When an archaeologist first begins to collect artifacts on a given site, they must use both Relative and Absolute Dating techniques. Both techniques are used to find out how old a specific site is, or how old an artifact may be. Evaluating a site using dating techniques aids the archaeologist in finding a specific context or use for artifacts. Both relative and absolute dating techniques require the analysis of artifacts, whether they be stone, bone, pollen, or tools, etc. The difference between relative and absolute dating is that, absolute dating can find an exact date of how old a specific object is (say 1,000 years old approx.), where as relative dating is an estimation based on other factors of a given site.

Relative dating is an archeological dating technique which assigns a speculative date to an artifact based upon many factors such as location, type, similarity, geology and association. Types of relative dating techniques include, dendrochrology, pollen analysis, ice core sampling, stratigraphy, seriation, linguistic dating, and climate chronology, in addition to many other types of dating. All of the dating techniques above are directly concerned with discovering the correct order of events at a site, and rely heavily on associations. Relative dating usually relies upon several standard factors within a site.

The reliance upon stratigraphy in relative dating, is concerned with how far apart geographically, one tool type or artifact is from another, or which tool type occupies which type of strata. This is best summarized in the law of supposition, which states that lower layers of earth or artifacts are older than those which lay on top. For example, a tool type found within a strata or level of sandy soil, is below a geographic strata of clay on a site, and can be considered to be older; or in the sense that it was created before the tool type above it. Seriation works upon the same principles. For example, the premise behind seriation is that a tool type will gradually integrate into the use of a tribe. When a tool or artifact is first introduced into a site, it is not used in great numbers, and relatively few are produced, but as the tool comes into more common use, the number of tools found within a site will grow. Based upon the stratigraphic evidence, a chart or timeline of usage for a tool type can be extrapolated upon (for more information please see the seriation section). By using seriation and stratigraphy an archaeologist can ascertain the phases a tool type may have gone through. For example in North America, using seriation and other relative as well as absolute dating techniques archaeologists have been able to ascertain the phases of the main arrow head points in North America, such as Clovis, Folsum, and Scottsbluff.

Another relative dating method is the geologic-climatic method. Since geology can give clues to climate, analysis of artifacts which are associated with geology can be dated if the age of a climatic event (such as an ice age) is known. Plant and animal fossils can also give a clue to the climatic period. For example, a modern animal of the jungle found in the middle of a desert site can signify that the animal supersedes the climatic change from jungle environment to desert. If the rate of desertification is known, than the fossil can be dated.

Pollen grains can also be used to date artifacts. Pollen can be analyzed to identify the plant life and the climate of the era which can contribute to creating a relative date for the items found with the grains of pollen. Again, association is used to connect two items found together.

Using known processes of change, relative dating can be used to predict the age of artifacts found under a variety of circumstances when absolute techniques are either not available or not conclusive. It is a very valuable tool used by archaeologists in the quest to place our history in order, and although it has its limits, it will be employed by archaeologists the world over as long as the science exists.

Authors: Amy Rasmussen, Jennifer Taylor