There are three main types of fossils: preserved organisms, mineral replacements, and impression fossils. Preserved organism fossils occur when the soft body parts of an animal are frozen in time with minimal decay. Mineral replacement fossils form when the hard parts of an animal decay and are replaced by minerals over time, eventually becoming stone. Impression fossils show detailed outlines or carbon deposits left behind when thin plants or small animals die and decay in sediment.

1. Types of
Fossils
Different kinds of fossils are
created different ways!
• Preserved organisms
• Mineral replacement
• Impression fossils

2. What is a preserved organism?
• Fossils frozen in time
• The soft body parts are preserved
as well as the hard parts
• Decay of the plant or animal is
minimal
How do we preserve things in our
homes?

3. Preserved Organisms

4. Mineral Replacement
• Hard parts of an animal decay slowly- like bones,
and claws
• when animal is buried water seeps through the
ground, through the bone.
• The seeping water dissolves the bone, and
minerals in the water replace the bone one cell at
a time.
• This eventually becomes stone.

5. When mineral replacement occurs it is
also called petrification

6. Mineral Replacement
The Utahraptor found at Dalton
Wells Quarry in east-central Utah,
near Moab!
The minerals that petrified this ammonite
fossil are all different and make it different
colors.

7. Impression Fossils
• These fossils can show detailed outlines of
organisms like thin plants or small animals,
which die in sediment.
• As they decay, they leave a carbon deposit
that shows as a dark print of the organism
• Impression fossils also include tracks

8. Impression Fossils
Dinosaur footprint in
sandstone found in
UTAH!
Trilobite Impression fossil. See how it is 3
dimensional? Can you tell the fossil is
darker then the gray stone?