Differentiate between three tectonic plates in tabular form?
Answers
Explanation:
there are three types of tetonic plates:
Convergent boundaries: where two plates are colliding.
Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. The denser plate is subducted underneath the less dense plate. The plate being forced under is eventually melted and destroyed.
i. Where oceanic crust meets ocean crust
Island arcs and oceanic trenches occur when both of the plates are made of oceanic crust. Zones of active seafloor spreading can also occur behind the island arc, known as back-arc basins. These are often associated with submarine volcanoes.
ii. Where oceanic crust meets continental crust
The denser oceanic plate is subducted, often forming a mountain range on the continent. The Andes is an example of this type of collision.
iii. Where continental crust meets continental crust
Both continental crusts are too light to subduct so a continent-continent collision occurs, creating especially large mountain ranges. The most spectacular example of this is the Himalayas.
2. Divergent boundaries – where two plates are moving apart.
The space created can also fill with new crustal material sourced from molten magma that forms below. Divergent boundaries can form within continents but will eventually open up and become ocean basins.
i. On land
Divergent boundaries within continents initially produce rifts, which produce rift valleys.
ii. Under the sea
The most active divergent plate boundaries are between oceanic plates and are often called mid-oceanic ridges.
3. Transform boundaries – where plates slide passed each other.
The relative motion of the plates is horizontal. They can occur underwater or on land, and crust is neither destroyed nor created.
Because of friction, the plates cannot simply glide past each other. Rather, stress builds up in both plates and when it exceeds the threshold of the rocks, the energy is released – causing earthquakes.
i) Converging and diverging tectonic plates:
Converging plates:
> When plate tectonics come towards each other.
> They either collide and crumble or slide under the other.
> They cause folding.
Diverging plates:
> When plate tectonics move against each other.
> They do not collide or crumble.
> They cause cracks on earth's crust.
-------------------------------------------------------------------------------------------------
ii) Bhangar and Khadar:
Bhangar
> Highland composed of old alluvium.
> Above the level of flood plain.
> Saturated with calcareous nodules called kankar.
> Not suited for agriculture.
Khadar
> Lowland composed of new alluvium.
> Flooded almost every year and thus every time new alluvium is deposited.
> Characterized by clay soil which is very fertile.
> Ideal for agriculture.
--------------------------------------------------------------------------------------------------
iii) Western ghats and eastern ghats:
Western ghats:
> Mark western edge of deccan plateau.
> They are continuous must be crossed through passes.
> Lie parallel to Arabian sea.
> They are higher at south.
> Average height: 900 - 1600m
> Highest peak: Anai Mudi
Eastern ghats:
> Mark eastern edge of Deccan plateau.
> They ate discontinuous and can be crossed without passes.
> They lie parallel to bay of Bengal.
> They are higher at north.
> Average height: 600m
> Highest peak: Mahendragiri