4.1: Introduction

Geologists view Earth as an operational system of interacting spheres. These spheres include the Geosphere (the solid body of the Earth), the Atmosphere (the gas envelope surrounding the Earth), the Hydrosphere (water in all its forms at and near the surface of the Earth), the Cryosphere (frozen water part of Earth), and the Biosphere (life on Earth in all its forms and interactions, including humankind).

Figure \(\PageIndex{1}\): The layered interior of the Geosphere. Note that Lithosphere includes both the crust and uppermost portion of the solid mantle. This layer composes Earth’s tectonic plates. (https://pubs.usgs.gov/gip/dynamic/inside.html United State Public Domain; U.S. Geological Survey, Department of the Interior.)

Earth materials are the foundational building blocks of the Geosphere and are generally thought of as the minerals and rock that compose the solid Earth. However, soil and loose fragments of rocks and minerals that exist at the surface are also considered Earth materials. Fossil fuels and water also exist as Earth materials in solid, liquid and gaseous states. Additionally, the envelope of gases that encircle the Earth is also considered Earth material. Therefore, Earth Materials encompass the entire Earth System where each of Earth’s spheres interact. This chapter examines the origin and properties of materials largely found in the outermost layer of the solid Earth, the lithosphere. The lithosphere is the outermost rigid sphere of the Geosphere which includes both the crust and the solid upper mantle. These bound layers compose Earth’s tectonic plates.