The document describes the different layers of the Earth, including the crust, mantle, outer core, and inner core, providing details on the thickness and composition of each layer. It explains that the mantle makes up most of the Earth's volume and drives plate tectonic processes through convective circulation. Additionally, it outlines that the lithosphere and asthenosphere describe the mechanical properties of the Earth, with the lithosphere comprising rigid tectonic plates floating on the weaker asthenosphere.

1. FINAL PRESENTATION: STRUCTURE OF THE EARTH Prepared by Oyahan Gallegos NMSU-A Summer 2009

2. Layers of the Earth: Source: www.csun.edu/.../ ES300/300earthinterior.jpg

3. Cross-section of the Earth Layer Thickness (km) Inner Core 1200 Outer Core 2300 Mantle 2900 Crust (Continental/Oceanic) 35-70 / 5-10

4. Properties of Earth Layers – Crust: Outermost layer of Earth (Biosphere) Comprised of continental and oceanic basins Thickness of continental crust is between 35 and 70 km Thickness of oceanic crust is between 5 and 10 km Composed mainly of alumino-cilicates

5. Properties of Earth Layers – Mantle: Thickness of mantle is 2900 m Composed mainly of ferro-magnesium silicates. It is about 2900 km thick Separated into the upper and lower mantle Most of the internal heat of the Earth is located in Mantle Large convective cells in the mantle circulate heat and may drive plate tectonic processes.

6. Properties of Earth Layers – Core: Core separated into the liquid outer core and the solid inner core The outer core is 2300 km thick The inner core is 1200 km thick The outer core is composed mainly of a nickel-iron alloy The inner core is almost entirely composed of iron Earth's magnetic field is believed to be controlled by the outer core.

7. Earth’s Layers Based on Mechanical Properties Lithosphere, - Comprised of the crust and solid portion of the upper mantle. - Divided into plates that move in relation to each other due to tectonic forces - Floats on top of a semi-liquid layer, “asthenosphere” Astenosphere, - Layer of the Earth found 100-500 km below the Earth's surface - Layer of Earth yields to persistent stresses more than the rigid crust or the core - Astenosphere allows the solid lithosphere to move around since the it is much weaker than the lithosphere

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