PLATE TECTONICS A REVIEW STRUCTURE OF THE EARTH

STRUCTURE OF THE EARTH Mantle � The Earth is made up of 3 main

THE CRUST � This is where we live! � The Earth’s crust is made

PLATE TECTONICS The Earth’s crust is divided into 12 major plates which are moved

WHAT ARE TECTONIC PLATES MADE OF? � Plates are made of rigid lithosphere. The

WHAT LIES BENEATH THE TECTONIC PLATES? � Below the lithosphere (which makes up the

WHAT HAPPENS AT TECTONIC PLATE BOUNDARIES?

Three types of plate boundary � Divergent � Convergent � Transform

1. WEGENER’S EVIDENCE � A) puzzle-fit of continents � B) fossil distribution � C)

Divergent Boundaries � Spreading ridges � As plates move apart new material is erupted

3. Age of Oceanic Crust Courtesy of www. ngdc. noaa. gov

Continent-Oceanic Convergence � Called SUBDUCTION

Continent-Continent Collision � Forms mountains, e. g. European Alps, Himalayas

What are Hotspot Volcanoes? � Hot mantle plumes breaching the surface in the middle

The tectonic plate moves over a fixed hotspot forming a chain of volcanoes. The

oldest island Direction of plate movement Hawaii - youngest

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PLATE TECTONICS - A REVIEW

STRUCTURE OF THE EARTH Mantle � The Earth is made up of 3 main layers: Outer core Inner core � Core � Mantle � Crust

THE CRUST � This is where we live! � The Earth’s crust is made of: Continental Crust Oceanic Crust - thick (10 -70 km) - buoyant (less dense than oceanic crust) - mostly old - thin (~7 km) - dense (sinks under continental crust) - young

WHAT IS PLATE TECTONICS?

PLATE TECTONICS The Earth’s crust is divided into 12 major plates which are moved in various directions. � This plate motion causes them to collide, pull apart, or scrape against each other. �

WORLD PLATES

WHAT ARE TECTONIC PLATES MADE OF? � Plates are made of rigid lithosphere. The lithosphere is made up of the crust and the upper part of the mantle.

WHAT LIES BENEATH THE TECTONIC PLATES? � Below the lithosphere (which makes up the tectonic plates) is the asthenosphere.

WHAT HAPPENS AT TECTONIC PLATE BOUNDARIES?

Three types of plate boundary � Divergent � Convergent � Transform

PLATE TECTONICS - THE EVIDENCE

1. WEGENER’S EVIDENCE � A) puzzle-fit of continents � B) fossil distribution � C) rock distribution � D) glacial evidence

2. DISTRIBUTION OF MID-OCEAN RIDGES

Divergent Boundaries � Spreading ridges � As plates move apart new material is erupted to fill the gap

3. Age of Oceanic Crust Courtesy of www. ngdc. noaa. gov

4. DISTRIBUTION OF EARTHQUAKES

Three types of plate boundary � Divergent � Convergent � Transform

5. DISTRIBUTION OF VOLCANOES

Continent-Oceanic Convergence � Called SUBDUCTION

Ocean-Ocean Convergence

Pacific Ring of Fire Hotspot volcanoes

6. DISTRIBUTION OF MOUNTAIN CHAINS

Continent-Oceanic Convergence � Called SUBDUCTION

Ocean-Ocean Convergence

Continent-Continent Collision � Forms mountains, e. g. European Alps, Himalayas

Himalayas

7. DISTRIBUTION OF OCEAN TRENCHES

Continent-Oceanic Convergence � Called SUBDUCTION

Ocean-Ocean Convergence

8. HOTSPOT VOLCANISM

What are Hotspot Volcanoes? � Hot mantle plumes breaching the surface in the middle of a tectonic plate The Hawaiian island chain are examples of hotspot volcanoes. Photo: Tom Pfeiffer / www. volcanodiscovery. com

The tectonic plate moves over a fixed hotspot forming a chain of volcanoes. The volcanoes get younger from one end to the other.

oldest island Direction of plate movement Hawaii - youngest