1 Unit 4 The Dynamic Crust. 2 A. The Earth in Cross Section I.There are 4 major zones that make up the Earth: A. : Outer, thinnest layer of the Earth.

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Unit 4The Dynamic Crust

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A. The Earth in Cross SectionI. There are 4 major zones that make up the Earth:

A. : Outer, thinnest layer of the Earth. There are two types:

1. : -Thickness:-Composition:-Density:

2. :-Thickness:-Composition:-Density:

_Continental_____________

__Oceanic______________

__30km (18.6 mi.)__Granite_______

___2.7g/cm3_____

_5km (3.1mi.)___Basalt______

__3.0g/cm3_______

_Lithosphere_______

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composed of

that is

composed of

that is

A. Crust

Ocean Continent

basalt

5 to 6 km thick

granite

up to 30 km thick

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B. _________________: Found below the crust. Has two parts:

1. _________________: Upper, “plastic” mantle.-partially melted material.

2. __________________: Rest of mantle; actual temperature is below the melting point.

NOTE: The boundary between the crust and mantle is called the __________________ ________________________, or MOHO.

C. _________________: Only liquid layer of the earth. Composed mainly of iron.D. _______________: Solid, innermost layer of Earth. Composed mainly of iron and nickel.

Mantle

Asthenosphere

Stiffer Mantle

MohorovicicDiscontinuity

Outer Core

Inner Core

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is is

B. Mantle

Asthenosphere Stiffer Mantle

Partiallymelted

Not melted

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composed of composed of

C. OuterCore

D. InnerCore

Only liquid layer

Iron

Solid centerof Earth

Iron and Nickel

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B. Crustal MovementI. Dynamic Crust

-The crust and outermost part of the Mantle is called the _________________

A. The first theory of crustal movement was introduced in 1915 by Alfred Wegener, and was called _____________

_____________________________________

--Evidence for this theory include:1. _____________________________

2. Correlation of rock layers/fossils:__________________________________________________________________________

Lithosphere

ContinentalDrift

Continents match up like a puzzle

Rock layers and fossils match upon the edges of different continents.

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3. Mountain chains: _____________________________________________________________________________________________________________________________________

4. Climate evidence: ___________________________________________________________________________________________________________________________________

Mountain chains on different continents match up. So do the fossils found in the mountain chains.

Ice cores taken from glaciers on different continents match up.

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Theory that the oceanic crust has been constructed by material from deep within the Earth that rises and spreads apart the mid-ocean ridges.

5. Crustal age: _______________________________________________________________________________________________

B.Sea Floor Spreading: _____________________________________________________________________________________________

1. Convection cell: ______________________________________________________________________________________________

Circulation of heated fluid caused by differences in density. This is what moves the plates.

The age of oceanic crust matches up at equal distances from mid-ocean ridges.

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2. Evidencea. Igneous Ocean Rocks: ______________

__________________________________________________________________________________________________________________

Rock that is closer to the mid-ocean ridges is younger and age increases as distance from the ridge increases.

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Every 10,000 years, the Earth’s magnetic field switches. This can be seen in the magnetic minerals within the basalt rock found on the ocean floor.

b. Magnetic Reversal: ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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driven by evidence

Sea Floor Spreading

ConvectionCells

IgneousOcean rocks

MagneticReversal

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C. Plate Tectonics: ____________________________________________________

II. Plate BoundariesA. Convergent: ____________________--3 Types:

1. __________________________: Two continental plates coming together.

Ex: ______________________________

States that Earth’s lithosphere is made up of a number of solid pieces, or plates, that move in relation to each other.

2 plates coming together

Continental-continental

Himalayan Mtns. (Indian-Australian and Eurasian Plate

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II. Plate BoundariesA. Convergent

2. ______________________: Oceanic and Continental plates coming together.--Typically will form an _____________ along an ________________________ , where the ocean plate pushes underthe continental plate. _________________

Ex: ____________________________________________________________________

Oceanic-continental

Oceanic trenchIsland-arc

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II. Plate BoundariesA. Convergent

3. _____________________: Two ocean plates coming together.

--Typically will form an _____________ as one plate pushes under the other.

Ex: _____________________________

Continental-Oceanic

Ocean trench

Peru-Chile Trench (Nazca and South American Plates

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B. Divergent: _________________________________________________

-Usually form ____________________

Ex: ________________________

2 plates moving away from each other (Sea-floor spreading)

Mid-Ocean Ridges

Mid-Atlantic Ridge (North American and Eurasian/African Plates

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meet at

Examples

Plate Boundaries

Plate Tectonics

moving plates

Convergent

Continental-Oceanic

Oceanic-Oceanic

Continental-Continental

come together

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Plate Boundaries

Divergent

Move apart

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I. Plate BoundariesC. Transform Fault:___________________

_______________________________________

-Forms where ____________________________________________________________

Ex: ____________________________________

2 plates sliding past each other

The Earth is cracked.

San Andreas Fault (Pacific and North American Plate

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Plate Boundaries

Transform

MoveHorizontallyPast Each Other

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C. Evidence of Crustal ActivityI. Crustal Activity

A. Deformed Rock Strata--Originally, sedimentary rocks form ____

______________________________________However, observations made of Earth’s surface indicate

that ___________________________________________________

This includes:1. Tilting:

_______________________________________

Rocks are pushed up at an angle.

The horizontal layers have been changed.

In horizontal layers called beds

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2. Folding: ______________________________________________________________

3. Faulting: _____________________________________________________________

Bends in the rock layers due to continental collisions.

Breaks in rocks where plate movement has occurred.

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B. Displaced fossils: _____________________________________________________________________________________________

II. Results of Crustal ActivityA. Earthquakes: _____________________

______________________________________________________________________________

--focus: ___________________________________________________________________

--epicenter: ________________________________________________________________

Fossils of organisms that lived in the seahave been found on mountain tops.

Any shaking, or rapid motion of Earth’s solid outer layers.

The place underground where theearthquake occurs.

The location at Earth’s surfacejust above the focus.

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--Types of earthquake waves:1. __________________: Also called compressional waves;

the motion of the ground is parallel to the direction of wave motion. These waves can pass through ______________ __________________________________

P-waves

Solids and Liquids

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2. _______________: Also called longitudinal waves; the motion of the ground is perpendicular to the direction of wave motion. These waves can pass through ___________________________________________________

3. ________________: Waves that ripple the surface of the Earth, causing most of the damage of an earthquake.

S-waves

SOLIDS ONLY

Surface Waves

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--When traveling through the same material, ___________ travel faster than ____________.

-Since these waves travel at different ________ in different ___________ materials, we can use earthquake waves to tell us about the __________________________.

-When an earthquake occurs, both ___________________________. In many places on Earth, both waves are received; however, in other places, _________________________.

-Since S waves cannot pass through a liquid, the conclusion is that _____________________________________________________________

S-waves

P-waves

speeds

interior of the Earth.

types of

and S-waves are given off

P-waves

only P-Waves are received

some parts of the Earth’s interior are liquid.

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-If an earthquake occurs under the ocean, the energy is also released through the ocean water. When it reaches the coastline of a continent or island, it may form a large, fast moving wave called a _________________.

They may move at speeds of _________ and may be ____________________high!!!

Tsunami

20-100 feet

500+ mph

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B. Earthquake Strength

-The strength of an earthquake can be determined in one of two ways:1. ______________: Used to describe the amount of energy released by an earthquake. It ranges from ___ to ___, and each increase on the scale indicates a release of ____ times more energy!!!--To record earthquake waves, seismologists use a _______________, which can be used to record the arrival time of the waves and the intensity of the waves.

Richter Scale

10032

seismograph

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2. __________________: Used to describe the earthquake in terms of the amount of damage done. It ranges from ___ to ___. These are based on personal accounts.

--Why is the Richter scale better to use when describing the intensity of an earthquake, rather than the Mercalli scale? _________________________

____________________________________________________________________________________________________________

Mercalli Scale

Because the Richter scale uses actualmeasurements rather than the Mercalli scale which uses personal accounts which can change from person to person.

XIII

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C. Volcanoes:

--How do they form?1. Molten rock from within the earth, called _______, along with gases, begins to rise up through cracks and weak spots in the crust.2. When this molten material, along with gases from inside earth, break through the surface, it may flow out on the surface, and then it is called _____.

--Where do they form?1. __________________________________

_______________________________________2. __________________________________

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3. __________: Weak points in the crust, located over unusually high heat flow in the mantle. Although the crust may move, ___________________________________________________________________________________

-Ex: ________________________________

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evidence

Continentaldrift

puzzle fit of continents

correlation of rock layers

mountainchains

climateevidence

crustal age

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crustal activity

deformedrockstrata

displacedfossils

tilting

folding

faulting

shallowfossilsat highelevation

deep fossilsin shallowwater areas

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results ofcrustalactivity

Earthquakes

typesof waves

P waves

S waves

L waves

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Earthquakes

measuredusing

RichterScale

MercalliScale

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erupts

erupts

erupts

Volcanoes

Shield

Composite

Cinder

lava

lava andash

ash andcinder