Plate Tectonics Mr. McKay Earth Science

Drifting Continents Evidence of drifting Fossils found on both of the continents of Africa and South America that are of the same organism Fossils: The preserved remains of ancient organisms German scientist Alfred Wegner came up with the theory of continental drift , he was actually a meteorologist and not a geologist The theory called the giant landmass that once was on Earth Pangaea Pangaea : Means all Earth Early Earth & Plate Tectonics

Evidence of drifting

Fossils found on both of the continents of Africa and South America that are of the same organism

Fossils: The preserved remains of ancient organisms

German scientist Alfred Wegner came up with the theory of continental drift , he was actually a meteorologist and not a geologist

The theory called the giant landmass that once was on Earth Pangaea

Pangaea : Means all Earth

Early Earth & Plate Tectonics

Fossil Evidence Fossils play a key role in supporting the theory of Continental drift Glossopteris is an extinct plant They are found in rocks that are around 250,000,000 years old ( 250 million) The seeds were to large to be carried by wind and too fragile to have survived ocean waves The fact that they are found in Antarctica implies that they had to be in a better climate than what is present Antarctica

Fossils play a key role in supporting the theory of Continental drift

Glossopteris is an extinct plant

They are found in rocks that are around 250,000,000 years old ( 250 million)

The seeds were to large to be carried by wind and too fragile to have survived ocean waves

The fact that they are found in Antarctica implies that they had to be in a better climate than what is present Antarctica

Fossils Glossopteris: a fern found on the southern continents Cynognathus: a land reptile found in South America and Africa Lystrosaurus: a land reptile found in Africa, Antarctica, and India Mesosaurus: a freshwater swimming reptile found in Africa and South America

Glossopteris: a fern found on the southern continents

Cynognathus: a land reptile found in South America and Africa

Lystrosaurus: a land reptile found in Africa, Antarctica, and India

Mesosaurus: a freshwater swimming reptile found in Africa and South America

Fossil Evidence From Rocks Not only fossils provide evidence for theory support Rocks in Africa and South America When you examine the continents from these two they look as if they could piece together like a puzzle The layers of coal depth line up with each other Rock deposits from glaciers also match

From Rocks

Not only fossils provide evidence for theory support

Rocks in Africa and South America

When you examine the continents from these two they look as if they could piece together like a puzzle

The layers of coal depth line up with each other

Rock deposits from glaciers also match

Divergent Boundary Divergent Boundaries Constructive-add new land Mid-ocean Ridge Ocean floor moves away on either side of the ridge Called sea-floor spreading Often offset by transform faults which causes a curve in the ridge Transform Faults Sea-Floor Spreading/Mid-Ocean Ridge Spreading Sea Floor Basic Plate Boundaries

Divergent Boundaries

Constructive-add new land

Mid-ocean Ridge

Ocean floor moves away on either side of the ridge

Called sea-floor spreading

Often offset by transform faults which causes a curve in the ridge

Magnetic Rock Strips Some minerals have magnetic properties These minerals line up with the Earth’s magnetic poles When the molten rock hardens, a permanent record of the Earth’s magnetism remains The Earth’s magnetic poles have reversed themselves from time to time Animation Sea Floor Spreading

Some minerals have magnetic properties

These minerals line up with the Earth’s magnetic poles

When the molten rock hardens, a permanent record of the Earth’s magnetism remains

The Earth’s magnetic poles have reversed themselves from time to time

Animation

Sea Floor Spreading

Convergent Boundaries Plates collide-destructive Two continents colliding build mountains or plateaus The Indian Plate and the Eurasian Plate collide to form the Himalayas which have Mt. Everest , the highest mountain on Earth.

Plates collide-destructive

Two continents colliding build mountains or plateaus

The Indian Plate and the Eurasian Plate collide to form the Himalayas which have Mt. Everest , the highest mountain on Earth.

Convergent Boundary Destructive-crust is destroyed (melted by the mantle) Called Subduction When oceanic and continental crust collide Oceanic crust is pushed down into the mantle and melted Some of this melted material surges upward

Destructive-crust is destroyed (melted by the mantle)

Called Subduction

When oceanic and continental crust collide

Oceanic crust is pushed down into the mantle and melted

Some of this melted material surges upward

The continental crust is also forced upward producing volcanoes The Cascade Range in Washington and Oregon are an example of this Convergent Boundaries Convergent Boundaries

The continental crust is also forced upward producing volcanoes

The Cascade Range in Washington and Oregon are an example of this

Convergent Boundaries When two oceanic plates collide subduction occurs The older denser plate is pushed into the mantle and melted Some of the material rises upward and erupts on the ocean floor forming an island arc

When two oceanic plates collide subduction occurs

The older denser plate is pushed into the mantle and melted

Some of the material rises upward and erupts on the ocean floor forming an island arc

Theory of Plate Tectonics Tectonics: refers to the branch of geology that is concerned with plate movements Theory of Plate Tectonics: Links together the ideas of continental drift and ocean floor spreading to explain how the Earth has evolved over time. It explains the formation, movements, collisions, and destruction of the Earth’s crust According to the theory the Earth’s uppermost layer, called the lithosphere, is made up of plates

Tectonics: refers to the branch of geology that is concerned with plate movements

Theory of Plate Tectonics: Links together the ideas of continental drift and ocean floor spreading to explain how the Earth has evolved over time.

It explains the formation, movements, collisions, and destruction of the Earth’s crust

According to the theory the Earth’s uppermost layer, called the lithosphere, is made up of plates

Lithospheric Plates There are seven major plates The Pacific Plate- which covers 1/5 of the Earth North American South American Eurasian African Indo-Australian Antarctic Plates There are also Many smaller plates Caribbean Arabian Plate Tectonics Review

There are seven major plates

The Pacific Plate-

which covers 1/5 of the Earth

North American

South American

Eurasian

African

Indo-Australian

Antarctic Plates

There are also Many smaller plates

Caribbean

Arabian

Plate Tectonics Review