the surface, causing erosion of rocks and cuts off the top. Looks like Dr. Stuart Thomson (Stuart N. Thomson), University of Arizona and his colleagues at Yale University, the University of Chile and University of Illinois failed to disprove the conventional wisdom. Scientists studied the features of rocks in the mountain Terra Del Fuego in the southernmost Andes and concluded that at this point be frozen in ice in rocks, bonding them and not allowing to develop erosion.
In such circumstances, the glaciers are the frame, a kind of armor, not giving the mountain tops to collapse. “Thomson Research shows that glaciers do not always destroy the rocks. Under certain climatic conditions, they are contrary restrain erosion. This means that the climatic conditions, favorable or not favorable to the erosion, affect the shape and dynamics of the mountains “- Dr. Brown wrote in the article, commenting on the study of Thomson. In the south, the Andes Mountains are not destroyed
Has always been, explains Thompson, that the height and power of rock mass depends on how clearly expressed in the region erosion. That is, if the rate of destruction of rocks as it changes – for example, by cooling or warming, it immediately affects the height and contours of the mountain peaks. For example, there is a zone of ablation (or melting), located below the power of the glacier. That’s where the glacier most of all it destroys the underlying rock. Now scientists believe that such a pattern of acts across the globe.
“According to our research, this relationship in the most southern tip of the Andes is not working. This area is indeed covered by glaciers. The paradox is that the height of the mountains increases towards the south, but at the same time high and growing area, where erosion would be to place the maximum rate “, – says Thomson.
To find out what is the reason for the paradox, Thomson and his colleagues decided to explore the contemporary erosion processes in this region of the Andes. They collected about 150 specimens and dated by isotopic analysis to determine when and at what rate species released from the burden of the glacier and how much they were exposed to erosion. The authors found that samples from the southernmost tip of the Andes (where the highest mountain) – the oldest. This means, Thomson concludes that these rocks just slowly eroded over the last five million years old (it was then covered Andes glacier).
But why is the icing on the southern Andes suspend erosion, and to the north, on the contrary, the destruction of rocks occur rapidly? Thomson found the answer to this question. “Our findings show that in cold climates, and conditions such as time and exist in the Andes, the glacier does not slip from the rocks, and freeze in them. So it protects the mountain, like the strong frame, rather than destroying them, as has always been “- sums up its work, Thompson said.

 
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Posted by on September 27, 2010 in Historical

 

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