Transcript sea floor is spreading

Plate Tectonics and
Continental Drift
Eric Angat
Teacher
Essential Question
How is earth’s
crust changed?
Continental drift and Plate tectonics theory
1.How is Earth crust similar to a jigsaw
puzzle?
2. How is Earth affected by the slow
movement of the tectonic plates?
3.How are mountain formed?
4.What kind of plate boundaries causes
earthquakes?
Continental drift and Plate tectonics theory
Videos: http://www.youtube.com/watch?v=ELd3ebldSTs
Continental drift and Plate tectonics theory
1.How is Earth like a jigsaw puzzle?
Earth’s crust is broken into many pieces
like a jigsaw puzzle.
2.How is Earth affected by the slow
movement of the tectonic plates?
The slow movement of tectonic
plates causes earthquakes,
subduction, form mountains,
volcanoes, rift valley, and trenches.
Continental drift and Plate tectonics theory
3.How are mountain formed?
Mountains form when tectonic plates collide
and uplift happen.
4.What kinds of plate boundaries cause
earthquakes?
Convergent boundary along the Pacific
Ring of Fire, Transform boundary,
earthquake happen along the fault line, and
divergent boundary vertically across the
Atlantic ocean.
Sea Floor Spreading
5. Who is Alfred Wegener?
6. Who is Harry Hess?
7. What is happening to the
Atlantic Ocean?
8. Where are the newest oceanic
crust found?
9. Why is Earth not getting bigger
in spite of sea floor is spreading?
10. What happens to the crust
subducted into the mantle?
Sea Floor Spreading
Videos: http://www.youtube.com/watch?v=oXYAdzmwQsc
Sonar (sound navigation and
ranging) is a technology that
uses acoustical waves to sense
the location of objects in the
ocean.
Sea Floor Spreading
5. Who is Alfred Wegener?
Alfred Wegener proposed the theory of
continental drift but he could not explain how
continents move.
6. Who is Harry Hess?
Harry Hess a geologist and navy
commander who proposed that
continents move because of sea floor
spreading.
Sea Floor spreading happening in
the Atlantic Ocean
Atlantic Ocean
widening on
both sides
Magma rises
forming new
crust.
Sea Floor Spreading
7. What is happening to the Atlantic
Ocean?
The Atlantic Ocean is widening because
of Sea Floor Spreading.
8.Where are the newer oceanic crust
found?
Newest oceanic crust are found
nearest the mid-ocean ridges.
Sea floor spreading is making the Atlantic Ocean wider.
But the Earth is
not growing
bigger! Why?
Because Pacific Ocean crust is subducted into the
mantle.
Subduction recycles
Earth’s crust into
new rocks.
Most earthquakes happen around the Pacific Ocean.
A lot of
volcanoes!
Sea Floor Spreading
9. Why is Earth not getting bigger when
the sea floor is spreading?
Because on the other side of Earth
there is subduction.
10. What happens to the crust subducted
into the mantle?
The crust gets melted and recycled
into new rocks, volcanoes form
adjacent to subduction zone.