Relative and Absolute Age Law of Superposition. Relative and Absolute Dating There are two major...

Relative and Absolute AgeLaw of Superposition

Relative and Absolute Dating

There are two major ways to date geologic events:

Relative dating-how old a rock is compared to surrounding rocks

Absolute dating-actual number of years since the rock was formed

Relative Dating

The various relative dating methods tell you whether a specific rock or layer of rocks is younger or older as compared to surrounding rocks

This type of dating does not give an exact age for the rock

• The Law of Superposition states that in an undisturbed sequence of sedimentary rock:Each layer is older than the one aboveEach layer is younger than the one below

Law of Superposition

• a vertical set of strata (layers) is a chronological record of the geologic history of that strata

• Youngest layers are on top and oldest on bottom

Law of Superposition

• Absolute Dating

– Absolute dating can give you the exact age of a rock

– This is accomplished using radioactive dating, which is also referred to as radiometric dating

– Based on the regular radioactive decay of certain elements