Planet EarthMs. Lyons

Minerals Rock is made up of one or more pure, naturally

occurring, non-living, crystal like materials call minerals.

Most minerals are quite rare. Only a few, such as quartz, feldspar and mica, are found throughout the Earth’s crust (the thin outermost layer of Earth)

Minerals Continued… A mineral can be an element (a pure substance)

or a compound (two or more elements combined)

Example: Quartz is a compound of silicon and oxygen

The Mohs Hardness Scale was developed to identify minerals according to how hard they are. A mineral that is rated 1 is very soft and a mineral that is rated 10 is very hard. (Gold is a 10- the hardest mineral)

Crystals Crystals are the building blocks of

minerals. A mineral’s crystals are used to help people identify it.

You can identify crystals using the Six Major Crystal Systems

Six Major Crystal Systems

Other Clues for Mineral Identification Lustre – The ‘shininess’ of the mineral Colour – The colour of the mineral can be used to

identify it. However a mineral will be a different colour if it is pure vs. if it is not.

Streak – Is the colour of the powdered form of the mineral (this is a good way to identify fake gold)

Cleavage and Fracture – The way a mineral breaks apart can be a clue to its identity. If it breaks along smooth, flat surfaces, it is said to have cleavage. If it breaks with rough or jagged edges it is said to fracture.

Rock Families Scientists have grouped Rocks into three

major families, or types, based on how they form.

The three families are igneous, sedimentary and metamorphic rocks.

Each can generally be identified by its appearance.

Igneous Rock Igneous rock forms when hot magma or lava

cools and solidifies. Magma is melted rock found beneath the

Earth’s crust where temperatures are high. When magma cools and hardens below the

Earth’s surface it is called intrusive rock. When magma breaks through the Earth’s surface

in a volcanic eruption, it is called lava. Rock that forms when lava cools is called

extrusive rock.

Igneous Rock

Sedimentary Rock Sedimentary Rock makes up about 75% of all

rocks that we see on Earth. This kind of rock is made from sediments.

Sediments are loose materials, such as bits of rock, minerals, and plant and animal remains that get packed in layers and cemented together.

The arrangement of these layers is called stratification.

Sedimentary Rock… The process of squeezing the layers together is

called compaction.

In some rocks, minerals dissolve as water soaks into the rock, forming a natural cement that sticks pieces of sediment together (this is called cementation)

Examples?

Sedimentary Rock Shale

Sandstone

Conglomerate

Metamorphic Rock Metamorphic Rock means ‘changed form’. This

type of rock may be formed below the Earth’s surface when extremely high pressures and heat cause the original rock or parent rock to change form.

The type of rock formed depends on the amount of pressure applied.

Metamorphic rock can change so completely that it no longer looks like the parent rock. There are enough common characteristics , however that geologists know they are related.

Metamorphic Rock For example limestone and marble look different,

but they both have a hardness value of 3, and both are made of the mineral calcite. Both limestone and marble react with dilute hydrochloric acid.

The Rock Cycle The Rock Cycle – Rocks continue to

change in an ongoing process. Rocks change as a result of the rock cycle. In order to identify rocks after they have weathered, you need to identify the minerals found within the rock.

The Rock Cycle

Rock Cycle

Sediment and Soil Soil is formed from the combination of compost

(which is decaying plant matter), rock, sediments, living material like twigs and leaves and dead worms or insects.

The dark coloured portion of the soil is called humus and is very fertile.

Soil Continued… Layers of soil make up a soil profile.

The top layer is called topsoil (it consists of humus and small grains of rock)

The second layer is lighter in colour, and contains less humus and larger rock chunks.

The third layer contains ever larger rocks that are only beginning the process of being broken down into soil.

Soil Profile

Erosion and the Moving Crust Erosion is the movement of rock and

mineral grains from one place to another.

Sediment comes from larger rocks that have broken down or worn away through weathering.

Sedimentation is the process where eroded material is deposited and built up.

Mechanical Weathering Mechanical Weathering is the physical break-

up or disintegration to rocks.

For example, gravity causes rocks to fall down a cliff and break apart.

Rocks rolling down a slope or in a fast-moving stream rub and bump against each other, becoming smoother and more rounded.

Frost Wedging Frost wedging – during the daytime in

the spring water runs into cracks in rocks. Then at night the water freezes in the cracks and pushes the rocks apart. Each day more water runs into these cracks until eventually the rock breaks apart.

Mechanical Weathering

Chemical Weathering Chemical Weathering breaks down minerals

through chemical reactions Some material may be dissolved, other materials

are weakened. Rocks react with water, with other chemicals dissolved in water, or with gases in the air.

An example of chemical weathering is acid rain, which contains dissolved chemicals from air pollution. Acidic rain reacts with some rocks such as limestone. The rock material dissolves easily in the water and washes away.

Chemical Weathering

Biological Weathering Biological Weathering is the physical or

chemical breakdown of rock caused by living organisms, such as plants, animals, bacteria and fungi.

Physical Biological Weathering occurs, for example, when a plant root wedges into a rock by forcing its way into a crack. As the root grows and expands, so does the crack, and the rock is pushed apart until it eventually crumbles and breaks.

Biological Weathering Biological Weathering can also be chemical. For

example acidic fluids produced by plant roots, bacteria, fungi and some insects and small animals can cause chemical reactions. As the rock slowly dissolves and flows away with rainwater, cracks and crevices increase in size until the rock finally breaks apart.

Erosion Mechanical, Chemical and Biological weathering

work together constantly to change our landscape.

Glaciers, gravity, wind and water all cause erosion. Changes in our earth’s surface that happen slowly (those caused by glaciers) are called “gradual changes”. Those that happen quickly like floods, landslides and rockslides are called “sudden changes”.

Water in motion is a very powerful cause of erosion

Weathering and Erosion http://www.teachertube.com/

viewVideo.php?video_id=20814&title=Weathering_and_Erosion_by_StudyJams

The Moving Crust The earth’s crust is the layer of the earth that

we walk on and build our homes on. It also includes deeper areas where minerals and oil and gas are mined.

The mantle is found under the crust. It is made of rock material.

The upper mantle is solid and the lower mantle has the consistency of taffy.

The earth’s crust and the upper mantle form the lithosphere.

Continued… The outer core is under the mantle and

consists of iron and nickel. The temperature here is 5500 degrees Celsius and is so hot that iron and nickel are in a liquid state.

The intense pressure of all the layers forces the inner core to have a temperature of over 6000 degrees Celsius.

Layers of the Earth

Continued…

Layers of Our World http://www.teachertube.com/

viewVideo.php?video_id=43078&title=Layers_of_Our_World

Geographic Information System

Continental Drift Continental drift is the belief that the

continents at one time where completely joined together and over the years have drifted apart.

A German scientist named Alfred Wegener found evidence that supported his theory. This evidence came in the form of rock similarities, fossil similarities, and climatic similarities between continents. Wegener believed that all of the earth’s continents had been joined together in a giant supercontinent called “Pangaea". He had difficulty proving this theory and died in 1930 still trying to prove it.

Advances in Technology Sonar (sound wave technology) revealed

to scientists that the ocean’s floor is not flat. It revealed that mountain ranges exist on the ocean floor.

What was causing the mountains to form?

Sea Floor Spreading Sea floor spreading is the process in which

an ocean floor slowly increases in size over time because of the formation of new igneous rock along a fault.

The ocean floor is spreading and getting wider by about 2cm per year (about the same speed at which your fingernails grow).

Sea Floor Spreading

Continued

Theory of Plate Tectonics Theory of plate tectonics states that the

earth’s crust is broken up into pieces called plates.

These plates are always moving on the earth’s mantle.

Plates that are moving together are called converging plates and plates that are pulling apart are called diverging plates.

One explanation for why plates move is based on the theory that a convection current is causing the earth’s plates to move.

Convection Currents Geologists are still not sure what causes

the Earth’s plates to move. One explanation is that convection currents in the mantle under the Earth’s crust move the plates.

A convection current is the flow resulting from the rise of warmer materials and the sinking of cooler materials.

Convection Currents Continued… When two plates collide or converge, one is

shoved under the other. These places are called subduction zones.

Scientists suggest that subduction zones form where convection currents cool and sink.

At the upper part of the mantle, the heated rock moves the plate along as if it were on a conveyer belt. When the rock cools, it sinks down into the mantle pulling the plate with it, forming an ocean trench.

… If there is Sea Floor Spreading does that

mean the Earth’s crust is getting bigger??

The theory of plate tectonics is our best explanation for the formation of earthquakes, volcanoes, and mountains.

Earthquakes

Why do they Happen? Earthquakes are usually caused when rock

underground suddenly breaks along a fault. This sudden release of energy causes the seismic

waves that make the ground shake. When two blocks of rock or two plates are rubbing

against each other, they stick a little. They don't just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that's built up. When the rocks break, the earthquake occurs.

How do we measure Earthquakes? Scientists use a machine called a seismograph

to measure earthquakes. This machine is attached to bedrock (the solid

rock that lies beneath the soil and looser rocks) in order to feel vibrations that result from an earthquake

Continued… Seismologists (scientists who study

earthquakes) use a method of measurement called the Richter Scale to describe the strength of the earthquake.

The smaller the number the less devastating the quake.

Most earthquakes that cause damage and loss of life register between 6 and 8 on the Richter Scale.

Earthquake Waves There can be many episodes of ground-

shaking movement in an earthquake caused by seismic waves.

Seismic waves are the energy waves that travel outward from the source of the earthquake.

Aftershocks are smaller quakes that happen after the initial quake.

Aftershock Damage Aftershocks can cause damaged buildings

to collapse. The Kobe earthquake in Japan, 1995, produced over 600 aftershocks.

Types of Earthquake Waves There are 3 kinds of seismic waves that

occur in an earthquake.

1) Primary or P waves2) Secondary or S waves3) Surface waves

Primary or P Waves Primary (P waves) travel the fastest of

all three types of waves and can pass through solids, liquids and gases.

These cause slight vibrations that rattle dishes and warn people that an earthquake is taking place and that larger earth movement may be on its way.

Secondary or S Waves Secondary (S waves) travel more slowly

than P waves and can only pass through solids.

Surface Waves Surface waves are the slowest of the

three waves, but their rolling motion causes the most damage.

They break up roads and buildings, because they cause one part of a structure to move up while the other part moves down.

These waves travel outward like the ripples in a pond when you throw a pebble.

What does the Seismograph tell you?

What can this tell us? The earthquake that happened in Japan

registered on the seismograph at the University of Manitoba.

This is because P waves travel right through the centre of the Earth. S waves did not register.

Because we know S waves cannot travel through liquid but P waves can, we can hypothesize that the Earth’s outer core is liquid.

Locating an Earthquake How do you estimate how far away a

thunderstorm is? The same theory applies to earthquakes.

P waves travel faster than S waves. Therefore the further apart the P and S waves are, the farther away the earthquake.

Source of the Earthquake Scientists have a special name for the source of

an earthquake. In fact, they use two names. The place deep in the crust where the earthquake

begins is called the focus of the earthquake. The primary and secondary waves come from the

focus of the earthquake.

The surface location directly above the focus is called the epicentre.

Surface waves travel out from the epicentre.

Types of Rock Movement in Earthquakes The rock in the Earth’s crust is under pressure all

the time from tremendous forces. These stresses can cause rock to bend and stretch. But when the pressure is too great, the rock breaks suddenly, creating a fault.

Movement along a fault can spread more than a kilometer in a second.

Fault zones exist where tectonic plates meet.

Normal Faults Normal faults occur because of tension forces (rock being

pulled apart). In this type of fault, rock generally moves down.

These generally happen on the sea floor and cause little damage

Reverse Faults Reverse faults occur because of compression

forces (rock being pushed together). In this fault, rock generally is forced upward.

Strike-Slip or Transform Faults Strike-slip or Transform faults occur because

of shear forces. Rock along the edges of these faults generally have many bumps and bulges.

Other Effects of Earthquakes Some earthquakes happen under the sea.

The water displaced by an earthquake can become a huge wave called a tsunamis.

Tsunamis can travel across oceans and cause great damage when they break on shore.

In mountains, earthquakes can trigger avalanches or rock slides.

Volcanoes

Volcanoes A volcano is an opening in the Earth’s

crust that releases lava, steam, and ash when it erupts (becomes active).

The openings in the earth’s crust when a volcano erupts are called vents. When volcanoes are not active, they are described as dormant.

How are Volcanoes Formed? Volcanoes are formed when rock surfaces beneath

the earth’s surface push against each other.

The rock pushing downwards begins to melt and turn into magma.

Eventually there is so much magma that it is forced up through cracks in the earth’s crust and an eruption occurs.

Volcanoes erupt in stages over a period of weeks, months, or even years.

Famous Volcanoes Mount St. Helens (U.S.A.) erupted in 1980.

Famous Volcanoes Mount Vesuvius in Italy has been dormant since

1944 and scientists believe that it is set to erupt any time.

A huge area beneath the peak is filling with magma. The situation is even more dangerous because the opening at the peak is sealed by a rock ‘plug’. Plans are being made for emergency measures if such an event occurs.

Mount Vesuvius erupted in 79 BC. Many things, including people were preserved in the ash.

Mt. Vesuvius

Ring of Fire The volcanoes around the Pacific Ocean

make up the Ring of Fire.

The name comes from the circle of volcanoes that pour red hot lava, fire and steam.

Most volcanoes in the Ring of Fire occur at subduction zones.

Ring of Fire

Mountains Mountain building takes many years, and it

creates some of the most beautiful scenery in the world!

How are Mountains Formed? Most mountains are large areas that have

been uplifted due to the movement or heating of plates.

The movement along these boundaries can create great heat and pressure. The pressure can cause the rocks to fold and fault, creating mountains!

Sometimes the heat can melt the rock and cause it to form volcanoes.

Continued… Sedimentary rocks that are places under

slow, gradual pressure can either fold or break.

Rock that has been heated and is soft begins to fold.

The top part of this folded rock is called the anticline, and the bottom of the fold is called the syncline

Continued… If the rock is too brittle to fold, it can break,

forming a fault. Faults can be the result of squeezing the earth’s crust or of stretching the earth’s crust.

When the earth’s crust is squeezed together, sedimentary rock forms into slabs that move up over each other like shingles on a roof. This process is called thrust faulting.

When the earth’s crust is stretched blocks of rock can tilt and slide down. Here, older rocks may end up on top of younger rock, and these huge amounts of rocks can form mountains called fault block mountains.

Fault Block Mountain

The Rockies The Canadian Rockies have been formed

by sedimentary rock sliding on the basement rock and pushing the crust upwards (Sedimentary rock is seen at the surface).

Continued… The American Rockies have been formed

by igneous and metamorphic (basement rock) rock being shoved on top of each other and pushed upwards (Basement rock is seen at the surface).

Age of a Mountain Young mountains are jagged at the top. Older mountains are more rounded

because their surfaces have been eroded and weathered due to mechanical, biological and chemical weathering

The Canadian Rockies are fairly young, the Laurentian Mountains in Quebec are older and are in the process of being worn down.

Fossils Fossils provide clues about when life

began, and when plants and animals first lived on the land.

How are Fossils Formed? A fossil is formed when soft parts of a dead

animal (skin, muscles and organs) decay quickly, but the hard parts of the animal (teeth, bones and shells) are altered and then fossilized.

Bones of the animal become petrified or turned into a rock like substance.

This happens when water penetrates the bones of the dead animal and dissolves the calcium carbonate in the bone. Then a very hard mineral (silica) is deposited and left behind. This mineral turns the bones into a rock like substance.

Types of Fossils Sometimes the actual organism or parts of it may be

preserved as a fossil. These are called original remains (ex. fly’s preserved in resin, dinosaurs preserved in tar pits and woolly mammoths preserved in ice.)

Trace fossils are evidence of animal activity (ex. Footprints, or worm holes that have become fossilized).

A mould is a type of fossil, in which the hard parts of the organism have dissolved, leaving a cavity in the rock.

A cast is a type of fossil in which sediments or minerals have filled a mould and hardened into rock.

Fossil Mould and Cast Formation

Geologic Time Principle of superposition states that in

undisturbed layers of sedimentary rock, the oldest layers are always on the bottom and the youngest layers are always on the top.

Strata is layers of sedimentary rock. Relative dating is a strategy that scientists use

to figure out the age of the rocks according to their position 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 The amount of certain elements in a rock can tell geologists

a great deal about the rock’s age. Over billions of years some elements can change into others.

Over a period of 4.5 billion years, half of the uranium in a rock will turn to lead. This is known as the half-life of uranium.

The half-life of a substance is the amount of time that a given amount of a radioactive substance takes to be reduced by one-half.

Radiometric dating is the process of determining the age of a rock specimen by measuring the amounts of radioactive particles that are present in the rock and by knowing the half life of the parent rock.

Geological Time Scale The geological time scale is a division of Earth’s history into

smaller units based on the appearances of different life forms

Precambrian period – was the first 4 billion years that the earth existed until 590 million years ago (during this time the first super continent called Rodinia was formed)

Paleozoic Era means ancient life (approximately from 590 million years ago to 248 million years ago)

Mesozoic Era means middle life (approximately from 248 million years ago to 65 million years ago)

Cenozoic Era means recent life (approximately from 65 million years ago to present day)

It is believed that the second super continent Pangea first split into a northern portion called Laurasia and a southern portion called Gondwanaland.

Fossil Fuels Petroleum is a type of oil found in rock formations in the

Earth’s crust. It is refined into products such as gasoline or jet fuel (it is most often found in sedimentary rock).

Fossil Fuels are fuels made of decomposed plants and other organisms that have been hardened and fossilized. Fossil fuels take millions of years to develop; examples of fossil fuels include oil, natural gas and coal.

Bitumen is a heavy almost solid form of petroleum. Some bitumen deposits are found near the surface of the Earth and can be mined or heated and pumped to the surface (to be used as gasoline and or jet fuel).

How Do You Find Oil and Gas? Scientists study surface rocks and samples

from deep within the ground to identify traps where oil and gas have accumulated within rock formations.

Oil and natural gas can move long distances through strata and sometimes escape at the surface. Sometimes the lighter compounds are removed by the air or water, leaving heavier types of oil behind.

Oil and Faults