![]() Image: Himalayas Map - Sven Manguard © Public Domain The Himalayas are found in a belt between the Indian sub-continent to the South and China on the Eurasian Plate to the North. When two plates with continental crust collide they are much less dense than the underlying mantle rocks so they cannot be subducted.Īs a result the rocks are folded and forced upwards to form a fold mountain chain such as the Himalayas. Image: Continental-continental convergence - USGS © Public Domain The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. Image: Aconcagua (aerial) - Beatriz Moisse © Wikimedia Commons under Creative Commons Attribution-Share Alike 3.0 Unported This is the highest mountain outside of the Himalayas. The highest mountain is called Acongagua at 6,961 metres. The average height is about 4,000 metres. The Andes are the longest continental mountain range in the world they are about 7,000 km long. Image: Peru-Chile trench - Interiot~commonswiki © Public Domain ![]() The reddish colours show the Andes Mountains. In the satellite image you can see the deep blue colour showing the trench. The overlying continental rocks will also be folded and pushed upwards to make fold mountains.Īn excellent example of this is along the Western edge of the South American Plate. This creates a very thick, sticky magma which is explosive if it reaches the surface (becomes lava). Rising magma will be formed and as it rises it starts to absorb the overlying continental crust. When a plate made up of oceanic crust is forced into a plate made up of continental crust the oceanic crust plate will be forced downwards into the mantle ( subduction). Image: Active Margin - Booyabazooka © Public Domain This magma is different from oceanic crust and it will form the types of rocks called continental crust. The seawater lowers the melting point of some of the rock melts and form magma. The oceanic crust has lots of cracks within it filled with seawater. When subduction happens a deep trench is formed as surface layers are dragged downwards. When two plates made up of oceanic crust are forced together then one of them will be forced downwards into the mantle. Image: Oceanic-oceanic convergence - USGS © Public Domain Image: Continental-continental destructive plate boundary - domdomegg © Wikimedia Commons under Creative Commons Attribution-Share Alike 4.0 International If one of the plates is made up of oceanic crust then it can be forced downwards into the mantle where parts of it will melt. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |