Journey To The Center Of The Earth 

The Crust

 

           Earth's crust is the outermost layer of the Earth and is usually referred to as the surface of the Earth or the ground. There are 15 major tectonic plates; the African, Antarctic, Arabian, Australian, Caribbean, Cocos, Eurasian, Indian, Juan de Fuca, Nazca, North American, Pacific, Philippine, Scotia, and South American plates. Tectonic plates move around and crash into each other causing earthquakes, volcanoes, mountains, continental drift, and other geologic activities on Earth's surface.  The crust is classified in two different catagories; continental crust and oceanic crust.

           

             As the name suggests oceanic crust is found at the bottom of the ocean (as know as the ocean floor). The oceanic crust is made of a dense, heavy rock called basalt. Usually the oceanic crust is about 4 miles thick. Oceanic rock is almost always heavier and denser than continental rock. Oceanic crust is still denser and heavier than continental. 

 

             Continental crust is found under masses, such as continents (yet again as the name suggests). The continental crust is made of a less dense rock called granite, like with rock the is in some counters. Usually the continental crust is about 6-47 miles thick and is almost always older than oceanic crust because oceanic crust is replaced often with new magma from the mantle. The heavier oceanic crust is constantly sliding under the lighter continental crust; this process is called subduction.