Plate Tectonics
Essay by review • December 26, 2010 • Study Guide • 1,606 Words (7 Pages) • 1,824 Views
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
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