2. Earth is divided into 3
basic layers:
1. Crust
2. Mantle
3. Core
These layers are then
subdivided into smaller layers.
3. Earth Layers
CRUST:
•Is the outermost layer on the earth.
•Thickness varies. Under mountains it
can be as thick as 60 km and less
than 5 km under the ocean.
•It is the least dense of all the layers.
(lightest layer)
•It is made up of silicon and oxygen
4. 2 TYPES OF CRUST:
• Continental crust
is less dense,
made of Granite.
• Oceanic crust is
very dense, made
of Basalt.
5. 2 TYPES OF CRUST:
• Continental crust is less dense,
made of Granite.
• Continental crust has a thickness
of 35 to 40 kilometers
and is mainly made up of the
elements sodium,oxygen, silicon,
aluminum, potassium, and
calcium.
• The continental crust is usually
found under land masses
6. 2 TYPES OF CRUST:
•Oceanic crust is very dense,
made of Basalt.
It has a thickness of 7 to 10
kilometers and found under
ocean floors.
8. MANTLE:
• Located below the crust.
• It is the largest layer (about 2900
km thick). Rock layers are
movable. (plastic)
• Hot soften rocks made up of more
magnesium and iron.
• Density increases with depth due
to increase in pressure.
9. MANTLE:
•The mantle makes up 80 percent
of the earth’s volume and 68
percent of the earth’s mass.
•It consists a temperature ranging
from 15,000-30,000 degree Celsius
•It is made up mostly of silicate
rocks made up of elements Fe, Si,
O and Mg.
10. MANTLE: Divided into 2 parts
• Upper mantle- 670 kilometers
thick
•Lower Mantle - 2230 kilometers
12. The boundary between upper
mantle and crust, is called
“Mohorovicic Discontinuity”
named after Andrija Mohorovicic
who is a Croatian Meteorologist
and Seismologist
13. ASTHENOSPHERE:
• Soft – can bend like plastic, layer in the
upper portion of the mantle
• It is located right below the Lithosphere.
Lithosphere floats on this layer (like
jello)
14. CORE: Located below the Mantle.
• It is divided into 2 layers
Outer Core
Inner Core
15. Outer Core:
• is liquid and is made up of mostly
iron (easily magnetized)
• The movement of materials in the
liquid O.C. is inferred to be the
cause of Earth’s magnetic field!
• The O.C. is about 2250 km thick.
•It was theorized that the liquid O.C.
is ithe source earth’s magnetic field.
16. Inner Core:
• Is the center of the Earth –
1200 km thick.
• It’s solid iron and nickel. Most
dense layer (heaviest)
• The increased pressure
causes the I.C. to be solid
17. The boundery between outer
core and inner core is called
“Lehmann Discontinuity.”
Named after Inge Lehmann a
Danish Seismologist who
discovered that the inner core
is solid while the outer core is
made up of molten materials.