Ancient Oceans Where Mountains Stand Today — Reading Comprehension

The tall mountains we see today were not always there. Millions of years ago, many mountain ranges were actually covered by deep oceans. Over long periods of time, Earth’s surface changed in amazing ways.

One important process is called plate tectonics. Earth’s outer layer is made of large pieces called plates. These plates move slowly, sometimes crashing into each other or pulling apart. When two plates collide, the land can get pushed up to form mountain ranges. This is how the Himalayas and the Alps were formed.

Before these mountains existed, the area was under the ocean. Over time, sediment—tiny bits of rock and sand—settled on the ocean floor. Layers of sediment built up and pressed together to become sedimentary rock. Sometimes, the remains of sea creatures were trapped in these layers. These remains became fossils, which are still found today high up in mountain rocks.

When the plates moved and pushed the ocean floor up, those layers of sedimentary rock rose to become mountains. That is why scientists can find seashell fossils on top of tall mountains, far from any ocean today. These fossils tell us that the area was once underwater.

Understanding how mountains were once oceans helps people find useful things, like minerals and oil, that formed in ancient seas. It also shows how powerful and slow Earth’s changes can be.

Interesting Fact: Fossils of ancient sea creatures have been found at the top of Mount Everest, the tallest mountain in the world!

What covered many mountains long ago?

What do fossils on mountains show?

Which rock forms from sediment?

What happens when plates crash together?

Why are seashells found on mountains?

How do scientists use this knowledge?

Plate tectonics means plates move.

What is a fossil?