HOW???

Plate Tectonics KEY VOCABULARY TERMS Crust Mantle Outer Core Inner Core Lithosphere Asthenosphere Convection Current Magma/Lava Law of Uniformitarianism Tectonic Plates Subduction Divergent Boundary Convergent Boundary Transform Boundary Mid-Ocean Ridge Rift Valley Deep-ocean Trench Pangaea Continental Drift Sea floor Spreading Magnetic Reversal Hot Spot

Today’s Learning Target: Learn how convection currents shape our earth.

QUICK REVIEW… Layers of the Earth Crust (2 types) Mantle Outer Core Inner Core Earth’s crust & the very top solid portion of the mantle form the lithosphere The lithosphere sits on top of the liquid asthenosphere

Drawings… Lithosphere Two types of Crust

LAW OF UNIFORMITARIANISM Law of Uniformitarianism: States that Earth is an always changing place The same forces of change are at work today that were at work in the past. Some changes are gradual; some changes are fast…some times both!

TECTONIC PLATES The Lithosphere is broken into many large and small slabs of rock called tectonic plates and where two plates meet, a lot of changes can occur.

Some things happen slowly, while others happen quickly Some things happen slowly, while others happen quickly. But what they both have in common is a lot of them stem from MOVEMENT …but…MOVEMENT OF WHAT???? HINT:

How do the tectonic plates move? The plates move because of convection currents. The hot, soft rock in the mantle rises…then it cools, and sinks. How do the tectonic plates move?

There are 3 types of plate boundaries TECTONIC PLATES 1. Divergent 2. Convergent 3. Transform There are 3 types of plate boundaries

DIVERGENT Key word: Divide

DIVERGENT

DIVERGENT Mid-ocean Ridges Rift Valleys Earthquakes Volcanoes What occurs at this boundary? New Crust Forms Mid-ocean Ridges Rift Valleys Earthquakes Volcanoes

REAL-WORLD EXAMPLES : Divergent Boundary Mid-Ocean Ridges like the Mid-Atlantic Ridge

Iceland

African Rift Valley

Drawings…Divergent

CONVERGENT Key word: Collide 3 types of convergent: Continental-continental Oceanic-oceanic Oceanic-continental

CONVERGENT: CONTINENTAL-CONTINENTAL

CONVERGENT: CONTINENTAL-CONTINENTAL What occurs at this boundary? High mountains Earthquakes

REAL-WORLD EXAMPLES: Continental-Continental Convergent High Mountains like the Himalayas

Drawings…Cont-Cont Convergent

Plate Tectonics Part 2

CONVERGENT: OCEANIC-OCEANIC

SUBDUCTION What is SUBduction? When one tectonic plate sinks under another plate IT CAN ONLY HAPPEN WHEN… Continental & oceanic plate collide = the oceanic plate ALWAYS sinks because it is more DENSE. Oceanic & oceanic plate collide = the denser plate sinks!

CONVERGENT: OCEANIC-OCEANIC What occurs at this boundary? Deep-ocean Trenches Volcanic Islands Earthquakes Hawaii is NOT on a plate boundary!

REAL-WORLD EXAMPLES: Oceanic-Oceanic Convergent Deep-ocean trenches like the Mariana Trench

Oceanic-Oceanic Convergent Example Volcanic Island Chains

Drawings…Oceanic-Oceanic Convergent

CONVERGENT: OCEANIC- CONTINENTAL

CONVERGENT: OCEANIC-CONTINENTAL What occurs at this boundary? Deep-ocean trenches Coastal mountains (some are volcanic) Earthquakes

REAL-WORLD EXAMPLES: Continental-Oceanic Convergent Coastal mountains like the Andes Mountains on the coast of South America

Oceanic-Continental Convergent

Drawings…Oceanic-Continental Convergent

TRANSFORM Key word: Slide

TRANSFORM

TRANSFORM What occurs at this boundary? Faults Earthquakes

REAL-WORLD EXAMPLES: Transform Boundary Faults, like the San Andreas Fault in California

Drawings…Transform Boundary

LANDFORMS VS. EVENTS Mid Ocean Ridge Rift Valleys New crust forms Volcano Earthquakes Volcanic eruption New crust forms Divergent: Cont-Cont Convergent: High Mountains Earthquakes Coastal Mountains Deep Ocean Trench Volcano Ocean-Cont Convergent: Earthquakes Volcanic eruption Transform: Fault line Earthquakes