Solid Earth System

The Earth is like an onion, it is made up of many layers.

Although we have not been to the center of the Earth, Earthquakes, and volcanoes tell us a lot about its interior.

The deepest man has dug into the Earth is 5 km in the South Africa gold mines.

Here the temperature increases by 10 to 15 ˚C for every kilometer down.

COVERS 71% OF THE EARTH’S SURFACE

AVG 3.8 KM IN THICKNESS

MOSTLY HYDROGEN AND OXYGEN

INCLUDES SNOW FIELDS AND GLACIERS

THE LAYER OF LIQUID WATER THAT LIES BETWEEN THE ATMOSPHERE AND MOST OF THE LITHOSPHERE

Interior Structure• Inner Core (kept solid by the immense pressure

of all the material on top of it.)

• Outer Core (less pressure allows it to be a liquid.)

• Mantle– Asthenosphere

– Lithosphere

• Crust

The interior of the EarthThe Earth is divided into layers in either of two ways:

1) Chemical Composition

-Crust

-Mantle

-Core

2) Physical Properties

-Lithosphere

-Asthenosphere

-Outer Core

-Inner Core

More about the layers

• The difference between the mantle and the crust is based on chemical composition.

• The difference between the asthenosphere and the lithosphere is based on viscosity (the ability to flow under pressure.)

Solid Inner Core2400 km diameterIron & Nickel

Liquid Outer Core2270 km thickIron & Nickel

Mantle2900 km thickBasaltic rocks: Olivine, Pyroxene

Crust20-100 km thickGranitic rocks: Feldspars

Interior section of mantle is a thick fluid called theasthenosphere. The outer mantle + the crust are rigidand are collectively called the lithosphere.

The crust

The crust is a very thin skin which surrounds the planet

There are two types of crust

Oceanic crust: which is thin (≈7 km) and is made up of dense volcanic rock (basalt)

Continental crust: is thick (≈ 35 km) and is less dense than oceanic crust. It is rich in quartz

and feldspar. It is thicker under mountains.

The LithosphereThe crust and the upper part of mantle form the Lithosphere.

It is fragmented into a series of segments called plates.

These plates move with respect to each other and are the cause of most Earthquakes and volcanoes.

The lithosphere is usually 100 km thick

The MantleIt is between the crust and the core. It is mainly solid, but acts as a fluid-like solid.

The upper part of the mantle is cooler and so stronger. This strong part of the mantle is joined together with the crust to form the lithosphere. It goes down to 1300˚C

The mantle which directly underlies the lithosphere is much hotter and so weaker, this is called the Asthenosphere.

(astheno means weak) it goes down to 1700 ˚C

The lithosphere slides over the Asthenosphere

The area below the this is called the lower mantle

Convection currents in the mantle

We think the mantle acts like hot and sticky tar.

It is heated by the core below it and cooled by the crust above.

When you heat a fluid it’s density drops and it expands.

If you cool it, it will contract and become more dense.

So the hotter material at the base rises toward the top while

the cooler material at the top sinks.

This generates slowly flowing convection currents in the Mantle

The Core

•The core is divided into two partsouter core which is liquidinner core which is solid

•The core is made up of mainly iron and nickel which makes it very dense

The movement of the liquid outer core generates the Earth’s magnetic field

The interior of the Earth has a major impact on other Earth systems.

•Convection currents in the mantle cause the movement of the plates

•The internal heat is responsible for volcanoes.

•The outer core generates the Earth’s magnetic field

•Earth’s early atmosphere and water was probably formed from volcanic gases derived from inside the Earth.

•The position of the continents effects ocean currents and so the Earth’s climate.

•Plates also effect the geographic distribution of organisms and so their evolution

What is the solid Earth Made of?

Planet Earth is a rocky planet. It is made up of rocks and minerals.

The Earth is made up of a number of Elements

The interior of the Earth is quite different than the exterior (continental crust)

How do we know?What evidence do we really have that the interior

of the earth is the way we think it is?

• Deep mines are hot!

• Heat and molten material escape from volcanos and geysers.

• Earthquake waves