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UNIT 5: PLANET EARTH
Topic 1: Minerals
rock – a natural material composed of one or
more minerals
mineral – an inorganic, naturally occurring solid
material
- can be an element (a pure substance
that cannot be broken down into
another substance by a chemical
means)
- or can be a compound (two or more
elements combined)
crust – the thin outermost layer of the Earth
- composed mainly of quartz, feldspar,
and mica
Clues to Mineral Identification
1. Hardness - Mohs hardness scale – in geology, a
scale that compares the hardness of ten
minerals; talc has a hardness of 1 (the softest)
and diamond a 10 (the hardest)
2. Lustre – the light-reflecting properties, or
“shininess”, of minerals
3. Color
4. Streak – the color of a mineral in powdered
form
5. Crystal formation – how it breaks apart when
you drop or break it.
cleavage – breaking along smooth, flat surfaces,
or planes
fracture – breaking with rough or jagged edges
[Handout 5-2 & Geologist Mystery 5-5]
[Take Home Quiz 5-6]
[Topic 1 Review – discuss]
Topic 2: Rocks and the Rock Cycle
Rock Families:
1. Igneous Rock- “fire” formed from rock cooling
-magma – melted rock, formed under the Earth’s
crust by high temperatures and pressure. When it
cools and hardens it is called intrusive rock. (eg –
granite) Magma may contain crystals, the larger the
crystals, the slower it cooled.
-lava – magma that breaks through the Earth’s
crust. When it cools on the surface of the Earth after
a volcanic eruption it is called extrusive rock.
[sketch Fig. 5.8 here]
2. Sedimentary Rock – rock made from sediment –
loose materials, such as bits of rock, minerals, and
plant and animal remains (“building up”)
- stratification – the arrangement of sedimentary
rock in visible layers
- compaction – the process by which sedimentary
rock is formed from sediment, through the weight
and pressure of water and other sediment (shale and
sandstone)
[sketch Fig. 5-12A here]
- cementation – a process by which particles are
held together by another material (conglomerate)
[sketch Fig. 5-12B here]
3. Metamorphic Rock – a type of rock made when
high pressure and heat act on another type of rock
and change it into a new form (shale
slate
schist)
- parent rock – the original rock that was acted on
by high pressure and heat to form a metamorphic
rock (granite
gneiss)
Rock cycle – the naturally occurring process in which
rocks continue to change form over long periods of
time
[sketch Figure 5.19 here]
[show "Rocks & Soil" video #337-25min]
Sediments and Soil
- compost – the part of soil composed of dead plant
matter
- humus – the dark colored part of soil that is rich in
nutrients, such as nitrogen, phosphorus, potassium,
and sulphur
- fertile – of soil, containing the nutrients needed for
plant growth
Soil Profile – a description of the characteristics of
the different layers that make up a particular soil
a) topsoil – the topmost layer of soil, which is
dark-colored and rich in humus
b) below the topsoil – generally lighter in color
because of leaching – the process by which
materials from soil are dissolved and carried
away by water
c) the bottom layer containing weathered rock
and minerals leached from above
[Topic 2 Review – discuss]
Topic 3: Erosion
- erosion – the process of moving soil and rock from
one place to another
- weathering - the process in which rocks are broken
down and sediment is formed by mechanical,
chemical, or biological means
1. Mechanical Weathering – (“wearing away”) the process by which rocks break-up or
disintegrate by actions of physical forces such as
wind, water, and gravity
- frost wedging – a process of mechanical
weathering that occurs when water goes through a
cycle of freezing and thawing: the water expands
and contracts in the cracks of a rock, eventually
breaking the rock apart
2. Chemical weathering – the break-up or
disintegration of rocks through the effects of
chemical reactions upon them
3. Biological weathering – the break-up or
disintegration of rocks through the effects of
physical or chemical effects of living organisms
such as plants, animals, bacteria, and fungi
[show "Glaciers on the Move" #306-307-30min]
The Changing Surface of Earth
Agents of erosion - 1. Glaciers
2. gravity
3. wind
4. water
- striation - a scratch or scrape mark in a rock made
by rock fragments moved along by a glacier
- moraine - a built-up of rocks caused by the
movement of a glacier
- erratic - large rocks left behind by glacial
movement, many kilometers from their source
- abrasion – the wearing down of rocks by wind, ice,
waves, and running water
[Topic 3 Review – discuss]
[Wrap-up Topics 1-3 Pg. 381]
[show "Earth's Crust" #337-25min]
Topic 4: The Moving Crust
Layers of Earth: A. Crust (5-60km deep)
B. Mantle – the middle layer
between the crust and the core, made
of rock (1000-4000 C) – liquid-like
rock
C. Outer Core (5500 C) – liquid
iron and nickel
D. Inner Core (6000 C) – solid ball
- continental drift – a theory about the Earth’s
structure; according to this theory, the continents have
slowly changed their positions over time; the slow
movements of continents (presented by biological
evidence, rock evidence and geological evidence of
climate observed by a scientist named Alfred
Wegener 1880-1930)
- sonar (sound navigation and ranging) – a technology
that bounces sound waves off an object to determine
its distance from the source of the waves
- sea floor spreading – the process in which an ocean
floor slowly increases size over time because of the
formation of new igneous rock along a fault
Theory of Plate Tectonics – theory suggesting the
lithosphere (Earth’s crust) is divided into plates that
interact with each other
- converging plates – two or more plates colliding
- diverging plates – two or more plates moving away
from each other
- convection current – continuous circulation of fluid
(either a liquid of gas), in which thermal energy is
transferred from hotter, less dense fluid to colder,
more dense fluid
- subduction zone – a place on the Earth’s crust where
high pressure pushes one very large piece of rock
below another; earthquakes are often formed in
subduction zones
[Topic 4 Review – discuss]
Topic 5: Earthquakes
seismograph - a sensitive machine that is attached to
bedrock in order to measure the strength of
earthquakes
bedrock - the solid rock that lies beneath the soil and
looser rocks
Richter scale - a scale on which the magnitude, or
strength, or an earthquake is measured
Earthquake Waves
seismic waves - the energy waves (either primary,
secondary, or surface) that are released by an
earthquake and travel outward from its focus
aftershocks - smaller ground movements caused by
seismic waves moving outward from an
earthquake's focus
Types of Earthquake Waves
 Primary (P) waves - the fastest moving seismic
waves produced
- originating from its focus
- can pass through solids, liquids, and gases
 Secondary (S) waves - the second fastest
- originating from its focus
- passes through solids only
 Surface waves - the slowest of the three waves
- originating from its epicentre
- do the most damage
focus - the place deep in the crust where the earthquake begins (source)
epicentre - the area on the surface of Earth that is
directly above the focus of the quake
Types of Rock Movement in Earthquakes
fault - an area where two very large rock surfaces
move against each other
- Normal Faults
(tension)
- Reverse Faults
(compression)
- Strike-Slip or Transform Faults
[Topic 5: Review - discuss]
(shear)
Topic 6: Volcanoes
volcano – an opening in Earth’s crust that can release
materials such as lava, smoke, and ash: volcanoes
can either be active (releasing materials) or
dormant (not active)
vent – an opening in Earth’s crust through which
magma can escape, forming lava
Ring of Fire – an area of volcanoes around the
Pacific Ocean [overhead]
- most occur at subduction zones (eg. Mount
St. Helens and Mount Pinatubo)
[video – Ring of Fire] [Seek-a-Word Puzzle]
[Topic 6 Review – discuss]
Topic 7: Mountains
mountain - a large, naturally occuring ring formation
of Earth’s surface that rises sharply above the
surrounding area
anticline – an upfold of rock layers in sedimentary
rock
syncline – a downfold of rock layer
[sketch and label Fig. 5.67 here]
thrust faulting – low angle faulting of rock
- process whereby sedimentary rock is squeezed
from the sides causing rock slabs to move up and
over each other like shingles on a roof
fault block mountain – mountains formed by the
process of thrust faulting
complex mountains – mountains that are formed by
the combined forces of folding and faulting
Ages of Mountains:
young mountains – mountains that are jagged at the
top (eg. Rockies, Himalayas, Alps)
old mountains – mountains that are more rounded in
appearance due to the process of being worn
down or eroded (Laurentians)
[Topic 7: Review – discuss]
[Wrap-up Topics 4-7 Pg. 417 #1,2,4,5,6]
Topic 8: Fossils
Types of Fossils:
petrification – process whereby a rock-like substance
is formed when water penetrates organic matter,
and deposits dissolve mineral matter
carbonization – process whereby the organism is
buried under sediment and the pressure and heat
build up leaving only a thin layer of carbon
residue outlining the organism ( the outline is
called a carbonaceous film)
original remains – organisms or parts of it may be
found encased in amber, ice, natural paraffin, or
tar
moulds and casts – formed when the organism dies,
decays, and leaves a natural cavity in the
sediment. Sometimes the cavity is not filled and
leaves a mould. Usually, more mineral matter is
moved in by water and fills the mould to form a
cast (many Alberta fossils are casts)
trace fossils – evidence of organism activity (worm
holes, burrows, footprints, tracks, tooth marks,
imprints of leaves, etc.)
[Topic 8 Review – discuss]
Topic 9: Geologic Time
principle of superposition – a geological theory
stating that in undisturbed layers of rock, the
oldest rock will be on the bottom and the
youngest layers will be on the top
strata – layers of sedimentary rock
relative dating – determining the order in which
geological events occurred and the relative age
of rocks by their positions in the strata
index fossil – a type of fossil that can be used to
determine the age of the material in which it is
found
Clues from Technology
half-life – the amount of time that a given amount
of radioactive substance takes to be reduced by
one-half [sketch Fig. 5-84 here]
radiometric dating – the process of determining the
age of a geological specimen by measuring the
relative amounts of radioactive particles that are
present in the specimen
radiocarbon dating – a method used to determine
the age of organic remains by measuring the
relative amount of radioactive carbon found in
the remains
Geological Time Scale
[sketch Fig. 5.87 here]
Summary:
Time measured in Eons/Eras/Periods
Cenozoic - Age of Mammals
Mesozoic - Age of Dinosaurs
Paleozoic - Age of Invertebrates and Amphibians
Rodinia – the earliest supercontinent thought to have
broken apart approximately 750 million years ago
- included all the large land masses
Pangaea – the second supercontinent thought to have
existed approximately 350 million years ago
- included all the present continents
[Topic 9 Review – discuss]
Topic 10: Fossil Fuels
petroleum – a type of oil found in rock formations
in the Earth’s crust
- refined into products such as gas or jet fuel
fossil fuels – fuels made of decomposed plants and
other organisms that have been hardened or
fossilized
- take millions of years to develop
- examples are coal, oil, and natural gas
Finding and Mining Fossil Fuels
Scientists study surface rocks and samples from deep
within the ground to identify traps where oil and gas
have accumulated within rock formations.
bitumen – a heavy, almost solid form of petroleum
- found near the surface of the Earth
- can be mined or heated and pumped to the
surface
[Topic 10 Review – discuss]
[Wrap-up Topics 8-10 Pg. 433-All]
[Distribute Unit 5 Map for review purposes]
[Unit 5 Review – Read “Unit at a Glance”, do selected
Questions Pg. 438 #1,2,4,5,7,8,12,16,19,21, 24,30*in
a) delete "to the surface"]