1. PLATE TECTONICS
By: Jacob Morgan

2. All About Plate Tectonics
The theory of plate tectonics was developed in the 1960's.
This theory explains the movement of the Earth's plates and also explains the cause of earthquakes, volcanoes, oceanic trenches, mountain range formation, and many other geologic phenomenon.
The plates are moving at a speed that has been estimated at 1 to 10 cm per year.

3. Out layers of the Earth
The top layer of the Earth's surface is called the crust . Oceanic crust is thinner and denser than continental crust.
Crust is constantly being created and destroyed; oceanic crust is more active than continental crust.
Under the crust is the rocky mantle, which is composed of silicon, oxygen, magnesium, iron, aluminum, and calcium. The upper mantle is rigid and is part of the lithosphere . The lower mantle flows slowly, at a rate of a few centimeters per year. The asthenosphere is a part of the upper mantle that exhibits plastic properties.

4. Continental Drift and Major Plates
The plates are made of rock and drift all over the globe; they move both horizontally and vertically.
Over long periods of time, the plates also change in size as their margins are added to, crushed together, or pushed back into the Earth's mantle. These plates are from 50 to 250 miles thick.
This is also made by mudslides and landslides this is most starts of plates getting thick.
The current continental and oceanic plates include: the Eurasian plate, Australian-Indian plate, Philippine plate, Pacific plate, Juan de Fuca plate, Nazca plate, Cocos plate, North American plate, Caribbean plate, South American plate, African plate, Arabian plate, the Antarctic plate, and the Scotia plate. These plates consist of smaller sub-plates.

5. Types of Plate Movement
At the boundaries of the plates, various deformations occur as the plates interact; they separate from one another and , collide.
Seafloor spreading is the movement of two oceanic plates away from each other. This is an ex: of divergent.
When two plates collide , some crust is destroyed in the impact and the plates become smaller. This is an ex: of convergent.
When two plates move sideways against each other , there is a tremendous amount of friction which makes the movement jerky. This is an ex: of lateral.

6. History of Plate Tectonics
Plate tectonic theory had its beginnings in 1915
Searching for evidence to further develop his theory of continental drift, Alfred Wegener came across a paleontological paper suggesting that a land bridge had once connected Africa with Brazil. Wegener's drift theory seemed more plausible than land bridges connecting all of the continents. But that in itself was not enough to support his idea.
Another observation favoring continental drift was the presence of evidence for continental glaciations in the Pennsylvanian period.
Striae left by the scraping of glaciers over the land surface indicated that Africa and South America had been close together at the time of this ancient ice age. The same scraping patterns can be found along the coasts of South America and South Africa.

7. Pangaea
Close examination of a globe often results in the observation that most of the continents seem to fit together like a puzzle: the west African coastline seems to snuggle nicely into the east coast of South America and the Caribbean sea; and a similar fit appears across the Pacific. 
The fit is even more striking when the submerged continental shelves are compared rather than the coastlines.
 In 1912 Alfred Wegener ( ) noticed the same thing and proposed that the continents were once compressed into a single protocontinent which he called Pangaea (meaning "all lands"), and over time they have drifted apart into their current distribution.
He believed that Pangaea was intact until the late  Carboniferous period, about 300 million years ago, when it began to break up and drift apart.
However, Wegener's hypothesis lacked a geological mechanism to explain how the continents could drift across the earths surface as he proposed.

8. Paleozoic Era
The Paleozoic is bracketed by two of the most important events in the history of animal life. At its beginning, multicelled animals underwent a dramatic “explosion” in diversity, and almost all living animal phyla appeared within a few millions of years.
At the other end of the Paleozoic, the largest mass extinction in history wiped out approximately 90% of all marine animal species.
The causes of both these events are still not fully understood and the subject of much research and controversy. Roughly halfway in between, animals, fungi, and plants alike colonized the land, the insects took to the air, and the limestone shown in this picture was deposited near Burlington, Missouri.

9. Alfred Wegener
In 1915, the German geologist and meteorologist Alfred Wegener( ) first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. The fossil record supports and gives credence to the theories of continental drift and plate tectonics.
Wegener hypothesized that there was an original, gigantic supercontinent 200 million years ago, which he named Pangaea, meaning "All-earth". Pangaea was a supercontinent consisting of all of Earth's land masses.

10. Pictures

11. Sources Cited