EARTH’S COMPONENTS & CHARACTERISTICS. STRUCTURE OF THE EARTH more dense materials sank to the center of the earth, less dense materials rose to surface.

EARTH’S COMPONENTS

& CHARACTERIST

ICS

STRUCTURE OF THE EARTH

• more dense materials sank to the center of the earth, less dense materials rose to surface

•

Layers of Earth

• Core- center, mostly iron– Inner core- 1220 km thick, solid

iron– Outer core- 3480 km thick, liquid

iron, creates magnetic field

• Mantle- 70% of earth’s interior, mostly made of Oxygen, Silicon, Magnesium– Lower mantle- closest to core,

gelatinous, where magma is formed

– Upper mantle- cooler, more solid, brittle

• Crust- outermost layer– Crust + upper mantle make up

lithosphere

The Lithosphere• The earth’s crust, freshwaters and oceans have

given humans the means to survive and prosper.• Thanks to the resources provided by the

lithosphere, we have built cities, farmed landscapes, developed technologies, fuelled engines and acquired our food.

The Lithosphere

• It is an average of 100km thick.

• It contains the minerals, rocks and soils that humans have used for building materials, metals and agriculture.

Minerals

• Minerals are solid substances with clearly defined composition and properties.

• In most minerals atoms are organized in the form of identically shaped crystals.

• Each mineral has its own distinct chemical composition.

Examples of Minerals

• Gold (Au)• Copper (Cu)

• Quartz (SiO2)

• Iron (Fe)

Gold OreQuartz

Classifying Minerals

Minerals are classified according to the following 4 properties:

1. Colour

2. Transparency

3. Hardness

4. Streak

1. Colour

• Minerals can have a characteristic colour.

eg: azurite is blue

• Minerals may vary in colour.

eg: quartz

2. Transparency

Minerals are one of the following:

• Transparent (let light pass through)

• Translucent (let light through but blurred)

• Opaque (no light passes through)

3. Hardness• Minerals are classified according to how

hard they are. • Mohs scale assigns a value from 1 to 10

to indicate a mineral’s hardness.– Talc is soft and scores a 1 on Mohs scale– Quartz scores a 7 – Diamond scores a 10

4. Streak

• When a mineral is rubbed on a surface it leaves a powder streak that is a characteristic colour for that mineral.

Rocks

• Rocks are heterogeneous solids composed of many minerals.

• The physical and chemical properties of rocks are not strictly defined.

• There are 3 types of rocks:1. Igneous

2. Sedimentary

3. Metamorphic

1. Igneous Rocks

• Formed when magma (molten rock) cools and solidifies– eg: granite

2. Sedimentary Rocks• Formed by the accumulation and

compaction of debris at the bottom of lakes and oceans.

Limestone is a sedimentary rock used in construction

3. Metamorphic Rocks

• Igneous or sedimentary rocks that have been transformed by heat or pressure underground.

Ex.: limestone turns to marble

Soils

• As rock erodes due to rain, frost and wind, the fragments of rock mix with decomposing plants and animals.

• Eventually, soil is produced.

• It takes 200 years to form 1cm of soil!

Types of Soil

• Topsoil: includes organic litter, such as fallen leaves and twigs. Provides plants with the nutrients they need.

• Subsoil: contains some rich soil as well as small rocks.

• Weatherized big rocks. solid rock which gives rise to the horizons above it.

Human Activity in the Lithosphere

• Mining

• Agriculture

• Energy production

• Urbanization

Mining of Minerals

Mining of Minerals

• Minerals are extracted from rock ores which are mined from the lithosphere.

• Quebec is known for large deposits of gold, copper, zinc, and most recently diamonds.

• Once the ore is extracted, the mineral is separated from the rock by chemical and physical means.

AgricultureDisadvantages:

•Habitat loss

•Soil degradation

•Clear cutting/ deforestation

•Pollution

Fossil Fuels• Coal, oil, natural gas• formed from the

remains of dead plants and animals

• Extracted from the lithosphere via mining, pumping/drilling

Urbanization