Archaeomagnetic work in Britain and Iraq
Archaeomagnetic studies were carried out on fired and sediment samples collected from predominantly 'rescue' British archaeological sites. Four of the fired sites were suitable for refraction and wall movement studies. The results showed no clear evidence for systematic wall movements or refraction. The scattered directions were explained in terms of local movements, inhomogeneous refraction, small scale anisotropy, fabric anisotropy and the presence of iron objects. The grain size and colour of some of the sediments were studied and it was found that the presence of shards affects the magnetization of the sediments but this will depend on the percentage of shards and their magnetization. No direct relation was found between the intensity and the stability of the sediments The brown and red samples appear to have the highest intensities and relatively higher stabilities. The accumulated British and French archaeomagnetic data were assessed and presented as an archaeomagnetic data bank which was re-evaluated. Revised archaeomagnetic curves were plotted for both Britain and Paris. A total of 96 samples were collected from 19 Iraqi archaeological sites. These were used to build an initial archaeomagnetic curve for Iraq. A comparison of different palaeointensity methods on specimens taken from a single Roman brick, 3 other Roman bricks, and on nine Iraqi samples showed that the Thellier and Kono and Ueno methods give the most reliable results. Magnetic characterization of 28 Iraqi obsidian artefacts (using their magnetizations and refractive indices) indicated that all samples except one came from a single source.