Changing Earth’s Surface Weathering and Erosion. Changes to Earth’s Surface Earth’s crust is...
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Transcript of Changing Earth’s Surface Weathering and Erosion. Changes to Earth’s Surface Earth’s crust is...
Changes to Earth’s Surface
Earth’s crust is constantly in a process of change Weathering Erosion Deposition
Weathering
The process by which rocks are broken down into small pieces called sediment
Caused by Wind Water Glaciers Meteorites
Erosion
Occurs when weathered material is carried away by wind or water
Responsible for some of our most impressive natural monuments Example—The Grand
Canyon
Deposition
Occurs when sediment is dropped off at a new location Wind or water slows
down or comes to a stop
Example—River Delta
Plate Tectonics
Theory that the lithosphere is divided into plates that are always moving
Pangaea Supercontinent that once existed over 350
million years ago Evidence: Puzzle piece fit of the continents, fossil
and soil matches on different continents
Responsible for the formation of volcanoes and earthquakes
Volcanoes
Form when magma rises to Earth’s surface
Pyroclastic Flow Ashes, Gases, and
Magma that ooze or explode from volcanoes
Can form at divergent boundaries or subduction zones
Divergent Volcanoes
Plates above the asthenosphere separate Magma rises up As lava cools, new crust is formed May be oozing or explosive
Subduction Volcanoes
Formed when a denser ocean plate sinks under a lighter plate (either ocean or land)
Magma comes to the surface
Shield Volcano
Broad and flat volcano Resemble a shield
laying on its side Built up slowly over
thousands of years, most often in layers of hardened lava
Mostly ooze lava from vents Example—Mauna Loa,
Hawaii
Composite Volcano
Formed of alternating layers of ashes and hardened lava
May be dormant for many years before exploding rapidly or may ooze for thousands of years Example—Crater
Lake, OR
Cinder Cone
Formed from blobs of congealed lava in a simple cone shape
Capable of violent explosions
Bowl-shaped crater at the summit Example—Paricutin,
Mexico
Earthquakes
Energy released from the snap and slide of Earth’s crust at a fault line Fault
2 or more plates slide past one another Focus
Point inside Earth where an Earthquake begins Epicenter
Point on Earth’s surface where Earthquake waves begin
3 Types of Seismic Waves
Primary (P) Waves Fastest and Smallest
Waves Secondary (S) Waves
Medium Waves Surface (R) Waves
Slowest and Most Dangerous Waves