Tectonic plates that are less dense than the mantle below.
3 of 17
Where do we get all the info about Earth from?
Seismic waves produced by earthquakes and man-mad explosions.
4 of 17
Why cant we get the information about earth ourselves?
Because the crust is too deep to dig through.
5 of 17
What moves the plates?
The convection currents.
6 of 17
Oceanic crust, continental crust. Which one is more dense?
The oceanic crust.
7 of 17
What is the name of the process that occurs when the 2 plates collide?
Subduction
8 of 17
Explain the process of subduction.
>the oceanic and continental plates collide > Oceanic plate sinks pulling more of the plate down >Partly melts as it reaches hotter part of the mantle.
9 of 17
Why do scientists now accept the plate tectonic theory?
>It explains a wide range of evidence >Has been tested and discussed by many scientists.
10 of 17
What happend in the 1960s that led to Wegner's continental drift theory becoming accepted?
New sea floor spreading evidence was found.
11 of 17
When are volcanoes caused?
When magma rises through the Earth's crust.
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Why does magma rise through the earth's crust?
Because it is less dense than the crust.
13 of 17
Why do geologists study volcanoes?
> To try to forcast future eruptions >Find out more about the earth's structure.
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What forms the different types of igneous rocks?
Lava
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What type of lava forms Iron-rich basalt rock?
Runny lava in slower volcanic eruptions.
16 of 17
An example of a rock that comes from thick lava in explosive eruptions.
Silica-rich rhyolite rocks.
17 of 17
Other cards in this set
Card 2
Front
Describe the lithosphere basically.
Back
Relatively cold and rigid.
Card 3
Front
What is the lithosphere made out of?
Back
Card 4
Front
Where do we get all the info about Earth from?
Back
Card 5
Front
Why cant we get the information about earth ourselves?
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