The Forces of the Earth

Plate tectonics and other cool stuff

Vocabulary

• Plates – huge moving slabs that form the Earth’s crust• Plate tectonics – the theory

that the Earth’s crust is made of plates that are constantly drifting apart and sliding together

Tectonic Plates

Vocabulary• Crust – the band of solid rock

on the Earth’s surface that floats on the mantle•Mantle – a partly melted,

white-hot inner layer of rock between the Earth’s curst and core

How Plates Move

Pangaea

Pangaea – the supercontinent that existed 225 million years ago

Plate BoundariesDivergent Boundaries

where plates pull apart

How Plates MoveConvergent Boundaries

Where plates meet

How Plates Move

Oceanic-Oceanic Convergence

Oceanic-Oceanic ConvergnceMid-Ocean Ridges

Birth of an Island Surtsey 1963

How Plates Move

Continental-Continental Convergence

Mountain Ranges

Rise of the Himalayas

Vocabulary• Magma – liquid rock within the Earth’s

mantle• Lava – liquid rock that has reached the

Earth’s surface• Subduction – the process by which the

Earth’s crust slides into the mantle and melts into magma

• Volcanism – the outpouring of molten rock onto the Earth’s surface through cracks in the crust

Subduction Zones

Trench FlippingStandard Subduction

How Plates MoveTransform-Fault Boundaries

Faulting – where two tectonic plates slide past one another

Fault Lines

San Andreas Fault

Ring of Fire

Hot SpotsHot spots – molten rock that forces its way through the crust, but is not located along a plate boundary

Vocabulary•Weathering – the slow

breakdown of rock into finer particles by natural means• Erosion – the breakdown and

movement of rock particles by running water, ocean currents, wind or ice

Weathering and Erosion

Glacial Erosion

Glacier – a river or sheet of ice that scrapes the soil off the land as it moves

Greenhouse Effect

• Greenhouse effect – the trapping of heat within the atmosphere and oceans by carbon dioxide

World Climates