Book 20, Question 24
Can a Mountain Wear Away to Nothing?
Yes, a mountain can wear away, but it takes millions of years! Rain, ice, wind, and rivers slowly break rock into pieces and carry it away. This wearing away is called erosion.
More fun facts
- The Appalachian Mountains formed when continents collided between 500 and 300 million years ago.
- In their prime, the Appalachians probably had peaks as high as the modern Himalayas and Alps.
- Over the past 300 million years, the Appalachians have eroded to more modest heights.
- Africa collided with ancestral North America around 270 million years ago, as the supercontinent Pangea formed.
- The Appalachian Mountains we see today are just the remnant cores of much taller mountains.
- As sandstone and quartzite from the mountains break into smaller pieces, they form sand, and some reaches the beaches of the Gulf and Atlantic.
- Hard rocks made from pebbles and sand resist erosion and form the peaks we see today.
Sources: National Park Service, U.S. Geological Survey
Questions kids ask
Were the Appalachians once taller?
Yes. They probably once had peaks as high as the Himalayas, but erosion has worn them down over 300 million years.