Forms the basis of archaeomagnetic dating
Archaeomagnetic dating is an absolute dating technique that relies on the fact that the earth’s magnetic field (the “North Pole”) changes in direction and intensity through time, and that certain archaeological features preserve evidence of the pole’s location at specific times.For example, a hearth made from clay is an excellent source of archaeomagnetic information because clay typically contains iron minerals that, when fired, become remagnetized parallel with the earth’s poles.Lengyel and Eighmy plotted the measurements from the Toqua samples against two possible curves.The results not only provide dates for Toqua, but also indicate that one of the curves, known as MCCV190 (Figure 1), is more accurate than the other. Plot of mean dates [black dots] for Toqua site buildings with multiple dated samples.The dig also attracts Universities from across the globe to bring students and volunteers to the site each summer for field trips. A new website has been set up by Sam Harris who is undertaking Ph D research into archaeomagnetic dating (this is explained on the website) based on samples he has taken at the Ness of Broadgar.Sam’s research should provide complimentary dates to the C14 ones we have done in conjunction with the Times of Their Lives Project.The dates from these various hearths place individual buildings in time, making it possible to determine which of the dated buildings are older and which more recent (Figure 2).In some cases, hearths were refurbished and multiple samples were taken from a succession of hearths in one building.
This will allow investigations of heated archaeological material from older parts of antiquity than previously permitted.
Further afield this will contribute to geophysical understanding of the Earth’s magnetic field in the past.
The Ness of Brodgar’s ongoing excavations have allowed a significant amount of sampling and will continue to do so as the Ph D progresses.
Additional Information More detailed information on the archaeomagnetic dates from Toqua can be found in: Lengyel, Stacey N., Jeffery L.
Ness of Brodgar excavations, led by Nick Card senior project manager for ORCA, were visited by photographer Tim Winterburn to shoot archaeological dig images for UHI. The dig forms a centrepiece of studies for The Archaeology Institute UHI archaelogy students, both undergraduate and postgraduate – affording a unique opportunity to work on a site of major international significance within a World Heritage Site.