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How Glaciers Move Mountains

written by: Matt Schelke•edited by: Niki Fears•updated: 12/15/2008

Glaciers, previously thought to cause mere surface erosion, actually have significant effects on a mountain's interior structure. Discover the details of this stunning discovery and how it effects our knowledge of climate.

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    Humans have always been fascinated by mountains. Ancient Polynesians had myths of volcanoes; the Greeks worshipped their gods on Mount Olympus. In the 20th century, mountaineering exploded. After Edmund Hillary’s first ascent up Everest, climbing was the hot new sport. But scientists have recently discovered that these monoliths may be affected in different ways than had been previously thought.

    Huge mountain ranges are formed by plate tectonics. Essentially, the earth is divided up into thick, slowly moving plates that cover thousands of square miles of land. When two of these plates collide, their edges are forced up, forming a mountain range. The Himylayas, for example, were created during the collision of the Indian subcontinent plate with the Asian plate.

    However, a team of scientists from the Virginia Tech Geosciences Department has found that more than just the plates influence mountain growth- erosion, and especially glacial erosion, is a major player.

    This may not seem exciting at first, but stop and think. Erosion changes the surface of a mountain, not the mountain’s interior processes. So how can a simple glacier change the movement of a whole mountain, and by extension, the movement of these gian plates?

    Aaron L. Berger, one of the researchers on the project, makes an analogy with a bulldozer. As a bulldozer pushes dirt, the dirt forms into a wedge shape. But if you remove dirt from the edges of the wedge, the bulldozer will push new dirt into the open space. It’s the same with mountains. Imagine that one of the plates is like a bulldozer, pushing into the other plate. If there’s a glacier eroding the “pushee”, then the pushee will fold and fault to fill the vacant space.

    One of the key implications of this discovery is that is reveals a connection between climate and mountain building. Glaciers, precipitation, and other agents of erosion are related to global temperatures. If temperatures rise (which is the current trend), the reforming of mountains described above may not occur due to lack of glacial ice. But, if pollution rises, the concentration of acids in rain will increase and concomitantly increase mountainous erosion.

    So what can this discovery teach us? First, it shows that natural processes are far more intertwined than previously thought. If glaciers can affect tectonic plate movement, what else can they affect? Second, it tells us that the effects of pollution and global warming are far more permanent than most average citizens think. Imagine if, by spraying a pesticide, you can move a mountain.