Dating Techniques In Archaeology



Chronology and dating methods

Retrieved June 17, From http: Article published January 24, The Canadian Encyclopedia http: While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Retrieved June 17,from http: Article published January 23, For those researchers working in the field of human history, the chronology of events remains a major element of reflection.

Archaeologists have access to various techniques for list of archaeological dating methods archaeological sites or the objects found on those sites. There are two main categories of dating methods in archaeology: Relative dating includes methods that rely on the analysis of comparative data or the context eg, geological, regional, cultural in which the object one wishes to date is found.

This approach helps to order events chronologically but it does not provide the absolute age of an object expressed in years. Relative dating includes different techniques, but the most commonly used are soil stratigraphy analysis and typology. On the other hand, absolute dating includes all methods that provide figures about the real estimated age of archaeological objects or occupations. These methods usually analyze physicochemical transformation phenomena whose rate are known or can be estimated relatively well.

This is the only type of techniques that can help clarifying the actual age of an object. Absolute dating methods mainly include radiocarbon dating, dendrochronology and thermoluminescence. Stratigraphy Inspired by geologystratigraphy uses the principle of the superposition of strata which suggests that, in a succession of undisturbed SOILSthe upper horizons are newer than the lower ones. Generally, each stratum is isolated in a separate chronological unit that incorporates artifacts. However, this method is sometimes limited because the reoccupation of an area may require excavation to establish the foundation of a building, for instance, that goes through older layers.

In this case, even if the foundation of the building is found in the same stratigraphic level as the previous occupation, the two events list of archaeological dating methods not contemporary. Stratigraphic dating remains very reliable when it comes to dating objects or events in undisturbed stratigraphic levels. For example, the oldest human remains known to date in Canada, found at Gore Creekhave been dated using soil stratification.

The bones were buried under and are therefore older a layer of ash that resulted from a volcanic eruption dating back to years BP Before Present; "present" indicates c. Subsequently, radiocarbon dating, an absolute dating technique, was used to date the bones directly and provided a date of BP, showing how useful the combined used of relative and absolute dating can be.

Moreover, stratigraphic dating is sometimes based on the objects that are found within the soil list of archaeological dating methods. Indeed, some items whose exact or approximate age is known are called "diagnostic artifacts. Their presence on archaeological sites is used to date the soil layers and the objects and events they are associated with and thus contributes to refine the chronology of sites. Typology Typology is a method that compares reference objects in order to classify them according to their similarity or dissimilarity and link them to a specific context or period.

This technique is frequently used when it is impossible to make use of absolute dating methods; it generally allows archaeologists to identify the period to list of archaeological dating methods a cultural site or object belongs, without specifying the date of occupation. This method is primarily applied to projectile points and ceramic vessels.

These present many characteristics that are used for comparing them, such as morphology and raw materials in the case of stone tools, and decorative techniques and motifs in the case of ceramics. Radiocarbon Dating Radiocarbon dating is the most widely used dating technique in archaeology. It relies on a natural phenomenon that is the foundation of life on earth. Indeed, carbon 14 14C is formed from the reaction caused by cosmic rays that convert nitrogen into carbon 14 and then carbon dioxide by combining with carbon 12 12C and carbon 13 13Cwhich are stable carbon isotopes.

Following the death of an organism, any exchange ceases and the carbon 14, which is radioactive and therefore unstable, slowly begins to disintegrate at a known rate half-life of years, ie, after this period only half of the total carbon 14 present at the time of death remains. A sample requires 10 to 20 grams of matter and usually consists of charred organic material, mainly charcoal, but bones see zooarchaeology and shells can also be dated using this technique.

An initial reading dates the specimen which is then calibrated by considering this date and its correspondence with the measurable level of carbon 14 stored over time in the growth rings of certain tree species, including redwood and pine bristol. Subsequently, the calibration of that date provides a time interval where the event or object being dated can be situated eg, AD. Radiocarbon dating, however, can only be used for dating objects that are less than 50 years.

Dendrochronology Dendrochronology is a method that studies the rings of tree trunks to define radiocarbon dating is used for sequences by analyzing the morphology of growth rings for a given species. This method is based on the principle that the variation in tree growth from one year to another is influenced by the degree of precipitation, sunshine, temperature, soil type and all ambient conditions and that, consequently, reference patterns can be distinguished.


Archaeological Dating Methods