'''Dating''' material drawn from the artifact or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence relative to datable contexts. Dating is carried out mainly post excavation but to support good practice some preliminary dating work called spot dating is usually run in tandem with excavation. Dating is very important in archaeology for constructing models of the past, as it relies on the integrity of datable objects and samples. Many disciplines of archaeological science are concerned with dating evidence.

== Absolute vs relative dating ==
=== Absolute methods ===

Absolute dating methods rely on using some physical property of an object or sample to calculate its age. Examples are:
* Radiocarbon dating - for dating organic materials
* Dendrochronology - for dating trees, and objects made from wood, but also very important for calibrating radiocarbon dates
* Thermoluminescence dating - for dating inorganic material including ceramics
* Optically stimulated luminescence or optical dating for archaeological applications
* hominid remains
* Numismatics - many coins have the date of their production written on them
* Magnetic Properties of Lead used to establish dates.  Chemistry Professor Shimon Reich, a specialist in superconductivity, has demonstrated a method for dating artifacts based on the magnetic properties of lead, a material widely used in Israel and elsewhere in antiquity.  Reich and coworkers found that at cryogenic temperatures, lead becomes a superconductor, but the corrosion products formed from centuries of exposure to air and water (lead oxide and lead carbonate) do not superconduct.  On the basis of magnetic measurements and comparison with artifacts that were known (using other techniques) to be up to 2500 years old, the group showed that the mass of lead corrosion products is directly proportional to an object's age (New Journal of Physics, 2003, 5, 99)

=== Relative methods ===

Relative or indirect methods tend to use associations built from the archaeological body of knowledge. An example is seriation. Ultimately, relative dating relies on tying into absolute dating with reference to the present. One example of this is dendrochronology which uses a process of tying floating chronologies of tree rings together by cross referencing a body of work.

In practice several different dating techniques must be applied in some circumstances, thus dating evidence for much of an archaeological sequence recorded during excavation requires matching information from known absolute or some associated steps, with a careful study of stratigraphic relationships.

===Age Equivalent Stratigraphic Markers===

'''Palaeomagnetism:''' The polarity of the Earth changes at a knowable rate. This polarity is stored within rocks, through this the rock can be dated

'''Tephrochronology:''' Volcanic ash has its own signature for each eruption. In a sedimentary sequence the associated material within the ash layer can be dated giving a date for the eruption. If this ash is found anywhere else in the world a date will already be known (bearing in mind transportation time).

'''Oxygen isotope chronostratigraphy:''' This is based on the climatic stages displyed in SPECMAP relating to different cold and warm stages experiened in deep time for example point 5.5 in the SPECMAP chronology describes the peak of the last interglacial 125'000 years ago.

== Stratigraphic relationships ==

Littéralement, la '''datation''' est l'attribution d'une date. Ce terme peut donc s’appliquer à un évènement passé, un objet, un couche géologique ou encore un niveau archéologique. 
<br>Il désigne globalement la démarche, scientifique ou non, qui consiste à déterminer l’intervalle de temps séparant l’élément daté du temps présent.

On parle de « unité de temps (années, secondes, etc.). Par opposition, l’expression « datation relative » désigne la démarche qui consiste à déterminer l'ordre chronologique d'évènements ou d'objets du passé, sans connaître leurs âges réels. Une confusion est parfois faite entre les deux, lorsque dans le cadre d'une datation relative, la chronologie s'étend jusqu'au présent — ainsi, les « âges » des périodes définies par datation relative en stratigraphie sont souvent pris pour argent comptant, bien qu'ils n'aient de sens que comme des intervalles de temps circonscrits définis ''par rapport'' à tous les autres.

== Datation par les sources écrites ==

Elle concerne la période historique. Avant le milieu du , les sources écrites (textes, inscriptions, etc.) constituaient les principaux éléments de datation à la disposition des historiens pour effectuer la datation des évènements historiques, avec les risques d’imprécisions et d’erreur que cela comporte.

== Datation relative ==

Avant le développement des méthodes de datation absolues, l’âge des évènements préhistoriques (ou des évènements historiques pour lesquels aucune source écrite n’était disponible) ne pouvait être établi que de manière relative : tel événement est plus ancien ''ou'' plus récent que tel autre.

La datation relative se base essentiellement sur les principes fondamentaux de la méthode stratigraphique, développée depuis le , à savoir le paléontologique des couches géologiques, était une source importante d’informations pour établir l’âge relatif de certains terrains.

Dans le domaine biologique, les radiations évolutives sont datées par des mesures de différentiation génétiques.