Earth Materials Introduction to Mineralogy and Petrology

The Earth has had a long history – 4.56 billion years, give or take a few million – but most of its chemical elements were created at a much earlier time. Most of this book is devoted to how atoms (or ions) fit together to form minerals, the basic building blocks of the Earth, and how such minerals became part of what we refer to as rocks. In this introductory chapter, however, we briefly cover the evidence for where Earth's chemical elements came from. Their creation occurred earlier in the history of the universe and was associated with processes taking place in stars and, in particular, those accompanying the death of massive stars. Material from these earlier stars was dispersed into space, and only much later did it come together to form the solar system and planet Earth.

We also review the basic large-scale internal structure of the Earth. Although we never see material from deep in the planet, its composition and movement play important roles in determining processes that create the Earth materials that we see in the crust. Ever since its formation, the planet has been cooling, and a direct consequence of this process has been plate tectonics. We learn in later chapters that almost all new Earth materials are formed in specific plate tectonic settings, and it is, therefore, important to review this material before delving into the details of minerals and rocks.