Geology

Geology is the study of the history of Earth. It is thought that Earth is about 4.6 billion years old. It has a very long history. Rocks provide a lot of important information about what happened in the past. Geologists study rocks to determine how they were made.

There are a few rocks that are made of just one mineral—such as marble or quartzite—but most rocks are made up of more than one mineral. Most rocks have elements such as silicon, carbon, iron, and oxygen.

The outer layer of the Earth is called the crust. At this point, we are not able to directly study anything below the Earth’s crust. We are only able to drill down a few miles. This makes it difficult to study what is going on inside the Earth, but rocks and the ground are constantly being shuffled and pushed around through the years.

One way that rocks are formed and built up is from volcanic activity. Magma lies beneath the Earth’s crust and is forced to the surface. Rocks are moved and overturned from earthquakes. All rocks are broken down by a process called weathering. The weather plays a role in erosion and the breakdown of rocks. Water, rain, ice, and wind all contribute to the breaking down of rocks.