Plate Tectonics

Plate Tectonics

By; Jason Caruso

Period: 6

The beginnings of the theory of plate tectonics date to around 1920, when Alfred

accounts of how today's continents were once a large supercontinent that slowly drifted to

Wegener. The German meteorologist and geophysicist, presented the first detailed

the positions there at today. Others created evidence, but continental drift did not attract

wide interest until the late 1950s.When scientists found the alignment of magnetic

particles in rock responded to the earth's magnetic field of that time. But paleomagnetic

polar changes showed that all continents had moved across the earth over time.

Evidence for movement and changes in the geosphere over time.

According to plate tectonics, the ocean basins are viewed as features that have

theoretically opened and closed, first tearing and then putting back together the

continental masses. Which are permanent features on the earth's surface. Geologists now

believe that the continents were put together 200 million years ago at the beginning of the

Mesozoic time to form a supercontinent called Pangaea. Initial cracking along a northern

continental mass, Laurasia, and a southern continental mass, Gondwanaland. Then plate

movements caused North American and Eurasian separation coincidentally with the

separation of South America, Africa, and India. Australia and Antarctica were the last to

separate. The major plates are named after the dominant geographic feature on them such

as the North American and South American plates.Plate motions are believed to have

transported large crustal blocks several thousand miles, disturbing very different terrains

together after collision with a larger mass. These terrains may include segments of island

arcs quite unrelated to the history of the continent onto which they are put to geather.

Some geologists believe that continents grow in size just by the addition of exotic

terrains.

The flow of matter and energy in the earth.

The flow of matter in the earth is the asthenosphere. It is made up of melted iron and

nickel. Which makes an extraordinarily hot liquid that flows around the earth's inner

core. The inner core is made up of solid iron and nickel. Eventually the entire

asthenosphere will become solid as well. But this will not occur for billions and billions

of years.

The lithosphere is also a flow of matter in the earth as well. The lithosphere creates

trenches and ridges. When the lithospheric plates move they can push the earth's crust in

to the mantle and under another layer of the earth's crust. That's how trenches are

formed. Ridges are created when asthenosphere and mantle's convection current pushes

up into the earth's crust and wears it away until a ridge is formed. All of these things

occur under water on the ocean floor. These are all the flow of matter and energy in the

earth.

The nature of the earth's interior.

Scientists believe that the earth's interior always moving. They believe that a current is

moving all the melted iron and nickel in circles around the earth's solid core. They call

this current a convection current. The current is caused by the temperature of the melted

iron and nickel. Since the temperature of the lithosphere is cooler closer to the core and

hotter closer to the crust it creates a current circling around. If the temperature was ever

to be the same the current would stop.

The reason the core is