Thursday, December 4, 2008

How fossils are made

Living things (usually aquatic) die and then get buried quickly under sand, clay or ash sediments. Usually, the soft parts decay or rot away, leaving the hard parts behind. These are ammonoids, one of the most common fossils that are found.

As time goes on more and more sediment accumulates. Pressure, heat and chemical reaction cause the sediments to harden into rock called sedimentary rock. Movement in the earth's crust, pushes the layers of sedimentary rock back up to higher ground.

Finally, through erosion caused by weather, wind and water, the fossils become exposed at the surface again.-IYPE

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