Dating

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Dating establishes the chronological sequence in which sites

were constructed, used and abandoned. Methods for dating objects can be divided

into two categories: relative dating and absolute dating.

Relative Dating:

A non-scientific approach which can only establish a sequence

into which the object can be placed. This will establish whether an object is

older younger than other objects. Includes: Stratigraphy, typology, fluorine,

and paleontological dating.

Absolute Dating:

Relies on scientific techniques to establish the date and is

therefore more accurate. Includes: Radio-carbon dating, dendrochronology, thermo

luminescence and potassium-argon.

RELATIVE DATING

Method

Description

Stratigraphy

The layering of archaeological deposits, one on top of the other,

over the years. The deeper in the site a layer is, the older it is.

Typology

Study of development of particular types of artefacts over a period

of time. Classification of the artefacts according to types, based on similarities

of shape, decoration and material used. Objects are arranged to form a

sequence, showing how their forms developed and changed.

Fluorine dating

Used in dating bones. Bones absorb fluorine from damp soil. Bones can

be checked against a fluorine test.

Paleontological dating

Based on the history of animal life. Palaeontologists know when

certain species appeared or became extinct. When their bones are found at a

site a rough date can be given.

ABSOLUTE DATING

Method

Description

Radio carbon dating

Based on measurement of the radioactive carbon content of organic

materials.

Dendrochronology

Uses tree rings to date objects made of wood and is remarkably

precise. Trees show a growth ring for every year of their life, and the

thickness of the rings is subject to seasonal variations.

Thermoluminescence

Used for ceramic artefacts. Mineral crystals accumulate and store

energy which is released when they are heated. By heating a sample of pottery

and measuring the amount of energy released, the time that has elapsed since

the pot was last fired can be calculated.

Potassium-argon

Used to date volcanic rock. The amount of argon gas remaining as

potassium in rock decays at a fixed rate can be measured to determine the age

of the rock.

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