Look Like This! It Used to Look Like This

Name ______

Looking at the world map, what do you notice about the shape of the continents?

The thing is…the world didn’t always

look like this! It used to look like this:

How is this possible?!?!?

Plate Tectonics Theory

oThe lithosphere is into a number of large and small and the plates are floating on the __

Lithosphere = the Earth’s ______ plus the upper portion of the ______ layer

Plate Boundaries

Divergent Boundary:

oPlates are moving ______from each other

oMidocean ridges are and ocean floor plates are created

Convergent Boundary:

oPlates are moving ______each other and are colliding (3 types)

1. When Ocean Plates collide with Contintental Plates

______, trenches

Create near coast volcanoes

______zones (a pattern of earthquakes as an ocean plate grinds down the underneath side of a continent)

2. When ocean plates collide with other ocean plates

______are created

(a pattern of volcanic islands created from a subduction zone that is located off the coast)

3. When a continental plate collides with another continental plate

______are created (example: HimalayanMountains)

Transform Fault Boundary

oPlates are neither moving toward nor away from each other, they are moving ______.

oThe plates may move in directions or in the directions but at different rates and frequent __are created (example: San Andreas Fault)

oPlates are destroyed as fast as they are created (2 ways)

oPlates may be subducted and or may push be pushed upward to form

How can Oreos model the plate boundaries?

Very carefully, take just the top cookie off the Oreo.

Break the top cookie into 2 equal halves.

Replace the cookie halves back on the Oreo

Using the cookie,

Demonstrate a transform fault boundary

Demonstrate a divergent plate boundary

Demonstrate a convergent plate boundary

Seafloor Spreading Theory:

Ocean floors are moving like broad ______

New ocean floor crust is being created at the ______

What causes this?

______within the mantle

The up-welling leg of the current creates a boundary which produces

The down-welling leg of the current creates one type of boundary that results in and a __zone

What evidence do we have to support this idea?

Midocean ridges are ______than surrounding ocean floors

______on ridges, earthquakes on ridges

Midocean ridge rocks are ______than surrounding ocean floor rocks

Midocean ridge volcanoes are ______than volcanoes further away

Ocean floor sediments are ______on the ridges and get ______as the distance from the ridges increase

Polar reversal magnetism proves that the ocean floor is moving away from the ridges

Speed of Spreading

Atlantic Ocean – ______cm/year

South Pacific Ocean – ______cm/year

Continental Drift Theory

The have shifted their position over geologic time and at one time all land masses were into one piece called __

oPangaea began to split apart 200 million years ago

oDiagram

North America

LaurasiaGreenland

Eurasia

Pangaea

Africa

West G.S. America

Gondwanaland

Antarctica

East G.Australia

India

The continents are like packages on the seafloor conveyor belt.