Reading Rocks — Reading Comprehension

Geologists study rock layers to learn about Earth’s past. These layers, also called strata, are formed over millions of years. Each layer can tell a story about what happened when it was made. For example, a sandy layer might show there was once a desert, while a muddy layer could mean there was a river or a lake.

Most rock layers are made from sedimentary rocks. These rocks form when pieces of sand, mud, and small stones are pressed together over time. Rain, wind, and rivers break down bigger rocks into tiny pieces, a process called weathering. These pieces are moved by water or wind and settle in new places. Over time, more layers pile up, and the weight turns them into rock.

Sometimes, living things like plants or animals get trapped in these layers. Their remains become fossils. By finding fossils in certain rock layers, scientists can tell what kinds of plants and animals lived long ago.

Rock layers can also show changes in the environment. For example, if a layer is tilted or broken, it might mean there was an earthquake or the land moved. This is called tectonic activity.

The Grand Canyon is a famous place where you can see many different rock layers. Each one is a different color and comes from a different time in Earth's history. By reading these layers, geologists can learn about ancient oceans, deserts, and forests that once covered the land.

Reading rock layers is like reading pages in a history book. Each layer holds clues about how Earth has changed over time, helping us understand where we come from and what our planet was like long ago.

Interesting Fact: The oldest rock layers in the Grand Canyon are over 1.8 billion years old!

What are rock layers also called?

What forms most rock layers?

Where can you see many rock layers?

Why might a rock layer be tilted?

What do fossils tell scientists?

What does a sandy layer show?

Rock layers are always flat. True or false?

What is 'weathering'?