Plate Tectonics is the theory that the outer area of the Earth is made of different plates that are always moving. The land and the water sit on these plates. Under the plates is lava and melted rock. Even though the plates are made of solid rock, they move on the liquid underneath. The plates are always moving.
Some scientists believe that there are seven or eight major plates that make up the plate tectonics of the Earth. There are also other plates that are minor plates that are hooked on to the major plates.
Each year, these plates move about one centimeter so even if you watched it for the whole year, you would not even know that it moved.
The seven different major plates include:
Some of the minor plates include:
There are two different types of tectonic plates including oceanic and continental plates. The plates are more than 60 miles thick.
There are three different types of boundaries in which the plates move, and these include convergent boundaries, divergent boundaries and transform boundaries.
Convergent boundaries are the places where the two plates will push together or move under each other. When the plates move under each other it is called subduction. The movement can be slow and can be where volcanoes and mountains are formed.
Divergent boundaries happen hen the two plates are pushed apart. When there is land and this happens, it is called a rift. New land can be made when magma goes from the mantle and reaches the surface and cools down.
When the plates slide past each other, this is called a transform boundary. These are also called faults and happen usually after an earthquake has happened.
The only way that you could really see the plate tectonics move would be if there was an earthquake. When an earthquake happens, it causes the plates to move and to even stack on top of each other.
Fault lines are where earthquakes and volcanoes are. This is where much of the activity happens.
The “Ring of Fire” is an area of all kinds of volcanic activity and earthquakes that is caused by a lot of tectonic plate movement.
The Hawaiian Islands are not part of the “Ring of Fire,” but are called hot spots because this is where magma rises up from the crust of the Earth through volcanoes.
The plates are what make up the lithosphere or the top layer of the Earth. The layer under the lithosphere is called the asthenosphere.
The asthenosphere is a layer of the Earth that is covered in molten rock. This rock is liquid and the rocks on these. This layer of the earth has constant radiation and heat that is hitting it from the center of the Earth. As this heat and radiation hits the rocks, the rocks become melted and turn to liquid.
The tectonic plates are floating on these rocks and are always moving around the Earth. This is like ice that floats on top of water.
When the tectonic plates are always moving, this is called the continental drift.
Since the rocks are constantly floating on liquid, sometimes they spread apart. When the plates spread apart from each other, this is called the spreading zone.
When the plates are not spreading apart, they are moving closer together. When the plates are moving together, this is the subduction zone.
When the plates are forced together, they are in the zone of convergence. When this happens, usually one plate will move under the other plate. When the plates get pushed down on one side, that side will go into the asthenosphere where it is hot, and that part of the plate will melt.
When the plate melts, this causes there to be a crack or a trench in the plate. These trenches or cracks are found in the deepest parts of the ocean. The trenches can be so deep that it causes the ocean to flow into them and that is where the ocean is the deepest.
Scientists have been able to look at the Earth for millions of years back because of scientific things such as maps, fossils and other evidence.
Because of this scientific evidence, scientists have been able to prove that the theory of tectonic plates is real.
Scientists were able to look at the map of the continents and see how the tectonic plates have caused the continents to form together almost like a puzzle.
Some scientists believe that the Earth used to be just one giant land mass. This was called Pangaea. Pangaea is a super-continent where there were no lines but just one complete land mass. Some scientists believe this happened over 500 million years ago.
Different fossils have been found on different continents. For example, one fossil was found on Australia that was the same as some of the fossils in Asia. This proved that the planets were once all together and were one piece.
Some scientists believe that the continents used to all share the same area and that there were plats that were on the super-continent and when the continents split apart, new plants were formed.
Some believe that mountains are formed by plates that move and crash into each other. When this happens, the edges of the plate will sometimes rise up and this is where mountains are formed.