Archaeomagnetic dating sites
In most case the archaeological evidence can be used to select the most likely of these.Given the number of contributing factors it is not possible to define the general precision of archaeomagnetic dates but there will be an error margin of at least ±50 years.The method has been shown to provide valuable archaeological information and supplement the suite of chronological tools available.In addition, the development of archaeomagnetic dating as a method, and the wider understanding of the Earth’s magnetic field, is hindered by the lack of data from Scotland.Dating by direction requires the exact position of the archaeological material in relation to the present geomagnetic field to be recorded, and so the material must be undisturbed and sampled in situ.Dating by intensity does not require in situ samples but is less precise and experimentally more difficult.The distribution of the archaeomagnetic dates produced on Scottish material.Key to placemark colours: Orange-Bronze Age; Green-Iron Age; White-Early Medieval; Yellow-Medieval; Pink-multiperiod sites. Full details are available from There have been a significant number of archaeomagnetic studies in Scotland, with 27 sites producing 103 dates.
As the geomagnetic field has occasionally had the same direction at two different times, it is also possible to obtain two or more alternative dates for a single archaeological event.If materials have been heated to a sufficiently high temperature (400°C) they may retain a thermoremament magnetisation, which reflects the Earth’s magnetic field at the time of last cooling.Suitable archaeological features would include hearths, kilns and other fired structures.The vast majority of UK studies are dating by direction, as intensity dating is not commercially viable at present For archaeological material to be suitable for dating using magnetic direction it must contain sufficient magnetised particles, and an event must have caused these particles to record the Earth’s magnetic field. soils, sediments, clays, contain sufficient magnetic minerals.There are primarily two types of archaeological events which may result in the Earth’s magnetic at a particular moment being recorded by archaeological material: heating and deposition in air or water.
Archaeomagnetism is a method for dating fired materials and sediments from archaeological sites, based on changes of the Earth’s magnetic field in the past.