Friday, March 8, 2013

Glaciers and mountains

Glaciers and mountains
Following pictures are same, except lower one has some lines added for illustration.
 
 

Let us discuss, how glacier made this valley. (You can click the pictures in this blog to enlarge them)
Yellow area in second picture shows the boundary of a glacier.
notice the red line, it makes the boundary that connects the highest points around this glacier. Any snow that falls within this boundary will become the part of this glacier.
Blue lines show the course of melting water, or semi melted snow.
As more snow falls, it will slide down the steep cliffs sooner or later, and will push the glacier further.
As the icy glacier moves, it will grind and cut more rubble from the rocks in its valley.
In long term, it makes the slopes on both sides unstable, and extra parts of the slopes fall down as a landslide to be carried away along the glacier.
Earthquakes speed up such landslides.(Remember mountain areas get more earthquakes)
Millions of years ago, area bounded by red line was almost a flat plateau. It has achieved this shape over time.
We can say "glaciers carved out these mountains".

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