❓ why
Why do mountain valleys often have U-shaped cross sections?
GeologyGlaciers
Quick Answer
Glaciers widen and deepen valleys much more than rivers do. Their grinding and plucking carve a broad U shape instead of a narrow V.
The Full Story
Rivers usually cut V-shaped valleys because they erode mostly downward. Glaciers, by contrast, are thick masses of moving ice that occupy the entire valley and erode the floor and sides at the same time. As they flow, they scrape, pluck, and quarry rock, turning a V-shaped river valley into a wider U-shaped trough. The Yosemite Valley in California is one of the most famous examples of glacial shaping.
Key Facts
1.Glaciers erode valley floors and walls
2.River valleys are usually V-shaped
3.Yosemite Valley is a classic U-shaped valley
YouTube Angle
Suggested video title for this topic:
"Why do glaciers carve valleys like giant scoops?"