Dating Fossils - Relative Dating Flashcards
What are the two types of fossil dating?
Absolute and Relative dating
Why is dating fossils important/useful?
Provides a timescale for evolution
What is stratigraphy
Study of position and order of strata (layers of earth’s crust) for creating a geological timescale
Which type of fossil dating uses stratigraphy?
Relative dating
How is relative dating done?
- Uses the relative position of rocks to estimate age of fossil using stratigraphy
Oldest fossils will be found in which strata?
Oldest strata (deepest strata at the bottom)
Why might relative dating provide inaccurate results?
- Rock layers may have been eroded
- Rock layers could have buckled or moved altering strata sequnce
Hence, going deeper doesn’t always mean going further back in time
What is another name for indicator fossils?
Index fossils
What can indicator fossils do?
They are used to age a fossil bed alongside stratigraphy
How are indicator fossils used?
Their presence indicates the surrounding rock to be a particular age. Thus, any other fossils found in that layer can be dated as well.
What are the 3 conditions that need to be met for a fossil to be considered an indicator fossil?
- Common around the world
- Distinctive/recognisable
- Survived on earth for only short period of time
Why must indicator fossils be found all across the world?
It makes is a reliable constant for reference and is universally acceptable standard
Why must indicator fossils exist on earth for a short period of time?
So more accurate and precise dating can be achieved.
