Layers of the Earth

1
Layers of the Earth

• Geosphere

2
The Earth as a System

• Integrated system of rock, air, water, and living
  things.
• This system is divided into four parts
• atmosphere (air)
• hydrosphere (water)
• biosphere (living things)
• geosphere (rock)

3
Geosphere

• Solid part of the Earths crust that consists of
  all rock, and the soils and sediments on Earths
  surface.
• Most located in Earths interior

4
Earths Interior

• Seismic Waves the waves that travel through the
  Earths interior during an earthquake.
• Altered by the type of material that it travels
  through.

5
Seismologists

• Scientists who measure changes in these waves to
  determine that the earths interior is made in
  layers.

6
Composition of the Earth

• Three layers
• crust
• mantle
• core
• Density increases towards the center of the Earth

7
Crust

• Thin, outer layer.
• Made up of light elements
• less than 1 of Earths mass
• 5-70km thick

8
Mantle

• Layer beneath the crust
• 64 of mass of Earth
• 2,900 km thick
• Made of
• lithosphere
• asthenosphere
• mesosphere

9
Lithosphere

• Outer layer
• cool, rigid
• divided up into huge tectonic plates

10
Asthenosphere

• 250 km thick
• solid, plastic layer made of rock
• flows very slowly and allows tectonic plates to
  move across

11
Mesosphere

• 2,250 km thick
• middle sphere
• lower part of mantle

12
Core

• 3,248 km radius
• sphere of hot, dense nickel and iron
• 4,000 - 5,000 C
• 1/3 of the Earths mass
• Made of
• Outer Core
• Inner Core

13

• Outer Core 2,200 km thick, outer shell, made of
  liquid nickel and iron
• Inner Core 1,228 km radius a sphere of solid
  iron and nickel

14
First Life???

• First life may have first evolved deep in the
  crust and then migrated to the surface when
  conditions became favorable.
• extremophiles
• Hypothesized that the biomass below the surface
  far exceeds the biomass at the surface.

15

• Be able to draw and label the three layers of the
  earth (crust, mantle, and core) as well as the 5
  layers based on physical properties (lithosphere,
  asthenosphere, mesosphere, outer and inner core).