Relative dating and absolute dating of fossils
Relative dating methods are used to determine only if one sample is older or younger than another.
Absolute dating methods are used to determine an actual date in years for the age of an object.
Since certain species of animals existed on Earth at specific times in history, the fossils or remains of such animals embedded within those successive layers of rock also help scientists determine the age of the layers.
Using thermoluminescence, pottery pieces as old as 100,000 years can be dated with precision. Known as dendrochronology (pronounced den-dro-crow-NOL-o-gee), tree-ring dating is based on the fact that trees produce one growth ring each year.
These include the uranium-thorium method, the potassium-argon method, and the rubidium-strontium method. Thermoluminescence (pronounced ther-moeloo-mi-NES-ence) dating is very useful for determining the age of pottery.
When a piece of pottery is heated in a laboratory at temperatures more than 930°F (500°C), electrons from quartz and other minerals in the pottery clay emit light.
With sensitive instrumentation, this range can be extended to 70,000 years.
In addition to the radiocarbon dating technique, scientists have developed other dating methods based on the transformation of one element into another.Dendrochronology: Also known as tree-ring dating, the science concerned with determining the age of trees by examining their growth rings.