Tectonics Flashcards
Crust
It is the outer layer of the Earth. It varies from 5 - 70 km thick. The oceanic crust is thinner and denser than the continental crust. It has an average temperature of about 750℃.
Lithosphere
A combination of the lower crust and upper mantle. This area is notable, as it is split into tectonic plates.
Asthenosphere
The point where the mantle becomes more fluid and it flows more easily. It is below the Lithosphere.
Mesosphere
The lower part of the mantle. The pressures start to get higher, causing it to be slightly more solid.
Mantle
About 2,900 km thick and contains 84% of the earth.
Outer Core
It is beneath the mesosphere and it is completely liquid. It has temperatures of about 6,100℃ and it is 2,200 km thick. Currents in it creates Earth’s magnetic field.
Inner Core
About 1,400km thick. It is solid due to the incredible pressure, and it is the same temperature as the outer core.
Convection Currents
Material in the Mesosphere heats up and rises. When this material hits the lithosphere it exerts pressure on it and drags the plates apart. This causes geological activity. Eventually, the material cools and sinks, to restart the process.
How is a volcano created?
When convection currents cause tectonic plates to pull apart, magma rises and fills this gap. This magma eventually solidifies into rock, but occasionally, lava breaks through in an eruption. This causes rock to settle in the form of a peak.
How does an Earthquake occur?
On the boundaries of Tectonic plates friction can occur as the plates rub against each other. This is called an earthquake.
What is a plate boundary?
Where two plates join.
What is a Divergent/Constructive plate boundary?
When two tectonic plates are drifting apart. This causes a gap to appear which magma fills. The magma then solidifies, which means that often volcanoes occur on these boundaries. Volcanic activity is generally quite gentle, and no friction means no earthquakes.
What is a Convergent/Destructive plate boundary?
When one continental and one oceanic, or two oceanic plates collide, the denser of the two slides (subducts) under the other. This causes large amounts of friction, which causes Earthquakes. As one of the plates sinks, it melts, exerting pressure on the crust. Magma can then burst through, causing explosive volcanic activity.
What is a Collision plate boundary?
When two continental plates collide into each other. Neither plate is dense enough to sink, so instead, ripples form in the crust when the plates push against each other. These ripples are mountains. There are also small amounts of friction. This means that mior earthquakes can occur.
What is a Conservative plate boundary?
This occurs when two plates are moving side by side, but at different speeds or in different directions. This causes large amount of friction, which means that Earthquakes are common on these boundaries.