What exactly are lithospheric plates made off?I'm currently tryin to write an essay "what are lithospheric plates and how do they move?" I have plently of information for the movement part but am...

What exactly are lithospheric plates made off?

I'm currently tryin to write an essay "what are lithospheric plates and how do they move?" I have plently of information for the movement part but am struggling to find enough worthwhile information about plates...and its due tomorrow, help!

Thank you

Asked on by masty88

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pohnpei397's profile pic

pohnpei397 | College Teacher | (Level 3) Distinguished Educator

Posted on

Lithospheric plates are made of parts of the Earth's crust and mantle.  So, in other words, they are made of the various kinds of rock that form the Earth's crust and mantle.

Each lithospheric plate has a little bit of crust (either continental, oceanic or some of each) that is riding on top of a large section of the plate which is composed of part of the Earth's mantle.

Plates are generally something in the range of 60 miles (100 kilometers) in thickness.  There are thirteen major plates and somewhere around twenty total lithospheric plates.

 

giorgiana1976's profile pic

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

Lithosphere includes the crust (continental or oceanic) and outside of the upper mantle.Average thickness of lithosphere is about 100 km.Lithosphere floats on the lower layer of earth called asthenosphera. Asthenosphera is a weak layer, in the viscous state. Due to convection movements within asthenosphera, solid lithosphere is fragmented into parts called tectonic plates that move independently one of another. These movements are called tectonic movements.

The outside of the lithosphere includes the crust of earth. Oceanic crust, called Sima has a thickness of 5-10 km and is composed mainly of basalt rocks.

Continental crust, called Sial, has a thickness of 20-70 km and is composed of rocks less dense than oceanic crust.

Upper mantle is composed of solid material, consistent. Mantle differs substantially from the crust by chemical composition, mechanical properties, types of rocks and seismic characteristics.

Crust is mainly a product of melting of mantle rocks. Due to melting, incompatible chemical elements are separate, less dense materials rising to the surface .

Rocks in the mantle have larger amounts of iron and magnesium,and less  silicon and aluminum than the crust.

krishna-agrawala's profile pic

krishna-agrawala | College Teacher | (Level 3) Valedictorian

Posted on

The outer rigid outer shell of earth that forms its land mass and bottoms of the oceans is called lithosphere. This outer solid crust is made up of about 30 rigid pieces called tectonic plates or lithospheric plates. These plates are floating on a layer of molten rocks and therefor move relative to each other although the speed of movement is very low - that is about 10 centimeters per year.

Tectonic plates are made up of earth's crust and outer most part of its mantle. Typically the plates are about 100 kilometers thick. The minimum thickness of plates can be as low as 8 kilometers at some places and maximum thickness is about 200 kilometers.

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