UNIT 4 THE RESTLESS EARTHPART I LESSONS 1, 2, & 3The Big Idea: The movement of tectonic plates accounts for important features of Earth’s surface and for major geologic events.

PEELING THE LAYERS

Crust-outermost solid layer of Earth. (composed of O, Si & Al)1. Continental2. Oceanic-denser; contains 2x Fe, Ca &

Mg

Mantle-region of hot, slowing flowing solid rock (composed of more Mg & less Al & Si)

Core- densest layer, mostly Fe & some Ni. Makes up about 1/3 of Earth’s mass.

Unit 4 Lesson 1 Earth’s Layers

HEAT IT UP!

Convection -movement of matter that results from differences in density caused by variations in temperature.

Convection in the mantle causes cooler rock to sink and warmer rock to rise.

Unit 4 Lesson 1 Earth’s Layers

EARTH’S 5 PHYSICAL LAYERS1. Lithosphere—outermost

layer, made of crust & the rigid part of the mantle divided into pieces called tectonic plates

2. Asthenosphere-layer of weak/soft mantle made of rock that moves very slowly.

3. Mesosphere-strong, lower part of mantle, rock flows more slowly than the rocks above. http://www.spring.net/geo/JohnVolos/Public/Portal/EARTH_MECHAN/structure_all.htm

Unit 4 Lesson 1 Earth’s Layers

PHYSICAL LAYERS CONTINUED

4. Outer core-liquid layer of Earth’s core

5. Inner core-the solid, dense center of our planet

Open topg. 198 cut out Earth’slayers &glue into notes

http://www.spring.net/geo/JohnVolos/Public/Portal/EARTH_MECHAN/structure_all.htm

Unit 4 Lesson 1 Earth’s Layers

PUZZLING EVIDENCE

Alfred Wegener- proposed continental drift; the continents once formed a single landmass, broke up, & drifted.

Pangaea-single landmass formed about 245 mya

Evidence

1. Fossils

2. Locations of Mtn ranges

3. Rock types

4. Ancient climatic conditions

Unit 4 Lesson 2 Plate Tectonics

Unit 4 Lesson 2 Plate Tectonics

MODERN DAY PROOF• Mid-ocean ridges-

underwater mtn rangesYoungest rock closest to ridge

Oldest rock further away

• Sea-floor spreading-molten rock from inside Earth rises at the ridges & forms new oceanic crust. Older crust is pushed away from the ridge, & the sea floor slowly spreads apart.

• Ocean trench-oceanic crust sinks into asthenosphere.

Unit 4 Lesson 2 Plate Tectonics

A GIANT JIGSAW

Plate tectonics- theory that describes large-scale movements of Earth’s lithosphere• Tectonic plates- lithosphere is divided into pieces

which move around on TOP of the asthenosphere

Unit 4 Lesson 2 Plate Tectonics

PLATE BOUNDARIESConvergent boundaries - form where two plates collide. This can happen in three ways, depending on the types of crust involved.

Divergent boundary - two plates move away from each other, and magma rises to form new lithosphere at mid-ocean ridges.

Transform boundary -two plates move past each other horizontally. The motion of the two plates often produces earthquakes.

Unit 4 Lesson 2 Plate Tectonics

http://geology.com/teacher/plate-tectonics.shtml

http://www.scec.org/education/k12/learn/plate4.htm

STRESSED OUTStress- amount of force per unit area that is placed on an object

Deformation- process by which rocks change shape when under stress.

Folding- when rock layers bend under stress

• Syncline-A fold in rocks in which the rock layers dip inward or upward from both sides toward the axis. (like a bowl)

• Anticline-A fold of rock layers that slope downward on both sides of a common crest.

Unit 4 Lesson 3 Mountain Building

http://geology1a-1.wikispaces.com/Folds+and+Faults+with+captions

FAULTED

Fault- a crack formed when large blocks of rock break & move past each other.

3 Main Kinds of Faults

1.strike-slip fault-fault blocks move past each other horizontally (common along transform boundaries)

Unit 4 Lesson 3 Mountain Building

http://geomaps.wr.usgs.gov/parks/deform/

2.Normal Fault- the hanging wall moves down relative to the footwall (Common along divergent boundaries)

3.Reverse Fault- then hanging wall moves up relative to the footwall. (Common along convergent boundaries)

Unit 4 Lesson 3 Mountain Building

http://geology1a-1.wikispaces.com/Folds+and+Faults+with+captions

MOVING ON UP

Uplift-process that can cause land to rise, can also contribute to mountain building.

Formation of Mountains

1. Folding-rock layers are squeezed together & pushed upward (convergent boundaries)

2. Volcanism-melted rock erupts onto Earth’s surface

3. Faulting –tension makes the lithosphere break into many normal faults.

Unit 4 Lesson 3 Mountain Building

http://freeroamingphoto.photoshelter.com/image/I000010wCG15TEDo