Download How thick is Continental crust?

DVD on Plate Tectonics:
3 minute clip on granite
Background:
How the Earth was made:
3.5 Billion years ago, oceans were
dominant, the first continental crust
was beginning to form…this would
later become the continents.
CHAPTER 7: PLATE TECTONICS---Inside the Earth
The Crust
The Earth's Crust is like the skin of an onion. It is very thin in
comparison to the other three layers. The crust is only about
3-5 miles thick under the oceans (oceanic crust) and about
25 miles thick under the continents (continental crust). The
deepest spot is 43 miles.
Notice how
thick the
continental
crust is
compared
to the
oceanic crust.
How thick is Oceanic crust?
3-5 Miles Thick
How thick is Continental crust? 5-25 Miles Thick
The temperatures of the crust vary from air temperature
on top to about 1600 degrees Fahrenheit in the deepest
parts of the crust.
You can bake a loaf of
bread in your oven at
350 degrees F., at 1,600
degrees F. rocks begin
to melt.
What type of energy is
produced using the
heat from the inside of
the Earth?
The crust of the Earth is broken into many pieces
called plates. There are about 15 plates.
The plates "float" on the soft, plastic mantle which is
located below the crust. These plates usually move
along smoothly but sometimes they stick and build up
pressure. The pressure builds and the rock bends until it
snaps. This is what we feel as an Earthquake!
Where
inside the
Earth is the
densest
material
found?
•Notice in the picture above how thin the crust of the
Earth is in comparison to the other layers.
•The seven continents and ocean plates basically
float across the upper mantle which is composed of
much hotter and denser material.
The Lithosphere: The crust and the upper layer of the
mantle together make up a zone of rigid, brittle rock
called the lithosphere.
•The crust is composed of two basic rock types, granite
and basalt.
•The continental crust is
composed mostly of granite.
•The oceanic crust consists
of a volcanic lava rock
called basalt.
•Basaltic rocks of the ocean plates are much denser
and heavier than the granitic rock of the continental
plates. Because
of this the continents ride
on the denser oceanic plates.
Clip on Granite
The Asthenosphere:
•The layer below the rigid lithosphere is a zone of
asphalt-like consistency called the asthenosphere.
•The asthenosphere is the part of the mantle that acts
like a solid and liquid. It flows and moves the plates of
the Earth.
What
happens to
the oceanic
crust when it
runs into the
continental
crust?
What parts of the Earth’s interior do the letters represent?
A. Oceanic Crust
B. Continental Crust
A
C. Lithosphere
B
C
D. Lithosphere
D
E
E. Part of the
Lithosphere
and the
Asthenosphere
(upper mantle)
AMAZING EARTH SCIENCE FACTS
1. The Earth consists of a solid inner core, a liquid outer
mantle
core, a plastic-like __________and
a thin rocky crust.
lithosphere is the crust and upper mantle
2. The _____________
Oceanic crust —high density, young age, thin,
3. ________________
and made of basalt
Continental crust —low density, old age, thick (think
4.__________________
Mt. Everest) made of granite