PLANET EARTH pp Earth’s Interior and Plate Tectonics Chapter 21, Section 1

The Earth is made of multiple layers: CRUST topmost layer of solid and cool rock  the “plates” Earth’s Interior- pages

TWO TYPES OF CRUST OCEANIC CONTINENTAL HOW ARE THE TWO TYPES OF CRUST DIFFERENT?

OCEANIC CRUSTCONTINENTAL CRUST ~ mi. thick -most thick beneath mountains -less dense (granite) than oceanic crust ~ 4-7 mi. thick -dense (basalt) *sinks under continental crust Nye & Earth’s Crust Vogue Song

Thickness of the crust in KILOMETERS

2. ___________ MANTLE located below the crust (more _______) DENSE ______ of earth’s total volume 80 %

-top (outer) part of the mantle and crust= __________________ (rigid and cool) ASTHENOSPHERE =“SOFT” LITHOSPHERE ASTHENOSPHERE -bottom (inner) part of the mantle = _______________________ (hot, soft, and easily deformed- like chewing gum) LITHOSPHERE = SOLID MANTL E CRUST

3. CORE mostly made of _________________ very hot 2 layers: 1) OUTER CORE 2)INNER CORE iron and nickel

b. Inner core (________ metal)- very high ____________ so atoms are forced together despite the ______. SOLID PRESSURE HEAT a. Outer core (________ metal)- even though it’s above the boiling point they do not boil due to high pressure (no gases) LIQUID Layers of the Earth (NASA)

S waves: can’t travel through core (outer/liquid)  transverse & can’t travel through liquid P waves: can travel through core but deflected  change in type of matter Evidence of Earth’s Internal Structure Layers of Earth Mr Lee

PLATE TECTONICS *Early 1900s- German scientist = _________________ Continental Drift Song  What observations intrigued Wegener? Alfred Wegener

Wegener hypothesized that all of the continents fit together in the past to form ____________ (Greek: _____________ ) PANGAEA“ ALL LANDS ” PERMIAN 225 million years ago PRESENT DAY 650 million years in under 2 minutes

What evidence exists to support the theory of plate tectonics and continental drift? How do we know this? Pangaea’ s Moving Farther Apart Song

– the same kinds of animals/plants once lived on continents that are now oceans apart. 1. ________FOSSILS Glossopteris fernLystrosaurus land reptile Mesosaurus FW reptile Cynognathus land reptile

2. ________________________________ AGE OF ROCKS (ON OCEAN FLOOR) Rocks are __________ near the center of the Atlantic Ocean. YOUNGER As distance from the center increases, the rocks are _______. OLDER

3. ______________________________MAGNETISM (discovered mid 1960s) Magnetic Reversals Explained

Seafloor Animation

bands of rock on the ocean floor have alternating magnetic polarities 3. Magnetism – (discovered mid 1960s) magnetic patterns (formed when rocks cooled) are symmetrical (same) on either side of the Mid-Atlantic Ridge

Continents are on the tectonic plates and move with the plates.

*Convection currents within the Earth= (hot rock rises…cooler rock falls) moves the plates. Convection Currents ExplainedConvection Currents Explained Convection & Plate MovementConvection & Plate Movement

Plate Boundaries (pages ) * Classified how to plates move in relation to each other

_________________ boundary: DIVERGENT Occurs where two tectonic plates move apart and create a gap.

Forms mid-ocean ridge (from rising magma). Hot rock from the asthenosphere rises up and cools to form new igneous rock. Divergent boundary

a. MID-ATLANTIC RIDGE Examples of Divergent Boundaries

* ICELAND is right ON the mid-Atlantic Ridge

Examples of Divergent Boundaries b. RED SEA (E. Africa)

How is the Red Sea forming? Look at diagrams and then describe in your own words… Crust in Pieces Song

_____________________ boundary: CONVERGENT Occurs where two plates push together

3 different situations for convergent boundaries… a.b. c.

a. Oceanic – Continental - Oceanic plate is more _______ and sinks below the continental plate. This is called _______________. DENSE SUBDUCTION DENSER

SUBDUCTION FORMS: TRENCHES Mountains / Volcanoes

EXAMPLES OF OCEANIC-CONTINENTAL CONVERGENT BOUNDARIES

1. CASCADE RANGE (Northwestern US)

EXAMPLES OF OCEANIC-CONTINENTAL CONVERGENT BOUNDARIES

2. ANDES MOUNTAINS- W. coast of S. America.

b. Oceanic – Oceanic – ________ and more ________ plate sinks below the other. DENSE OLDER

EXAMPLES OF OCEANIC-OCEANIC CONVERGENT BOUNDARIES 1. Aleutian Islands, Alaska

EXAMPLES OF OCEANIC-OCEANIC CONVERGENT BOUNDARIES 2.Japan

c.Continental – Continental – ________ and more ________ plate sinks below the other. OLDERDENSE Cont-Cont Animation

EXAMPLES OF CONTINENTAL-CONTINENTAL CONVERGENT BOUNDARIES HIMILAYAN MOUNTAINS (like MT EVEREST and K2) The 10 highest mountains in the world are found here

* Convergent Boundaries create ____________ and ________________, especially around the _________ Ocean in the _______________. EARTHQUAKES VOLCANOES PACIFIC “RING OF FIRE”

What is special about Hawaii?

Hot Spot Animation

3. ___________________ boundary: Fault = a break in a body of rock. One block slides relative to the other (lots of friction) FAULT TRANSFORM Occurs where two plates slide past each other horizontally- along a fault

TRANSFORM FAULT BOUNDARY What do you see? How did this happen?

EXAMPLE OF A TRANSFORM FAULT BOUNDARY San Andreas Fault- California/Mexico

TRANSFORM FAULT BOUNDARY- visuals…

DivergentConvergentTransform Continental crust  rift valley Oceanic crust  mid- ocean ridge Cont/Cont. plates  mountain range Plates move against each other. Stress builds up… Stress is released  earthquake! Oceanic/Oceanic or Oceanic/Continental  subduction A Review of Earth’s Interior and Plate Tectonics Video