continental drift & pangaea
DESCRIPTION
CONTINENTAL DRIFT & PANGAEA. In 1912, Alfred Wegener proposed the idea that the continents were once part of a huge land mass, called Pangaea (all lands), that later broke apart. He was convinced because:. 1. the continent’s shape roughly fit together like a puzzle. - PowerPoint PPT PresentationTRANSCRIPT
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Plate Tectonic movement shapes the Earth• Plate tectonics = process that underlies earthquakes and volcanoes
and that determines the geography of the Earth’s surface- Earth’s crust and upper mantle are separated into lithospheric
plates that move in different directions and at different rates• Crust = lightweight thin component of Earth’s surface• Mantle = malleable layer on which the crust floats composed of
silica and magnesium oxides• Core = molten heavy center of Earth made mostly of iron and
nickel
• Plate Tectonics Video
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Earth has 15 major tectonic plates
Movement of these plates influences climate and evolution
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Pangaea: the supercontinent
Pangaea = at least twice (probably more) in Earth’s history, all landmasses were joined in one supercontinent
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Earth’s crust is constantly created and destroyed
• Divergent plate boundaries = magma surging upward to the surface divides plates and pushes them apart, creating new crust as it cools and spreads
• Transform plate boundary = two plates meet, slipping and grinding alongside one another- Friction spawns earthquakes
along slip-strike faults
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Tectonic plates can collide• Convergent plate boundaries = where plates collide• Subduction = one plate of crust may slide beneath another
- Magma erupts through the surface in volcanoes• Two colliding plates of continental crust may lift material from
both plates- Resulted in the Himalaya and Appalachian mountains