Plate T

ectonics

The Earth

• The Earth is composed of 3 different compositional layers, the crust, mantle, and core.

• The crust is the exterior surface that we walk on. It is also the thinnest layer. 2 types, continental and oceanic.

• The mantle is the middle layer between the crust and the core. It is the thickest layer. Rocks here are in a plastic like state.

• The core is the heart of the Earth. The core has the highest temperature.

The Earth

• The Earth is also composed of 5 physical layers or mechanical layers.

• These layers are called physical layers because each layers has a different set of physical properties.

Lithosphere

• Lithosphere: made up of the crust and the upper rigid part of the mantle, also known as a tectonic plate.

• A tectonic plate can be made of granitic (land, light) or basaltic (ocean, heavy) crust.

Asthenosphere

• Plastic like layer of the mantle on which tectonic plates (lithosphere) slide around on.

• The asthenosphere is made of solid rock but the rock flows very slowly. It is NOT molten, it is solid.

Mesosphere

• Mesosphere: lower part of the mantle.

• Rocks here are still solid, but flow like the asthenosphere.

Outer Core

• Outer Core: outer layer of the core. There are no rocks here, all have melted (or turned to magma).

Inner Core

• Inner Core: Innermost layer, the rocks here are formed due to extreme pressures inside the Earth. This pressure causes the rocks to be solid and not melt even though temperatures are extremely high.

• The inner core is made up mainly of Iron and Nickel which are 2 of the most dense elements inside Earth.

Review Question

• What are Earth’s compositional layers?

• What are Earth’s mechanical layers?

• What makes these layers different from each other? Mechanical vs compositional

Plate Tectonics

• The Earth’s outer layer (lithosphere) is broken up into large pieces called tectonic plates.

• These plates move around on the asthenosphere.

• The movement of these plates cause different major geological events to happen such as volcanoes, earthquakes, and tsunamis.

Boundaries between Plates

• Tectonic plates can slide past one another, crash into each other, or pull apart from one another.

• Evidence of the plates moving is supported by earthquakes, volcanoes, mountain building, and tsunamis.

Types of plate boundaries

• Strike-slip or Transform boundary: plates are sliding past each other. Earthquakes are the result.

• Convergent: plates are colliding together. Mountains, subduction zones, and volcanoes are the result.

• Divergent: plates are separating or pulling apart from each other. New sea-floor forms here mid-ocean ridges are the result.

• The Mid-Atlantic Ridge is the driving force behind the theory of plate tectonics.

• Subduction zone: Zone where 2 plates meet underground. Friction here cause rock to melt.

Review Questions

• How does the Earth behave at the following faults: transform, convergent, divergent?

• What is a tectonic plate?

• What is the Mid-Atlantic ridge and what is it responsible for?

• What evidence is there for the theory of plate tectonics?

Convergent Boundaries

Oceanic - Oceanic

Oceanic-Continental

Continental-Continental

Evidence – Earthquakes• Earthquakes: happen when tectonic plates are

sliding past each other (transform boundary). The plates bind up on each other and when enough tension between the plates is built up, they slip, causing an earthquake.

• The ground in an earthquake actually moves cause damage to buildings, roads, etc.

• Earthquakes that happen under water can cause a tsunami (tidal wave) to occur.

• **Measured with the Richter Scale 1-10.**

Evidence - Volcanoes• Volcanoes: Created where plates are converging on each

other. 1 plate will slide under the other plate causing enough friction in a localized area to cause the rock to melt. This molten rock will burn up to the surface and create a volcano over time. Most volcanoes are located in the Pacific Ring of Fire because of subduction zone around the Pacific Ocean.

• Not all volcanoes are created this way. Some are created at hot spots such as the Hawaiian Islands. A hot spot is an area where magma has burned through the lithosphere and created a volcano or volcanic island not at a plate boundary.

• Volcanoes can cause major problems worldwide with ash deposits on land and ejected into the atmosphere.

Pacific Ring of fire/ Volcanoes worldwide

Cinder Cone - smallest, least destructive

Shield Volcano - largest, not very destructive

Composite (Strato) Volcano – mid sized, most destructive

Composite volcanoEruptions range from Simple lave flows to Major eruptions.

Mt. Rainier, Washington

Hydrothermal Vents • Also called geysers or black smokers.• Vents: opening where magma can flow onto

Earth’s surface, typically found at divergent boundaries.

• A hydrothermal vent is an area where water is in contact with magma below the surface of the earth. These vents can be found on land and under water.

• Examples, Old Faithful at Yellowstone and black smokers on the ocean floor.

Hydrothermal vents

Black smokers

Erupts every 35-120 Minutes. In YellowstoneNational Park, Wyoming

Review Questions

• Why are volcanoes evidence of plate tectonics?

• Why are earthquakes evidence of plate tectonics?

• What problems can earthquakes and volcanoes cause?

• What is a hydrothermal vent? Where are they located? Why are they evidence of plate tectonics?

Conclusion

• The Earth is made up of compositional layers, crust, mantle, and core. The physical layers are known as the lithosphere, asthenosphere, mesosphere, outer core, and inner core.

• The Earth’s surface is broken into plates called tectonic plates. These plates move around on the asthenosphere causing major geologic events such as mountain building, earthquakes, tsunamis, and volcanoes.

Conclusion

• The plates can have different boundaries such as transform, convergent, and divergent.

• The Mid-Atlantic ridge is the driving force for the theory of Plate Tectonics.

• Hot spots are created when magma burns through a tectonic plate (not at a boundary) and creates a volcanic island.

• Geysers and hydrothermal vents occur on land and under water when water comes into contact with magma.

GPS

• S6E5. Students will investigate the scientific view of

how the earth’s surface is formed. – b. Investigate the contribution of minerals to

rock composition.

Minerals

The Building Blocks

Minerals

• Mineral: Is a naturally formed, inorganic solid with a crystalline structure

Minerals are made of elements

• An element is a pure substance that cannot be broken down into simpler substances by ordinary chemical means

• made of elements, such as oxygen, iron, gold, silver, hydrogen, aluminum, etc.

• Elements are made up of atoms.

• An atom is the smallest part of an element that has all the properties of that element.

• When more than 1 type of atom are chemically bonded together, they make a compound.

Review

• What is a mineral?

• What is an element?

• What are elements made of?

• What is an atom?

• What is a compound?

Rocks

What are they, where do they come from?

GPS• S6E5. Students will investigate the scientific view of

how the earth’s surface is formed. – a. Compare and contrast the Earth’s crust, mantle, and core

including temperature, density, and composition. – b. Investigate the contribution of minerals to rock composition.

– c. Classify rocks by their process of formation.

– d. Describe processes that change rocks and the surface of the earth.

– g. Describe how fossils show evidence of the changing surface and climate of the Earth.

What is a rock?

• Rock: solid mixture of crystals of one or more minerals, some rocks, such as coal, are made of remains of organic material (dead plants and animals).

• Rocks can range in size from a grain of sand to thousands of miles long.

The value of rock(s)

• Rock has been used in the past to make many objects such as hammers, knives, spears, statues, etc.

• Today it is used to make buildings, scalpels, statues, counter tops, etc.

• Rocks provide a history of what Earth and other planets were like before recorded history. A rock is much like a time capsule.

The value of rock(s) cont’d

• Some rocks contain fossils that help to provide clues as to what Earth was like millions of years ago.

• We would know very little about the Earth before recorded history without rocks and fossils.

The rock cycle:

Sediments Sedimentary Rock

Igneous Rock Metamorphic Rock

Magma/Lava

CC

WE

HP

HP

HP

HP= heat and pressure

WE = weathering and erosion

M = meltingCC = compaction and cementation

WEWE M

MM

CS = Cool and solidify

CS

How do rocks melt?

• 1. Increase in Temperature: an increase can cause rocks to melt.

• 2. Release of Pressure: causes rocks to stay a solid deep inside the Earth. When these rocks move towards Earth’s surface the pressure is released and the rock melts.

• 3. Change in Composition: when water or carbon dioxide enter a rock near its melting point, it lowers it melting point enough to cause the rock to melt.

How to classify rocks• Composition: Elements

a rock is made of. • A rock that has a

majority (60% and above) of one mineral will have a composition close to that mineral

• Likewise if a rock has no dominant mineral it will have a unique composition.

How to classify rocks• Texture: determined by

the sizes, shapes, and positions of mineral grains of which it is made of.

• 3 types: fine-grained, medium-grained, and coarse-grained.

• The longer it takes magma to cool, the larger the crystals (grains) grow.

• Fine-grained: extremely small grains.

• Medium-grained: sand sized grains.

• Coarse-grained: contains larger grains such as pebbles or broken pieces of other rocks.

Review Questions

• What is a rock?

• Why are fossils important?

• Name the 3 ways rocks can melt.

• How is composition different from texture?

• What are the 3 main textures?

Types of rocks

• There are 3 types of rocks:

• Igneous• sedimentary• metamorphic

Magma

• The type of magma will determine what type of igneous rock (felsic/mafic), that is formed.

• This will, in time, affect the type of rock it forms later on.

Igneous Rocks• Magma that has

cooled and solidified. • Two types of igneous

rocks: felsic and mafic.

• Types of igneous formation: intrusive and extrusive.

Felsic Vs. Mafic

• Felsic:• light colored, less

dense.• Rich in elements

such as silicon, aluminum, sodium, and potassium.

• Ex. granite.

• Mafic• dark colored, more

dense.• Rich in iron,

magnesium, and calcium.

• Ex. gabbro

Intrusive• Intrusive: When magma cools

beneath the Earth’s surface. • Intrusive igneous formations

can be found on Earth’s crust.

• Usually has a coarse grained texture because it has a long time to cool.

• Examples: dike, volcanic neck, pluton, sill, batholith, and laccolith.

Extrusive• Extrusive: created when

lava cools and solidifies on Earth’s surface or under water.

• Most volcanic rock is extrusive.

• Contains either small or no crystals. (fine-grained)

Igneous Rocks Review

• Is affected by a change composition, pressure, and/or temperature.

• There are 2 types of igneous rocks, intrusive and extrusive.

• They are further classified as mafic or felsic, fine, coarse, or medium grained textured, and their compositions.

Review Questions

• What is an igneous rock?

• How are felsic rocks different from mafic rocks?

• How does magma affect igneous rocks?

• How are intrusive rocks different from extrusive?

Sedimentary Rocks

The breakdown!!

Sedimentary Rock• Weathering: when rocks are broken down by wind, water,

ice, sunlight, and gravity.• Weathering creates small fragments of rock called sediments.• These sediments are moved around by weathering forces.• Eventually these sediments are deposited in layers. Usually

at the bottom of slow moving water.• The sediments will form layers, one on top of another. After

time and pressure, the layers will be compacted and cemented. This forms a sedimentary rock. These lines are called strata.

Classification of Sedimentary Rocks

• 3 main types:– clastic– chemical– organic

Their grain size also helps to classify the rock:

fine, medium, and coarse-grained.

Clastic • Clastic: Made from fragments of other rocks and minerals

• this is a coarse-grained, conglomerate. (made up of other pieces of rock.

• Fragment size helps determine clastic rock name.

Chemical

• Chemical: Forms from solutions of minerals and water.

• Usually as water evaporates, the minerals are left behind and solidify and form a chemical sedimentary rock.

Organic

• Organic: Rock that forms from the remains of once living organisms.

• Fossils are classified as organic sedimentary rocks.

• Fossils are the remains of once living organisms that have solidified to form rock.

• Most fossils are found where water once was or is.

Review Questions

• What is a sedimentary rock?

• What are the 3 main types?

• How do the 3 types of sedimentary rocks form?

• What type of sedimentary rock is a fossil?

Metamorphic Rock

• Metamorphic rock: Rocks whose structure, texture, or composition have been changed.

• All types of rocks can become a metamorphic rock - igneous, sedimentary, and metamorphic.

Where do they come from?

• If the temperature or pressure of a rocks new environment changes from the one it formed it, the rock will undergo metamorphism.

• Most metamorphic rocks are created from an increase in pressure deep inside the Earth.

• Temperatures as low as 50 degrees Celsius and as high as 1000 degrees Celsius can cause rocks to metamorphose. Temperatures hotter than that melt a majority of rocks.

Contact versus regional metamorphism

• Contact metamorphism: happens when rocks come into contact or are close enough to magma to alter the rocks composition.

• Only happens at igneous intrusions.

• Rocks are “cooked”

• Regional metamorphism: happens when rocks pressure builds up on a rock or when Earth’s crust collides together at fault boundaries.

• Rocks can undergo both regional and contact metamorphism.

Metamorphic rock composition

• Composition changes after metamorphosis due to the heat and pressure.

• Some metamorphic rock compositions can be only created at certain temperatures and pressures.

Metamorphic rock textures

• Foliated: mineral grains are aligned, some look like pages in a book, while others do not.

• Example: gneiss, and schist.

• Nonfoliated: metamorphic rock that does not contain aligned mineral grains. The grains seem to grouped together instead of organized into layers.

• Examples: marble and quartzite.

Review:• Rock is a solid mixture of crystals or one or more minerals.

• 3 types of rock: igneous, sedimentary, and metamorphic.

• Rocks go through a cycle called the rock cycle.

• Igneous rocks are formed from cooled magma or lava.

– types: intrusive and extrusive

• sedimentary rocks are formed from remains of other rocks and sometimes organic material.

– Types: clastic, chemical,and organic

• Metamorphic rocks are created when rocks undergo a change.

– Types: foliated and nonfoliated.

Review Questions

• What is a metamorphic rock?

• What are the 2 main types of metamorphic rocks?

• How are the 2 types different from each other?

• How is regional metamorphism different from contact metamorphism?

Chapter 5

Energy Resources

Natural Resources

• Any natural material that is used by humans.

• Examples: water, petroleum, minerals, wind, sunlight, wood, nuclear and animals.

• Most have to be changed or altered for human use.

Renewable Resources

• Renewable resource: A resource that can be replaced at a close rate to how fast it is used.

• Example: trees, can be replaced in as little as 15 years.

• Examples: wood, biomass (trash), geothermal, solar, wind, hydroelectric, nuclear, hydrogen, and ethanol.

Nonrenewable Resources

• Nonrenewable resource: Resource that is used at a much faster rate at which is can be replaced.

• Example: petroleum (used to make gas), takes millions years to form.

• Examples: petroleum, coal, and natural gas (fossil fuels)

• The U.S. gets about 85% of its energy from fossil fuels.

Fossil Fuels

• Fossil Fuels: created from organisms that lived long ago…from a few thousand to several million of years. Tremendous amounts of pressure from layers of earth turns these organisms into fossil fuels.

• We obtain these fuels from pumping them out of of the ground or by digging them by using mines (deep or shallow).

• To get the energy from fossil fuels, we typically burn them.

Problems with Fossil Fuels

• When fossil fuels burn, they release compounds into the atmosphere that can combine with water to create smog, ozone, or acid precipitation.

• These by-products can harm or even kill animals, plants, and humans. Many respiratory diseases such as asthma are caused by these pollutants.

Alternative Resources

• Alternative resources: Another form of energy used that does not pollute the Earth’s atmosphere like fossil fuels do.

• Examples: nuclear (fusion and fission), chemical energy, solar energy, wind power, hydroelectric, gasohol (gas + alcohol), geothermal, methane, etc.

Inexhaustible Resources

• Inexhaustible resources: Energy forms such as nuclear, hydroelectric, solar, wind, and geothermal are considered inexhaustible resources because they would never run out (at least for the next 5 billion years or so).

Types of Energy: what / where they come from

• Hydroelectric: water

• Solar: sun

• Geothermal: Earth (heat from inside)

• Nuclear: energy from atom (splitting (fusion) or forcing them together (fission)).

• Wind: wind (ultimately the sun)

• Petroleum: dead plants & animals (organic)

• Biomass: dead plants, animals, & animal waste

• Chemical: reacting chemicals create energy

• Natural gas: organic matter (dead plants and animals).

Conclusion

• We use many different types of energy sources on Earth, most have to altered to be an effective form of energy while others do not.

• Some pollute the Earth’s atmosphere (fossil fuels) while others do not (wind, solar, etc)

• Some resources (fossil fuels) will run out, others renewable and inexhaustible resources will never run out.

Review Questions

• What are natural resources?• How are renewable different from

nonrenewable?• What are fossil fuels?• What are some problems with fossil fuels?• What are some alternative resources?• What are inexhaustible resources?