The Lithosphere and the
Observatory Chapter 6: pages
Why study the lithosphere and
• The earth’s crust, freshwaters and oceans have given
humans the means to survive and prosper.
• Thanks to the resources provided by the lithosphere
and hydrosphere, we have built cities, farmed
landscapes, developed technologies, fuelled engines
and acquired our food.
• Observatory textbook pages 183-200
1. The Lithosphere
• The lithosphere is the
hard shell of the Earth,
consisting of the crust and
the topmost part of the
• It is an average of 100km
• It contains the minerals,
rocks and soils that
humans have used for
building materials, metals
• Minerals are solid inorganic substances
with clearly defined composition and
• In most minerals atoms are organized in
the form of identically shaped crystals.
• Each mineral has its own distinct chemical
• 4000 different minerals exist on Earth.
Examples of Minerals
• Gold (Au) • Quartz (SiO2)
• Copper (Cu) • Copper sulfate
• Iron (Fe) (CuSO4)
EST Gold Ore
Minerals are classified according to the
following 4 properties:
• Idiochromatic minerals have a
eg: azurite is blue
• Allochromatic minerals vary in colour.
Minerals are one of the following:
• Transparent (let light pass through)
• Translucent (let light through but blurred)
• Opaque (no light passes through)
• 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
• When a mineral is rubbed on a surface it
leaves a powder streak that is a
characteristic colour for that mineral.
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
• Once the ore is extracted, the mineral is
separated from the rock by chemical and
• Rocks are heterogenous solids
composed of many minerals.
• The physical and chemical properties of
rocks are not strictly defined.
• There are 3 types of rocks:
1. Igneous Rocks
• Formed when magma (molten rock) cools
– 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
3. Metamorphic Rocks
• Former igneous or sedimentary rocks that
have been transformed by heat or
– eg: granite turns to gneiss
– eg: limestone turns to marble
• As rock erodes due to
rain, frost and wind, the
fragments of rock mix
plants and animals.
• Eventually, soil is
• It takes 200 years to
ST form 1cm of soil!
• As soils thicken they form distinct layers
Importance of Soils
• Soils absorb, filter and store water.
• Create a habitat for micro-organisms that
decompose organic matter.
• Create a habitat for a variety of insects
and a nutrient source for plants.
• Resist changes in pH through their
buffering capacity. Soils can neutralize
ST acids or bases.
Environmental Damage to Soils
• The use of heavy machinery compacts the soil
which reduces the oxygen content and prevents
rain from penetrating; the rainwater runoff
carries away the nutrients needed for plant
• Accelerated crop rotation prevents soils from
regenerating nutrients naturally; as a result more
fertilizers have to be used.
• Excessive use of pesticides contaminate the
soil and can reduce biodiversity by killing many
beneficial microorganisms and insects.
• Soils that are permanently frozen
• 50% of Canada is covered in permafrost
• Can be up to 500m thick
• Found at high latitudes and altitudes
• Makes construction difficult
• If the permafrost melts, the ground
1.5 Energy Resources from the
• Fossil Fuels
• Geothermal Energy
• Coal, oil, natural gas
• 60% of the world’s
• formed from the
remains of dead plants
and animals (p. 196)
• When organisms died
they sank to the bottom
of lakes and oceans
and were covered with
layers of sediment
• Over millions of years
they slowly turned to
EST fossil fuels
Problems with Fossil Fuels
• When fossil fuels burn they release
thermal energy (heat) which can be
converted into mechanical or electrical
energy (eg: car engine, home heating).
• Fossil fuels will eventually run out within
the next few decades.
• Furthermore, burning fossil fuels
produces gases which are damaging to
Gases released when burning
• CO2 and CO major
• SO2 and NOx creates acid rain
• NOx produces smog
• Note that the fossil fuel natural
gas or methane (CH4) is itself a
greenhouse gas 21 times more
powerful than CO2
• Uranium is a radioactive
element found in the
• When the nuclei of uranium
atoms split a huge amount of
energy is released (nuclear
• This nuclear energy can be
harnessed and converted into
electrical energy inside a
nuclear power plant.
Advantages of Nuclear Energy
• < 1 kg of uranium can produce as much
electrical energy as 70 000 kg of coal.
• Fission of the uranium atoms does not
release greenhouse gases.
Disadvantages of Nuclear
• The energy emitted from
fission is accompanied by
• Risk of an accident a constant
• Waste is produced which
remains radioactive for
hundreds of years.
• There is no method to
“neutralize” radioactivity so the
waste is stored underwater in
large pools or buried in old
• Molten rock beneath the lithosphere
contains a huge amount of heat energy.
• To harness this geothermal energy a fluid
is circulated deep underground which heats
up and rises to the surface with a higher
• This warm fluid can be used to heat
buildings (eg: Carleton University).
• Geothermal energy is renewable and non-
polluting (no greenhouse gas emissions).
• A few geothermal systems for heating
ST buildings are now in use but they remain
EST expensive to construct.
• Answer questions 1 to 19 on pages 214-
• Use your notes and refer to pages 183 to
200 in Observatory to guide you in your