Rocks and Erosion

Look at the layers in the rock. What kind of rock is this?

It’s sedimentary rock!

The Badlands in South Dakota

Wind and sand has caused continued weathering of the soft sedimentary rock.

Look at the layers of sediment. It tells you about the weather during the time the particles were deposited. The larger the sediment, the heavier and faster the flow of water.

These large stones were deposited first.

Then, this mud was deposited.

Next, larger stones were left

Look at the boulders way up on top!

Small plants, called lichens, make small cracks in the rock. Seeds can fall in the crack and grow.

Water can get in the cracks and freeze. That makes the cracks larger. Eventually the rock will break, or weather.

As the plants grow, their roots make larger cracks.

This hill is an example of soil erosion. Although trees help hold soil in place, the steep hill makes it easy for rainwater to carry soil downhill.

This is a red granite quarry in Wisconsin. Red granite is Wisconsin’s state rock.

Granite is very hard so buildings and monuments are often made of it.

Granite can be many different colors, but it all has large crystals.

What kind of rock is granite?

It is an igneous rock!! Granite is created from magma that cools

inside the earth, so crystals have more time to grow.

Diamond Head is a inactive volcano in Hawaii. The islands were created from underwater volcanoes. They are mainly igneous rock.