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The Lithosphere
Definition…

The lithosphere is the rigid portion of
the Earth. It includes the Earth’s crust
and the upper mantle.

The lithosphere includes all mountains,
plains, volcanoes, sea floors, etc.
The Importance of the Lithosphere

It is essential to life!
◦ Allows plants to grow, (agriculture).
◦ Provides minerals that plants need to grow and
develop.
◦ Provides various habitats to animals.
◦ Home to multiple natural resources, like oil, natural
gas and coal.
◦ Provides resources and materials needed for
construction and general daily use.
THE INTERNAL STRUCTURE
OF THE EARTH
The Internal Structure of the earth
Earth’s Crust
 Upper Mantle
 Lower Mantle
 Outer Core
 Inner Core

Earth’s Crust

Main Characteristics:
◦ The solid part of the Earth.
◦ Most living things are found here.

Temperature:
◦ 5° C, (average).

State:
◦ Solid

Thickness:
◦ 5 to 65 km
◦ The crust is thickest below continents and
thinnest below oceans.
Upper Mantle

Main Characteristics:
◦ Composed of partially-melted rocks.
◦ Continental drift and tectonic plates are
influenced by the movement of the upper
mantle.
◦ Igneous and metamorphic rocks originate here.

Temperature:
◦ 1,000 ° C – 1,800°C

State:
◦ Semi-fluid

Thickness:
◦ 670 km
Lower Mantle

Main Characteristics:
◦ Solid despite the very high temperature
because of the enormous pressure.
◦ Composed mainly of silica, iron and magnesium.

Temperature:
◦ 1,800°C – 3,700°C

State:
◦ Solid

Thickness
◦ 2,285 km
Outer Core

Main Characteristics:
◦ Earth’s magnetic field originates here.
◦ Composed of iron and nickel.

Temperature:
◦ 3,700 ° C – 4,500°C

State:
◦ Liquid

Thickness:
◦ 2,270 km
Inner Core

Main Characteristics:
◦ Solid despite the very high temperature
because of the enormous pressure.
◦ Composed of iron and nickel.

Temperature:
◦ Over 4,500°C

State:
◦ Solid

Thickness:
◦ 1,216 km
Brain Pop!

https://www.brainpop.com/science/eart
hsystem/earthsstructure/
ROCKS AND MINERALS
Minerals
A mineral is a pure substance which is is
natural and non-living.
 They are formed inside the crust of the
Earth.

…

Minerals are classified according to a
number of properties:
◦
◦
◦
◦
◦
Colour
Streak
Brilliance
Hardness
Magnetism
Colour:
A mineral usually has one dominant
colour, but can sometimes be found in
other colours. Minerals of the same
type can even be found in multiple
colours, like quartz.
Brilliance:
The reflection of light off of the
surface of a mineral. There are
three categories: metallic, submetallic and non-metallic.
Streak:
The colour of the powder left
by a mineral once it is
scratched on an unpolished
piece of porcelain.
Hardness:
The resistance of a mineral from
scratching. The Mohs Scale classifies
minerals from softest to hardest, on a
scale of 10.
Magnetism:
A property of minerals that
contain a quantity of iron.
These minerals with either
attract or repel a magnet.
Rocks

A rock is a heterogeneous assembly of
minerals that are more or less large and
more or less varied.
Rock Classification


Rocks are classified based on their origin.
Igneous Rocks
◦ Formed from the cooling and solidification of
magma.

Sedimentary Rocks
◦ Result from the erosion of sediments. Over
time, these sediments compact and harden.

Metamorphic Rocks
◦ Result from the transformation of another
rocks after intense heat and pressure.
Igneous Rocks
Formed from the semi-fluid rocks in the
upper mantle, called magma.
 The magma cools and solidifies,
allowing for the formation of igneous
rocks.
 The minerals in these rocks are very
distributed.
 There are two types of igneous rocks:

◦ Intrusive
◦ Extrusive
Intrusive Igneous Rocks
Result from the VERY SLOW cooling of
magma within the earth’s crust.
 Because these rocks were formed over
thousands of years, the minerals are
very large and apparent.
 Examples: diorite, gabbro

Extrusive Igneous Rocks
Result from the VERY RAPID cooling of
magma once the volcano erupts. The
lava cools instantly through contact
with air and water.
 The minerals do not have time to form,
so they are microscopic.
 Examples : obsidian, basalt

Sedimentary Rocks





Form at the surface of the Earth.
Natural events like freezing, movement of
glaciers, waves and precipitation cause
rocks to erode and sediments to form.
These sediments are then transported by
wind and water.
The sediments are disposed in layers, one
on top of the other.
Over time, these sediments will compact
and harden, forming sedimentary rocks.
…
Certain sedimentary rocks contain
fossils or impressions.
 The analysis of these layers can tell us
very much about the history of the
Earth.
 The oldest layers are on the bottom,
while the youngest layers are on the
top.

Metamorphic Rocks
Rocks that undergo structural changes.
 Igneous, sedimentary and even
metamorphic rocks are transformed
under the action of intense heat and
pressure, inside the mantle.
 The mineral rearrange and dispose
themselves in bands.

Igneous
Sedimentary
Metamorphic
How are they
formed?
By the cooling of
magma.
By erosion and the
transportation of
sediments and
fragments that are
disposed and
compact and
harden over time.
By already-formed
rocks that are
modified under the
action of intense
heat and pressure.
What are they
made of?
Minerals like
feldspath, quartz
and elements found
in magma.
Grains of minerals,
debris and fossils.
Variable materials.
How are they
structured?
The minerals are
usually all over the
place. No real
structure.
Formed in layers,
which may or may
not be evident.
-In bands which are
light and dark.
-Rigid layers.
SOIL
Brain Pop!

http://www.brainpop.com/science/earth
system/soil/
Earth vs. Soil

Earth:
◦ All of the surfaces of the planet that are not
covered in water.

Soil:
◦ The superficial layer of material that allows
the growth and development of plants.
 Soil is a mixture of all regions of the biosphere,
(atmosphere, hydrosphere and the lithosphere).
Formation of Soil

Soil is formed of two things: the bedrock, (a
thick layer of rock located underground), and
of organic material, (humus).

Soil is the result of two processes:
1. The alteration of bedrock.
2. The influx of organic material by living things.
Process #1: The Alteration of the
Bedrock

The bedrock is broken/damaged by
mechanical and chemical erosion.
Caused by the infiltration of water into the
fissures of the bedrock. When the water
freezes, the ice expands, putting a
pressure on the bedrock that causes it to
break into fragments, (mechanical
erosion).
 The acids in water cause degradation to
the bedrock, (chemical erosion).

Process #2: The Influx of Organic
Material by Living Things

Partially-decomposed organic material,
called humus, accumulates on the
surface.
◦ This is made up of plant debris, (leaves,
fruits, roots, bark), and animal debris,
(feathers, skin, excrement, cadavers).

The microorganisms present in humus is
necessary for soil development.
So…

Rock fragments + microorganisms and
humus = soil!
Soil Profile

The horizons, (the layers), of soil have
various textures and colours.
Horizon A
Also called topsoil.
 This is a layer of organic material,
(humus), that keeps the soil humid.
 Few minerals, since water carries them
down towards horizon B.

Horizon B
Also called subsoil.
 Contains many minerals but little
organic material.

Horizon C
Contains large fragments of brokendown bedrock and many minerals.
 Very little organic material.

Texture and Structure of Soil

The texture of soil depends on the sizes
of the particles within it.

Soil is generally a mixture of three
particle types: sand, clay and silt.
Soil
Texture of Particles
Permeability
(Does water pass
through easily)
Sand
Large particles
Yes
Silt
Partially fine
particles, partially
large particles
More or Less
Clay
Fine
No