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PAST LIFE
Lesson 2 - Page 4

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The most common type of fossil preservation is with alteration. The original organic material is partially or totally changed into new material. There are four common types of preservation with alteration including carbonization, permineralization, recrystallization, and replacement. These processes involve a chemical reaction with the organism and its surrounding.

Carbonization is a chemical reaction when water transforms the organic material of plant or animal to a thin film of carbon. Nitrogen, hydrogen, and oxygen are driven off as gases, leaving an outline of the organism. Organisms often preserved by carbonization include fish, leaves and the woody parts of plants.


Carbonization of leaves


Carbonization of fish fossil

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