TEXT: BREAK IT & MOVE IT

Glaciers could never make the track team. Most of them move too slowly – only 25 centimeters a day. They creep along, changing everything underneath them. Glaciers melt and refreeze which weakens the structure of the rocks in and under them. Great force from a glacier’s weight presses down on the rocks. Glaciers weather (break down) rocks as they move.

Force from the weight, along with melting and refreezing, moves the ice along. Water that melts from the glacier collects below and also helps the heavy ice to move. It carries and pushes the weathered rocks. The glacier erodes (moves) rocks from their original place. These weathered and eroded rocks can be found hundreds of miles away. This is called deposition (adding sediments to land).

As a glacier weathers and erodes the land in its path, it carves out a specific kind of valley. Because glaciers are wide, their valleys are U-shaped, with steep sides and a round valley floor. Glaciers may not be fast, but they are stronger than the whole weight-lifting team.

VIDEO: HOW DO GLACIERS MOVE?

Before we learn how glaciers change Earth’s surface, let’s learn how they move.

Click the link to watch the 7 minute video clip to learn how the Mendenhall Glacier in Juneau, Alaska moves.

How Glaciers Carve U-Shaped Valleys

Imagine a massive river of ice slowly moving down a mountain, so heavy and powerful that it can reshape entire landscapes. That's exactly what glaciers do! These incredible ice giants are like nature's sculptors, and one of their most impressive masterpieces is the U-shaped valley.

What is a U-Shaped Valley?

A U-shaped valley looks exactly like its name suggests - it has steep, nearly vertical sides and a flat, wide bottom, just like the letter "U". Unlike V-shaped valleys carved by rivers, which have pointy, sloping sides, glacier valleys are much wider and more dramatically shaped.

How Do Glaciers Create These Valleys?

Glaciers are extremely powerful. As they move slowly down a mountain, they do three important things:

1. Scrape the ground: The massive weight of the glacier presses down on rocks and soil.

2. Carry rocks: As the glacier moves, it picks up rocks and carries them along.

3. Erode the landscape: These rocks act like sandpaper, grinding away at the mountain sides and bottom.

Over hundreds or even thousands of years, the glacier cuts deeper and wider, creating a broad, U-shaped valley. When the glacier eventually melts, it leaves behind this distinctive landscape.

Real-World Examples

You can find U-shaped valleys in many mountainous regions around the world. Some famous examples include:

• Yosemite Valley in California, USA

• Glacier National Park in Montana, USA

• The Norwegian fjords

• Many valleys in the Alps of Switzerland and France

A Slow but Powerful Sculptor

Glaciers might move slowly - sometimes just 25 centimeters per day - but they are incredibly strong. They can reshape entire mountain landscapes, turning rough, jagged terrain into smooth, wide valleys that tell the story of Earth's incredible geological history.