Joshua Baker
P2 3/13/15
The amazing world of techtoniques.
- First thing you need to know about plate techonics is it was discoverd in the 1960s. then there are three layers of the earth outer layer,mantle and core. The outer layer is called the crust and it is pretty much a HUGE, thick layer, its 25km-50km deep. its very low in densaty. Then also there is a oceanic crust and its only 5-10 km thick, but with more density.
- Then the mantle is mostly consists of rock, that mainly contains minerals and rocks, such as iron and magnesium.
- Lastly the core which is like a fireball that contains iron and nickel.
continental drift
Continental drift is the movement of continents, which casues the plates to move and drift. In 1910,a perosn of the name Wegener had a hypothesis, which was that all the continents were once together and attached together and now they have moved appart from each other and that theroy is known as pangea.
The reasons they think pangea is real.
There has been very many theorys aboout pangea, and the two reasons they think the continents were onced together is because if you put the continents together like a puzzle they fit perfectly and aslo they found fossils on india that matched the rest of the fossil across the world, and it was a perfect fit to the rest of the fossil.
Sea floor spreading
Sea floor spreading is when new ocean floor is created by lava from the earth's core comes to the top of the earth and is where the sea floor is sprreading it rises between the two ocanic ridges spreads out. The person who found about sea floor spreading is Henry Hess.
sea-floor spreading helps scientists explain continental drift
Seafloor spreading is caused by two plates moving apart, which is caused by plate tectonics also continental drift is caused by plate tectonics. So continental drift is pretty much the same as seafloor spreading. So if they sea floor is spreading what about the land on top of it, it would aslo carry with the sea floor spreading because its attached together.
convection
Convection currents move plates, so if there is a volcano that pushes hot, new lava up and old lava away which causes the plates to move closer together or farther away causing more convection currents.
Theory of plate tectonics
The theory of Plate tectonics is that the earth's crust is divided into muiltable plates that are being pushed and pulled by the iner part of the earth surface.
plate boundries
There are five plate boundries transform, divergent, convergent, and convergent with subduction. Transfrom is when two plates move up and down against each other. Next there are two divergents one is ocianic and one is contiental, but they both do are the same thing but one is undewater and the other is on land. But they both are two plates moving apart from each other causing rift valleys or mid-oceanic ridge. Next conevergent subduction is ehen you have a continental plae crashing into a oceanic plate, and sense the oceanic plate is more dense it gets moved push down tored the center of the earth(mantle), this causes volcanoes and trenches. Next they we have convergent continents which is when two continental plates colliding together which causes forms of mountians.
Ring of fire
The ring of fire is a ring of volcanoes around the Pacific Ocean, which are caused from subduction, which is when you have a continental that collides with the oceanic plate and pushes the dense oceaon down to the mantle.