FINAL PRESENTATION:FINAL PRESENTATION:STRUCTURE OF THE EARTHSTRUCTURE OF THE EARTH

Prepared byPrepared byOyahan GallegosOyahan Gallegos

NMSU-ANMSU-ASummer 2009Summer 2009

Layers of the Earth:Layers of the Earth:

Source: www.csun.edu/.../ ES300/300earthinterior.jpg

Cross-section of the Earth

Layer Thickness (km)

Inner Core 1200

Outer Core 2300

Mantle 2900

Crust (Continental/Oceanic) 35-70 / 5-10

Properties of Earth Layers – Crust:

Outermost layer of Earth (Biosphere)Comprised of continental and oceanic basinsThickness of continental crust is between 35 and 70 kmThickness of oceanic crust is between 5 and 10 kmComposed mainly of alumino-cilicates

Properties of Earth Layers – Mantle:Thickness of mantle is 2900 m Composed mainly of ferro-magnesium silicates. It is about

2900 km thickSeparated into the upper and lower mantleMost 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.

Properties of Earth Layers – Core:Core separated into the liquid outer core and the solid

inner coreThe outer core is 2300 km thick The inner core is 1200 km thickThe outer core is composed mainly of a nickel-iron alloyThe inner core is almost entirely composed of ironEarth's magnetic field is believed to be controlled by the

outer core.

Earth’s Layers Based on Mechanical PropertiesLithosphere, - 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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