stardust

"Arquaeological Explorations." (Essay, Part 1).

When archaeologists find relics or artifacts of ancient people (a group of relics that are found together are called "a find"), they meticulously analyze these remains, thus adding to the knowledge of human history. They describe each relic, noting every detail. They catalog each relic of a find, indicating every category to which it could logically belong. The archaeologists also date the relic, determining its age.
Archaeological dating is a highly developed aspect of the analysis of a relic. Basically, the methods of dating fall into 2 categories: methods of chronometric dating and methods of relative dating. Archaeologists need the results of both types of dating because each type provides distinctly important information.
Chronometric dating methods, as their name implies, measure time. Archaeologists use these methods to establish the number date of a relic or artifact, some as ancient as 3,500,000 B.C. One of the methods of chronometric dating is dendrochronology. This method uses the careful study of tree rings to establish the age of a relic or artifact.
Dendrochronology is based on the fact that trees produce a new layer, a ring of growth on their trunks (main stems) every year. Dendrochronologists can count these rings to tell the age of a tree. Because of variations in climate, some of the rings will be distinctive. For example, during a year with an unusually large amount of rain, a tree will grow more than in other years and produce a ring that is wider than any other ring. Conversely, during an exceptionally dry year, a tree will produce a distinctively narrow ring, the opposite of a wet year. The rings of trees in a particular area form recognizable patterns because they experience the same weather. Consequently, dendrochronologists can match the rings of one tree with the rings of another. (Essay, Part 1).