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

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Presentation on theme: "UNIT 4 THE RESTLESS EARTH PART I LESSONS 1, 2, & 3 The Big Idea: The movement of tectonic plates accounts for important features of Earth’s surface and."— Presentation transcript:

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

3 PEELING THE LAYERS Crust-outermost solid layer of Earth. (composed of O, Si & Al) 1.Continental 2.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

4 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

5 EARTH’S 5 PHYSICAL LAYERS 1.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. Unit 4 Lesson 1 Earth’s Layers

6 PHYSICAL LAYERS CONTINUED 4.Outer core-liquid layer of Earth’s core 5.Inner core-the solid, dense center of our planet Open to pg. 198 cut out Earth’s layers & glue into notes Unit 4 Lesson 1 Earth’s Layers

7 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

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9 MODERN DAY PROOF Mid-ocean ridges- underwater mtn ranges Youngest 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

10 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

11 PLATE BOUNDARIES Convergent 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

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13 STRESSED OUT Stress- 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

14 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

15 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

16 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


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