Summary
Contents
Subject index
This unique addition to reference literature provides an introduction to the major concepts and contemporary issues that are essential for students of environmental science and environmental studies to know. With over 200 entries authored by world-class names like Anthony Brazel, John Day and Edward Keller, this text is divided into six sections: Environmental Science, Environments, Paradigms & Concepts, Processes & Dynamics, Scales & Techniques, and Environmental Issues.
Earth Structure
Earth Structure
The Earth consists of several shells around a central core; from the Earth's surface inward, they are: lithosphere, asthenosphere, mantle, outer core, and inner core (Fig. 16).
Figure 16 Structure of the interior of the Earth.
The lithosphere is made up of the crust and the uppermost mantle. The outer crust comprises less than 1% of the Earth's mass. The continents are imbedded in the outer crust and are up to 33 km thick, whereas the ocean floors are about 7 km thick. The lower crust is about 160 km thick consisting of solid rock mainly of basaltic composition. Eight elements make up 99% of the Earth's crust: oxygen, magnesium, aluminium, silicon, calcium, sodium, potassium, and iron.
The mantle makes up about ...
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