Hickory Bluff Project
Come Explore Your Heritage. Dive Into The Past
Issue 7: More on Dates?
One of the first questions we ask at an archaeological site like Hickory Bluff is "how old is it?" There are several ways of determining the age of a site. The methods range from examining the artifact styles to scientific laboratory procedures such as radiocarbon dating.
Stone Tools and Pottery
Artifacts such as stone tools or pottery were made in specific styles or shapes. Pots often had particular decorations on their surfaces. These styles can be compared within the site, and in a process known as seriation, an order or sequence of artifacts can be constructed. The process is based on the idea that artifacts with the greatest similarities in style or design are likely to be closest in age. This provides and estimate of the relative dates of the artifacts - their age relative to other artifacts at the site. The ages of some of the styles are known from other sites, and so in a process known as cross dating, we can determine the specific ages of some of the material at Hickory Bluff.
Radiocarbon Dates
Radiocarbon dating gives more definite information. In this case it is not the style or form of the artifact that provides the information, but it's chemical make-up. Organic material, or material from things that were once living, such as wood, seeds, bone, or shell, can be subjected to laboratory testing that tell us how long ago the material was alive. This gives us a good estimate of when the material was used - when a tree was cut down for firewood, for example. Charcoal is the most frequently dated material. This is because most organic material deteriorates fairly rapidly in the soil. Carbonized material, like charcoal, resists decay and so is more likely to survive to the present. The lab results provide a date that is not dependent on other material from the site, and so the date is referred to as absolute, rather than relative. Artifacts that are excavated with the dated objects may often be of the same age.
