Plate Tectonics

1. Heat from the core & the mantle itself causes convection currents in the mantle.

1. Heating and cooling of the fluid, changes in the fluid's density, and the force of gravity combine to set convection currents in motion.
2. The flow that transfers heat within a fluid.

1. Radiation
2. Conduction
3. Convection

1. Evidence from rock samples

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   • Scientists drill holes for samples
2. Evidence from seismic waves

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   • Seismic waves in Earth

1. Temperature

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   • The deeper you go, the higher.
2. Pressure

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   • The deeper you go, the stronger the pressure.

1. Lower Mantle

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   • Solid and extends down the core.
2. Lithosphere

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   • Uppermost part of mantle.
3. Athenosphere

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   • Soft layer of mantle, bendable.

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• The layer of solid rock that forms Earth's outer skin.

1. It is between 5 to 40 km thick

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   • Note: Under mountains, could be 70 km!

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• Both together are 3486 kilometers thick.

1. Outer Core

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   • A layer of molten metal that surrounds the inner core and it is 2266 kilometers thick.
2. Inner Core

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   • A dense ball of solid metal that is 1216 kilometers thick.

1. Evidence from fossils

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   • A fossil is any trace of an ancient organism.
2. Evidence from land features

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   • Mountains & other features on the continents provided evidence for continental.
3. Evidence from Ancient Climate Zone

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   • Evidence from fossils/rocks can help find out what climate it was from.

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• Wegener's Hypothesis was that all the continents were once joined together in a single land mass and have since drifted apart.

1. Ages of rocks
2. Eruptions of molten material
3. Magnetic stripes

1. Continually adds new material to the ocean floor.

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• Tens of million years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.
• The process which the ocean floor sinks beneath a deep-ocean trench and back into the mantle is called SUBDUCTION.

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• The theory of plate tectonics explains the formation, movements, and subduction of Earth's plates.

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• There are three kinds of plate boundaries: spreading boundaries, colliding boundaries, and sliding boundaries. A different type of plate movement occurs along each type of boundary.

1. Spreading Boundaries

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   • The place where two plates move apart is called a spreading boundary.
2. Colliding Boundaries

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   • The place where two plates come together, or collide, is called a colliding boundary.
3. Sliding Boundaries

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   • A sliding boundary is a place where two plates slip past each other, moving in opposite directions.