How do valleys form in mountains?
Show answer & explanation
Answer: Glaciers and rivers carve rock
Glaciers and rivers carve rock ✓ — Correct! Valleys form through erosion over millions of years. Rivers cut V-shaped valleys by wearing away rock and carrying sediment downstream. Glaciers carve U-shaped valleys—their immense weight and movement grind rock like sandpaper. Freeze-thaw cycles fracture rock, accelerating the process. Gravity pulls loosened material downhill, deepening valleys!
Wind erodes softer areas — Wrong. Wind can erode, especially in dry climates, but water and ice are far more powerful at carving mountain valleys.
Underground caves collapse — Wrong. While cave collapses create sinkholes, mountain valleys are primarily carved by surface erosion from glaciers and rivers.
More Earth Science questions
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- In folded Appalachians, why can one rock layer become a ridge while its neighbor becomes a valley?
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