Earth Science

Earth History

Types of Fossilization

Study Tip
Well-preserved fossils are found buried deep in the soil, where they are protected from erosion.

Types of Fossilization

  • It is very uncommon for soft organic tissue to be preserved in a fossil. However, there are a few exceptions.
  • Insects preserved in ancient tree sap called amber have been preserved perfectly.
  • Mammoths and Neanderthals have been found preserved in glaciers, leaving intact DNA evidence.
  • The most common method of fossilization is premineralization, which occurs when organisms are buried in sediment. The water deposits minerals into the empty spaces of the organism, producing a fossil.
  • A mold can form when a bone or a shell dissolves and leaves behind an empty space in the shape of the material. A cast is formed when a mold is filled with sediments later on.
  • Replacement is when a bone or a shell dissolves, and is replaced by a different mineral.
  • Compression is when remains are compressed by high pressure, leaving behind an imprint.
Study Tip
Well-preserved fossils are found buried deep in the soil, where they are protected from erosion.
Well preserved fossil
A well preserved fossil is one that preserves much of a former organism’s structure.
Concept Check
  • What are the five different types of fossilization?