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Ch. 1 Sec. 3 – Forces of Earth. Objectives. Describe the layers found within the earth. Discuss the forces that change the earth’s surface. Earth’s Layers. Inside our Earth. 3 layers: Crust, Mantle, and Core. Core can be split up into two parts: outer and inner core. Crust.
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Objectives • Describe the layers found within the earth. • Discuss the forces that change the earth’s surface.
Inside our Earth 3 layers: Crust, Mantle, and Core. Core can be split up into two parts: outer and inner core.
Crust • Uppermost part of the Earth, includes continents and ocean floors. • Approx. 31 to 62 miles deep.
Mantle • Mantle is below crust, or the outside part of Earth. • The mantle is made up of rock material, and is 1,800 miles thick. • The mantle has two layers. The outer layer is mostly in a liquid state of hot magma, and the inner is a solid state. The magma is just under the crust, which causes our plates to move.
Mantle layers • Inner and outer layers of mantle • Liquid magma is the outer layer. • Rock is the inner layer. Liquid hot magma!
Core • Under the mantle is the core, which is made up of hot iron and other metals and rocks. • The inner core is solid, but the outer core is liquid because the temperatures are so hot and have melted the metals.
Why does our Earth move? • Plate Tectonics: The earth is made up of plates that are under continents and ocean floors that are moving on magma in the mantle.
Pangaea and the Plate Tectonic Theory • At one point, all the continents were one super continent, all connected, and they drifted apart. This was called Pangaea.
Transform Boundary • occur where plates slide or, grind past each other along transform faults. • The San Andreas Fault in California is an example of a transform boundary exhibiting dextral motion.
Divergent Boundary • Divergent boundaries occur where two plates slide apart from each other. • Mid-ocean ridges (e.g., Mid-Atlantic Ridge) and active zones of rifting (such as Africa's Great Rift Valley) are both examples of divergent boundaries.
Convergent Boundaries • occur where two plates slide towards each other commonly forming either a subduction zone (if one plate moves underneath the other) or a continental collision (if the two plates contain continental crust). • Examples of this are the Andes mountain range in South America and the Japanese island arc.
