1.1 Why Study Petrology? Overview

More than 99% of the earth is made of igneous rocks, metamorphic rocks, and magmas. A knowledge of those rocks, their properties, and the processes that form them is essential to understanding the earth. Most igneous and metamorphic rocks are formed out of our sight, well below the earth’s surface. But some have found their way to the surface and we can get clues from those rocks about the ones we cannot see. Petrologists study igneous and metamorphic rocks to discover and decipher the clues they contain to reveal and interpret the processes that formed them.

Study igneous and metamorphic rocks if you want to know about the earth beneath its surface. Study igneous and metamorphic rocks if you want to understand how these rocks may have been formed, and the evidence for different possible interpretations of their history. Study igneous and metamorphic rocks if you admire their beauty and hope to read the stories written in their mineralogy, texture, and chemistry. Study igneous and metamorphic rocks and you may learn to love them.

Petrologic concepts are not inherently difficult to comprehend. However, the wide variety of igneous and metamorphic rocks and the language used to describe, name, discuss, and interpret them can be daunting. Those who study petrology learn paths through the maze of rock types and vocabulary and become familiar with the most common rocks. Similarly, the chemical data and phase diagrams used to interpret igneous and metamorphic rocks can be initially overwhelming. But those who study petrology learn to appreciate and extract useful information from rock chemistry and experimental results. By giving you interactive control over various diagrams used by petrologists, this website will help you explore and better understand their use.

If you are reading this, you already have some reason for looking at a website about igneous and metamorphic rocks. Therefore, you probably already have an answer to the question "Why study petrology?" If so, and if you are satisfied with the answers you have, skip this topic and move on to other topics, or diagrams, or tools, or the rock library. Choose from the menu items on the sidebar.

However, if you are not yet sure of the benefits of studying igneous and metamorphic rocks, more help is offered here. If you need motivation, click on the "Motivation Needed" button to see some examples of things that excite petrologists, some of the questions that petrology can address.


Alternatively, you might wish to hear what others who have studied petrology say when asked, "Why study petrology?" Click on the "Expert Opinions" button and then choose from a list of petrologists who have provided answers.


Or read some more about why you should study igneous or metamorphic rocks.