Absolute dating on rocks
Using logs recovered from old buildings and ancient ruins, scientists have been able to compare tree rings to create a continuous record of tree rings over the past 2,000 years.
This tree ring record has proven extremely useful in creating a record of climate change, and in finding the age of ancient structures. The thick, light-colored part of each ring represents rapid spring and summer growth.
Absolute dating is rather limited as to the materials that can be dated, and mostly (but with a few exceptions) only works on igneous and metamorphic rocks.
Absolute dating is difficult, time-consuming, expensive, and relatively inaccessible.
This is a method that does not find the age in years but is an effective technique to compare the ages of two or more artifacts, rocks or even sites.
It implies that relative dating cannot say conclusively about the true age of an artifact.
Absolute ages: Absolute dating is mostly based on isotopic measurements of certain radioactive trace elements and their decay products, not field relationships. it can assign an actual quantified age to something.
Relative dating is usually easy and often requires nothing more than careful field observation, which in many cases can be made in a few seconds.
These tree ring variations will appear in all trees growing in a certain region, so scientists can match up the growth rings of living and dead trees.
Using these methods, the scientist determines a date range for when an event took place rather than where it fits in the overall record. The techniques scientist need for absolute dating did not become available until the later half of the 20th century.
Absolute dating uses clues, such as the emperor's face on a coin, to date an artifact.
Relative dating is qualitative - i.e it can only say one thing is older or younger than another.
Relative ages: Relative ages are based mainly on observed or inferred field relationships and stratigraphy/biostratigraphy, rather than laboratory measurements.