Fossils: Study Guide
There are 9 Types of Fossils:
Fossils in Rock: Hard body parts get buried quickly, preserved &
the sediment turns to rock.
Mineral Replacement: Minerals fill in the pores of an organisms’
tissues.
Fossils in Amber: (Amber = hardened tree sap) The organism gets
stuck, then the sap hardens. These are the best insect fossils.
Mummification: It dries out so quickly, there is no time for the
body to decay.
Frozen Fossils: The animal falls into the Ice (glaciers) for
thousands of years. These are some of the best larger fossils.
Fossils in Tar: Thick, sticky pools of tar trap the animals.
(example: La Brea Tar Pits in LA)
Trace Fossils: Animal tracks fill with sediment & turn to rock,
burrows are shelters when animals dig into the ground, and
coprolites are preserved feces
Mold: Cavity in the ground where it was buried
Cast: When the mold fills with sediment & becomes rock
Relative Dating:
The use of rocks and fossils to determine whether an object or event is older or
younger than other objects or events.
Answers: Oldest rock layer is on the bottom,
the youngest rock layers is on the top.
Absolute Dating:
Finding the age of an object, such as a fossil or rock layer, by determining the exact
number of years it has existed. For example: by measuring the amount of
radioactive decay of the isotopes.