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Published on Feb 18, 2008
If you were to explore the ground in almost any terrestrial region on Earth, chances are you would find soil. This layer of Earth's surface is essential to life. It supplies, both directly and indirectly, what we eat and wear, as well as the oxygen we breathe. Even so, it's easy to take soil for granted. You might assume that the soil near your home or elsewhere has been there forever. However, the land surface has changed dramatically over geologic time. For instance, depending on its location, soil formation may have been interrupted by volcanic activity, glacial movement, or climate change. In some parts of the world, entirely new land masses are forming as you read this. So what is soil, how does it form, and how does it support life?