Rock Cycle

Fascinating Fact Up to 100,000 tons of rock a year fall to earth from space. The largest meteorite in the world lies in the ground in Africa and weighs more than 60 tons.

Did you know that rocks are constantly being recycled? Recycle means to take something old and change into something new. So some of these old rocks that have been around for more than four billion years are being changed into different rocks. Of course, that doesn't happen over night. It takes millions of years. To better understand how this happens, let's take a journey through the rock cycle.

First, our journey begins in the mantle. Here we see some red hot magma that is being pushed up towards the crust. Some of this magma creeps into the cracks of the volcano; while, the rest is forced out of the top of the volcano. Once the magma is out of the volcano, it is called lava. The lava cools and forms igneous rocks.

Then some of the igneous rocks roll down the mountains formed by the volcanoes and eventually end up in the ocean. As they roll, bits and pieces of the igneous rocks are broken and form sediments. Layer after layer of sediments are pressed and cemented together forming sedimentary rocks.

Some of the sedimentary rocks on the very bottom get hot because of the pressure and change to metamorphic rock. When the metamorphic rock is buried deeper, it gets hotter and melts. Once again, it becomes magma and may eventually be pushed up and out of a volcano.

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Copyright March, 2000