PLATES ARE CREATED: In the diagram below you can see that the continental crust is beginning to separate creating a diverging plate boundary. When a divergence occurs within a continent it is called rifting. A plume of hot magma rises from deep within the mantle pushing up the crust and causing pressure forcing the continent to break and separate. Lava flows and earthquakes would be seen. In the diagram below you can see that the continental crust is beginning to separate creating a diverging plate boundary. When a divergence occurs within a continent it is called rifting. A plume of hot magma rises from deep within the mantle pushing up the crust and causing pressure forcing the continent to break and separate. Lava flows and earthquakes would be seen.
diverge plates animation.gif (16916 bytes) This is an example of a divergent plate boundary (where the plates move away from each other). The Atlantic Ocean was created by this process. The mid-Atlantic Ridge is an area where new sea floor is being created.

 

diverge plates with opening rift valley animation.gif (18569 bytes) As the rift valley expands two continental plates have been constructed from the original one. The molten rock continues to push the crust apart creating new crust as it does.

 

diverge3 animation widening ocean.gif (17635 bytes) As the rift valley expands, water collects forming a sea. The Mid-Atlantic Ridge is now 2,000 meters above the adjacent sea floor, which is at a depth of about 6,000 meters below sea level.

 

diverge4 animated sequence.gif (25011 bytes) The sea floor continues to spread and the plates get bigger and bigger. This process can be seen all over the world and produces about 17 square kilometers of new plate every year.

 

 
The Earth is producing "new" crust where two plates are diverging or spreading apart. This occurs in the middle of our great oceans. The mid-ocean ridges are the longest continually running mountain range in the world. These ridges are connected and are about 40,000 miles long!!
 
One of these mid-ocean ridges, the Mid-Atlantic ridge , is spreading apart making the Atlantic Ocean wider. As the two plates move the mantle melts, making magma and lava fill the void with newly formed rock. The bottom of the Atlantic Ocean is filled with some of the "youngest" crust on Earth. The island of Iceland, located in the North Atlantic, is still being formed at this Mid-Atlantic ridge.

Click on the "Next" button to learn how the Earth destroys "Old Crust"!!!

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