Plate Tectonic Theory Presented By Rana Faizan Saleem

Plate Tectonic Theory Presented By Rana Faizan Saleem Roll. No. (10)

Introduciton This Presentation explain you: Ø Pangea/Continental Drift Theory. Ø Why Pangea Theory Rejected? Ø What are Tectonic Plates? Ø Tectonic Plate Theory. Ø Different Plate Boundries. Ø How Earth Magnetic Field Formed?

What Is Pangaea? Ø Pangaea is a theory that a young German scientist named Alfred Wegener came up with in 1910. Ø Theory stated: “All the Continents were joined together about 250 million years ago to form a Supercontinent, called Pangaea. Over time this super-continent drifted apart to make continents on which we are living today, This theory is called continental drift theory. ”

Why Continental Drift Theory rejected? Ø This theory rejected by scientists because Alfred Wegener could not explain what force pulls or pushes Continents. Ø He died in Greenland on his expedition. At the time of his death no one believed his theory. Ø There are following evidences for his theory: (i) Same Fossils (ii) Landforms (iii)Shapes like Jigsaw Puzzle

Plate Tectonics Ø Lithosphere is divided into small and large plates, called Tectonic Plates. These plates floating on the suface of Asthenosphere. Plate Tectonics Explain: (1) Earthquakes (2) Mountains (3) Volcanos

What Cause Plates to Moves? � Hot magma in the Earth moves toward the surface, cools, then sinks again. � Creates convection currents beneath the plates that cause the plates to move.

Plate Boundaries There are three types of Plate Boundries: (1)Divergent Boundaries (2)Convergent Boundaries (3)Transform Fault Boundaries

Divergent Plate Boundries � When two plates diverge or moving far apart from each other due to magma eruption. � Mid-Oceanic ridges happens in this type.

Convergent Plate Boundaries Ø When two plates collide into one another. Ø One of the plates will Subduct under other, Subduct means slide underneath. Ø There are three types of convergent plate boundaries: (1) Ocean to Ocean (2) Continent to Continent (3) Ocean to Continent

Ocean to Ocean Ø When two ocean’s crust collide together. Ø When this happens the older oceanic crust will be subducting under the younger crust. Ø And Island arcs are created by this type of collision.

Continental to Continental Ø When two continental plates collide together. Ø Both plates have same density due to which no plate subducting other. Ø Both plates applied equal force due to which rock crumble and Himalayas formed.

Ocean to Continental Ø Oceanic crust is more denser than Continental crust. Ø Due to high density oceanic plate underneath the continental plate, this process is called “Subduction”. In this process continental plate forced on oceanic plate to subduct. Ø When oceanic crust enters into mantle it starts floating backward, in other words magma erupts and Volcanoes created.

Transform Fault Boundaries Ø When two plates neither moves apart nor collide towards but moves along side each other. Ø The plates can move side wise in same direction or in different direction also. Ø Earthquakes these plates. happens due to movement of

How Earth Magnetic Field Produced? Ø It is produced by outer-core of earth which is made of liquid iron and nickel. Ø Moving magnetic material produced moving magnetic field which then turns to create moving electric field, called as geodynamo. Ø It helps us to find directions. Ø It protect us from cosmic rays.

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