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Geo Chap 1 and 2
Geography The Earth's Structure & Plate tectonics
Term | Definition |
---|---|
Crust | The outermost layer, made of solid rock. |
Mantle | It consists of several layers of rock. The rock varies from semi-molten at the surface to molten deeper down. |
Outer Core | Consists mainly of iron. It is so hot it is a constant molten state. |
Inner Core | Consists of iron and nickel. Even though it is the hottest layer of Earth, the inner core is solid because it is under intense pressure. |
Lithosphere | The name given to the crust and the upper part of the mantle. |
Oceanic - Crust | This material is referred to as sima because it is made out of two basic substances, silica and magnesium. |
Continental - Crust | This material is referred to as sial because it is made out of two basic substances, silica and aluminium. |
Continental Shelf | The submerged edge of a continent where the sea is relatively shallow compared with the open ocean. |
The Asthenosphere | The region just below The Lithosphere. |
Plates | Very large sections into which the outer layers of Earth are broken. |
Divergent Plate Boundaries | Where plates separate and move apart from one another. Since new rock is formed, these are constructive boundaries. |
Convergent Plate Boundaries | Where plates collide with one another. Since rock is destroyed, these are destructive boundaries. |
Transform Boundaries | Where plates grind past one another. Since rock is neither formed nor destroyed, these are passive boundaries. |
Subduction | The process where the heavier plate slides beneath the lighter plate and downwards into the mantle. |
Divergent oceanic | Mid-ocean ridge Volcanic islands, eg. Mid-Atlantic Ridge Iceland. |
Divergent continental | Riff Valley, new seas, eg. Africa Rift Valle, Red Sea. |
Convergent oceanic-oceanic | Volcanic island arc, eg. Japan. |
Convergent oceanic-continental | Volcanoes, mountain chain Ocean trenches, eg. Andes, Peru- Chile Trench. |
Convergent continental-continental | Moutain chain, plateau, eg. Himalayas. |
Transform | Fault lines and valleys, eg. San Andreas Fault. |