Tectonic Plates. The LITHOSPHERE, or Earth’s outer layer, is broken up into huge pieces called _________ __________. –These plates are continuously.

Tectonic PlatesTectonic Plates

Tectonic PlatesTectonic Plates The LITHOSPHERE, or Earth’s outer The LITHOSPHERE, or Earth’s outer

layer, is broken up into huge pieces layer, is broken up into huge pieces called _________ __________.called _________ __________.–These plates are continuously These plates are continuously

________. ________.

Let’s look at pg. 396Let’s look at pg. 396

tectonic plates

moving

Answer this question…Answer this question… How do we know so much about the How do we know so much about the

mantle and the core?mantle and the core?– Seismic waves, or vibrations produced Seismic waves, or vibrations produced

from earthquakes, travel at different from earthquakes, travel at different speeds through the Earth. Their speed speeds through the Earth. Their speed depends on the density and composition depends on the density and composition of the material they pass through.of the material they pass through.

– Traveling through a solid will go faster Traveling through a solid will go faster than through a liquid.than through a liquid.

Restless ContinentsRestless Continents Look at pg. 400!Look at pg. 400! In the early 1900s, ___________ ___________ In the early 1900s, ___________ ___________

wrote about his hypothesis of ____________ wrote about his hypothesis of ____________ ______.______.

Continental drift = the _____________ once Continental drift = the _____________ once formed a single ______________, then broke up, formed a single ______________, then broke up, and drifted to their current locations.and drifted to their current locations.

Continental drift also explained why __________ of Continental drift also explained why __________ of the same plant and animal species are found on the same plant and animal species are found on continents that are on different sides of the Atlantic continents that are on different sides of the Atlantic Ocean.Ocean.

Alfred Wegener

continentaldrift

continents

landmass

fossils

PangaeaPangaea Wegener thought Wegener thought

that all of the that all of the present continents present continents were once were once __________ in a __________ in a single, huge single, huge continent called continent called ______________.______________.

Pangaea is Greek Pangaea is Greek for for ______________.______________.

joined

Pangaea

“all earth”

Events caused by Events caused by Earth’s Earth’s plate movement:plate movement:

1.1. Sea-floor spreading Sea-floor spreading3.3. Earthquakes Earthquakes2.2. Mountain building Mountain building 4.4. Volcanoes Volcanoes

Mountain BuildingMountain Building

______________ exist because ______________ exist because tectonic plates are continually tectonic plates are continually ______________ and ___________ ______________ and ___________ with one another.with one another.

________________ or ____________ ________________ or ____________ can form mountains in several ways.can form mountains in several ways.

Mountains

moving colliding

Compression tension

3 types of mountains:3 types of mountains:

1.1. Folded Mountains:Folded Mountains: --Form when rock layers are _______________ --Form when rock layers are _______________

together and pushed ___________.together and pushed ___________.

--Example: Appalachian Mountains--Example: Appalachian Mountains

squeezedupward

2.2. Fault-Block Mountains: Fault-Block Mountains:--Form when tectonic forces put --Form when tectonic forces put ___________on the Earth’s crust causing ___________on the Earth’s crust causing large blocks to_________ _________.large blocks to_________ _________.

--Example: Tetons in Wyoming--Example: Tetons in Wyoming

tensiondrop down

3.3. Volcanic Mountains- Volcanic Mountains-

--Form when _________ rises to the Earth’s --Form when _________ rises to the Earth’s surface and erupts.surface and erupts.– Example: Mount St. Helens Example: Mount St. Helens

magma

EarthquakesEarthquakes Most earthquakes take place near the edges of Most earthquakes take place near the edges of

__________ ___________.__________ ___________. As tectonic plates push, pull, or slip past each As tectonic plates push, pull, or slip past each

other, stress increases along breaks in the Earth’s other, stress increases along breaks in the Earth’s crust, or ___________. crust, or ___________.

In response to this stress, rock in the plates In response to this stress, rock in the plates _______________. _______________.

__________ _______________: Imagine a __________ _______________: Imagine a stretched rubber band. You can only stretch rock stretched rubber band. You can only stretch rock so far before it breaks. When the rock breaks, it so far before it breaks. When the rock breaks, it releases ________________.releases ________________.

tectonic

faults

plates

deforms

Elastic deformation

energy

Sea-Floor SpreadingSea-Floor Spreading

Process by which new oceanic Process by which new oceanic ________________ forms as __________ ________________ forms as __________ rises toward the surface and solidifies.rises toward the surface and solidifies.

Occurs at ____________ __________, or Occurs at ____________ __________, or underwater mountain chainsunderwater mountain chains

As ___________ __________ move away As ___________ __________ move away from each other, the sea floor spreads apart from each other, the sea floor spreads apart and magma fills the gap.and magma fills the gap.

lithosphere magma

mid-ocean ridges

tectonic plates

Look at page 402…Look at page 402…

Figure 3: Sea-Floor Figure 3: Sea-Floor SpreadingSpreading

VolcanoesVolcanoes Likely to form at _________ ______ _________. Likely to form at _________ ______ _________. ________ _________ _____ _________, plate ________ _________ _____ _________, plate

boundaries surrounding the Pacific Ocean, boundaries surrounding the Pacific Ocean, contains nearly _____ of the world’s active contains nearly _____ of the world’s active volcanoes.volcanoes.

About _____ of active volcanoes on land form About _____ of active volcanoes on land form where plates ______________, and about ______ where plates ______________, and about ______ form where plates ____________. form where plates ____________.

At these plate boundaries it is possible for At these plate boundaries it is possible for _____________ to form and travel to the surface._____________ to form and travel to the surface.

The Ring of Fire

75%

15%

80%

collideseparate

magma

tectonic plate boundaries

The Ring of FireThe Ring of Fire

3 Types of Boundaries…3 Types of Boundaries…

Look at pg. 404-405Look at pg. 404-405

1. Convergent Boundaries:1. Convergent Boundaries:

--Formed when two tectonic plates --Formed when two tectonic plates ____________________

a. Continental-Continental a. Continental-Continental CollisionsCollisions

b. Continental-Oceanic Collisionsb. Continental-Oceanic Collisionsc. Oceanic-Oceanic Collisionsc. Oceanic-Oceanic Collisions

COLLIDE

2. 2. Divergent Boundaries:Divergent Boundaries:

--Formed when two tectonic plates --Formed when two tectonic plates ________________________SEPARATE

3. Transform Boundaries:3. Transform Boundaries:

--Formed when two tectonic plates --Formed when two tectonic plates ________ past each other horizontally________ past each other horizontallySLIDE